Biochem MCQ 2019

Question 1

In what organs Pentose Phosphate Pathway is a Major metabolic Pathway?

Answer 1

1)Mammary glands 2)Erythrocytes 3)Liver

Question 2

Which of the following signaling molecules possess subunits in their structure:

• 1)PKC
• 2)PKA
• 3)Heterotrimeric G protein
• 4)Insulin receptor
• 5)EGF

Answer 2

2)PKA 3)Heterotrimeric G protein 4)Insulin receptor

Question 3

Which of the following enzyme reactions is producing FADH2 and not NADH:

• 1)Alpha-ketoglutarate Dehydrogenase
• 2)Malate Dehydrogenase
• 3)Succinate Dehydrogenase
• 4)Isocitrate Dehydrogenase

Answer 3

3

Succinate Dehydrogenase produces FADH2.

Question 4

Which of the following enzyme reactions is rate limiting step of the TCA cycle:

• 1)Alpha-ketoglutarate Dehydrogenase
• 2)Malate Dehydrogenase
• 3)Succinate Dehydrogenase
• 4)Isocitrate Dehydrogenase

Answer 4

4

Isocitrate Dehydrogenase is rate limiting step of the TCA cycle.

Question 5

Substrates of Phosatidylserine Synthase 1 Enzyme:

• 1)Phosphatydilcholine
• 2)Phosphatydilethanolamine
• 3)CTP
• 4)Serine
• 5)ATP
• 6)DAG
• 7)CDP-DAG

Answer 5

1 , 4

Phosatidylserine Synthase 1:

Substrates: Phosphatydilcholine + Serine

Products: P-Serine + Choline

Question 6

How many 2,3 BPG Molecules bind to the Tetramer Hemoglobin?

Answer 6

1

Question 7

Phosphorylase Kinase:

1) Phosphorylates Glycogen Phosphorylase
2) Activates Glycogen Phosphorylase
3) Has Alpha, Beta, Gamma, Delta Subunits
4) Its Delta subunit is a Calmodulin.
5) Hydrolyzes the phosphate groups of Phosphorylase.

Answer 7

1 , 2 , 3 , 4

• Phosphorylase Kinase: Phosphorylates and Activates Glycogen Phosphorylase.
• Has Alpha, Beta, Gamma, Delta Subunits.
• Its Delta subunit is a Calmodulin.

Question 8

Fructose Intolerance Cause?

Answer 8

Aldolase B deficiency

Question 9

Why do you treat patients with tPA?

1) Protease that dissolves Fibrin.
2) Protease that converts Plasminogen to Plasmin.
3) it is no inhibited by plasma protease inhibitors.
4) Acts primarily in the location of Fibrin.

Answer 9

2 , 4

tPA is a protease that converts Plasminogen to Plasmin.

It acts primarily in the location of Fibrin.

Question 10

What is the role of Hypertriacylglyceremia (HTG) in the development of Artherosclerosis?

Answer 10

HTG increases the shuttling of CETP (Cholesterol-ester transfer protein) HDL and VLDL with consequent formation of small dense LDL and Loss of HDL.

Question 11

When Gla-domains are NOT formed in the blood coagulation proteins:

1) In Vit K - deficiency
2) In the presences of coumarin-derivatives
3) In the Liver disease when carboxylase cannot work
4) When in Hepatocyte, the epoxide reductase does not reduce vitamin K.

Answer 11

1 , 2 , 3 , 4

1) In Vit K - deficiency
2) In the presences of coumarin-derivatives
3) In the Liver disease when carboxylase cannot work
4) When in Hepatocyte, the epoxide reductase does not reduce vitamin K.

Question 12

Unit of specific activity?

Answer 12

U/milligram

Question 13

Lactose can be formed in a single step from:

Answer 13

1)Glucose 2)UDP-Galactose

Question 14

In Partial Thromboplastin time (PTT) we learn about: 1)Factor VIII 2)Factor V 3)Factor X 4)Factor XII 5)Factor XI

Answer 14

1 , 2 , 3 , 4 , 5 Factor VIII, Factor XII, Factor XI -Belong to Intrinsic Pathway . Factor V and Factor X Belong to Common

Question 15

True for Cori Cycle: 1) Liver takes up Lactate from Blood Circulation 2) Our body produces Lactate under resting conditions 3) Requires Energy 4) Links to types of tissues through the Circulation

Answer 15

1, 2 ,3, 4 1) Liver takes up Lactate from Blood Circulation 2) Our body produces Lactate under resting conditions 3) Requires Energy 4) Links to types of tissues through the Circulation

Question 16

True for the formation of Malonyl-CoA: 1)Catalyzed by Citrate Lyase 2)Co-factor is Biotin 3)Negative feedback regulation by Palmitoyl-CoA 4)Regulated by Insulin and Glucagon 5)Requires ATP andBicarbonate

Answer 16

2 , 3 , 4 , 5 2)Co-factor is Biotin 3)Negative feedback regulation by Palmitoyl-CoA 4)Regulated by Insulin and Glucagon 5)Requires ATP andBicarbonate

Question 17

Per Os administration of Uridine is a choice of treatment in case of: 1)UMP Synthase deficiency. 2)Orinithine transcarbamoylase deficiency. 3)Gout if allopurinol treatment causes orotic aciduria. 4)Solid tumers during 6-aza-uridine treatment.

Answer 17

1 , 2 , 3 , 4 -UMP Synthase deficiency. -Orinithine transcarbamoylase deficiency. -Gout if allopurinol treatment causes orotic aciduria. -Solid tumers during 6-aza-uridine treatment.

Question 18

Aldolase B: 1)Cleaves F1,6BP 2)Cleaves F1P 3)Deficiency causes Essential Fructosuria 4)Deficiency causes Hereditary Fructose Intolerance 5)Symptoms of the deficiency are Hypoglycemia and Hyperuricemia.

Answer 18

1 , 2 , 4 , 5 Aldolase B cleaves mainly F1P. Deficiency causes Hereditary Fructose Intolerance and its Symptoms are Hypoglycemia and Hyperuricemia.

Question 19

The binding of oxygen to Myoglobin relationship curve looks: 1)Sigmoidal 2)Linear - Positive 3)Linear - Negative 4)Hyperbolic

Answer 19

4 Hyperbolic

Question 20

What is the “Induced fit” Concept: 1)Enzyme substrate binding induces an increase in the reaction entropy, therby catalyzing the reaction. 2)When a substrate binds to an enzyme the latter induces water loss. 3)Substrate binding may induce a Conformational change in the enzyme leading to better orientation of their functional groups 4)Enzyme specificity is induced by Substrate-Enzyme complex formation

Answer 20

3 Substrate binding may induce a Conformational change in the enzyme leading to better orientation of their functional groups

Question 21

Which of the following lipoproteins doesn’t contain TAGs: 1)HDL3 2)HDL2 3)VLDL 4)Chylomicron

Answer 21

1) HDL3 HDL-Two ConTains TAGs

Question 22

Choose the WRONG statement for Rynodine receptor: 1)its a Calcium channel 2)Has 4 subunits 3)It is the largest ion channel 4)Regulated by calmodulin 5)Same isoform for Heart and Skeletal Muscle

Answer 22

5 is Wrong! RYR1 - Skeletal Muscle RYR2 - Cardiac Muscle

Question 23

Function of ABCA1 Transporter:

Answer 23

Pumps out cholesterol from extrahepatic tissue (to HDL)

Question 24

True for the selectivity of Ion channel: 1)They can discriminate between identically charged ions. 2)They can only discriminate between Cations and Anions. 3)in Ca free media Ca channels become permeable for Na 4)Conserved P-loop Sequences determine selectivity of K, Na and Ca channels 5)Some ion channels are non-Selective.

Answer 24

1 , 3 , 4 , 5 -They can discriminate between identically charged ions. -In Ca free media Ca channels become permeable for Na -Conserved P-loop Sequences determine selectivity of K, Na and Ca channels -Some ion channels are non-Selective.

Question 25

Open Probability is: 1)Total time spent open 2)Total observation time 3)Total time spent open/Total observation time 4)Total observation time/Total time spent open

Answer 25

3 Open Probability is:Total time spent open/Total observation time.

Question 26

Which are True: 1)Glycolysis takes part in all humen cells. 2)the presence of oxygen is necessary for glycolysis 3)Pasteur effect is the phenomenon by which oxygen indirectly induces glycolysis 4)In mitochondrium containing cells end product of glycolysis is pyruvate 5)RBCs are capable of producing 4 mol of ATP from 1 mol of glucose.

Answer 26

1 , 4 Glycolysis takes part in all humen cells and In mitochondrium containing cells end product of glycolysis is pyruvate.

Question 27

The induction of which proteins causes a decrease in the number of LDL receptors: 1)SRE 2)SREBP 3)SCAP 4)INSIG 5)IDOL

Answer 27

4 , 5 INSIG and IDOL are decreasing the number of LDLR, when induced by Insulin pathway and LXR respectively.

Question 28

Isoelectric Point Defenition:

Answer 28

The pH at which a particular molecule carries no net electrical charge or is electrically neutral in the statistical mean

Question 29

Which is NOT an electron carrier: 1)NAD 2)FAD 3)Biotin 4)Ubiquinone

Answer 29

3 Biotin is actually a Carboxyl-group carrier.

Question 30

Which enzyme is not involved in Heme biosynthesis: 1) Heme Oxygenase 2) Aminolevulinic acid -Synthase 3)Aminolevulinic acid dehydratase 4)Urophorphyrinogen III Synthase 5)Urophorphyrinogen III Co-Synthase

Answer 30

1) Heme Oxygenase It is part of the Breakdown pathway.

Question 31

Choose the enzymes induced by the Liver in Long term Starvation: 1) Aminotransferase 2) Phosphgluconate Dehydrogenase 3)Phosphenolpyruvate Carboxykinase (PEPCK) 4) Pyruvate Dehydrogenase 5) Malic Enzyme

Answer 31

1 , 3 Aminotransferase and PEPCK

Question 32

Amino acids that enter the citric acid cycle as Alpha-Ketoglutarate: 1)Pro 2)Arg 3)Glu 4)Cys 5)Phe

Answer 32

1, 2 , 3 Amino acids that enter the citric acid cycle as Alpha-Ketoglutarate: Pro, Arg, Glu as well as His which is not asked.

Question 33

Amino Acid without chiral Center

Answer 33

Gly

Question 34

ABCG5 Function?

Answer 34

Pumps Cholesterol to Billiary Capillaries

Question 35

Synthesized in the Zona Fasciculata of Adrenal Cortex: 1) Angiotensin II 2) Corticosterone 3) Cortisol 4) Angiotensinogen 5) Androstenedione

Answer 35

2 , 3 Corticosterone and Cortisol

Question 36

Thrombomodulin effect on Blood coagulation: 1)Accelerates Activation of Protein C by thrombin 2)Inhibits fibrinogen conversion to Fibrin. 3)Activation of platelet by thrombin is inhibited by TM. 4)Inactivates Thrombin.

Answer 36

1 Thrombomodulin accelerates Activation of Protein C by thrombin. It changes Thrombin specificity and doesn’t act directly on none of the factors.

Question 37

Which of the following conversions takes more than one step: 1)Alanine to Pyruvate 2)Glutamate to Alpha-Ketoglutarate 3)Aspartate to Oxaloacetate 4)Proline to Glutamate 5)Phenylalanine to Succinate

Answer 37

4 , 5 take more than one step. 1 ,2 ,3 are all transaminations carried by a single enzyme.

Question 38

Major end product steroid hormone of Corpus Luteum:

Answer 38

Progesterone

Question 39

What Statement is true for Insulin receptor substrate 1 (IRS1): 1)It is a Serine/Threonine kinase 2)It is a Phosphotyrosine docking protein 3)It binds to the Insulin receptor 4)Insulin receptor phosphorylates it on serine residues. 5)IP3 activates it.

Answer 39

2 It is a Phosphotyrosine docking protein.

Question 40

True for the Dissolution of Fibrin: 1)Plasmin hydrolyzes the bonds between Fibrin monomers 2)Leukocytes participate in the process 3)Lys-Gln Isopeptide Cleavage occurs 4)Multiple peptide bonds within the fibrin monomers are hydrolyzed 5)A possible product is D-Dimer

Answer 40

2 , 4 , 5 2)Leukocytes participate in the process (Monocytes and Neutrophills) 4)Multiple peptide bonds within the fibrin monomers are hydrolyzed 5)A possible product is D-Dimer

Question 41

Give at least 2 Cellular Elements Activating Glycogen Phosphorylase:

Answer 41

1) Calcium Signal 2) cAMP - PKA system 3) Phosphorylase Kinase

Question 42

What is the dominant Electrophilic conjugation type in phase 2 Biotransformation:

Answer 42

Glutathione Conjugation

Question 43

Type IIb (White) fibers : 1)has low glycogen content 2)has alot of capillaries 3)has low amount of mitochondria 4)Has high TAG content

Answer 43

3 Type IIb (White) fibers has low amount of mitochondria

Question 44

Which of the following is NOT involved in Muscle contraction: 1)RYR 2)DHP 3)Nicotinic Ach Receptor 4)Beta receptor 5)L-type Calcium Channel

Answer 44

Beta receptors: They are part of the Sympathetic nervous system. All the rest take part in the Neuromuscular junction.

Question 45

True for Transamination: 1) It is a reversible reaction 2) Co-factor for its enzymes is Pyridoxal Phosphate 3) First step is Ketoacid attaching to Lysine Residue of Enzyme forming a Schiff base 4)The Schiff base is in Tautomerism: equilibrium between Aldmine and Ketamine

Answer 45

All are true: 1) It is a reversible reaction 2) Co-factor for its enzymes is Pyridoxal Phosphate 3) First step is Ketoacid attaching to Lysine Residue of Enzyme forming a Schiff base 4)The Schiff base is in Tautomerism: equilibrium between Aldmine and Ketamine

Question 46

Aminophenazone N-demythlation is catalyzed by: 1)Cytochrome Oxidaze 2)Catalase 3)CYP Isoenzyme 4)Superoxide dismutase 5)S-Adenosyl-Methionine

Answer 46

3 CYP Isoenzyme

Question 47

Substrates of Phosatidylserine Synthase 2 Enzyme: 1)Phosphatydilcholine 2)Phosphatydilethanolamine 3)CTP 4)Serine 5)ATP 6)DAG 7)CDP-DAG

Answer 47

2 , 4 Phosatidylserine Synthase 2: Substrates: Phosphatydilethanolamine + Serine Products: P-Serine + Ethanolamine

Question 48

Products of Oxidation of 3 moles of Glucose by the Pentose Phosphate Pathway?

Answer 48

3 Moles of Pentose 6 Moles of NADPH 3 Moles of CO2

Question 49

What will increase in plasma due to the activity of Glucagon or ACTH?

Answer 49

Unesterified Fatty Acids

Question 50

____ is a Primary bile acids formed by Hydroxylation, Side chain cleavage and Conjugation.

Answer 50

Taurocholic Acid is a Primary bile acids formed by Hydroxylation, Side chain cleavage and Conjugation.

Question 51

Which enzyme will produce Dihydrotestosterone (DHEA) from Testosterone:

Answer 51

5-Alpha-Reductase

Question 52

Inhibitor of Ribonucleotide Reductase: 1)Acyclovir 2)Methotrexate 3)araCTP 4)5-fuloro-deoxy-UMP

Answer 52

1 Acyclovir is a Reductase inhibitor

Question 53

Roles of Nucleotides:

Answer 53

1) Hydrolysis of PP bound ATP to give energy. 2) DNA and RNA building blocks 3) act as Co-Enzymes 4) Second Messenger 5) Allosteric Effectors of Metabolic Processes

Question 54

Orotic Aciduria is Caused by Deficiency of Enzymes in: 1)Epinephrine Synthesis 2)Purine Catabolism 3)Purine Synthesis 4)Pyrimidine Breakdown 5)Pyrimidine Synthesis (One Answer)

Answer 54

5) Pyrimidine Synthesis Bifunctional Enzyme UMP Synthase is Deficient. (Orotate Phosphorybosyl transferase + OMP Decarboxylase)

Question 55

Choose the Substrates of PKA: 1)Glycogen Phosphorylase 2)Glycogen Synthase 3)Pyruvate Kinase 4)Hormone sensitive Lipase

Answer 55

ALL ! 1 , 2 , 3 , 4 -Glycogen Phosphorylase -Glycogen Synthase -Pyruvate Kinase -Hormone sensitive Lipase

Question 56

True for 26S Proteasome: 1) Recognizes Misfolded proteins 2) Recognizes Ubiquitinated proteins 3) It is an ATPase 4) Beta subunits are the Catalytic ones 5) Alpha subunits are activators of Beta subunits

Answer 56

2 , 3 , 4 2) Recognizes Ubiquitinated proteins 3) It is an ATPase 4) Beta subunits are the Catalytic ones

Question 57

Enzymatic Regulation of PDH Complex:

Answer 57

• PDH Kinase inactivates - PDH phosphatase activates

Question 58

Which compound is substrate of Monoamine Oxidase: 1)Glutamate 2)Serotonin 3)Dopamine 4)Norepinephrine 5)Glutamine

Answer 58

2 , 3 , 4 Serotonin, Dopamine and NE are all metabolized by MAO.

Question 59

Hyperuricemia will be the result of : 1)Glucose-6-phosphatase deficiency 2)HGPRT deficiency 3)Chemotherapy and Radiation therapy 4)PRPP-Amidotransferase Deficiency 5)Orotate-Phosphoribosyltransferase

Answer 59

1 , 2 , 3 Glucose-6-phosphatase and HGPRT deficiency. and Chemotherapy and Radiation therapy all cause an increase in Uric Acid in the Blood. (also in Mcardle disease)..

Question 60

True for Enzymes: 1)Increase the equilibrium constant for a reaction, thus favoring the product formation 2)for effectivity they have to be equimolar to their substrates 3)They lower the activation energy for the reaction 4)They increase the stabillity of the product side. 5)Are never covalently attached to substrates or product.

Answer 60

3 They lower the activation energy for the reaction

Question 61

Compounds or Enzymes of De-Novo Synthesis of AMP: 1)Ribose-5-Phosphate 2)Orotate 3)Aspartate carbamoyltransferase 4)Phosphrybosilformylgylcinamide synthetase 5)IMP

Answer 61

1 , 4 , 5 1)Ribose-5-Phosphate 4)Phosphrybosilformylgylcinamide synthetase 5)IMP (Orotate - Salvage , Asp carbamoyl… - Pyrimidines)

Question 62

True for the results of Hypoxanthine-Guanine-Phosphoribosyl transferase deficiency:

1) Hypoxanthine is not converted to IMP
2) Hypoxanthine is not converted to GMP
3) Guanine is not converted to GMP
4) De-Novo Purine nucleotide synthesis is enhanced
5) Hyperuricemia develops

Answer 62

1 ,3 , 4 , 5 are True for HGPRT def . (Lesch nyhan): Hypoxanthine is not converted to IMP.

Guanine is not converted to GMP.

De-Novo Purine nucleotide synthesis is enhanced and Hyperuricemia develops.

Question 63

Enzymes of Pyrimidine Salvage Reactions:

1) Thymine phosphribosyl transferase
2) Uridine-Cytidine Kinase
3) Deoxy-Cytidine Kinase
4) OMP Decarboxylase

Answer 63

1 , 2 , 3

1) Thymine phosphribosyl transferase
2) Uridine-Cytidine Kinase
3) Deoxy-Cytidine Kinase

Question 64

Enzymes that catalyze the synthesis of long chain fatty acids in vertebrate cells (Pick one): 1)Are encoded in mitochondrial genes 2)Act as seven separate protein 3)Are part of a single polypeptide chain containing several distinct enzyme activities. 4)Are loclized in the mitochondrial matrix 5)None of the above

Answer 64

3 FA Synthase is a single polypeptide chain containing several distinct enzyme activities!

Question 65

True for Kidney Cortex in starvation: 1)Glucagon activate Gluconeogenesis 2)Catecholamines activate Gluconeogenesis 3)Gluconeogenesis happens later than in Liver 4)There is high expression of Phosphofructokinase-1

Answer 65

2 , 3 Catecholamines activate Gluconeogenesis in the Kidney Cortex, this happens after a while in starvation - later than in Liver (pH dependent manner).

Question 66

Synthesis of Tyrosine requires: 1)Phe 2)Phe Hydroxylase 3)Tetrahydrobiopterin 4)Dihydrobiopterin Reducatase 5)Alanine amino transferase activity in order to transform Phe to Phenyl-Pyruvate.

Answer 66

1 , 2 , 3 , 4 Synthesis of Tyrosine requires: Phe , Phe Hydroxylase, Tetrahydrobiopterin, Dihydrobiopterin Reductase.

Question 67

Which of the following are Essential Amino Acids:

1) Ile
2) Ser
3) Cys
4) Phe
5) Trp

Answer 67

Isoleucine, Tryptophan and Phenylalanine are Essential amino acids.

Question 68

How is Glycogen Phosphorylase is allosterically regulated:

1) Activated by AMP
2) Inhibited by ATP
3) Inhibited by AMP
4) Activated by ATP
5) Inhibited by Glucose

Answer 68

1 , 2 , 5

Glycogen Phosphorylase is allosterically Activated by AMP and allosterically Inhibited by Glucose and ATP.

Question 69

Amino acids that are Ketogenic and Glucogenic:

1) Ile
2) His
3) Val
4) Arg
5) Tyr

Answer 69

1 , 5

Isoleucine and Tyrosine can form Ketone bodies as well as Glucose.

Question 70

Glucagon regulation of Glycogen Storage (Pick One):

1) Simulates the Formation and Inhibits Breakdown 2)Inhibits the Formation and Stimulates the Breakdown 3)Inhibits Both Formation and Breakdown
4) Stimulates Both Formation and Breakdown
5) Stimulates Both Formation of Glycogen and Ketones

Answer 70

2

Glucagon inhibits the formation and stimulates the Breakdown

Question 71

Amino acids with 4 carbons:

Answer 71

Asp , Asn ,Thr

Question 72

Select the True statements:

1) Basic amino acids have net Positive charge at Neutral pH.
2) The Isoelectric point of basic amino acids is above 7 pH.
3) The Isoelectric point of the basic amino acids can be calculated as the average of their three pKa values.
4) Arg is a basic amino acid.

Answer 72

1 , 2 ,4 1)Basic amino acids have net Positive charge at Neutral pH. 2)The Isoelectric point of basic amino acids is above 7 pH. 4)Arg is a basic amino acid.

Question 73

Are these two sentences true? Is there any connection? 1) Presynaptic Noradrenergic axon terminals retake up NE by Co-transport with Na. 2)NE re-uptake is decreased in Hypoxia.

Answer 73

Both sentences are True: Presynaptic Noradrenergic axon terminals retake up NE by Co-transport with Na (Secondary active transport). NE re-uptake is decreased in Hypoxia.(Na/K ATPase Low)

Question 74

Glutamate is reduced to glutamic semialdehyde in the course of the formation of: 1)Proline 2)Ornithine 3)Glutamine 4)Glutathione 5)Gamma amino-butyrate

Answer 74

1 , 2 Glutamate is reduced to glutamic semialdehyde in the course of the formation of Proline and Ornithine.

Question 75

In Fructose metabolism: 1)First step is a phosphorylation of fructose to F1P 2)First step is a phosphorylation of F1P to F1,6BP 3)First step is catalyzed by Fructokinase 4)All the same enzymes of glucose metabolism

Answer 75

1 , 3 First Fructose is converted to F1P by Fructokinase.

Question 76

The accumulation of Citrate will: 1)Activate Glycolysis 2)Inhibit Glycolysis 3)No affect Glycolysis 4)Inhibit Gluconeogenesis

Answer 76

2 Inhibit Glycolysis

Question 77

Which enzymes allows connection between the TCA cycle and Purine Nucleotide cycle: 1)Succinate Dehydrogenase 2)Citrate Synthase 3)PDH 4)Fumarase 5)Malate Dehydrogenase

Answer 77

4 , 5 - Malate Dehydrogenase and Fumarase: Fumarate coming from Adenylosuccinate lyase reaction can enter as malate to the mitochondrion and form oxlaoacetate.

Question 78

True for HSL: 1)Activated in a cyclic AMP dependent manner. 2)Glucocorticoides induce transcription of the Enzyme. 3)Well-Fed induce transcription of the Enzyme. 4)Acts on the Surface of Endothelial Cells 5)Secreted by the Pancreas

Answer 78

1 , 2 are True for Hormone Sensitive Lipase. Activated in a cyclic AMP dependent manner. Glucocorticoides induce transcription of the Enzyme.

Question 79

Which is the 30 Carbon Atoms Cholsterol precursor:

1) Isopernyl pyrophosphate
2) farnesyl pyrophosphate
3) Geranyl pyrophosphate
4) Squalene
5) Lithocholine

Answer 79

4

Squalene = 30 Carbons

Question 80

Select the FALSE statement: 1)Arginine may be produced in the Kidney 2)Ornithine is synthesized from Glutamate 3)Nitrogen atoms in urea are derived from free ammonium ions and from Aspartate. 4)Urea can be produced in the Kidney.

Answer 80

4 is Wrong! Urea is produced in the Liver exclusively. only few parts of the urea cycle can occur in the kidney.

Question 81

Pick the molecule that cannot go through the mitochondrial membrane: 1)Malate 2)Aspartate 3)Glutamate 4)Oxaloacetate

Answer 81

4 Oxaloacetate cannot go through the mitochondrial membrane.

Question 82

UGT Enzyme location:

Answer 82

Endoplasmic Reticulum

Question 83

Adenosine Deaminase reaction product:

Answer 83

Inosine

Question 84

False for Nicotinic Receptors: 1)Activated by Ach 2)Linked to Myasthenia Gravis 3)Receptor Ion channel 4)Release Sodium only

Answer 84

4 Nicotinic AchR are releasing Na+ as well as K+

Question 85

Which bases have an Amino-group in their structure: 1)Cytosine 2)Thymine 3)Uracil 4)Guanine 5)Adenine

Answer 85

1 , 4 , 5 -Cytosine -Guanine -Adenine

Question 86

Cyclooxygenase:

1) Catalyses the conversion of Archidonate into Prostaglandins and Thromboxanes.
2) Inhibited by Aspirin
3) Hydrolyses the polyunsaturated fatty acid in SN2 position of Phopholipids
4) Is activated by indometacin
5) Inactivated in a Suicide Inhibition

Answer 86

1 , 2 , 5

Cyclooxygenases catalyse the conversion of Archidonate into Prostaglandins and Thromboxanes. Inhibited by Aspirin. Inactivated in a Suicide Inhibition

Question 87

On which Lipoproteins ApoB-100 is found?

Answer 87

VLDL, IDL, LDL

Question 88

Aspirin is used as a treatment for Myocardial infraction because:

Answer 88

It inhibits COX in Platelets.

Question 89

Rate limiting step of Catecholamines synthesis: Enzyme, Co-factor, 3 Regulation ways

Answer 89

Tyrosine Hydroxylase Tetrahydrobiopterin regulated by: Ca++ and Phosphorylation which stimulate it. Norepinephrine cause negative feedback

Question 90

Which is the unique enzyme expressed only in Zona Glomerulosa?

Answer 90

Aldosterone Synthase (18-Hydroxylase+Oxidase)

Question 91

Pathways active in the Liver during Well-Fed state: 1)TAG Formation from FFA and Release of VLDL 2)Beta-Oxidation 3)Ketogenesis from Lactate 4)Lactate turning to Pyruvate and then to Acetyl-CoA 5)Lactate turning to Pyruvate and then to Oxaloacetate

Answer 91

1)TAG Formation from FFA and Release of VLDL 5)Lactate turning to Pyruvate and then to Oxaloacetate

Question 92

Co-factors of Fatty Acid synthesis Pathway:

Answer 92

1)ACP 2)Biotin 3)NADPH

Question 93

Typical Phase I reaction is : 1)Sulfatation 2)Glutathionation 3)Alklylation 4)Oxidation 5)Acetylation

Answer 93

4)Oxidation (or Hydroxylation) By Cytochrome P450 enzymes

Question 94

Gilbert Syndrome is an unconjugated Hyperbillirubinemia just as ________ Syndrome.

Answer 94

Crigler - Nailar Syndrome

Question 95

Correct ORDER for the enzymes of the De-Novo synthesis of Orotate: 1)Carbamoyl-Phosphate Synthase 2 2)Dihydroorotase 3)Asp transcarbmoylase 4)Dihydroorotate Dehydrogenase

Answer 95

1–>3–>2–>4 CPS2->Asp Transcarbomoylase->Dihydroorotase->Dihydroorotate Dehydrogenase

Question 96

The Brain Prefers ___ but can use ___ as an energy source.

Answer 96

1) Glucose 2) Ketone Bodies

Question 97

Results of 2,3BPG IN RBC’s ?

Answer 97

1) Glycolysis results in less ATP (2,3 BPG amount dependent) 2) Hemoglobin Binding - Oxygen release is Increased.

Question 98

Carries most information on membrane topology of an ion channel: 1)Electromicroscopic image 2)The number and composition of subunits 3)Hydropathy plot 4)Molecular weight

Answer 98

3 Hydropathy plot Carries most information on membrane topology of an ion channel.

Question 99

Consequence of inherited Adenosine Deaminase Deficiency?

Answer 99

Immunodeficiency

Question 100

Serine, Alanine and Cysteine are all catabolyzed to form: 1)Alpha-Ketoglutarate 2)Succinate 3)Fumarate 4)Pyruvate 5)None of the above

Answer 100

4 Serine, Alanine and Cysteine are all catabolyzed to form: Pyruvate

Question 101

Heparin is commonly used in treatment of Thrombosis because: 1)Inactivates Thrombin efficiently and directly. 2)Inhibits prothrombin activation by thrombin. 3)Facilitates thrombin inactivation by Antithrombin. 4)Enhances Plasmin efficiency.

Answer 101

3 Facilitates thrombin inactivation by Antithrombin.

Question 102

Characteristics of Leptins: 1) These are Complex carbohydrates 2) Polypeptides produced by Adipocytes 3) There are types of obesities associates with their signal loss 4) Their production is proportional with the mass of Adipocytes. 5)High leptin level correlates to increased appetite.

Answer 102

2 , 3 , 4 Polypeptides produced by Adipocytes. There are types of obesities associates with their signal loss. Their production is proportional with the mass of Adipocytes.

Question 103

Causes of Hyper-Homocysteine: 1)Lack of B6 2)Lack of B12 3)Enzyme Deficiency 4)Lack of Methionine

Answer 103

1 , 2 , 3 Lack of B6 or B12. Enzyme Deficiency - S-adenosylhomocysteinase. all cause Hyper-Homocysteine

Question 104

Which deficiency could causes PKU: 1)Dihydrobiopterin reductase 2)Vitamnin B6 3)Phenylalanine Hydroxylase 4)Biopterin Synthesis 5)Vitamin C

Answer 104

1 , 3 ,4 Phenylalanine Hydroxylase - No outlet to Tyr Dihydrobiopterin reductase - No BH4 Co-factor Biopterin - No BH4 Co-factor

Question 105

Which of the following is NOT common for FA Synthesis and Beta oxidation:

1) Acyl-CoA derivatives are intermediates
2) Double bonds are oxidized or Reduced by Pyrimidine nucleotide coenzymes.
3) These processes occur in Mito. Matrix
4) A derivative of Pantothenic acid is involved

Answer 105

3 is WRONG Beta oxidation happens in the mito. matrix while FA Synthesis in the Cytosol

Question 106

True for synthesis of Norepinephrine:

1) Rate limiting step is Dopamine hydroxylase reaction 2)All pathway enzymes are located in NE axon terminal 3)Calcium activates Tyrosine Hydroxylase
4) Catechol-O-Methyltransferase doesn’t participate

Answer 106

3 , 4

In the synthesis of Norepinephrine:

Calcium activates Tyrosine Hydroxylase

Catechol-O-Methyltransferase doesn’t participate (COMT is for NE degradation)

Question 107

The Ribosyl Phosphate needed for the synthesis of orotidylate, Inosinate and Guanylate is most directly provided by:

Answer 107

PRPP: 5-Phosphoribosyl-1-Pyrophosphate

Question 108

True for Skeletal Muscle Lipid Metabolism:

1) LPL activity Increases in starvation
2) Synthesis of Ketone Bodies in starvation
3) In aerobic exercise conditions :Beta-Oxidation active
4) FA Oxidation - long term exercise energy supply

Answer 108

1 , 3 , 4

LPL activity Increases in starvation (Only in Muscle)

3) In aerobic exercise conditions : Beta-Oxidation active
4) FA Oxidation - long term exercise energy supply

Question 109

In De-Novo Pyrimidine Synthesis which of these Enzymes is involved:

1) Adenine Phosphoribosyl transferase
2) Glutamine Phosphoribosyl-pyrophosphate amidotransferase
3) Orotic Acid Phosphoribosyl transferase
4) Hypoxanthine-Guanine Phosphoribosyl Transferase
5) Cytosine Phosphoribosyl Transferase

Answer 109

3

Orotic Acid Phosphoribosyl transferase is part of De-Novo Pyrimidine Synthesis.

Question 110

Amino Acids with 2 Chiral Centers:

Answer 110

Threonine and Isoleucine

Question 111

The amino acid that is released into the bloodstream by the muscle:

1) Trp
2) Val
3) Ala
4) Leu

Answer 111

The amino acid that is released into the bloodstream by the muscle Alanine.

Question 112

Which CYPs are not participating in Aldosterone synthesis from Cholesterol: 1)Scc 2)17 Hydroxylase 3)2 Hydroxylase 4)Aromatase

Answer 112

2 , 4 17 Hydroxylase and Aromatase are not involved in Aldosterone synthesis.

Question 113

Disease caused by Clc channel mutation: 1)Meysthenia 2)Myotonia 3)Epilepsy 4)Cystic fibrosis 5)Long QT syndrome

Answer 113

2 Myotonia

Question 114

Order of Enzymes of Cateocholamines Synthesis (5+Cofactors):

• Tyrosine Hydroxylase
• Dopamine - Beta Hydroxylase
• Phenylalanine Hydroxylase
• DOPA Decarboxylase
• Phenyl-Ethanolamine-N-Methyltransferase

Answer 114

1) Phenylalanine Hydroxylase (BH4)
2) Tyrosine Hydroxylase (BH4)
3) DOPA Decarboxylase (PLP)
4) Dopamine - Beta Hydroxylase (Vit C/Ascorbate)
5) Phenyl-Ethanolamine-N-Methyltransferase (SAM)

Question 115

Proteins participating in Reverse cholesterol transport:

1) ApoA1
2) LCAT
3) AopB48
4) ApoC2
5) LPL

Answer 115

1 , 2

ApoA1 activates LCAT - Esterifying Cholesterol

Question 116

What Enzyme of the Glycolysis forms GTP?

Answer 116

None

Question 117

Select the true statements: 1)Cholesterol is formed from HMG-CoA synthesized in the Mitochondria 2)Cholesterol is formed from HMG-CoA synthesized in the Cystosol 3)Mevalonatel is formed from HMG-CoA Carboxylation 4)NADPH is needed for Mevalonate Synthesis 5)Production of isopentenyl-pyrophoshate also requires a decarboxylase

Answer 117

2 , 4 , 5 2)Cholesterol is formed from HMG-CoA synthesized in the Cystosol 4)NADPH is needed for Mevalonate Synthesis 5)Production of isopentenyl-pyrophoshate also requires a decarboxylase

Question 118

What binds the Sodium-Potassium ATPase on the outer membrane side:

1) Ouabain
2) Na+
3) K+
4) ATP

Answer 118

1 , 3

Ouabain and K

Question 119

Squalene synthesis from farnesyl pyrophosphate results in the release of two moles of PPi for each Squalene. This is part of the Synthesis of:

1) Cholesterol
2) Pyrimidine
3) Pentose Phosphate Pathway

Answer 119

1) Cholesterol

Squalene synthesis from farnesyl pyrophosphate results in the release of two moles of PPi for each Squalene.

Question 120

True for AMPK Phosphorylation in the muscle (Pick one):

1) Activates Glycogen Phosphorylase
2) Catalyzes F2P conversion to F2,6BP
3) Inactivates ACC thus decreases Malonyl-CoA con.
4) inactivates PDH - TCA Cycle inhibited 5)Activates FA Synthesis

Answer 120

3) Inactivates ACC thus decreases Malonyl-CoA con. More oxidizing less producing Fat Acids. gotta get those ATPs.

Question 121

In the conversion of dUMP to dTMP the Methyl group donor is:

1) SAM
2) N5-N10-Methylyene Tetrahydrofolate
3) N5-Methyl Tetrahydrofolate
4) Tetrahydrofolate

Answer 121

2) N5-N10-Methylyene Tetrahydrofolate

Question 122

Which of the following are involved in the uptake of cholesterol originating from peripheral tissues:

1) LDLR
2) Scavenger receptor A
3) Scavenger receptor B1
4) LXR
5) ABCA1

Answer 122

1 , 3

Scavenger receptor B1 and LDLR

Question 123

In one cycle of Beta oxidation how many ATP would be formed?

Answer 123

1 NADH and 1 FADH2 formed will give off together: 4 ATP Molecules (2.5+1.5)

Question 124

Which amino acid has the derivative of Melanin?

Answer 124

Tyrosine

Question 125

All of the following are gluconeogenic enzymes, EXCEPT: 1)F1,6BPase

2) G6Pase
3) PK
4) PC
5) PEPCK

Answer 125

3

Pyruvate Kinase is Glycolytic.

Question 126

What is the dominant Nucleophillic conjugation type in phase 2 Biotransformation:

Answer 126

Glucuronic acid Conjugation

Question 127

What is the treatment for Hyperammonemia?

Answer 127

Sodium Phenylbutyrate and Sodium Benzoate. Both are alternative Nitrogen carriers - Mixed to form Lactulose. (Also low Protein diet).

Question 128

True for Hemoglobin:

1) It is a tetramer
2) The Fe2+ moves into the plane of the heme on oxygenation.
3) The subunits have low affinity (T) state and High affinity in (R) State.
4) Bisphosphoglycerate stabilizes the R-form.

Answer 128

1 , 2 ,3

Hemoglobin is a tetramer, It’s Fe2+ moves into the plane of the heme on oxygenation. The subunits have low affinity (T) state and High affinity in (R) State.

Question 129

Glutathione Reductase in RBC:

1) NADH Increase
2) H2O2 Increase
3) Removal of H202
4) Inhibits PPP
5) Reducing Glutathione for Glutathione Peroxidase reaction.

Answer 129

3 , 5 Glutathione Reductase in RBC: Removal of H202 + Reducing Glutathione for Glutathione Peroxidase reaction.

Question 130

Balance of ATP Formation/Consumption of Anaerobic Glycolysis:

Answer 130

2 ATP consumed and 4 ATP formed

Question 131

What is the committed step of of cholesterol biosynthesis?

Answer 131

HMG-CoA Reduction to Mevalonate by HMG-CoA Reductase.

Question 132

Which of the following is a Proton pump in the Electron transport chain:

1) Ubiquinone
2) Complex II
3) Complex I
4) Cytochrome C

Answer 132

3

Complex I is a Proton Pump, the rest are simply passing along the Electrons

(Complex II = Succinate Dehydrogenase)

Question 133

What are the two distinct activities of the Debranching Enzyme?

Answer 133

1) alpha-1-6 Glucosidase, Debranching Activity
2) Transferase Activity

Question 134

In Prothrombin time assay (PT) we can learn about : 1)Factor VII 2)Factor V 3)Factor X 4)Factor XII 5)Factor XI

Answer 134

1 , 2 , 3 Factor VII, Factor V, Factor X - Belong to Extrinsic Pathway.

Question 135

What is the common when Reaction when Hypoxanthine is converted to Xanthine and when Xanthine is converted to Uric Acid? Name the enzyme!

Answer 135

Oxygenation!

Xanthine Oxidase creates these Purine degredation products Hypoxanthine - 1 Oxygen Xanthine - 2 Oxygens Uric Acid - 3 Oxygens

Question 136

False one for Ion channels:

1) Select among identically charged ions
2) Saturate at High ion concentration
3) Throughput rate approaches the Diffusion limit.
4) Transport Ions with their hydration shells

Answer 136

4 Ion channels mimic the Hydration shell while transfer the Ions without it.

Question 137

What are the two basic Precursors forming Heme? Enzyme of the first step of the pathway?

Answer 137

Glycine and Succinyl-CoA

ALA Synthase

Question 138

Treatment for Parkinson Disease (Pick one - Major)):

1) L-DOPA
2) MAO-B inhibitors
3) Peripheral Decarboxylase Inhibitors
4) Dopamine receptor agonists.

Answer 138

3

Treatment for Parkinson Disease is Peripheral Decarboxylase Inhibitors

Question 139

True for StAR protein:

1) It is a Cholesterol Carrier
2) It promotes the cleavage of the 21-OH group
3) It promotes the cleavage cholesterol side chain with P450 which is found on the ER membrane.
4) It promotes the cleavage cholesterol side chain with P450 which is found in the Mitochondria.

Answer 139

1 , 4

It is carrying cholesterol into the close by Mitochondrion and therefore promoting its chance to be cleaved by CYP responsible for Side chain cleavage (Scc).

Question 140

In Prothrombin time assay (PT) we can learn about : 1)Fibrinogen

2) Prothrombin
3) Factor VIII
4) Factor IX
5) Factor XI

Answer 140

Only 1 and 2!

PT checks the Extrinsic and Common pathway.

3 , 4 ,5 are Intrinsic Pathway.

Question 141

Which are NOT classified as Ketone bodies : 1)Dihydroxyacetone 2)Acetoacetate 3)Beta-Hydroxybutyrate 4)Alpha-Hydroxybutyrate 5)Oxaloacetate

Answer 141

1 , 4 , 5 Dihydroxyacetone, Alpha-Hydroxybutyrate and Oxaloacetate are NOT Ketone bodies.

Question 142

Perquisite for Thromboxane synthesis are:

1) Availability of phospholipid containing arachidonate for PLA2
2) Active Lipooxygenase
3) Functional COX
4) Corticosteroids do not inhibit COX

Answer 142

1 , 3 , 4

Availability of phospholipid containing arachidonate for PLA2, Functional COX, Corticosteroids do not inhibit COX are all needed for TXA2 formation.

Question 143

What is the Location of Glucose-6-Phosphatase Enzyme:

Answer 143

Glucose-6-Phosphatase is on Endoplasmic reticulum

Question 144

What is the basis of time-dependent changes in membrane permeability ?

Answer 144

Opening of discrete protein pores aka Ion Channels

Question 145

Give at least 3 Functions of LXR:

Answer 145

1) Positive regulation of ABCA1 Transporter (also General cells)
2) Positive Regulation of CYP7A1 Enzyme (In the Liver)
3) IDOL All working to Reduce cellular Cholesterol Conc.

Question 146

Which of the following provides Nitrogens to form Nucleotides: 1)Amido-groups of Gln 2)Amino-groups of Glu 3)Aspartate 4)Glycine 5)NH3

Answer 146

1 , 3 , 4 Amido-groups of Gln, Aspartate and Glycine are all providing Nitrogens for Nucleotide formation.

Question 147

Are these sentences true? Is there any interrelation between them? 1)Hypertriglyceridemia favors the progression of Atherosclerosis. 2)The Cholesteryl-Ester transfer protein shuttles between HDL and VLDL , as well as between VLDL and LDL exchanging triacylglycerols for cholesterol esters.

Answer 147

Both are true: 2 )leads to 1)

Question 148

Happens after 3 days of starvation:

1) Glutamine is released from the liver will be higher than Glutamate intake.
2) Glutamine is taken by the Kidney
3) Glutamine is taken by the Liver
4) Muscles will release a large amount of Amino acid

Answer 148

2 , 4 -

True after 3 days of starvation Glutamine is taken by the Kidney Muscles will release a large amount of Amino acid

Question 149

What receptor in the CNS functions as a Na and Ca Channel?

Answer 149

NMDA

Question 150

Threonine Dehydratase: Substrate, Product and Coenzyme.

Answer 150

Threonine Dehydratase: Substrate - Threonine Product - Alpha-ketobutyrate + Ammonia Coenzyme -PLP

Question 151

Why Coumarol is an antithromobotic drug?

Answer 151

-Inhibits Vit K reduction thus preventing incorporation of gamma-Carboxyglutamate into prothrombin (and other Factors with Gla domain )

Question 152

Function of NPC1L1 Transporter:

Answer 152

Pump in cholesterol into Epithelial Intestinal cells.

Question 153

How many unitary charges allows activation of VDC?

Answer 153

12 -16

Question 154

Possible utilization of Glucose in Erythrocytes (at least 2):

Answer 154

1) Anaerobic Glycolysis
2) Pentose Phosphate Pathway
3) Glucouranate Pathway

Question 155

True for Nicotinic Ach receptor:

1) It is a Homopentamer, it dysfunction can lead to myasthenia.
2) It is a Heteropentamer, it dysfunction can lead to myasthenia.
3) It is a Tetramer, its dysfunction can lead to myotonia. 4)The ligand binding domain is a 4 fold symmetrical gating ring.
5) The ligand binding domain is a 5 fold symmetrical ring.

Answer 155

2 , 5

It is a Heteropentamer, it dysfunction can lead to myasthenia. The ligand binding domain is a 5 fold symmetrical ring.

Question 156

Treatments for symptoms of Antiphospholipid syndrome:

1) Vit K
2) Vit K anatagonists
3) Folic Acid
4) Antifolates
5) Heparin
6) Protamine

Answer 156

2 , 5

Vitamin K antagonists and Heparin

Question 157

Looking at a Lineweaver plot, If the enzyme linear function changed with inhibition in a way that Vmax and Km are lower, which inhibition occurred?

Answer 157

Uncompetitive inhibition decreases Vmax and Km.

Question 158

Pituitary hormone promoting the conversion of cholesterol to Progenenolone in the gonads:

Answer 158

LH - Lutenizing Hormone

Question 159

4 general types of Phase I reactions in Biotransformation:

Answer 159

1)Oxidation 2)Reduction 3)Hydrolysis 4)Hydration

Question 160

Von Gierke Disease is caused by deficiency of : 1)Glycogen Synthase 2)Glycogen Phosphorylase 3)Glucose-6-Phosphatase 4)UDP-Glucose-Uridylyl transferase

Answer 160

3) Glucose-6-Phosphatase Deficiency. It is a glycogen storage disease when one cannot simply break down Glycogen = Accumulation, Lactic Acidosis, Hypoglycemia are the symptoms.

Question 161

The synthesis of Purines and Pyrimidines differs in:

Answer 161

Purine synthesis starts with the formation of PRPP, whereas Pyrimidines incorporate the PRPP near the end of the Pathway.

Question 162

In the Respiratory chain, ATP Synthase is inhibited by: 1)Oligomycin 2)Statins 3)Barbiturates 4)Cyanide

Answer 162

1 In the Respiratory chain, ATP Synthase is inhibited by Oligomycin.

Question 163

Which is FALSE for starvation: 1)Kidney Glutaminase level is elevated 2)Glucagon activates Gluconeogenesis in the Kidney 3)Glutamine is a Glucose precursor in the kidney 4)Glucagon activates Gluconeogenesis in the Liver

Answer 163

2 Glucagon is not activating Gluconeogenesis in the Kidney but Catecholamines do.

Question 164

In the Respiratory chain, Complex IV is inhibited by: 1)Oligomycin 2)Statins 3)Barbiturates 4)Cyanide

Answer 164

4 In the Respiratory chain Complex 4 is inhibited by Cyanide.

Question 165

While in starvation state the Liver has an active: 1)Glut 2 2)Acetyl-CoA carboxylase 3)Hexokinase 4)PFK2

Answer 165

1 While in starvation state the Liver has an active Glut 2

Question 166

10 ml of 0.1M Arg solution (starting from fully protonated form) is titrated with 0.1 N NaOH. At which of the NaOH additions do you expect buffer formation:

1) 5ml
2) 10ml
3) 15ml
4) 20ml
5) 25ml

Answer 166

1 , 3 , 5

5 , 15 and 25 ml will yield a Buffer solution.

Since 10, 20 , 30 ml will be the Eq points - Buffering in between them.

Its Eq point signfys the de-portonation of 1 functional group - 3 for Arg.

Question 167

True for Neurons metabolism (MCQ):

1) The importance of PPP in neurons is negligible.
2) have Highly active Gln Synthase.
3) They are extremely sensitive to oxygen depletion.
4) Gln could be used as energy source.
5) Able to produce and consume Lactate.

Answer 167

3 , 4 , 5 are true for Neuron metabolism.

• They are extremely sensitive to oxygen depletion.
• Gln could be used as energy source.
• Able to produce and consume Lactate.

Question 168

True for Ribonucleotide Reductase (MCQ):

1) Thioredoxin acts as an essential electron carrier
2) There is a separate enzyme for: ADP, CDP, GDP, UDP
3) Mechanism involves formation of Free Radical
4) Acts on Nucleotide Diphosphates
5) Glutathaione is Part of the Electron transfer

Answer 168

1 , 3 , 4 , 5

1) Thioredoxin acts as an essential electron carrier
3) Mechanism involves formation of Free Radical
4) Acts on Nucleotide Diphosphates
5) Glutathaione is Part of the Electron transfer

Question 169

What is the difference in the Negative Feedback regulation of Hexokinase and Glucokinase?

Answer 169

Glucokinase is not inhibited back by G6P while Hexokinase Does. (But by Fructose 6 phosphate)

Question 170

Which of Urea Cycle enzymes are located in the Mitochondria:

1) CPS1
2) Ornithine transcarbamoylase
3) Argininosuccinate Lyase
4) Argininosuccinate Synthetase
5) Arginase

Answer 170

1 , 2

Carbamoyl Phosphate Synthetase 1 (CPS1) and Ornithine transcarbamoylase are found in the Mitochondria.

Question 171

SAM is a Methyl Donor in the Synthesis of:

1) Carnitine
2) Creatine
3) Choline
4) Epinephrine

Answer 171

All of them!

1)Carnitine 2)Creatine 3)Choline 4)Epinephrine

Question 172

FALSE for Fatty Acid Elongation System (Pick one):

1) In SER
2) uses Malonyl-CoA
3) Produces Steroyl-CoA from Palmitoyl-CoA
4) Direct Precursor of Added Carbons is Acetyl-CoA
5) It involves same four step sequence of FA Synthase

Answer 172

4

Direct Precursor of Added Carbons is Acetyl-CoA

Question 173

Give us GABA Shunt:

Answer 173

1) Ketoglutarate
* -Ketoglutarate DH*
2) Glutamate
* -Glutamate DH*
3) GABA
* -GABA Transaminase*
4) Succinate Semialdehyde
* -Succinate Semialdehyde DH*
5) Succinate

Question 174

Are these two sentences true? Is there any connection?

1) Dopamine-Beta-Hydroxylase is localized in vesicles of noreadrenergic axons
2) Dopamine is formed in synaptic vesicles

Answer 174

1 is true but 2 is false.

Dopamine-Beta-Hydroxylase is localized in vesicles of noreadrenergic axons, this is why Noradrenaline is formed in synaptic vesicles.

Question 175

Which Amino acids are purely Ketogenic?

Answer 175

Leucine and Lysine

Question 176

What is the fate of the 1’ Carbon in Pentose Phosphate Pathway?

Answer 176

Becomes CO2

Question 177

True for Alpha-2-Plasmin Inhibitor:

1) One of the most efficient (endo) protease inhibitors
2) It forms equimolar complex with plasmin leading to activity loss
3) Fibrin-bound plasmin is an easier target for it
4) It is bound to fibrin by FXIII

Answer 177

1 , 2 , 4

1) one of the most efficient (endo) protease inhibitors
2) It forms equimolar complex with plasmin leading to activity loss
4) It is bound to fibrin by FXIII

Question 178

Mechailis-Menten Equation:

Answer 178

Vi = [S]xVmax / ([S] + Km)

Question 179

Enzymes catalyzing the Nucleotide Salvage reactions : 1)Uridine Kinase

2) Cytidine Kinase
3) Aspartate Carbamoyltransferase
4) Hypoxanthine-Guanine-Phosphorybosil transferase
5) PRPP - Amidotransferase

Answer 179

1 , 2, 4

1) Uridine Kinase
2) Cytidine Kinase
4) Hypoxanthine-Guanine-Phosphorybosil transferase

(3 and 5 are for De-Novo)

Question 180

What are the most important xenobiotics inducers of CYP1 ?

Answer 180

Polycyclic aromatic hydrocarbons

Question 181

All of the following enzymes catalyze anaplerotic reactions except: 1)Pyruvate Dehydrogenase 2)Glutamate Dehydrogenase 3)Pyruvate Carboxylase 4)Phosphoenolpyruvate Carboxykinase

Answer 181

1 All of the following enzymes catalyze anaplerotic reactions except Pyruvate Dehydrogenase.

Question 182

Why do endothelial cells Inhibit Platelet activation:

1) Synthesize and Secrete PGI2
2) Contain Ecto-ADPase
3) Produce Plasminogen Activators
4) Produce TFPI

Answer 182

1 , 2

• Synthesize and Secrete PGI2
• Contain Ecto-ADPase

Question 183

Give at least 3 Functions of the Liver in Hemostasis:

Answer 183

• Synthesis of several coagulation factors - Gln to Gla conversion with Vit K - Take up inactive Fibrinolytic and Coagulation factors - Synthesis of Inhibitors of Fibrinolysis and Coagulation

Question 184

Which enzyme catalyzes the reaction below: Substrates: Phosphatadylcholine+Cholesterol Products: Lysophosphatadylcholine + Cholesterol Ester Where does this occurs?

Answer 184

LCAT - Lecthin-cholesterol acyltransferase. Occurs in circulatory system (Plasma).

Question 185

In Orotic Aciduria - what will Uridine consumption cause?

Answer 185

UMP formation and nucleotide formation will be possible - It is the treatment.

Question 186

Triggers for Platelets activation:

1) Tissue factor
2) Thrombin
3) Collagen
4) PAF
5) Factor XIIa

Answer 186

2 , 3 , 4

Thrombin -Collagen -PAF

Question 187

After long starvation the Renal Cortex starts _____ activated by _____ .

Answer 187

After long starvation the Renal Cortex starts Gluconeogenesis activated by Epi/Norepi.

Question 188

Check if the following sentences are True and have any connection:

1) Both phosphoenolpyruvate and ATP contain high-energy phosphate bonds.
2) The reaction catalyzed by Pyruvate Kinase is Reversible.

Answer 188

Statement 1 is True but 2 is False.

1) Both phosphoenolpyruvate and ATP contain high-energy phosphate bonds.
2) The reaction catalyzed by Pyruvate Kinase is actually IRREVERSIBLE.

Question 189

Fructose 1 , 6 Bisphosphatase has a key role in Gluconeogenesis. Its allosteric Modulators:

1) F1,6BP
2) F2,6BP
3) Citrate
4) AMP
5) ADP

Answer 189

2 , 4

F2,6BP and AMP activate the Kinase part of this Tandem enzyme - Stopping Gluconeogensis and Activating Glycolysis.

Question 190

Which amino acids has a Guanidino group in its side chain:

1) His
2) Lys
3) Tyr
4) Arg
5) Tyr

Answer 190

4

Arginine has a Guanidino group in its side chain.

Question 191

The binding of oxygen to Hemoglobin relationship curve looks:

1) Sigmoidal
2) Linear - Positive
3) Linear - Negative
4) Hyperbolic

Answer 191

1

Sigmoidal

Question 192

Which molecular events contribute to the Chronotropic effect of NE:

1) Activation of PKA
2) Sigma 2 receptor activation
3) Dephosphorylation of Phospholamban
4) Increased Ca concentration Intracellularly
5) Activation of Sarcoplasmic Reticulum Ca ATPase

Answer 192

1 , 4 , 5

Activation of PKA will cause activation of DHP, RYR and SERCA which will cause faster and stronger Ca signals cycles.

Question 193

Substrates of Thrombin:

1) Fibrin
2) Factor V
3) Factor VI
4) Factor VIII
5) Factor XI

Answer 193

2 , 4 , 5

• Factor V
• Factor VIII
• Factor XI

(Also factors XIII and Fibrinogen)

Question 194

Looking at a Lineweaver plot, If the enzyme linear function changed with inhibition in a way that Vmax is lower, which inhibition occurred?

Answer 194

Non-Competitive inhibition decreases Vmax.

Question 195

True for White Adipose tissue metabolism:

1) High rate of Glycolysis in well fed state.
2) Leptin inversely correlates with the Mass of them.
3) Glycolysis is essential for the esterification of fatty acids in these cells.
4) Lipoprotein lipase is activated by physical exercise in the capillaries of fatty tissue.
5) Glucose uptake is Insulin dependent in them.

Answer 195

1 , 3 , 5 are true for White Adipocytes Metabolism

1) High rate of Glycolysis in well fed state.
3) Glycolysis is essential for the esterification of fatty acids in these cells.
5) Glucose uptake is Insulin dependent in them.

Question 196

Biotin is a co-factor for these enzymes: 1)Phosphoenolpyruvate Carboxykinase

2) Pyruvate Carboxylase
3) Pyruvate Dehydrogenase
4) Acetyl-CoA Carboxylase
5) Propionyl-CoA Carboxylase

Answer 196

2 , 4 , 5

Biotin is a Carboxyl group carrier so it is involved in carboxylation reactions (not all)

Question 197

Which of the following could be converted to Serine in a single Step (Pick one):

1) Pyruvate
2) Citric Acid Cycle Intermediates
3) Ornithine Cycle Intermediates
4) Glycine
5) Choline

Answer 197

4

Glycine is converted to Serine in one step

Serine hydroxymethyl transferase catalyzes this reversible reaction.

Question 198

Role of FXII in blood coagulation:

1) Initiate the blood coagulation cascade
2) Induce fibrinolysis
3) May cause Vasoconstriction
4) May cause Vasodilation
5) Useful for diagnosis of factor defects

Answer 198

1 , 2 , 3 , 4 , 5

1) Initiates the blood coagulation cascade
2) Induce Fibrinolysis
3) May cause Vasoconstriction (Kalkrein)
4) May cause Vasodilation (Kalkrein)
5) Useful for diagnosis of factor defects

Question 199

What are the 3 different modes of regulation of HMG-CoA Reductase?

Answer 199

Regulation of HMG-CoA Reductase:

1)Induction

2)Allosteric Inhibition

3)Protein Degradation

Question 200

Chylomicrons:

1) Are secreted by hepatocytes
2) Contain ApoB100
3) Accumulated in familial lipoprotein lipase deficiency
4) TAG content is hydrolyzed by HSL
5) TAG content is hydrolyzed by Lipoprotein lIpase

Answer 200

3 , 5

Chylomicrons TAG content is hydrolyzed by Lipoprotein lIpase and they accumulate in familial lipoprotein lipase deficiency

Question 201

Insulin is an example of a(n) _____ hormone.

Answer 201

Insulin is an example of a Peptide hormone.

Question 202

What are the biological roles of Bile Acids:

1) They contribute to the activation of pancreatic lipase in the intestine.
2) Their micelles are essential for cholesterol absorption in the intestine.
3) They are ligands of FXR
4) Their micelles are essential for cholesterol disposal in the intestine.
5) They are ligands of LXR

Answer 202

1 , 2 ,3 , 4

1) They contribute to the activation of pancreatic lipase in the intestine.
2) Their micelles are essential for cholesterol absorption in the intestine.
3) They are ligands of FXR
4) Their micelles are essential for cholesterol disposal in the intestine.

Question 203

What is the main effector of Cooperativity in case of Glucokinase?

Answer 203

Glucose Cellular Concentration

Question 204

What will rule out the possibility of Reaction coupling between two reactions?

Answer 204

1) Activation Energy for both reactions is High.
2) The Delta-G sign for both reactions is the same.

Question 205

The following hormones activate Adenylate cyclase through Gs mechanism:

1) Glucagon
2) Insulin
3) Histamine
4) Vit D
5) Adrenaline

Answer 205

1 , 3 , 5

Glucagon Histamine Adrenaline

Question 206

Starvation results in decreased activity of (MCQ):

1) Hexokinase
2) Glucokinase
3) PDH
4) PK
5) PC

Answer 206

2 , 3 , 4

Glucokinase , PDH , PK

Question 207

True for Bile acids:

1) Synthesized in the Intestine
2) Their polarity increase in the synthesis process
3) They are needed for the solubilization of Cholesterol
4) Deoxycholic is one of the primary bile acids
5) Lack of bile acid results in steatrorhea

Answer 207

2) Their polarity increase in the synthesis process
3) They are needed for the solubilization of Cholesterol
5) Lack of bile acid results in steatrorhea

Question 208

Which of the following proteins is an oxygen sensitive gene product: 1)Hexokinase 2)VEGF 3)Erythropoetin 4)GLUT1

Answer 208

1 , 2 , 3 , 4 Hexokinase, VEGF, Erythropoetin ans GLUT1 are all products of HIF1 induction in Hypoxia.

Question 209

When Glucagon level in blood is rising which enzyme activity decreases in the Liver: 1)Pyruvate Kinase 2)Pyruvate Carboxylase 3)PEPCK 4)PDH 5)PFK1

Answer 209

1 , 4 , 5 Glucagon inhibits the Glycolytic enzymes:PK, PDH, PFK1.

Question 210

____ is synthesized in the Zona Glomerulosa and metabolized to form Tetrahydro______-3-glucuronide in the liver and removed in the Liver.

Answer 210

Aldosterone is synthesized in the Zona Glomerulosa and metabolized to form Tetrahydroaldosterone-3-glucuronide in the liver and removed in the Liver.

Question 211

Which Amino Acids are forming Alpha-KG

Answer 211

1) Proline 2) Glutamate 3) Glutamine 4) Arginine 5) Histidine

Question 212

In anaerobic muscle preparation lactate formed from glucose labeled in C2 would be labeled in : 1)All three carbon atoms 2)The carboxyl atoms only 3)The carbon carrying the OH only 4)Methyl Carbon only 5)Methyl and Carboxyl Carbons

Answer 212

3 The carbon carrying the OH only

Question 213

What is common for the regulation of Glycogen Phosphrylase and Phosphorylase Kinase?

Answer 213

Both are Active upon Phosphorylation.

Question 214

Activation of Pancreatic Lipase?

Answer 214

Co-lipase activates in the Duodenum

Question 215

True for Steps of Heme Bio-transformation:

1) Heme is hydrolyzed and Forms Bilirubin
2) Heme is Reduced and Forms Bilirubin
3) Heme is Oxidized and forms Bilirubin
4) Bilirubin is conjugated with two Glucose molecules
5) Bilirubin is conjugated with Glucuronate

Answer 215

True for Steps of Heme Bio-transformation:

Heme is Oxidized and forms Bilirubin

Bilirubin is conjugated with Glucuronate

Question 216

When oxygen binds a heme-containing protein, two open coordination bonds of Fe2+ are occupied by :

1) 2 Oxygen atoms
2) Oxygen molecule and Histidine Nitrogen atom.
3) Oxygen molecule and Heme Nitrogen atom.
4) 2 Oxygen molecules
5) Oxygen atom and Histidine Nitrogen atom.

Answer 216

2

In Oxyhemoglobin coordination bonds of Fe2+ are linked to Oxygen molecule and Histidine Nitrogen atom.

Question 217

Type I (Red) fibers :

1) has low Myoglobin content
2) has low glycolytic capacity
3) has low amount of blood vessels
4) Has low TAG content

Answer 217

2

Type I (Red) fibers has low glycolytic capacity

Question 218

Hemophilia enzyme deficiency?

Answer 218

Hemophilia A - Factor VIII

Hemophilia B - Factor IX

Hemophilia C - Factor XI

Question 219

True for Astroglia Metabolism:

1) Astrocytes has the greatest CNS Glycogen amount.
2) Astrocytes have less mitochondria than Neurons
3) Astrocytes convert Gln to Glu
4) Astrocytes take up Lactate produced by Neurons
5) Pyruvate Carboxylase is localized in Astrocytes

Answer 219

1 , 2 , 5 are true.

3 - Astrocytes actually convert Glu to Gln.

4 - NEURONS take up Lactate produced by ASTROGLIA.

Question 220

Turnover number formula :

Answer 220

Vmax / E E = Concentration of enzyme

Question 221

What are true for the very long term starvation (longer than one week):

1) Stress hormones initiate gluconeogenesis in the kidney.
2) Gluconeogenesis in the Liver is decreased by acidosis.
3) Ketone bodies production decreases as starvation proceeds.
4) Ketone bodies suppress proteolysis
5) The serum level of FFAs increase

Answer 221

1 , 2 ,4 , 5

1) Stress hormones initiate gluconeogenesis in the kidney.
2) Gluconeogenesis in the Liver is decreased by acidosis.
4) Ketone bodies suppress proteolysis
5) The serum level of FFAs increase

Question 222

Correct order of Enzymes for FA Synthesis:

• Ketoacyl Reductase
• Hydroxyacyl Dehydratase
• Thioesterase
• Enoyl Reductase

Answer 222

1) Ketoacyl Reductase
2) Hydroxyacyl Dehydratase
3) Enoyl Reductase
4) Thioesterase

Question 223

True for Digestive Enzymes:

1) Carboxypeptidase is a Carboxyl Protease
2) Elastase and Pepsin are Thiolprotease
3) No Zn+ Could be found in the GI enzymes system
4) Trypsin and Chymotrypsin are Serine Proteases

Answer 223

Only 4

Trypsin and Chymotrypsin are Serine Proteases

Question 224

examples for ____ are deoxycholic acid and LIthocholic acid.

Answer 224

examples for Secondary Bile Acids are deoxycholic acid and LIthocholic acid.

Question 225

The Lineweaver -Burk plot:

1) Is a double reciprocal presentation of the Michaelis-Menten Equation.
2) Simplifies the determination of Km and Vmax.
3) Is used to calculate the degree of cooperativity among enzyme subunits.
4) Is a one-side reciprocal presentation of the Michaelis-Menten Equation.

Answer 225

1 , 2

The Lineweaver -Burk plot is a double reciprocal presentation of the Michaelis-Menten Equation, that simplifies the determination of Km and Vmax.

Question 226

Following glycogenolysis Glucose-1-P is converted next to:

Answer 226

Glucose-6-P

Question 227

True for Neurons Metabolism:

1) Use nearly full capacity of their oxidative energy production.
2) High rate of uptake and utilization of Branched Chain amino acids.
3) Free NH4 will be decreased by High activity of Glutamate Dehydrogenase
4) Ketone Bodies can partially replace Glucose as an energy source.
5) High rate of De-Novo fatty acid synthesis.

Answer 227

1 , 2 , 4 , 5

1) Use nearly full capacity of their oxidative energy production.
2) High rate of uptake and utilization of Branched Chain amino acids.
4) Ketone Bodies can partially replace Glucose as an energy source.
5) High rate of De-Novo fatty acid synthesis.

Question 228

Choose the Inhibitory Allosteric effectors of PFK1:

1) ATP
2) Citrate
3) ADP
4) F2,6BP
5) AMP
6) H+

Answer 228

1 , 2 , 6

ATP , Citrate , H+

(ADP, F2,6BP and AMP are Allosteric Activators)

Question 229

Which of the following amino acids contain 6 carbons: 1)Leu

2) Ile
3) Ala
4) Arg
5) Lys
6) Gln

Answer 229

1 , 2 , 4 , 5

Leucine, Isoleucine, Arginine and Lysine all have 6 Carbon atoms

Question 230

Order the following tissues from Highest to Lowest energy content: Liver, Muscle , Blood, Adipose Tissue

Answer 230

1)Adipose Tissue 2)Muscle 3)Liver 4)Blood

Question 231

Function of SRB1 :

Answer 231

Selective cholesterol uptake from HDL

Question 232

What is the most important Anapleorotic Process in the muscle: 1)Pyruvate Carboxylase reaction 2)Purine Nucleotide Cycle 3)Glutamate Dehydrogenase 4)PEPCK

Answer 232

2

Most important Anapleorotic Process in the muscle is Purine Nucleotide Cycle because it forms Fumarate.

And muscles contruits to ammonia elimination + do not need nucleotide synthesis as much

Question 233

Not true for Phospholemman (FXYD1): 1)Present in the heart 2)Activates Na/K ATPase 3)It is a subunit of Na/K ATPase 4)PKA phosphorylates it

Answer 233

2 Phospholemman (FXYD1) upon phosphorylation has less affinity to Na+. This is an Adrenergic B1 effect preventing arrhythmia

Question 234

Which enzyme catalyzes the NADH producing step of Glycolysis?

Answer 234

Glyceraldehyde 3 Phosphate Dehydrogenase (GAPD)

Question 235

Kendrew’s studies of Moglobin structure demonstrated that:

Answer 235

Myoglobin structure was very compact, with virtually no internal space available for water molecules.

Question 236

Which are one step reactions:

1) Pyruvate - > Alanine
2) Arginine ->Creatinine
3) Serine->Choline
4) Serine - > Glycine
5) Aspartate - > Oxaloacetate

Answer 236

1 , 4 , 5

1) Pyruvate - > Alanine
4) Serine - > Glycine
5) Aspartate - > Oxaloacetate

Question 237

True for sphingolipid synthesis (Pick one):

1) All carbons of Palmitate and Serine are incorporated into sphingosine.
2) Phosphatidic acid is the key intermediate in the pathway
3) CDP-sphingosine is the activated intermediate
4) CO2 is produced during the synthesis of Ceramide from Palmitate and Serine.
5) Glucose-6-P is the direct precursor of the Glucose is cerebrosides.

Answer 237

4

CO2 is produced during the synthesis of Ceramide from Palmitate and Serine.

Question 238

Neurotransmitters are transported into Synaptic vesicles. Which protein is not part of this: 1)VAchT 2)VGLUT 3)SERT 4)V-type-ATPase

Answer 238

3 SERT is actually related to Serotonin reuptake.

Question 239

If a cell has adequate supply of Adenine nucleotides but requires more guanine nucleotides: 1)Glutamine-PRPP amidotransferase will not be fully activated 2)AMP will feedback inhibitor of condensation of IMP with Aspartate. 3)ATP will stimulate the production of GMP from IMP. 4)ATP will inhibit IMP dehydrogenase

Answer 239

1 , 2 , 3 -Glutamine-PRPP amidotransferase will not be fully activated - Negative feedback from AMP Product. -AMP will feedback inhibitor of condensation of IMP with Aspartate + Less GTP needed in Purine Nucleotide cycle. -ATP will stimulate the production of GMP from IMP.

Question 240

Which of the following fates are probable for Glutamate after synaptic transmission: 1)Glutamate can enter the postsynaptic neurons by inotropic receptors. 2)Glutamate Dehydrogenase splits the molecule in the synaptic cleft. 3)Glutamate will be taken back to Astrocytes by Na-Co-transport. 4)Glutamate will be transformed to Glutamine in Astrocytes.

Answer 240

3 , 4 Glutamate will be taken back to Astrocytes by Na-Co-transport than it will be transformed to Glutamine in Astrocytes.

Question 241

In Glycogenolysis the enzyme ______ breaks an _____ bond to release a molecule of _____ .

Answer 241

In Glycogenolysis the enzyme Glycogen Phosphorylase breaks an Alpha 1-4 bond to release a molecule of Glucose-1-P.

Question 242

How does synthesis of Purines and Pyrimidines differs in regard to incorporation of PRPP?

Answer 242

Purine synthesis starts with the formation of PRPP, whereas Pyrimidines incorporate the PRPP near the end of the Pathway.

Question 243

What Amino Acids will form Succinyl-CoA?

Answer 243

1)Ile 2)Val 3)Met 4)Thr

Question 244

Minimal Glucose input for production of 1 Molecule of Cholesterol:

Answer 244

9 molecules of Glucose. 30 Carbons are needed. Keep in mind each glucose gives 4 C to form 2 Acetyl-CoAs.

Question 245

Gamma-Carboxy-Glutamate (Gla) is an amino acid present in the structure of several hemostatic factors and bone proteins. which statements are valid for Gla. which statements are true for Gla:

1) Gla has more negative charges than glutamate and so its side chain can bind cationic phospholipids.
2) Gla has more negative charges than glutamate and so its side chain can repulse anionic phospholipids.
3) Gla residues for a chelate with Ca
4) Vitamin K epoxide is needed for the synthesis of Gla
5) Warferin binds Vitamin K and thus prevents Gla synthesis.

Answer 245

Only 3!

Gla residues for a chelate with Ca. If you take a look in Kolev’s slides, there is a picture indicating how Gla domains are formed - it rules out 4 and 5.

Question 246

Are these two sentences true? Is there any connection? 1)Activity of Hexokinase is higher at lower glucose concentrations than that of Glucokinase assuming equal Vmax. 2)Km value of Hexokinase is lower.

Answer 246

Both are true. HK has a lower Km we understand it has higher affinity to Glucose than GK and that’s why HK will be more active even in low concentrations.

Question 247

Glutamine is the Nitrogen donor in synthesis of: 1)Inosinate (IMP) 2) Orotate 3) UMP 4) CTP 5) All

Answer 247

5) All: Inosinate (IMP) Orotate UMP CTP

Question 248

G6PD Deficiency Consequence?

Answer 248

1)Less NADPH 2)More Glutathiones are in oxidized form 3)More Methemoglobin is formed under physiological conditions 4) Oxidizing Agents oxidize H2O2

Question 249

Which of the following reactions with Folic acid (F) are Irreversible:

1) N10-N5-Methylene THF to N5-Methyl-THF
2) N10-N5-Methylene THF to N5-Oxymethyl-THF
3) N5-Foromino-THF to N10-FormyL-THF
4) N10-N5-Methenyl THF to N10-N5-Methylene THF
5) N5-Methyl-THF to THF

Answer 249

1 , 5

1) N10-N5-Methylene THF to N5-Methyl-THF
5) N5-Methyl-THF to THF

Question 250

Which of the following participates in the regulation of Glycolysis (in the liver):

1) Beta-Receptor
2) Protein Kinase A
3) cAMP
4) Gs Protein
5) Gi Protein
6) Phosphoprotein Phosphatase

Answer 250

2 , 3 , 4 , 6

Protein Kinase A cAMP Gs Protein (Glucagon receptor)

PP1 (from Insulin’s stimulation of PFK2)

(1 - Liver adrenaline receptor is Alpha-1)

Question 251

Choose the Positive allosteric effectors of PFK1: 1)ATP 2)Citrate 3)ADP 4)F2,6BP 5)AMP 6)H+

Answer 251

3 , 4 , 5 F2,6BP , AMP , ADP

Question 252

_____ activates pancreatic lipase in the presence of colipase and triglyceride containing Micelles.

Answer 252

Primary Bile Acids activates pancreatic lipase in the presence of colipase and triglyceride containing Micelles.

Question 253

Correct statements for Tetrahydrofolate: 1)Can receive a methyl group from Gly, Ser, Trp, His 2)its derivatives are interconvertable 3)Can donate Methyl group to Met 4)All are correct

Answer 253

1 , 2 Can receive a methyl group from Gly, Ser, Trp, His its derivatives are interconvertable

Question 254

What inhibits PRPP Glutamyl amidotransferase: 1)AMP 2)IMP 3)NADH 4)PRPP

Answer 254

1 , 2 Negative feedbacking that shit

Question 255

Order of Elements in the Major route of Extra-hepatic tissue Cholesterol to disposal as Bile Salts in the Intestines: 1) LDL 2) HDL 3) CETP 4) LPL 5)Hepatic Lipase 6)LDLR 7)CYP7A 8)ABCA Transporter

Answer 255

8 , 2 , 3 , 1 , 6 , 7

Question 256

Correct order for enzymes of FA Synthesis: 1) Acetyl-CoA Carboxylase 2) Ketoacyl Reductase 3) Malonyl- transacylase 4) Acetyl-Acyl-transacylase 5) Ketoacyl-Synthase

Answer 256

• > Acetyl-CoA Carboxylase - > Acetyl-Acyl-transacylase - > Malonyl- transacylase - > Ketoacyl-Synthase - > Ketoacyl Reductase

Question 257

Biotransformation Typical Phase I reaction is : 1)Sulfatation 2)Glutathionation 3)Alklylation 4)Oxidation 5)Acetylation

Answer 257

4)Oxidation (or Hydroxylation) By Cytochrome P450 enzymes

Question 258

IDOL Protein: Expression Regulation and Function?

Answer 258

Expression is under control of LXR - High Cholesterol. IDOL increases the degredation of LDLR.

Question 259

True for Bile acids synthesis in the Liver:

1) They activate the participating Hydroxylase enzymes
2) The first step is formation of 7-Alpha-hydroxycholsterol.
3) 7-Hydroxylase activity is inhibited by bile acids.
4) Lithocholic acid is formed in several steps from 11-hydroxycholsterol
5) Cholic acid formed form 11-hydroxycholesterol can be conjugated with Taurin.

Answer 259

2 , 3 are true for Bile acids synthesis.

The first step is formation of 7-Alpha-hydroxycholsterol catalyzed by 7-Hydroxylase activity is inhibited by (FXR Which ligands are) bile acids.

Question 260

___ is giving Cholesterol Esters to ___ in exchange for getting back TAGs, this is supported by CETP.

Answer 260

HDL3 is giving Cholesterol esters to VLDL in exchange for getting TAG , this is supported by CETP.

Question 261

Definition of Turnover Number

Answer 261

Maximum Number of Substrate converted to Product per second by each active site (unit s-1)

Question 262

Which of the following cannot contribute to Gluconeogenesis: 1)Alanine 2)Palmitate 3)Alpha-Ketoglutarate 4)Glutamate 5)Pyruvate

Answer 262

2 Palmitate

Question 263

Which has no role in the cellular effects of Muscarinic Receptor activation: 1)Increase in Calcium concentration intracellularlly 2)Activation of PLC 3)Na uptake 4)Activation of K channel 5)Activation of G protein.

Answer 263

3)Na uptake Not part of Muscarinic Receptor activation processes.

Question 264

The product of glutathione peroxidase catalyzed reaction is: 1)NADH 2)H2O 3)H2O2 4)ATP

Answer 264

2 The product of glutathione peroxidase catalyzed reaction is H2O.

Question 265

Cells expressing Liver-X-receptor are: 1)Hepatocyte 2)Enterocyte 3)Macrophage 4)Adipocyte 5)Pneumocyte

Answer 265

ALL are expressing LXR but the Liver has the highest expression of it, hence the name.

Question 266

Which of the following mechanisms are characteristic for the ER: 1) SERCA 2)PMCA 3)IP3 Receptor 4)RYR 5)Sodium-Calcium exchanger

Answer 266

1 , 3 , 4 PMCA - Plasma membrane Calcium ATPase Na/Ca Exchanger is on Mitochondrial and Plasma Membranes

Question 267

Are these two sentences true? Is there any connection? 1)The regeneration of S-adenosylmethionine doesnt require energy 2)Methyl group is directly transferred from Methyl-H4folate to S-Adenosylhomocysteine.

Answer 267

Both are FALSE! ATP is required in SAM regeneration. and Methyl group is directly transferred from Methyl-H4folate to Homocysteine (not SAH)

Question 268

When will Tissue factor appear in blood: 1)Bacterial Infection 2)Embryo Death during Pregnancy 3)Snake Bite 4)Surgery

Answer 268

3 , 4 Only when Subendothelial tissue is exposed to the blood vessel lumen the TF appears.

Question 269

True for K+ VDC: 1)Octamer of 4xKIR and 4xSUR 2)Tetramer of 4xSUR 3)Tetramer of 4xKIR 4)Inhibited by sulfonylureas 5)Inhibited by Dizoxine

Answer 269

3 K+ Voltage dependent channels are made of 4 KIR subunits.

Question 270

_____ has a Omega-6, 20:4 and Delta 5, 8, 11, 14 structure it is precursor for Eicosanoids. ___ and ___ are examples for Eicosanoids.

Answer 270

Arachidonic Acid has a Omega-6, 20:4 and Delta 5, 8, 11, 14 structure it is precursor for Eicosanoids. TXA2 and PGF2 are examples for Eicosanoids.

Question 271

FALSE for Na-K ATPae: 1)Ouabain binds on the Extracellular side 2)It results in a High concentration of K in the Cell 3)E1 state has a low affinity to ATP 4)E2 state has a low affinity to ATP

Answer 271

3 Na-K ATPae E1 state has actually a HIGH affinity to ATP

Question 272

Which are True for Hemoglobin tetramer: 1)Hemoglobin has 4 heme groups 2)Hemoglobin binds a maximum of 4 O2 3)Hemoglobin binds 4 BPG molecules

Answer 272

1 , 2 Hemoglobin has 4 heme groups therefore it binds a maximum of 4 O2.

Question 273

The steps of Glycolysis between Glyceraldehyde-3-P and 3-Phosphoglycerate involve all EXCEPT: 1)ATP Synthesis 2)Utilization of Pi 3)Oxidation of NADH to NAD+ 4)Formation of 1,3 Bisphophoglycerate 5)Catalysis by Phosphoglycerate Kinase

Answer 273

3 is Wrong! NAD+ is actually being reduced to NADH in GAP dehydrogenase reaction.

Question 274

Lipoprotein lipase hydrolyzes TAGs of (MCQ): 1)VLDL 2)Nascent Chylomicron 3)Mature Chylomicron 4)Chylomicron Remnant 5)IDL

Answer 274

1 and 3 VLDL and Mature Chylomicron

Question 275

which one is not a PDE inhibitor: 1)Caffeine 2)Mehtylxanthine 3)Theophylline 4)Aspirin

Answer 275

4 Aspirin is not a PDE inhibitor.

Question 276

Select the correct statements: 1)HSL cleaves all 3 Fatty acids from TAG 2)Adipocytes express HSL 3)Phosphorylated form of HSL is Inactive 4)The-TAG derived glycerol cannot be phophorylated in adipocytes. 5)The Liver and the Intestine express Glycerol Kinase

Answer 276

2 , 4 , 5 2)Adipocytes express HSL. 4)The-TAG derived glycerol cannot be phophorylated in adipocytes. 5)The Liver and the Intestine express Glycerol Kinase.

Question 277

What is the first ATP producing step of Glycoslysis?

Answer 277

1, 3 Bisphosphoglycerate to 3 Phosphoglycerate by 3-Phosphoglycerate Kinase

Question 278

Select the FALSE statement: 1)Methemoglobin Reductase converts Hemoglobin ferric to ferrous Ion. 2)Ferric Hemoglobin forms in Healthy people as well. 3)Mutation of proximal His to Tyr results in Methemoglobinemia. 4)Imbalanced production of globin chains results in sickle-cell anemia. 5)Deoxy-Hemoglobin aggregates may from in RBCs of people having hemoglobin-S

Answer 278

4 is FALSE Imbalanced production of globin chains results in Thalassemia NOT sickle-cell anemia.

Question 279

What are the Essential amino acids? Why are they essential?

Answer 279

PVT TIM HALL or PIMP in VAL Thorens - so easy . Phe , Val , Trp , Thr , Ile , Met , His , Arg , Leu , Lys We cannot synthesize them. Arg is Semi-Essential.

Question 280

True for ABCA1 Transporter: 1)It is the major transporter of bile salts. 2)LDL binds to it 3)HDL bind to it. 4)It is necessary for the efflux of cholesterol from cells 5)High cellular cholesterol content stimulates its transcription.

Answer 280

3 , 4 , 5 ABCA1 Transporter binds HDL. Is necessary for the efflux of choleste rol from cells and High cellular cholesterol content stimulates its transcription.

Question 281

A cell that is unable to obtain Tetrahydrofolate would be probably deficient in the biosynthesis of: 1)Orotate 2)Thymidylate 3)CMP 4)UMP 5)All of the above

Answer 281

2 Thymidylate synthase reaction requires THF as a methyl group donor.

Question 282

Glycogen branching enzyme catalyzes (Choose one): 1) Degradation of glycogen tree branches 2) Alpha 1-6 bonds formation 3)Alpha 1-4 bonds formation 4)Removal of unneeded Glucose residues at the end of the branch.

Answer 282

2 Alpha 1-6 bonds formation are for the branching points. Alpha 1-4 are for the chain bonds.

Question 283

Which Enzyme is defective in the Lesch-Nyhan Syndrome?

Answer 283

HPRT: Hypoxanthine-Guanine Phosphoribisyltransferase

Question 284

During acidosis the Urea cycle: 1)Slows down 2)Speeds up 3)Unchanged

Answer 284

During acidosis the Urea cycle slows down.

Question 285

True for Competitive Inhibition: 1)Km elevates 2)Vmax elevates 3)Fractional activity of enzyme is smaller at higher concentrations of the substrate. 4)Fractional activity of Inhibitor is smaller at higher concentrations of the substrate.

Answer 285

1 , 4 In Competitive Inhibition Km elevates and Fractional activity of Inhibitor is smaller at higher concentrations of the substrate.

Question 286

What is the mechanism of Aspirin inhibition of COX1?

Answer 286

Irreversible Acetylation

Question 287

Choose the correct statement: 1)Cyclooxygenase contains one (of two) active center with Heme 2)Ser-530 of COX is acetylated by Aspirin 3)Cyclooxygenase is a mem. bound monotopic enzyme 4)Cyclooxygenase active form is as monomers 5)Cyclooxygenases are suicides enzymes

Answer 287

2 , 5 During activity Cyclooxygenase destruct themselves Suicide enzymes. Ser-530 of COX is acetylated by Aspirin.

Question 288

ABCG5/G8 Function:

Answer 288

Pump out cholesterol (of Hepatocytes) into Billiary capillaries

Question 289

Endogenous inhibitors of Thrombin: 1)Heparin 2)Heparan Sulfate 3)Antithrombin 4)Thrombomodulin 5)Alpha-1-Protease inhibitor

Answer 289

3 , 5 3)Antithrombin 5)Alpha-1-Protease inhibitor

Question 290

Choose the elements involved in Cysteine formation: 1)Methionine 2)Adenosylhomocysteinase 3)Serine 4)Cystathaione Synthase 5)Cystathionase

Answer 290

2 , 3 , 4 , 5 - Parts of the SAM Cycle.

Methionine is also part of it, but more distant (depends on the answer combo)

Question 291

True for FXR: 1)Its expression is restricted to the Liver. 2)Its major ligand is the lithocholic acid. 3)Responsible for Negative regulation of ABCA1 4)Responsible for Negative regulation of CYP7A1 5)Higher level of active FXR results in enhancement of bile acid reabsorption in the Ileum.

Answer 291

3 , 4 , 5 FXR is responsible for Negative regulation of ABCA1 and CYP7A1. Higher level of active FXR results in enhancement of bile acid reabsorption in the Ileum.

Question 292

When there is Beta-Oxidation of Odd number Fatty acid, the final product is____ and it is Converted to D-Methmalonyl-CoA by _____ with ____ as Cofactor.

Answer 292

When there is Beta-Oxidation of Odd number Fatty acid, the final product is Propionyl-CoA and it is Converted to D-Methmalonyl-CoA by Propionyl-CoA Carboxylase with Biotin as Cofactor.

Question 293

A transition state analouge: 1)Resembles the active site of general acid-base enzymes. 2)typically reacts more rapidally with enzyme than the normal substrate. 3)Is less stable when binding to an enzyme than the normal substrate 4)stabilizes the transition state for the normal enzyme-substrate complex 5)Resembles the transition state structure of the normal enzyme substrate complex.

Answer 293

5 Transition state analouge resembles the transition state structure of the normal enzyme substrate complex.

Question 294

True for Serotonin: 1)It is the main product of Tryptophan catabolism 2)Serotonin is 5-Hydroxy-Trypamine. 3)Its Synthesis requires Tetrahydrobiopterine. 4)Its Synthesis requires Tetrahydrofolate. 5)It plays a role in the regulation of Sleep.

Answer 294

1 , 2 , 3 , 5 Serotonin is formed in a pathway from Tryptophan by Trp Hydroxylase (Tetrahydrobiopterine) and Aromatic AA Decarboxylase (PLP). It regulates mood and sleep.

Question 295

Activation of PKC is: 1)Calcium dependent 2)Calcium independent 3)DAG Dependent 4)Phorbol Ester dependent 5)Phospholipid dependent

Answer 295

1 , 2 , 3 , 4 , 5 (Phorbol esters are DAG analogues)

Question 296

In the synthesis of Phosphatadylcholine from phosphatadylethanolamine the methyl group donor is: 1)Methanol 2)S-Adenosylmethionine 3)Tetrahydrofolate derivative 4)Choline 5)Serine

Answer 296

2 S-Adenosylmethionine is the methyl donor in the formation of Phosphatadylcholine.

Question 297

Are the two following statements true? Is there any connection between them? 1) Beta-1 receptor stimulation results in release of Ca from Sarcoplasmic reticulum in the Heart muscle cell 2)Beta-1 receptor stimulation results in the activation of the Sarcoplasmic Ca-ATPase

Answer 297

Both statments are true. PKA is active in both. 1) PKA activates DHP+RYR channels (early) 2) PKA activates SERCA through Phosphlamban (late)

Question 298

Which of the Following catalyzes a reaction with Ammonia: 1)Arginase 2)Glutamate Dehydrogenase 3)AMP Deaminase 4)Glutaminase 5)AMP Synthase

Answer 298

1 , 2 , 3 , 4 1)Arginase 2)Glutamate Dehydrogenase 3)AMP Deaminase 4)Glutaminase

Question 299

What is the link to SAM cycle (step) of the Folate cycle which Irreversible? Why?

Answer 299

N5-Methy-THF to THF. Methyl group donation.

Question 300

Which is the main apoprotein component of nascent chylomicron: 1)ApoCII 2)ApoA1 3)ApoB48 4)ApoB100

Answer 300

3 ApoB48 - Chylomicron Cholesterol transport ApoB100 - LDLRs ApoE - Cleavage of Remenants ApoA1 - HDL LCATs ApoCII - Chylomicron and VLDL - LPLs Activation

Question 301

Products of Prostanoids formation:

Answer 301

1)PGI2 2)PGE2 3)PGD2 4)PGF2-Alpha

Question 302

Amylase substrates: 1)Glycogen 2)Maltose 3)Amylopectin 4)Maltriose 5)Isomaltose

Answer 302

1 , 3 Amylase substrates are Glycogen and Amylopectin. Amylase Products are Maltose, Maltriose and Isomaltose.

Question 303

True for vWF: 1)Activates Tenase complex 2)Activate in a Multimeric form 3)Activate in a Monomeric form 4)Helps in attachment of Platelets to Sub-endothelial tissues 5)Inhibits Fibrinolysis

Answer 303

2 , 4 -Activate in a Multimeric form. -Helps in attachment of Platelets to Sub-endothelial tissues.

Question 304

D-Methmalonyl-CoA is Converted to ____ by ____ and then to Succinyl-CoA by Methmalonyl Isomerase with ____ as cofactor.

Answer 304

D-Methmalonyl-CoA is Converted to L-Methmalonyl-CoA by Methmalonyl Racemase and then to Succinyl-CoA by Methmalonyl Isomerase with Vit B12 as cofactor.

Question 305

Choose the FALSE one for Drug metabolism: 1)Conjugation is the first reaction in Biotransformation. 2)Usually the in 1st step substrate becomes water soluble. 3)In the Preparatory Phase, actually reactive intermediates are formed. 4)The conjugated derivatives are usually inactive.

Answer 305

1 is WRONG! Conjugation is actually the second reaction in Biotransformation.

Question 306

What are the negative and positive regulators of Isocitrate Dehydrogenase:

Answer 306

Positive Regulators: ADP and Ca Negative Regulators: ATP and NADH

Question 307

True for Tetrahydrofolate reactions: 1)One carbon units carried by Tetrahydrofolate may be derived from Serine, Glycine or Tyrosine. 2)All one carbon units bound by Tetrahydrofolate can be transformed into each other. 3)Methyl Group carried by Tetrahydrofolate is derived from Methionine.

Answer 307

2 All one carbon units bound by Tetrahydrofolate can be transformed into each other.

Question 308

The E3 subunit of PDH enzyme complex is also part of :

Answer 308

E3 of PDH also in: -alpha-KGDH -BCKADH -Glycine cleavage complex

Question 309

Two cells cooperate in ovarian production of Estradiol from cholesterol:

Answer 309

Theca interna and Granulosa cells

Question 310

What is characteristic for Fibrinolysis: 1)Fibrin is degraded by Proteolytic enzymes 2)Cross links between fibrin (FXIIIa job) are not degraded 3)Plasmin is synthesized in proenzyme form. 4)Alpha2 plasmin inhibitor is more efficient if Plasmin is Fibrin bound.

Answer 310

1 , 2 , 3 -Fibrin is degraded by Proteolytic enzymes -Cross links between fibrin (FXIIIa job) are not degraded -Plasmin is synthesized in proenzyme form.

Question 311

How does PKA regulates Glycogen Synthase?

Answer 311

Phosphorylates and Deactivates it.

Question 312

In Lactic Acidosis: 1)Elevated Lactate production results in increased pH. 2)Enzyme deficiency of Pyruvate Carboxylase results of Hypperammonemia. 3)Dihydrolipoyl Dehydrogenase enzyme deficiency effects only Glycolysis. 4)Dihydrolipoyl Dehydrogenase enzyme deficiency effects Glycolysis, TCA Cycle, and catabolism of Branched Chain Amino Acids. 5)NaHCO3 alone is a very effective treatment.

Answer 312

2 , 4 -Enzyme deficiency of Pyruvate Carboxylase results of Hypperammonemia. -Dihydrolipoyl Dehydrogenase enzyme deficiency effects Glycolysis, TCA Cycle, and catabolism of Branched Chain Amino Acids.

Question 313

Cytochrome P450 Enzyme participates in: 1) FA Desaturate System 2) Bile Acid Synthesis 3) Drug Hydroxylation 4) Citrate Cycle 5) Glucocorticoid Synthesis

Answer 313

1) FA Desaturate System 2) Bile Acid Synthesis 3) Drug Hydroxylation 5) Glucocorticoid Synthesis

Question 314

Low group transfer potential indicates a tendency of the molecule to ___ a group.

Answer 314

Receive a group. For example G6P has Low phosphryl group potential preventing it from releasing Pi .

Question 315

Insulin activates Glycolysis in the Liver by ___ the F2,6BP concentration.

Answer 315

Increasing

Question 316

False one for Potassium channels: 1)The K+ channel has an inverted Teepee structure. 2)K+ channels share a conserved P-loop region 3)Na+ is excluded from K+ channel because it is too large. 4)K+ channels have a water filled central cavity.

Answer 316

3 Na+ is excluded from K+ channel because it is too SMALL. electrostatic interactions are no energetically favorable for it’s transport.

Question 317

How is Platelet activation inhibited in the clinical practice:

Answer 317

Acetylsalicylic acid - > inhibits COX - > No TXA2.

Question 318

Which enzyme catalyzes the reaction transforming Inosine into hypoxanthine?

Answer 318

Purine Nucleoside Phosphorylase (“PNP”)

Question 319

What are the two major different Eicosanoids synthesis pathways?

Answer 319

Cyclooxygenase Pathway - Prostaglandins and Thromboxanes Lipoxygenase Pathway - Leukotrienes and Lipoxins.

Question 320

Which statements are valid for the PGI2: 1)Synthesized from free arachidonate 2)It is released from Phospolipids by PLA2 3)Synthesized in Platelets by Prostacyclin synthase

Answer 320

1 and 3

PGI2 is synthesized from free arachidonate

Synthesized in Platelets by Prostacyclin synthase

(Old name for COX)

Question 321

True for tPA activation: 1)Fibrinogen stimulates it 2)Fibrin stimulates it 3)Partial degredation of Fibrin stimulates it 4)Carboxypeptidase B stimulates it 5)Some of plasmin fibrin degredation products Stimulates it.

Answer 321

2 , 5 Fibrin , Some Plasmin fibrin degredation products.

Question 322

10 ml 0.1 Glutamate solution (starting from fully protonated form) is titrated with 0.3 N NaOH in which NaOH ml do you expect buffer formation?

Answer 322

5 ml 15 ml 25 ml

Question 323

Which one is NOT true: 1)Vmax=Et x Kcat 2)Turnover number is Kcat 3)1 U is 1 Mol substrate/Minute 4)Specificity constant is Kcat/Km.

Answer 323

1 U is 1 Mol substrate per Second.

Question 324

Which lipids are essential for the normal function of the alveolar Surfactant: 1)Dipalmitoyl-Phosphatadylcholine 2)Oleyl-Palmitoyl-Phosphatadylcholine 3)Cholesteryl-Ester 4)Phosphatadyethanolamine 5)Spingomyelin

Answer 324

1 , 4 Phosphatadyethanolamine and Dipalmitoyl-Phosphatadylcholine are needed for Surfactant.

Question 325

True for Amylase: 1)Produced in Pancreas and Salivary Glands. 2)Cleaves Alpha 1-4 and 1-6 bonds 3)Function not effected by Gastric pH. 4)Doesn’t Cleave disaccharides 5)Amylopectin is a substrate.

Answer 325

1 , 4 , 5 1)Produced in Pancreas and Salivary Glands. 4)Doesn’t Cleave disaccharides 5)Amylopectin is a substrate.

Question 326

Which Calcium channel in the Heart is rapidly inactivated?

Answer 326

T-type

Question 327

Which Amino acid is not a Precursor of Fumarate: 1)Asp 2)Asn 3)Phe 4)Tyr 5)Trp

Answer 327

5 Tryptophan is not a precursor of Fumarate.

Question 328

FALSE for GABA-A receptors: 1)its activation causes Hyperpolarization 2)It’s a Chloride channel 3)Activation of it could cause insomnia. 4)It can bind Ethanol

Answer 328

Activation of GABA-A receptors could NOT cause insomnia .

Question 329

Causes of Thrombophillia: 1)Protein C deficiency 2)Antithrombin deficiency 3)FVII deficiency 4)FV resistance against activated protein C (APC resistance. 5)FXI deficiency

Answer 329

1 , 2 , 4 1)Protein C deficiency 2)Antithrombin deficiency 4)FV resistance against activated protein C (APC resistance.

Question 330

NPC1L1 Function?

Answer 330

Pumps Cholesterol to the Intestinal Epithelial Cells.

Question 331

In Transamination of Alanine to form Alpha-KG, which co-factor is used?

Answer 331

PLP

Question 332

Galactosemia cause:

Answer 332

Galactose-1P Uridylyl Transferase or Galactokinase Deficiency

Question 333

The following fatty acid, in which the indicated carbon is labled with [14C], is fed to an animal. [14C]H3(CH2)9COOH After 30 minutes of Beta oxidation, the label would most likely be recovered in which form: 1)Acetyl-CoA 2)Propionyl-CoA 3)Palmitoyl-CoA 4)Both Propionyl-CoA and Acetyl-CoA.

Answer 333

2 Propionyl-CoA, since this is a Fatty acid with Odd number carbon chain and Beta oxidation starts from Carboxylic end of the FA.

Question 334

What harmful intermediate will inevitably form in the process of elimination of xenobiotics:

Answer 334

In biotransformation ROS are formed.

Question 335

True for IP3 receptor (MCQ):

1) Localized on ER and Plasma Membrane
2) it is a Calcium channel
3) it has 4 Calcium binding sites
4) Binds ATP
5) Is activated by Phospholipase C

Answer 335

2 , 4 , 5

*Phospholipase C forms the ligand IP3

*Also not sure if it directly binds ATP but this was the combo

Question 336

Which weak Andronergic Steroid is synthesized in the fascicular zone of Adrenal Cortex: 1)Dehydroepiandrosterone 2)Corticosterone 3)Progenolone 4)Progesterone 5)Testosterone

Answer 336

1 Dehydroepiandrosterone aka DHEA

Question 337

Which are positions and configurations of the OH groups in Primary Bile Acids:

Answer 337

OH on 3 , 7 , 12 positions in Primary Bile Acids all in alpha configurations.

Question 338

Transketolase requires the Coenzyme: 1)Pyridoxal Phosphate 2)Thiamine Pyrophosphate 3)Cobalamin 4)Tetrahydrofolate

Answer 338

2)Thiamine Pyrophosphate (TPP) (Part of the Pentose Phosphate Pathway)

Question 339

False one for CFTR channels: 1)Transports Cl 2)It is an ABC protein 3)Inhibited by PKA phosphorylation 4)has two transmembrane domains (TMD)

Answer 339

3 CFTR is actually activated by PKA phosphorylation

Question 340

Product of the reaction catalyzed by the Thymidylate Synthase?

Answer 340

dTMP

Question 341

Activation of Trypsin?

Answer 341

Enteropeptidase arriving to duodenum cleaves Trypsinogen (Zymogen) to form Trypsin. (Limited Proteolysis)

Question 342

Which protein binds calcium in Vesicular Synaptic transmission: 1)Synaptotagmin 2)Synaptobrevin 3)SNAP25 4)Syntaxin

Answer 342

1 Synaptotagmin binds calcium in Vesicular Synaptic transmission

Question 343

Inhibitors of Cyclooxygenase: 1)Docosahexanoic Acid 2)Arachidonic Acid 3)Acetylsalicylic acid 4)Thromboxane

Answer 343

1 , 3 Docosahexanoic Acid and Acetylsalicylic acid

Question 344

Which of the following is involved in the activation of pancreatic proenzymes:

1) Carboxypeptidase A
2) Enteropeptidase
3) Trypsin
4) Chymotrypsin
5) Pancreatic Lipase

Answer 344

2 , 3

Enteropeptidase arrives to the Duodenum to cleave and activate Trypsin which later cleaves and activates the rest of the Pancreatic Proenzyme Proteases .

Question 345

What is true about voltage gated Cl- channels structure: 1)Two subunits each creating a pore 2)Two subunits creating a pore together 3)Single polypeptide with two pores 4)Single polypeptide with one pore

Answer 345

1 Two subunits each creating a pore

Question 346

What of the following statements explains the Relatively specific effect of Strophantin on the Heart? 1)Na-Ca exchanger is found only the Heart 2)Na-K ATPase alpha subunit in heart bind strophantin with the lowest affinity 3)Na-K ATPase alpha subunit in heart bind strophantin with the lowest Km 4)Strophantin Binds to Na-K ATPase intracellularly in the heart.

Answer 346

3 Na-K ATPase alpha subunit in heart bind Strophantin with the lowest Km. Strophantin = Cardiac Glycoside

Question 347

Which of the following Amino Acids have their Alpha-Amino groups removed by Dehydratase?

Answer 347

Serine and Threonine

Question 348

Norepinephrine break down to:

Answer 348

MHPG or VMA

Question 349

What are the Irreversible steps of Glycolysis?

Answer 349

1) F6P to F1,6BP by PFK1 2) PEP to Pyruvate By Pyruvate Kinase 3) Glucose to G6P by Hexokinase

Question 350

True for ATP sensitive potassium channel: 1)Inhibited by ADP and Activated by ATP 2)Inhibited by ATP and Activated by ADP 3)ATP binds on intracellular Domain 4)ATP binds on extracellular domain

Answer 350

2 , 3 ATP sensitive K+ channel Inhibited by ATP and Activated by ADP, ATP binds on intracellular Domain.

Question 351

In Activation of PLC : 1)Serpentin receptors are involved 2)cAMP is involved 3)Heterotrimer G proteins are involved 4)DAG is involved

Answer 351

1 , 3 GPCRs (in this case Gq) are G-proteins coupled receptors. Linked to heterotrimeric G proteins and also called Serpentins.

Question 352

Which are NOT classified as Ketone bodies : 1)Dihydroxyacetone 2)Acetoacetate 3)Beta-Hydroxybutyrate 4)Alpha-Hydroxybutyrate 5)Oxaloacetate

Answer 352

1 , 4 , 5 Dihydroxyacetone, Alpha-Hydroxybutyrate and Oxaloacetate are NOT Ketone bodies.

Question 353

Which Sentence is NOT valid for Cholesterol overload : 1) Inhibits LDLR expression 2) Affects the Cholesterol Synthesis in the Cells 3)Inhibits HMG-CoA reductase 4) Cause formation of Cholsteryl-Esters by LCAT in the Cells

Answer 353

4) Cause formation of Cholsteryl-Esters by ACAT in the Cells NOT LCAT.

Question 354

Name the Protein induced by ACTH in the adrenal cortex:

Answer 354

StAR protein or : Steroidgenic Acute Regulatory Protein.

Question 355

Which steroid hormone is synthesized by 11-Beta-Hydroxylase: 1)Aldosterone 2)Cortisol 3)Testosterone 4)Estradiol 5)Progesterone

Answer 355

2 Cortisol is synthesized from by 11-Beta-Hydroxylase 11-deoxycortisol.

Question 356

True for vWF: 1)Substrate of Thrombin 2)Secreted from Endothelial Cells 3)Contributes to Aggregation of Platelets 4)Contributes to Adhesion of Platelets 5)Binds to Factor VIII in the circulation

Answer 356

2 , 4 , 5 2)Secreted from Endothelial Cells 4)Contributes to Adhesion of Platelets 5)Binds to Factor VIII in the circulation

Question 357

Which of the following can be synthesized by plants but NOT by Humans: 1)Palmitate (18;0) 2)Stearate (20:0) 3)Linoleate (18:2) 4)Pyruvate 5)Phosphatydilcholine

Answer 357

3 Linoleate (18:2) is an essential Fatty acid (Omega-6). (the other important one is Linolenate (18:3)- Omega - 3)

Question 358

Work both in Gluconeogenesis and Glycolysis: 1)Hexokinase 2)Glucose-6-Phosphatase 3)3-phophoglycerate kinase 4)PFK1 5)Pyruvate Kinase

Answer 358

3 Since 3-phosphoglycerate catalyzes a reversible reaction it is working in Glycolysis and Gluconeogenesis both.

Question 359

Enzymes in De-Novo Synthesis of Pyrimidines: 1)Pyrimidine phosphorybosiltransferase 2)Aspartate Carbamoyltransferase 3)Ornithine Carbamoyltransferase 4)CTP Synthetase

Answer 359

2 , 4 2)Aspartate Carbamoyltransferase 4)CTP Synthetase (3 - Urea cycle , 1 - Salvage)

Question 360

Product and Substrate of major regulatory enzyme of the cholesterol synthesis pathway:

Answer 360

HMG-CoA reductase: Substrate is HMG-CoA and Product is Mevalonate.

Question 361

Pick the FALSE statement:

1) If Delta-G is negative the reaction is Exergonic.
2) Irreversible reactions have Delta-G of small value.
3) If Delta-G is Positive the reaction is Endergonic.
4) Exergonic processes are coupled to Endergonic ones

Answer 361

2 Irreversible reactions have Delta-G of LARGE value.

Question 362

Which of the following compounds will be reduced by Ribonucleotide Reductase: 1)TMP 2)UMP 3)dUDP 4)UDP 5)UTP

Answer 362

4 (Di)Ribonucleotide Reductase reduces: UDP , CDP, GDP and ADP. (dTMP will come from thimydilate synthase reaction)

Question 363

What is Glycogenin:

Answer 363

The Primer on which new Glycogen chains are synthesized.

Question 364

True for Kidney Metabolism: 1)PFK1 is active mainly in the Cortex 2)Hexokinase is active mainly in the Medulla. 3)PEPCK activity is associated with the Cortex 4)Acidosis-Induced Glutamate activity localized in cortex. 5)G-6-Pase activity in cortex.

Answer 364

2 , 3 , 5 -> Medulla=Glycolytic and Cortex=Glucogenic. 2)Hexokinase is active mainly in the Medulla. 3)PEPCK activity is associated with the Cortex 5)G-6-Pase activity in cortex.

Question 365

In anaerobic muscle preparation lactate formed from glucose labeled in C3 and C4 would be labeled in : 1)All three carbon atoms 2)The carboxyl atoms only 3)The carbon carrying the OH only 4)Methyl Carbon only 5)Methyl and Carboxyl Carbons

Answer 365

5 Methyl and Carboxyl Carbons. Remember: Aldolase reaction products are Not symmetrical.

Question 366

Degradation of cAMP:

1) catalyzed by PDE
2) inhibited by Caffeine
3) Activated by cGMP
4) Catalyzed by Adenylate Cyclase

Answer 366

1 , 2 Catalyzed by PDE inhibited by Caffeine

Question 367

Which molecule has a lower group transfer potential than ATP: 1)Creatine Phosphate 2)Phosphoenolpyruvate 3)Glucose-6-phosphate 4)1,3Bisphosphoglycerate

Answer 367

Glucose-6-phosphate has a lower group transfer potential than ATP. It is less likely to Donate a phosphate group in comparison to ATP.

Question 368

Alpha-Ketoglutarate Dehydrogenase complex consists of the following enzymes, coenzymes and prosthetic groups: 1)Dihydrolipoyl succinyltransferase 2)Pyridoxal-5-Phosphate 3)Lipoic Acid 4)Alpha-Ketoglutarate-Decarboxylase 5)Pyruvate Decarboxylase

Answer 368

1 , 3 , 4 1)Dihydrolipoyl succinyltransferase 3)Lipoic Acid 4)Alpha-Ketoglutarate-Decarboxylase

Question 369

False for Isoenzymes: 1)Catalyze the same reaction 2)Have different structure 3)Always share the same allosteric regulators 4)Can be tissue specific

Answer 369

3 Isoenzymes have different allosteric regulators.

Question 370

Phosphrylated and Active in the Liver During Starvation: 1)PFK1 2)Glycogen Synthase 3)Pyruvate Kinase 4)Glycogen Phosphorylase 5)Phosphorylase Kinase

Answer 370

4 , 5 Glycogen Phosphorylase and Phosphorylase Kinase

Question 371

Which of these proteins are activated by Calcium but not by Ca-Calmodulin complex: 1)PFK1 2)RYR 3)Actin-Myosin complex 4)PKC

Answer 371

2 , 4 PKC and RYR can be activate by Ca ion one its own.

Question 372

False for Oxidative Decarboxylation of Pyruvate: 1)Catalyzed by a large Enzyme Complex in the Cytosol 2)If it happens in anaerobic conditions E2 is not used 3)it is a Substrate level phosphorylation - ATP formed 4)E1 prosthetic group is Biotin

Answer 372

All are false - now for the Truth about PDH: 1)Catalyzed by a large Enzyme Complex in the Mito. 4)E1 Prosthetic group is TPP

Question 373

True for the mechanism is regulating the synthesis of Testosterone: 1)Cholesterol side chain cleavage is inhibited by cAMP 2)Testosterone induces the release of GnRH from Hypothalamus 3)LH activates Adenylate cyclase in Leydig Cells

Answer 373

3 LH activates Adenylate cyclase in Leydig Cells leading to the expression of 17β-hydroxysteroid dehydrogenase - Testosterone Conversion

Question 374

Which of the following circulatory elements will decrease the affinity of hemoglobin for oxygen: 1)High 2,3 BPG 2)High pH 3)High CO2 4)Low CO2 5)High [H+]

Answer 374

1 , 3 , 5 High 2,3BPG, CO2 and [H+] will all decrease the affinity of hemoglobin for oxygen.

Question 375

Correct the order by energy output (Highest on Left): 1)Glucose>Alanine>Palmitate 2)Palmitate>Alanine>Glucose 3)Palmitate>Glucose>Alanine 4)Glucose>Palmitate>Alanine 5)Alanine>Glucose >Palmitate

Answer 375

3 Palmitate>Glucose>Alanine 108 ATP > 34 ATP~ > 7ATP~

Question 376

True for Hereditary Fructose Intolerance: 1) Cause is inadequate function of Aldolase B 2) Accompanied by Hypoglycemia 3) Results in Liver Damage 4) Glycogenolysis is Increased 5) Results in the accumulation of of F1P

Answer 376

1 , 2 ,3 ,5 1) Cause is inadequate function of Aldolase B 2) Accompanied by Hypoglycemia 3) Results in Liver Damage 5) Results in the accumulation of of F1P

Question 377

Are these two sentences true? Is there any connection? 1)RBCs form large amounts of 2,3 bisphosphoglycerate 2)Glycolysis in RBCs yield less ATP than in other cells.

Answer 377

Both 1 and 2 are True. Because RBCs have a shunt reaction that (sometimes) produces 2,3BPG instead of 1,3BPG Glycolysis in them results in production of less ATP.

Question 378

What factor is involved in the efflux of Calcium from Mitochondria: 1)Ca-uniporter 2)IP3-receptor 3)Na-Ca exchanger 4)T-Channel 5)Rynodine receptor

Answer 378

3 Na-Ca exchanger

Question 379

Cortisol formation from Progenalone - CYPs:

Answer 379

1)17 Hydroxylase 2)21 Hydroxylase 3)11 Hydroxylase (3-beta-HSD also after 1 but not CYP)

Question 380

An example for an Eicosanoid hormone is : 1)Testosterone 2)Epinephrine 3)Thyroxine 4)Thromboxane 5)Retinoic Acid

Answer 380

4 Thromboxane

Question 381

Choose on true statement for FA Activation : 1)UDP Acids are formed 2)Requires ATP and CoA 3)Requires Carnitine 4)CoA group comes from Malonyl - CoA 5)Phosphorylation with ATP

Answer 381

2 Requires ATP and CoA

Question 382

True for Malignant Hyperthermia: 1)It is characterized by muscle rigidity 2)It is the result of abnormal CNS Thermoregulation 3)It is the result of RYR mutation 4)Can be treated with calcium channel blockers 5)It is accompanied by intensive Lactate production in the Muscles

Answer 382

1 , 3 , 5 are True for Malignant Hyperthermia.

Question 383

Pituitary hormone promoting the conversion of cholesterol to Progenenolone in the Adrenal Cortex:

Answer 383

ACTH - Adrenocorticotropic Hormone

Question 384

Which are valid for Bile acids:

1) In its synthesis the Cholesterol side chain is oxidized
2) In its synthesis carbon atoms 7 and 12 are methylated
3) The secondary bile acids are produced from primary ones through deconjugation and dehydroxylation of 7th Carbon atom
4) Glycocholic and Taurocholic are primary bile acids
5) Litocholic is formed from Glycocholic by bacteria in colon

Answer 384

1 , 3 , 4 are valid for Bile acids

1) In its synthesis the Cholesterol side chain is oxidized
3) The secondary bile acids are produced from primary ones through deconjugation and dehydroxylation of 7th Carbon atom
4) Glycocholic and Taurocholic are primary bile acids

Question 385

What is a substrate for CYP11: 1)Aldosterone 2)Testosterone 3)Progesterone 4)Corticosterone

Answer 385

4 Corticosterone

Question 386

High group transfer potential indicates a tendency of the molecule to ___ a group.

Answer 386

Donate a group. For example PEP has High phosphryl group potential allowing it to aid in ATP formation in donating Pi.

Question 387

Tryptophan derivatives: 1)Lys 2)Acetoacetyl-CoA 3)Nicotinamide 4)Ala 5)Serotonin

Answer 387

2 , 3 , 4 , 5 -Acetoacetyl-CoA -Nicotinamide -Alanine -Serotonin

Question 388

Desaturase system requires all of the following EXCEPT: 1)O2 2)Cyt B5 3)ATP 4)NADPH

Answer 388

3 ATP is not needed

Question 389

3 ways for Oxidation of Ethanol? Location of each?

Answer 389

Alcohol Dehydrogenase - Cytosol CYP2E1 - SER Catalase - Peroxisome

Question 390

Which one is true for - Glutamate->Alpha-KG reaction: 1)Requires ATP 2)Doesn’t require co-factors 3)Accompanied by ATP hydrolysis catalyzed by the same enzyme 4)Catalyzed by GDH 5)Is a reductive deamination

Answer 390

4 GDH - Glutamate Degydrogenase Glu+H20+NAD(P)+ ->KG+NH4+NAD(P)H

Question 391

Which steroid synthesis pathway doesn’t involve 21-hydroxylation: 1)Aldosterone 2)Cortisol 3)Testosterone 4)Progesterone

Answer 391

3 , 4 Synthesis of Testosterone and Progesterone doesn’t require 21-Hydroxylation.

Question 392

What Enzyme of the TCA cycle forms GTP?

Answer 392

Succinyl CoA synthetase

Question 393

False for Acetylcholine: 1)Synthesized by Choline-acetyltransferase 2)De-Novo choline synthesis is carried out by Neurons. 3)There are High and Low affinity Cholin transporters on Neurons 4)Acetylcholine is degraded by Acetylcholinesterase.

Answer 393

2 De-Novo choline synthesis is carried out is not happening in the Neurons therefore they have High and Low affinity Cholin transporters for reuptake.

Question 394

Select the True statements: 1)Glycogen Phosphorylase is more active in its phosphorylated form. 2)Glycogen dephosphorylase is more active in its phosphorylated form. 3)Glycogen Synthase is more active in its phosphorylated form. 4)Glycogen Synthase is more active in its dephosphorylated form. 5)Glycogen Synthase is more active in its phosphorylated form and Dephosphorylated.

Answer 394

1 , 4 1)Glycogen Phosphorylase is more active in its phosphorylated form. 4)Glycogen Synthase is more active in its dephosphorylated form.

Question 395

The enzyme that trasforms UDP-Galactose to UDP-Glucose is:

Answer 395

an Epimerase

Question 396

Thymidylate Synthase: Substrate , Product, Co-Factor, Inhibitor.

Answer 396

S) dUMP P) dTMP Cofactor is Tetrahydrofolate(-Methylene) , Inhibitor is Methotrexate

Question 397

Which is NOT an Intermediate of the Synthesis of Lansterol from Acety-CoA: 1) Isopentyl pyrophosphate 2) Beta-Hydroxy-Beta-MethylGlutaryl-CoA 3) Beta- Hydroxybutyrate 4) Mevalonate

Answer 397

3) Beta Hydroxybutyrate is just a pathetic Ketone Body.

Question 398

White Adipocytes in Well-Fed State: 1)HSL digests VLDL and Chylomicrons 2)LPL is inactive 3)Glycolysis produces NADH for the production of Phophoglycerate 4)Triacylglycerol is deposited in lipid droplets 5)High rate of Glucose influx into them.

Answer 398

3 , 4 , 5 are true for White Adipocytes in Well-Fed State: Glycolysis produces NADH for the production of Phophoglycerate. Triacylglycerol is deposited in lipid droplets .High rate of Glucose influx into them.

Question 399

Are these two sentences true? Is there any connection? 1)Rate limiting step of urea cycle is CPS 1. 2)Increasing N-Acetylglutamate concentration will enhance urea synthesis.

Answer 399

Both are True. Because Rate limiting step of urea cycle is CPS 1 and N-Acetylglutamate is its allosteric activator - Increasing N-Acetylglutamate concentration will enhance urea synthesis.

Question 400

What are the Obligate Glucose organs?

Answer 400

1)Brain 2)Renal Medulla 3)Testis 4)Lens and Cornea

Question 401

Patients with deficiency of Carbamoyl-Phosphate Synthatase 1 and Ornithine transcarbamoylase are treated with Sodium Benzoate and Sodium Phenylacetate. Why?

Answer 401

Benzoate conjugates with Gly and removes one Nitrogen. Phenylacetate conjugates with Gln and removes two Nitrogen atoms. The products are released into urine.

Question 402

The Allosteric activator of Pyruvate Carboxylase: 1)Acetyl-CoA 2)Oxaloacetate 3)CoA 4)ATP 5)NADH

Answer 402

1 Acetyl-CoA

Question 403

Which of the following statements are true for Urea Cycle?

1) TCA cycle internediate is formed in it.
2) Its enzymes are located either in the cytosol or Mitochondria.
3) Condensation of Citruline and Glutamate requires ATP.
4) Synthesis of Urea costs hydrolysis of three group transfer potential bonds.

Answer 403

1 , 2 , 4

In the Urea Cycle Fumarate is formed which is a TCA cycle internediate. Its enzymes are located either in the cytosol or Mitochondria. (3ATPs cost)

Question 404

Mcardle Disease: Cause and Symptoms?

Answer 404

Cause : Muscle Glycogen Phosphorylase Deficiency Symptoms: Poor exercise tolerance (Normal Blood glucose level)

Question 405

Recognize the enzyme complex from these lines: Factor Xa hydrolyzes two peptide bonds. Vitamin K antagonist inhibit its formation. Factor Xa efficiency increases in it by orders of magnitude.

Answer 405

Prothrombinase Complex

Question 406

Which lipoprotein carries Cholesterol to the extra-hepatic tissues:

1) VLDL
2) IDL
3) LDL
4) HDL
5) Chylomicron

Answer 406

3

LDL carries Cholesterol to the extra-hepatic tissues.

Question 407

Correct order for enzymes of Ketone Bodies Synthesis: 1)HMG-CoA Lyase 2)Thiolase 3) 3(Beta)-hydroxybutyrate dehydrogenase 4)HMG-CoA Synthase

Answer 407

• > Thiolase - > HMG-CoA Synthase - > HMG-CoA Lyase - > 3(Beta)-hydroxybutyrate dehydrogenase

Question 408

Phosphorylation of Glucose (MCQ): 1)Requires ATP 2)Catalyzed by Cell Specific Kinases 3)Catalyzed by Hexokinase 4) It is Reversible

Answer 408

1 , 2 Requires ATP Catalyzed by Cell Specific Kinases

Question 409

Select one true statement: 1)Plasma membrane is not permeable for Na 2)Increasing K intracellularly activates Na/K ATPases 3)Na/K ATPases decrease the extracellular K 4)Na/K ATPases function requires the Na electrochemical gradient.

Answer 409

3)Na/K ATPases decrease the extracellular K

Question 410

What is the difference in the Isoenzyme regulation of PFK2 by PKA in the Skeletal Muscle in comparison to other tissues? Why?

Answer 410

There is NO phosphorylation of the Skeletal Muscle Isoenzyme of PFK2 by PKA - Due to Alternative Splicing. Liver type gets phosphorylated and Inactivated by PKA. Heart type gets phosphorylated and Activated by PKA.

Question 411

Which are the One Carbon derivatives of Tetrahydrofolate?

Answer 411

1) Methyl -Tetrahydrofolate 2)Methylene -Tetrahydrofolate 3)Methenyl -Tetrahydrofolate

Question 412

Disease caused by K+ voltage gated channel mutation: 1)Meysthenia 2)Myotonia 3)Epilepsy 4)Cystic fibrosis 5)Long QT syndrome

Answer 412

5 Long QT Syndrome

Question 413

Choose the Correct Statements: 1) Nascent HDL doesn’t contain Cholesteryl Esters 2) TAGs are transferred from VLDL to HDL 3) Cholesterol Are transferred from VLDL to HDL 4) Hepatic Lipase degrades TAGs in HDL 5) Liver takes up HDL-derived Cholesterol in LDL form.

Answer 413

1) Nascent HDL doesn’t contain Cholesteryl Esters 2) TAGs are transferred from VLDL to HDL 4) Hepatic Lipase degrades TAGs in HDL

Question 414

PDH Cofactors:

Answer 414

1)TPP 2)Lippoate 3)CoA 4)FAD 5)NAD

Question 415

A reaction of Glyceraldehyde-3-P with Fructose-6-P catalyzed by Transketolase (PPP) will form?

Answer 415

Erythrose-4-P and Xylulose-5-P

Question 416

Which are true for AMPK in the muscle : 1)Phosphorylates glycogen synthase kinase 2)Enhances the rate of glycolysis 3)Increases the rate of protein synthesis 4)One target of it is Acetyl-CoA Carboxylase 5)It will increase indirectly the entry of FA to Mitochondria.

Answer 416

4 , 5 4) One target of it is Acetyl-CoA Carboxylase 5) It will increase indirectly the entry of FA to Mito. (Phosphorylates glycogen synthase kinase only in Liver)

Question 417

factors of CTP Synthesis: 1)NADH 2)FADH2 3)Mg2++ 4)Acetyl-CoA 5)ATP

Answer 417

3 , 5 ATP and Magnesium ion

Question 418

When Insulin level in blood rises which enzyme activity elevates: 1)G6PD 2)Malic Enzyme 3)Pyruvate Carboxylase 4)PEPCK 5)Citrate Lyase

Answer 418

1 , 2 , 5 Insulin is Pro-FA Synthesis, it is Lipogenic. G6PD and Malic Enzyme helps form NADPH Citrate Lyase helps form more Acetyl-CoA - Lipogenic.

Question 419

Choose the Correct statement for Eicosanoid synthesis: 1)Thrombaxanes are produced from Arachidonate via the “linear path”. 2)Early step of the Pathway is inhibited by Aspirin 3)Aspirin acts by blocking the synthesis of Arachidonate 4)Plants can synthesize Leukotrines but Humans cant.

Answer 419

2 Early step of the Eicosanoid synthesis pathway is inhibited by Aspirin.

Question 420

Glutathione is a(n): 1)Product of Glutamate and Methionine 2)Tripeptide of Glycine, Glutamate and Cysteine 3)Enzyme essential in the synthesis of Glutamate 4)Methyl donor group in many synthesis pathways

Answer 420

2 Tripeptide of Glycine, Glutamate and Cysteine

Question 421

In what metabolic Situation will the Following process be active continuously: 1) Glycogenolysis 2) Glutamine Synthesis 3) Ketone Bodies Synthesis

Answer 421

Starvation

Question 422

PGI2 is formed from?

Answer 422

Arachidonic Acid

Question 423

How do Platelets aid Thrombus formation:

1) ADP Secretion
2) With their Phospholipid surface binding coagulation factors
3) TXA2 Secretion
4) with Secretion of vWF
5) PAI-1 Secretion

Answer 423

1 , 2 , 3 , 4, 5

1) ADP Secretion
2) With their Phospholipid surface binding coagulation factors
3) TXA2 Secretion
5) PAI-1 Secretion
4) with Secretion of vWF (Activated platlets are able to screte it!)

Question 424

Which Amino Acids are modified in Collagen, which Vitamin is Needed for the Modification?

Answer 424

Proline and Lyine - Hydroxylation

Vitamin C

Scurvy is happening when there is no Vit C

Question 425

Amino acids of Catalytic triad of Serine Protease:

Answer 425

His , Ser , Asp

Question 426

Na - H Exchanger :

Where is it found?

Function - What goes in and out?

pH will ____ if it is inhibited.

Answer 426

Located in the Intercalated cells of collecting ducts of kidney.

H- Out and Na - In.

pH will rise if it is inhibited.

Question 427

Regulators of HMG-CoA Reductase:

Answer 427

• Statins
• Cholesterol
• AMPK

Question 428

Reaction of PEPCK:

Answer 428

Substrates: Oxaloacetate and GTP

Products: PEP, GDP and CO2

Question 429

Effects of Strophantine:

Answer 429

Na/K ATPase Inhibition (Partial) :

Leads to Na/Ca exchanger reversal and therefore to Increase in Ca intracellularly -

Increased heart muscle contratillity.

Question 430

Acetylcholine-Esterase Inhibitor

Answer 430

DFP

Question 431

5-alpha-Reductase reaction:

Answer 431

Substrates: Testosterone + NADPH H+

Products: Dihydrotestosterone + NADP+

Question 432

PRPP Synthase reaction:

Answer 432

Substrates : Ribose-5-P + ATP

Products : PRPP +AMP

Question 433

Effect of AMPA activation on NMDA:

Answer 433

When AMPA receptors are stimulated, they open and depolerize. The cell depolarization causes the removal of Mg2+ ion that was inhibiting the NMDA.

This causes Activation of NMDA.

Question 434

Mechanism of Ecstasy:

Answer 434

▪ Binds and inhibits noradrenaline transporters, dopamine transporters and serotonin transporters (highest affinity).
▪ Serotonin release and subsequent depletion.
▪ Inhibition of tryptophan hydroxylase and monoamine oxidase (effect on metabolites synthesized in the periphery).
▪ Dopamine release and subsequent depletion.
▪ Generation of toxic free radicals - neurodegeneration.
▪ Cardiovascular and sympathetic effects (tachycardia, arrhythmia, vasoconstriction).
▪ Increased body temperature.
▪ Hyperactivity.

Question 435

Select the true statments:

1) Formation of Tyr is an essential step in the metabolism of Phe
2) Phenylalanine may lose its amine group through tramsamination
3) Carbon skeleton of Phe yeilds Acetoacetate
3) Carbon skeleton of Phe yeilds HMG-CoA

Answer 435

1 , 2 , 3

1) Formation of Tyr is an essential step in the metabolism of Phe
2) Phenylalanine may lose its amine group through tramsamination
3) Carbon skeleton of Phe yeilds Acetoacetate

Question 436

Lipoproteins that are digested by Hepatic Lipase:

Answer 436

IDL

HDL2

Question 437

List at list two signs of LPL deficiency:

Answer 437

Hypertriacylglyceremia

Pacreatitis

Xanthomas

Lipemia

Hepatosplenomegally

Question 438

List at least two functions on Carnitine

Answer 438

FA transport into Mitochondria

Chort chain acyl-CoA export from mitochondria

Maintainance of free CoA-SH level

Question 439

Answer 439

A - Urea

B - Glutamate

C - Cholesterol

D - Aspartate

E - Arginine

F - Carbamoyl Phosphate

Question 440

Conversion from Cholesterol to Pregnenolone:

Enzyme and Co-Factors

Answer 440

Substrates: Cholesterol + 3 NADPH + 3 H+ + 3 O2

Pregnenolone + 4-methylpentanal + 3 NADP+ + 3 H2O

By Cholesterol Side Chain Cleavage Enzyme

Question 441

Which of the following statements is True:

1) Cyclooxygenase activity needs organic epoxide initiators
2) Steroid hormones contribuit to biosynthesis of COX
3) Tyr-385 is in Ionized form in COX protein
4) COX activity needs an organic peroxide activity
5) The active COX is monomeric

Answer 441

3

Tyr-385 is in Ionized form in COX protein

Question 442

Which of the following reactions with Folic acid (F) are Reversible:

1) N10-N5-Methylene THF to N5-Methyl-THF
2) N10-FormyL-THF to N10-N5-Methenyl THF
3) N10-N5-Methenyl THF to N10-N5-Methylene THF
4) N5-Methyl-THF to THF

Answer 442

2 , 3 Are Reversible

• N10-FormyL-THF to N10-N5-Methenyl THF
• N10-N5-Methenyl THF to N10-N5-Methylene THF

Question 443

Which two “kinds” of Amino acids share a common transporter on the Blood Brain Barrier?

Answer 443

BCAAs share the same transport protein into the brain with aromatic amino acids (Trp, Tyr, and Phe).