Quiz 1 LOs Flashcards
What is the rate limiting enzyme of glycolysis?
What 2 molecules activate it?
What 2 molecules inhibit it?
PFK-1
ACTIVATE: AMP, F-2,6-BP
INHIBIT: ATP, citrate
Which of the following glucose transporters is located in the liver with the lowest affinity, and which is regulated by insulin?
GLUT1
GLUT2
GLUT3
GLUT4
GLUT2 is in liver with lowest affinity
GLUT4 is regulated by insulin
Pyruvate kinase is a major regulated step in glycolysis. What 2 molecules stimulate activation, and what 3 molecules inhibit its activity?
Note: Pyruvate kinase works and you’re “in”, but when it’s off “GAA”
ACTIVATE: Insulin, F-1,6-BP
INHIBIT: Alanine, ATP, Glucagon
Note: Pyruvate kinase works and you’re “in”, but when it’s off “GAA”
Which of the two hormones is associated with dephosphorylation?
A. Glucagon
B. Insulin
Insulin
Taurus’ are Pretty Fucking Kind, but Tarui disease is not. PTs present with exercise induced cramps, hemolytic anemia, high bilirubin and jaundice. Teuri disease is caused by a deficiency in what major enzyme of glycolysis?
PFK-1
T/F: It seems like insulin and phosphatases is always vs. glucagon and cAMP/PKA
True
Pyruvate can be converted to alanine through what two metabolic processes?
Gluconeogenesis
Urea cycle
About 95% of glycolysis related anemias are associated with defects in what enzyme?
Pyruvate kinase
What are two major clinical markers for hemolytic anemia?
A. Lactate dehydrogenase, conjugated bilirubin
B. Pyruvate kinase, PFK-1
C. Lactate dehydrogenase, unconjugated bilirubin
D. None of the above
Lactate dehydrogenase, unconjugated bilirubin
Fanconi-Bickel syndrome is a “TWO-NAME SYNDROME”, with a lot of words to TRANSPORT. Presentation includes hepatosplenomegaly, failure to thrive, and resistant rickets. What deficiency is causes this two-name syndrome?
GLUT2 defect that prevents transport of glucose, galactose, and fructose to be transported
Which of the following, is an activator for all of the major regulatory steps of gluconeogenesis that include the following enzymes: Pyruvate carboxylase, PEP carboxykinase, F-1,6-Biphosphatase, and Glucose-6-phosphatase?
A. AMP
B. Cortisol
C. Citrate
D. ADP
Cortisol
What is the rate limiting enzyme of gluconeogenesis?
What are the 2 aCCtivators?
What are its 2 inhibitors?
Fructose-1,6-biphosphatase
ACTIVATORS: Citrate, Cortisol
INHIBITORS: AMP, F2,6BP
What are the only 3 activators of PEP carboxykinase that stimulate its activity in gluconeogenesis?
Cortisol
Glucagon
Thyroxine
What are the 2 activators of pyruvate carboxylase and its only ADept inhibitor as it acts in gluconeogenesis?
ACTIVATOR: Cortisol, Acetyl CoA
INHIBITOR: ADP
NOTE: pyruvate carboxylase has an ADept inhibitor
If F2,6BP activates PFK-1 in glycolysis then it makes sense that F2,6BP inhibits what enzyme in gluconeogenesis?
Fructose-1,6-biphosphatase
Which of the following enzymes is the only one to be found in the mitochondria and utilizes biotin (B7)?
A. PEP carboxykinase
B. Fructose-1,6-biphosphatase
C. Glucose-6-phosphatase
D. Pyruvate carboxylase
Pyruvate carboxylase
Tarui disease is caused by a deficiency in PFK-1. What other disease is similar to Tarui disease in gluconeogenesis?
Fructose-1,6-biphosphatase deficiency and Tarui disease present similaraly
Lactic acidosis, hypoglycemia
Explain how glucose is made into fructose in cells that have sorbitol dehydrogenase in the Polyl pathway. Include intermediates and enzymes used.
Glucose + Aldose reductase –> sorbitol + sorbitol dehydrogenase —> fructose
Cells lacking sorbitol dehydrogenase: Kidney, retina, schwann cells
Fructose w/ _________ makes F6P, and enters in glycolysis. While fructose with _______ makes F1P, skipping major regulatory step and entering glycolysis at intermediate Glyceraldehyde 3 phosphate
Hexokinase
Fructokinase
In fructose metabolism, what two enzymes bypass the major regulatory step of glycolysis?
Fructokinase
Triose Kinase
Galactosemia has non-classical and classical versions depending on the deficinent enzyme. What is the deficient enzyme in either version that leads to the buildup of galactose or galactitol causing cataracts?
Classical: GALT/glacatose 1P uridyltransferase
Non-classical: Glactokinase
T/F: Galactose is one step away from Galactitol via aldolase reductase
True
What is the rate limiting enzyme of the PPP?
Glucose-6-phosphate dehydrogenase
Which of the following is the likely result with GSD 0? Bonus: what enzyme is deficient?
A. Long chains with few branches
B. Short chains with many branches
C. Free glucose unable to be converted to glycogen
D. None of the above
Free glucose unable to be converted to glycogen
Enzyme: Glycogen synthase (rate limiting enzyme)
Which of the following is the likely result with Andersen disease (GSD IV)? What enzyme is deficient
A. Long chains with few branches
B. High number of short branches
C. Free glucose unable to be converted to glycogen
D. None of the above
Long chains with few branches
Enzyme: Glucosyl (4:6) transferase
What is the rate limiting enzyme of glycogenolysis and glycogenesis?
Glycogenesis: Glycogen synthase
Glycogenolysis: Glycogen phosphorylase
Which of the following is the likely result with Cori disease (GSD III)? What is the deficient enzyme?
A. Long chains with few branches
B. High number of short branches
C. Free glucose unable to be converted to glycogen
D. None of the above
High number of short branches
a-1,6-glucosidase
In terms of phosphorylation, which form of glycogen synthase is active and which form of glycogen phosphorylase is active?
DEphosphorylated glycogen synthase is active
Phosphorylated glycogen phosphorylase is active
T/F: Glucagon does not act on the muscle
True
ATP citrate lyase is the enzyme responsible for converting citrate back to acetyl CoA and OAA once out in the cytosol in FA synthesis. What are citrate lyase’s 2 activators, and what are the 2 inhibitors?
ACTIVATORS: Glucose, Insulin
INHIBITORS: PUFA, leptin
T/F: Oxaloacetate is unable to enter and exit mitochondria directly
True
In fatty acid synthesis, which of the following acts as an inhibitor in every major phase?
A. PUFA
B. Leptin
C. Insulin
D. Glucagon
PUFA
T/F: Carboxylase enzymes generally utilize biotin as a cofactor
True
What is the rate limiting step and enzyme in fatty acid synthesis?
Acetyl CoA –> Malonyl CoA
Acetyl-CoA carboxylase
The presence of malonyl coA inhibits the function of what rate limiting enzyme in fatty acid degredation, in order to prevent them from occuring at the same time?
Carnitine acyl transferase
Phase III of fatty acid synthesis is chain formation where 2carbon units are added to the fatty acyl chain in 7 reactions to form palmitate. What is the name of the enzyme complex that carries this out?
Fatty Acid Synthase Complex
Fatty acid synthase is a complex of 2 identical dimers made up of 7 enzymes and what additional protein with a flexible arm?
Acyl Carrier protein
What 2 hormones/hormone types stimulate the activity of Fatty Acid Synthase Complex?
Insulin
Glucocorticoid hormones
Because the brain requires longer chain fatty acids (C18-24), it is necessary for palmitate to be lengthened. This addition can only happen in 2 different locations, and each use their own carbon donor plus NADPH for reducing power. What are the 2 locations where this occurs, and what are their respective carbon donors?
Smooth ER uses Malonyl CoA
Mitochondria uses Acetyl CoA
What are the 4 human desaturases and where do they each present a new double bond?
delta4: 4-5
delta5: 5-6
delta6: 6-7
delta9: 9-10
TAGs are made in through de novo synthesis in all of the following locations except for which, which is where dietary TAGs are processed?
A. Hepatocytes
B. Adipocytes
C. Intestinal cells
D. None of the above
Intestinal cells
What is the name of the lipoprotein that contaiins apolipoproteins and other lipids synthesized from the small intestines? These lipoproteins later enter the lymphatic system through the thoracic duct.
A. Chylomacroons
B. VLDLs
C. LDLs
D. Chylomicrons
Chylomicrons
In the de novo synthesis of TAGs made in the liver glucose and glycerol combine to form glycerol-3-phosphate. This glycerol-3-phosphate is used as the backbone and combined with FFAs to form TAGs. These TAGs are packaged into lipoproteins that are called:
A. Chylomacroons
B. VLDLs
C. LDLs
D. Chylomicrons
VLDLs
T/F: TAG synthesis in adipocytes is promoted by excess carbohydrates and fats
True
De novo synthesis of TAGs in adipose tissue utilizes what enzyme that combines chylomicrons and VLDLs?
Capillary Lipoprotein Lipase
The breakdown of TAGs involves the work of 3 major lipases. What are their names in the order in which they are used?
- Hormone Sensitive Lipase
- Lipoprotein lipase
- Monoacylglycerol lipase
Unlike short and medium chain FAs, long and very long chain FAs cannot diffuse into the mitochondria and must be actively transported. What is the name of the transporter responsible for shuttling the LCFA and VLCFA into the mitochondria?
Carnitine shuttle
What is the rate limiting enzyme of the carnitine shuttle during fatty acid oxidation? What is it inhibited by
CArnitine palmitotransferase I
Inhibited by Malonyl CoA
Ketone bodies are water-soluble, acidic compounds that are only produced in the liver. What are the names of 3 ketone bodies?
Acetoacetate
B-hydroxybutyrate
Acetone
What are the 3 purposes of nutrition?
- Promote growth and development
- Provide energy
- regulate metabolism
Which of the following proteins is stabilized through hydrophobic interactions with the membrane?
A. Integral membrane proteins
B. Peripheral proteins
C. Lipid anchored proteins
D. None of the above
Integral membrane proteins
Which of the following proteins is loosely bound to membrane through electrostatic interactions?
A. Integral membrane proteins
B. Peripheral proteins
C. Lipid anchored proteins
D. None of the above
Peripheral proteins
Lipid anchored proteins are tethered to the plama membrane through which of the following interactions?
A. Electrostatic
B. Hydrophobic
C. Covalent
D. Ionic
Covalent
All of the following phospholipids are normally found in the outerleaflet except for which of the following which is only found during apopotosis?
A. Phosphatidylcholine
B. Glycolipids
C. Sphingomyelin
D. Phosphotidylserine
Phosphotidylserine
Which of the following diseases leads to an accumulation of sphingomyelin in the lysosomes of the liver, spleen, CNS, or bone marrow? What is the deficient enzyme?
A. Fanconi-Bickel syndrome
B. Niemann-Pick disease
C. Andersen Disease
D. Cori disease
Niemann-Pick disease
deficient in Acid Sphingomyelinase which breaks down sphingomyelin into ceramide and phosphorylcholine
During blood transufsions why is it important to cross match? In other words what are you ensuring doesn’t interact between the donor and recipient?
Cross-matching is necessary to ensure the donor’s blood antigens doesn’t interact with the recipients antibodies in the plasma
In terms of ABO blood system, antibodies are found in the ______ while antigens are found in the _____.
plasma
RBC surface
In order to be a universal donor, what is required of your blood. What is required for a universal acceptor?
Universal donors have no blood group antigens
- like Type O w/ H antigen
Universal acceptors have no antibodies in their plasma
- like Type AB
A patient is diagnosed with advanced liver cirrohsis, and another patient with Beta-lipoproteinanemia. Oddly enough, you notice high levels of excess free cholesterol in the blood. Which of the following issues might you look out for when analyzing the blood further?
A. Spur cell anemia B. Neimann-pick disease C. Acanthocytes D. All of the above E. A and B F. A and C
F.
Spur cell anemia
Acanthocytes
A patient presents with renal cholic (abdominal pain associated with kidney stones). PT comes back with a positive nitroprusside test and you diagnose them with Cystinuria. If you were to collect samples of crystals passed by this patient, what might you find they are made of?
Dimeric AA: Cystine
Dibasic AAs: Ornithine, Lysine, Arginine
CORK
PT presents with cerebellar ataxia, nyastygmus, photodermatitis, and photosensitivity. You record low levels of melatonin, serotonin, and niacin. What is the most likely disease, and what AA is likely not being transported?
Hartnup disease
Tryptophan: an important precursor for serotonin, melatonin, niacin
PT presents with CHF, and you wish to better control this. You select a drug that inhibits the Na/K ATPase that would lead to an increase in intracellular [Na] and impair the secondary NCX which increase [Ca] causing a stronger contraction in cardiac muscle. What is the name of the drug you most likely selected?
Digoxin
Ouabain
T/F: Phosphatase removes a phosphate while phosphorylase is a type of phosphotransferase that adds an additional phosphate group originally from an inorganic compound
True
In order to establish a proton gradient protons must be pumped from the ______ to the ________. This is done through the movement of electrons through the complexes
Matrix (low)
Inner membrane space (high)
When the transfer of electrons is inhibited in the OxPhos 3 things happen. Which of the following is not one of them?
A. Decrease in proton pumping
B. Decrease in proton gradient
C. Increase in proton pumping
D. Inhibition of ATP synthesis
Increase in proton pumping
Which of the following occurs when ATP synthase is uncoupled from ETC as seen in hybernating animals?
A. Proton leakage back into matrix B. Inhibition of ATP synthase C. Acceleration of TCA and e- transfer to O2 D. Heat production E. All of the above F. All but C
All of the above
All of the following is true of the malate-aspartate shuttle except which of the following that is true of the glycerophosphate shuttle? What change would you make to make them all correct?
A. Operates in heart, liver, kidneys
B. Generates FADH2 in the inner mito-membrane
C. Allows entry of oxidant at Complex I
D. All the above are correct
Generates FADH2 in the inner mito-membrane
Malate-aspartate shuttle generates NADH in the mitochondrial matrix
All of the following is true of the glycerophosphate shuttle except which of the following that is true of the malate-aspartate shuttle? What change would you make to make them all correct?
A. Operates in brain and muscle
B. Generates FADH2 in the inner mito-membrane
C. Allows entry of oxidant at Complex I
D. All the above are correct
Allows entry of oxidant at Complex I
Glycerophosphate shuttle allows entry of FADH2 at CoQ
An excess in citrate favors which of the following processes?
A. Aerobic glycolysis (pyruvate –> acetyl CoA)
B. TCA
C. Non-oxidative glycolysis (pyruvate–> lactate)
D. Activity of PDC
Non-oxidative glycolysis (pyruvate–> lactate)
Which of the following peptidases would clip at the end of a peptide at the C terminus?
A. Aminopeptidase
B. Carboxypeptidase
C. Endopeptidase
D. Enteropeptidases
Carboxypeptidase
Which of the following peptidases is responsible for cleaving and activating zymogens in extracellular environment?
A. Aminopeptidase
B. Carboxypeptidase
C. Endopeptidase
D. Enteropeptidases
Enteropeptidases
What AAs are ketogenic only, and which are both ketogenic and glucogenic?
Ketogenic only: KL
BOTH: WIFTY
Patients with MSUD are likely to have what AA found in thier urine?
Branched Chain AA
Treated with thiamine (B1)
PT presents with urine of a musty smelling odor. Analysis shows elevated levels of phenylactate and phenylacetate which are known to block neurotransmission and myelin formation. PT is diagnosed with PKU (Phenylketonuria). What AA is converted erroneously to cause this issue. What AA can be used to treat this issue to supplement the poorly processed AA?
Phenylalanine
Tyrosine
PKU is caused by defective activity og phenylalanine hydroxylase
PLP is needed in transaminase or aminotransferases and is the active form of which of the following B vitamins?
A. B1
B. B2
C. B6
D. B12
B6
T/F: Phenylalanine is converted to Tyrosine through the activity of phenylalanine hydroxylase
True
In order for Tryptophan to make niacin, which of the following vitamins is needed?
A. B1
B. B3
C. B6
D. B12
B6
NOTE: B3 is niacin
Melanin is a product of which of the following AAs?
A. Threonine
B. Tyrosine
C. Tryptophan
D. None of the above
Tyrosine
Dopamine, norepinephrin
Thyroid hormones
Melanin
Serotonin and melatonin are products of which of the following AAs?
A. Threonine
B. Tyrosine
C. Tryptophan
D. None of the above
Tryptophan
THe goal of the urea cycle is to remove nitrogen in the form of ammonia. In the brain ammonia is removed as what two AAs?
Glutamate
Glutamine
B1
thiamine
B2
riboflavin
B3
niacin
Pantothenic acid
B5
Pyridoxine
B6
B7
Biotin
Folic acid
B9
B12
Cobalamin
Vitamin C
Ascorbate
What are the 4 fat soluble vitamins
ADEK
BeriBeri has two forms dry and wet. Deficiency in what vitamin leads to BeriBeri? Describe each form briefly.
Thiamine deficiency (B1)
Dry: Muscle wasting and partial paralysis
Wet: Peripheral edema and cardiac failure
Accumulation of sorbitol causes cataracts
True
A deficiency in what enzyme impairs the breakdown of medium chain FAs, often leading to secondary carnitine deficiency. The number of C8 fatty acids accumulate in the liver impairing urea cycle and increasing ammonia levels.
Medium chain acyl CoA dehydrogenase
The degredation of very long chain FAs occurs in what cellular location and utilizes what enzyme in the first step?
This enzyme is specific to the organelle
Peroxisome
Acyl-CoA oxidase
Uracil replaces what pyrimidine base in RNA?
Uracil replaces Thymine
All of the following are true of xanthine oxidase, except for which of the following that is true of adenosine deaminase?
A. Converts hypoxanthine to xanthine
B. Target for gout treatment
C. Converts xanthine to uric acid
D. Excess leads to hemolytic anemia, and deficiency leads to SCID
Excess leads to hemolytic anemia, and deficiency leads to SCID
NOTE: Adenosine deaminase-performs an irreversible hydrolytic deamination making adenosine to inosine
HGPRT is able to generate which of the following purines in the purine salvage pathway, while APRT is able to generate what?
A. AMP
B. IMP
C. GMP
HGPRT: IMP and GMP
APRT: AMP
T/F: On pyrimidine synthesis the rate limiting step is the formation of carbomoyl aspartate
True
Transaminases transfer an amino group to an a-ketoacid and are coupled with what co-enzyme? What B vitamin is the coenzyme derivative of?
PLP-pyridoxyl-5-phosphate
B6
Which of the following enzymes is used to remove the NH4 from glutamine creating glutamate?
A. Glutaminase
B. Glutamine synthase
Glutaminase
Which of the following enzymes is used to add an ammonia to glutamate to make glutamine?
A. Glutaminase
B. Glutamine synthase
Glutamine synthase
What is the name of the enzyme responsible for removing the ammonia from Glutamine in the brain?
Glutamine synthase
Removal of excess NH4 from the muscle requires what enzyme?
A. Glutaminase
B. Glutamine synthase
C. Alanine Transaminase
D. Aspartate transaminase
Alanine Transaminase
What are the names of the 3 uncouplers?
DNP, aspirin, thermogenin (UCP-I)
Arsenic attacks what complex in cellular metabolism?
E2 of pyruvate dehydrogenase complex
T/F: Excess citrate reduces the activity of PDC causing favoribility of nonoxidative glycolysis, pushing increase pyruvate conversion to lactate
True
Increase of citrate activates which of the following enzymes?
A. Pyruvate Dehydrogenase
B. PFK1
C. Acetyl CoA carboxylase
D. All the above
Acetyl CoA Carboxylase
- enzyme produces acetyl CoA and Maloney’s CoA pushing lipid synthesis
Transaminases like alanine transaminase or aspartate transaminase require what coenzyme?
A. Vitamin B6 derived PLP
B. Vitamin B12 cobalamine
C. Vitamin B7 biotin
D. Vitamin B5 pantothenic acid
Vitamin B6 derived PLP
PLP = pyridoxal phosphate