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Biochem Exam 2 > EXAM 2 > Flashcards

EXAM 2 Flashcards

0
Q 
1. Free energy delta G is the most important concept in the metabolism which exactly tells the energy status of a biochemical reaction whether the reaction is spontaneous or non-spontaneous. which of the following metabolic reaction with a given free energy would be irreversible under in vivo conditions?
A. delta G=0
B. delta G=+ive
C. delta G= -ive
D. Both delta G=0 & -ive
E. Both delta G=0 & +ive
A

C. delta G= -ive

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1
Q 
2. Which of the following substances derived from adipose tissue contributes to net gluconeogenesis in the liver?
A. Alanine
B. Glutamine
C. Glycerol
D. Pyruvate
E. None of the above
A

C. Glycerol

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2
Q 
3. Asians and Chinese may flush and feel ill after drinking a small amount of ethanol in alcoholic beverages, which is often due to the deficiency of acetaldehyde dehydrogenase present in hepatocytes. Which of the following metabolite would be the most probable cause for inducing the above condition?
A. Glycerol
B. Acetate
C. Acetaldehyde
D. Methanol
A

C. Acetaldehyde

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3
Q 
4. Which of the following metabolic intermediate is the highest energy compound that is functioning as a direct phosphate donor to ATP synthesis during glycolysis?
A. Phosphoenolpyruvate
B. Glucose-6-phosphate
C. Fructose-6-phosphate
D. 2, 3, Bisphosphoglycerate
E. Phosphoglyceric acid
A

A. Phosphoenolpyruvate

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4
Q 
5. In Kreb's cycle, the number of ATP molecules produced during complete oxidation of acetyl CoA is:
A. 12
B. 36
C. 9
D. 11
E. 3
A

A. 12

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5
Q 
6. Lactate that is formed in the muscle cells during strenuous execise is efficiently recycled for the synthesis of glucose in the liver by:
A. Cori cycle
B. TCA cycle (?)
C. Glycolysis
D. Oxidative phosphorylation
E. Urea cycle
A

A. Cori cycle

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6
Q 
7. Which of the following electron transport chain components of mitochondria is also acting as a biosignature for Apoptosis?
A. Cytochrome C
B. Ubiquinone
C. Complex 1
D. ATP synthase
A

A. Cytochrome C

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7
Q
  1. Which of the following statements is correct about lactose intolerance?
    A. Inflammatory bowel disease (IBD) can also cause lactose intolerance
    B. Normally the lactase activity decreases with the progression of an individual age that leads to lactose intolerance
    C. Celiac disease can also lead to lactose intolerance
    D. Lactase deficiency in some African population is a main factor of lactose intolerance
    E. All of the above
A

E. All of the above

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8
Q 
9. Under fasting conditions in metabolically active cells c-AMP is formed from ATP by a membrane bound enzyme adenylate cyclase that is stimulated by which of the following hormones?
A. Insulin
B. Glucagon
C. Progesterone 
D. Testosterone
E.  Both progesterone and testosterone
A

B. Glucagon

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9
Q 
10. In typical excercising muscle cells when oxygen supply becomes a limiting factor the pyruvate is mostly converted into:
A. Phosphoenolpyruvate
B. Lactate
C. Alanine
D. Acetyl CoA
E. Glycerol
A

B. Lactate

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10
Q 
11. Glucose is the "onliest" source of energy in which of the following cell types?
A. Neurons
B. Erythrocytes
C. Sperm
D. Hepatocytes
E. None of the above
A

A. Neurons

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11
Q 
12. Glucose cannot enter or diffuse directly into the cells but its transport is mostly mediated by a family of glucose transporters present in the cell membranes that display a tissue-specific pattern of expression. Which of the following glucose transporters is primarily found in liver and pancreatic B-cells?
A. GLUT-1
B. GLUT-2
C. GLUT-3
D. GLUT-4
E. GLUT-5
A

B. GLUT-2

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12
Q
  1. In a mouse model experiment, complete gene knock-out for a-ketoglutarate dehydrogenase (-/-) was successfully produced. Absence of this enzyme would totally halt the Kreb’s cycle, severely affecting the ability of the cell to form NADH and ATP. Which of the following statements is correct?
    A. Liver cells of the animals will be most affected
    B. Muscle cells of the animals will be most affected
    C. Erythrocytes of the animals will be most affected
    D. All of the animals will most probably die
A

A. Liver cells of the animals will be most affected

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13
Q 
14. Under normal physiological conditions glucose is broken down into how many molecules of pyruvate in glycolysis?
A. 1
B. 3
C. 4
D. 2
E. 6
A

D. 2

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14
Q 
15. Gluconeogenesis occurs predominantly from the following compounds, except:
A. Lactate
B. Glycerol
C. Amino acids
D. Fatty acids
A

D. Fatty acids

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15
Q
  1. Which of the following statements is correct about the anti-abuse drug Disulfiram?
    A. Inhibiting pyruvate dehydrogenase complex
    B. Activating alcohol dehydrogenase
    C. Inhibiting glucose-6-phosphatase
    D. Inhibiting acetaldehyde dehydrogenase
A

D. Inhibiting acetaldehyde dehydrogenase

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16
Q 
17. How many ATP molecules are produced on complete oxidation of glucose in the brain cells?
A. 36
B. 24
C. 12
D. 32
A

D. 32

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17
Q
  1. All of the body cell types do require glucose for the production of energy because glucose serves as the easiest source of energy-rich metabolite for carrying out all of the central metabolic processes of the cell at the physiological pace. This is why nature maintains a constant glucose homeostasis of the body. Which of the following statements best describes the energy status of glucose in the body?
    A. Constant production of ATP in the cells
    B. Hyperglycemia/or higher blood-glucose concentrations under non-diabetic conditions
    C. Diminished activity of glucokinase in the absence of insulin
    D. Na+ dependent glucose transport in the GI tract
    E. None of the above
A

D. Na+ dependent glucose transport in the GI tract

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18
Q 
19. Which of the following is a non-reducing sugar?
A. Glucose
B. Fructose
C. Galactose
D. Sucrose
A

B. Fructose

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19
Q 
20. Routine examination of the urine of an asymptomatic pediatric patient showed a positive reaction with clinitest (a copper reducing method of detecting reducing sugars), but a negative reaction with the glucose oxidase test. Which of the following sugars is least likely to be present (assuming a single elevated saccharide)?
A. Lactose
B. Fructose
C. Glucose
D. Sucrose
A

D. Sucrose

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20
Q 
21. Where is the most glucose synthesized in the body?
A. Kidney
B. Liver
C. Small intestine
D. Heart muscles
E. Adipose tissue
A

B. Liver

21
Q 
22. Acetyl CoA is an obligate activator of:
A. PEP carboxylase
B. Pyruvate carboxylase
C. Glucokinase
D. G-6 phosphatase
E. None of the above
A

B. Pyruvate carboxylase

22
Q 
23. Which of the following is not a glycogenic amino acid?
A. Alanine
B. Leucine
C. Tyrosine
D. Arginine
A

B. Leucine ***(NOTE: the term is glucogenic. not glycogenic)

23
Q 
24. Which of the following enzymes is specifically turned "ON" by insulin during glycolysis?
A. Phosphfructokinase-I
B. Phosphofructokinase-II
C. Pyruvate kinase
D. Hexokinase
E. None of the above
A

B. Phosphofructokinase-II

24
Q 
25. A young black man entered his physician's office complaining of bloating and diarrhea. His eyes were sunken and the physician noted additional signs of dehydration. The patient's temperature was normal. He explained that the episode had occurred following a birthday party at which he had participated in an ice cream eating contest. The patient reported prior episodes of a similar nature following ingestion of a significant amount of dairy products. This clinical picture is most likely due to a deficiency in:
A. Salivary a-amylase
B. Isomaltase
C. Lactase
D. Pyruvate kinase
E. Sucrase
A

C. Lactase

25
Q 
26. In sucrose, galactose and glucose are linked by a characteristic glycosidic linkage:
A. Galactosyl-a (1-1)-glucose
B. Galactosyl-a (1-4)-glucose
C. Galactosyl-b (1-4)-glucose
D. Galactosyl-b (1-6)-glucose
E. Galactosyl-a (1-6)-glucose
A

C. Galactosyl-b (1-4)-glucose

26
Q 
27. A patient presents with symptoms of weakness, fatigue, shortness of breath, and dizziness. His hemoglobin level was less than 7mg/dl (normal for a male being greater than 13.5mg/dl). Red blood cells isolated from the patient showed abnormally low level of lactate production. A deficiency of which of the following enzymes would be the most likely cause of this patient's anemia?
A. Lactate dehydrogenase
B. Pyruvate dehydrogenase
C. Pyruvate kinase
D. Glucokinase
E. Malate dehydrogenase
A

C. Pyruvate kinase

27
Q
  1. The additive property of free energy changes (delta Gs) is the most significant tool with nature employed in most biochemical reactions by which metabolic intermediates of a metabolic pathway follow a particular direction. A (initial substrate)(delta G=-ive)—> B (delta G=+ive)—> C(delta G=+ive)—> D(delta G=+ive)—>E(delta G=-ive)–> F (final product). Which of the following statements is correct about this metabolic pathway?
    A. The pathway will proceed as written only if the overall delta G is positive
    B. The pathway will proceed as written only if the overall delta G is negative
    C. No it will not proceed as written because many of the metabolic steps in this pathway have delta G positive
    D. The pathway will proceed only if the overall delta G is zero
    E. Metabolic pathways don’t utilize standard free energy changes of different metabolic reactions to pass in a particular direction
A

B. The pathway will proceed as written only if the overall delta G is negative

28
Q 
29. For ATP production through oxidative phosphorylation which of the following compounds serves the final electron acceptor in the mitochondrial electron transport chain (ETC)?
A. NAD+
B. Oxygen
C. ATP synthase (complex V)
D. Cytochrome C
E. Water
A

B. Oxygen

29
Q
  1. Which one of the following is an example of Tender Loving Care For Nancy enzyme?
    A. a-ketoglutarate dehydrogenase
    B. Branched chain a-keto acid dehydrogenase
    C. Pyruvate dehydrogenase
    D. All of the above
A

D. All of the above

30
Q 
31. The maturity onset diabetes of the young type 2 (MODY2) (insulin dependent) is a rare form of diabetes found in patients with a substantially decreased activity of the following metabolic enzyme:
A. Glucokinase
B. Hexokinase
C. Glucose-6-phosphatase 
D. Pyruvate carboxylase
E. Phosphfructokinase-1
A

A. Glucokinase

31
Q 
31. Which of the following glucose transporter is abundantly present in the muscle?
A.GLUT-1
B. GLUT-2
C. GLUT-3
D. GLUT-4
E. GLUT-5
A

D. GLUT-4

32
Q 
32. Which of the following cell type is devoid of glycolysis?
A. Neurons
B. Beta pancreatic cells
C. Erythrocytes
D. Sperm cells
E. None of the above
A

E. None of the above

33
Q
  1. Which of the following reactions is unique to gluconeogenesis?
    A. Lactate——->Pyruvate
    B. Phosphoenolpyruvate———-> Pyruvate
    C. Glucose-6-phosphate———-> Fructose-6-phosphate
    D. …..-glycerate——> 3-phosphoglycerate
    E. X——> Phosphoenolpyruvate
A

E. Oxaloacetate —> phosphoenolpyruvate

34
Q 
34. A 2 month old child is evaluated for failure to thrive. During the examination, the child has a seizure. Stat serum chemistries demonstrate severe hypoglycemia, hyperlipidemia, lactic acidosis, and ketosis. Physical examination is remarkable for hepatomegaly, a finding confirmed by CT scan. Which of the following best accounts for this presentation?
A. Gaucher disease
B. McArdle disease
C. Niemann-Pick disease
D. Pompe disease
E. Von gierke disease
A

E. Von gierke disease

35
Q 
35. Dehydrogenases such as glucose-6-phosphate dehydrogenase serve to transfer H+ from one substrate to another in coupled oxidation-reduction reactions, ultimately (in the respiratory chain) generating energy by oxygen/water reduction. Dehydrogenases can use which of the following compounds as an electron acceptor?
A. H2O
B. NAD+
C. O2
D. Peroxide
E. None of the above
A

B. NAD+

36
Q
  1. Type II diabetes is often treated with Metformin. Which of the following statements about Metformin action is correct?
    A. It selectively activates glucokinase enzyme
    B. It induces insulin expression
    C. It inhibits glycogen breakdown
    D. It inhibits gluconeogenesis
    E. It activates glycolysis, Krebs cycle, and ETC
A

D. It inhibits gluconeogenesis

37
Q 
37. This is the first of 3 critical enzymes which require ABC (ATP, Biotin, CO2):
A. Pyruvate carboxylase
B. Propionyl CoA carboxylase
C. Acetyl CoA carboxylase
D. None of the above
A

A. Pyruvate carboxylase

38
Q 
38. Fructose 2,6 bisphosphate, an important metabolic intermediate (whose synthesis is turned ON/OFF with insulin), is acting as a potent inhibitor of which of the following enzyme?
A. Fructose 1,6 bisphosphatase 
B. Phosphofructokinase-I
C. Glucokinase
D. Pyruvate kinase
E. None of the above
A

A. Fructose 1,6 bisphosphatase

39
Q 
39. Which of the following controls (respiratory control) the synthesis of ATP during oxidative phosphorylation?
A. NADH
B. FADH2
C. Acetyl CoA
D. ATP
E. ADP
A

E. ADP

40
Q 
40. A 2 yr old boy was brought in the emergency room, suffering from severe hypoglycemia. On physical examination he was found to have hepatomegaly. Laboratory examinations indicated that hepatocytes contained greater than normal amounts of glycogen that was of normal structure. Enzyme assay likely confirmed a deficiency in which of the following enzymes?
A. Glycogen synthase
B. Glycogen phosphorylase
C. Pyruvate Carboxylase
D. Amylo-a(1-6)- glucosidase
E. Glucose 6 phosphatase
A

E. Glucose 6 phosphatase

41
Q 
41. Sudden infant death syndrome (SIDS) isn't any one illness or disease. Rather, it's the diagnosis given when a child under a year old dies suddenly and an exact cause can't be found after a death scene investigation, an autopsy, and a review of the child's medical history. That it can happen without warning makes SIDS particularly devastating for families and is the leading cause of death for babies between 1 month and 1 year old. Which one of the following important metabolic enzymes could be most likely involved in some cases of SIDS patients?
A. Succinate hydrogenase
B. Pyruvate dehydrogenase
C. NADH dehydrogenase
D. Glycogen phosphorylase
E. Fatty acyl CoA dehydrogenase
A

E. Fatty acyl CoA dehydrogenase

42
Q
  1. In the past, 2,4-dinitrophenol an anti-obesity agent was used as a weight reducing drug until side effects like fatigue, breathlessness, and severe hyperthermia precluded its use. What is the mechanism of its action that results in weight loss?
    A. 2,4 dinitrophenol is an allosteric activator of ATP synthase and thus increases the rate of H+ translocation and oxidation of fats and other fuels
    B. 2,4 dinitrophenol inhibits transport of pyruvate into the mitochondria. Fats are therefore metabolized to glycerol and subsequently to pyruvate, depleting fat stores
    C. 2,4 dinitrophenol allows oxidation of fats in adipose tissue without production of ATP. Fat oxidation can thus proceed continuously and fat stores will be used up
    D. 2,4 dinitrophenol causes ATP to be produced at a higher rate than normal, thus causing weight loss
    E. 2,4 dinitrophenol causes ADP to decrease which in turn increases rate of oxidative phosphorylation
A

C. 2,4 dinitrophenol allows oxidation of fats in adipose tissue without production of ATP. Fat oxidation can thus proceed continuously and fat stores will be used up

43
Q 
43. Which of the following is the lysosomal glycogen storage disease?
A. Glycogen storage disease type I
B. Glycogen storage disease type II
C. Glycogen storage disease type III
D. Glycogen storage disease type IV
E. Glycogen storage disease type V
A

B. Glycogen storage disease type II

44
Q 
44. The best example of tissue specific uncoupling agent of oxidative phosphorylation is:
A. Aspirin
B. Thermogenin
C. 2,3 DNP
D. Glycogenin
E. Oligomycin
A

B. Thermogenin

45
Q 
45. Hers IV Glycogen storage disease is due to deficiency of:
A. Muscle glycogen phosphorylase
B. Hepatic glycogen phosphorylase
C. Glycogen synthase
D. Glucose 6 phosphatase
E. None of the above
A

B. Hepatic glycogen phosphorylase

46
Q 
46. For the proper metabolic handling of cells, tissues, and organs, metabolic pathways are tightly regulated by metabolic sensors, allosteric effectors, and long term regulators such as hormones. Notably, hormones play a substantial role for the intergration and regulations of these biochemical pathways. Which of the following metabolic pathway is not under the control of hormones?
A. Glycolysis
B. Krebs cycle
C. Gluconeogenesis
D. Glycogen synthesis
E. None of the above
A

E. None of the above

47
Q 
47. Which of the vitamin deficiency will affect the activity of a-ketoglutarate dehydrogenase?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin B
E. Vitamin E
A

D. Vitamin B

48
Q 
48. What is the normal blood-glucose concentration?
A. 1 mM
B. 3 mM
C. 5 mM
D. 7 mM
E. 9 mM
A

C. 5 mM

49
Q 
49. Which of the following serves third of the 3 critical (substrate level phosphorylation) substrates in the human body?
A. Phosphenol pyruvate
B. 1,3 bisphosphoglycerate
C. Succinyl CoA
D. 2, 3 bisphosphoglycerate
E. None of the above
A

C. Succinyl CoA

50
Q 
50. Glycogen structure is defective in:
A. Von Gierke disease
B. Pompe disease
C. Cori disease
D. McArdle disease
E. Hers disease
A

C. Cori disease

Biochem Exam 2 (1 decks)

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