Glycolysis- Multiple Choice Questions

1). A patient has chronic obstructive pulmonary disease, enough oxygen is not reaching her tissues.  All of the followings are  expected except-

a) The electron transport chain would be inhibited

b) Glycolysis would be activated by a low ATP/ADP ratio

c) More than normal amounts of ATP would be synthesized .

d) Concentrations of NADH and pyruvate would be lower than normal

e) More than normal amounts of lactate would be produced

2). A 45- year- old woman is diagnosed with breast cancer. The oncologist orders a positron emission tomography(PET) scan of the head to rule out metastasis. This imaging modality covalently links a radioactive isotope most commonly to Glucose to appreciate highly active areas in the body such as tumor. Which of the following traps the tracer in the cell ?

a) Insulin

b) GLUT-1

c) GLUT-4

d) Glucokinase

e) PFK-1

3) A 45-year-old obese man complains of having to get up frequently to urinate at night-time. He has also noticed that he is constantly thirsty and hungry. The patient is diagnosed with type 2 diabetes mellitus. If this is a problem at the level of glucose transporters , which tissue would be most affected?

a) Liver

b) Red blood cells

c) Muscle and adipose tissue

d) Brain tissue

e) Small intestine.

4) A 24-year woman is getting training for her first marathon. Her coach instructed her to keep a pace that allows her to stay below her anaerobic threshold. Under such conditions pyruvate does not accumulate as it is converted to-

a) Ethanol

b) Lactic acid

c) Acetyl co A

d) Alanine

e) Oxaloacetate.

5) A patient presents with dizziness, fatigue and tremors. A fingerstick test indicates a blood glucose level of 45 mg/dl (hypoglycemia). Glucagon is released under such condition . Which of the following allosteric modifier of PFK-1 would be  most effective in switching off glycolysis ?

a) Low level of citrate

b) Low level of Fr, 2,6 bisphosphate

c) Low level of ATP

d) Low level of NAD+

e) Low level of Glucose-6-P

6) A 30 -year-old woman is enduring her second trimester of pregnancy. The  greater affinity fetal hemoglobin acquires oxygen released from the lesser affinity maternal hemoglobin due to the effect of an allosteric modifier, which is-

a) Fr-2,6 bisphosphate

b) 2,3 bisphosphoglycerate

c) Citrate

d) Acetyl co A

e) Fr-1,6 bisphosphoglycerate

7) A pediatric hematologist sees an 18 month-old patient with jaundice, splenomegaly and hemolytic anemia. Blood smear indicates red blood cells that are more rigid in appearance than normal. A diagnosis of pyruvate kinase deficiency is made. What products would be made in low amounts ?

a) Acetyl co A

b) Glucose

c) Lactate

d) ATP

e) Alanine

8)  In an embryo with a complete deficiency of pyruvate kinase, how many net moles of ATP would be generated in the conversion of one mole of glucose to one mole of pyruvate ?

a) 0

b) 1

c) 2

d) 3

e) 4

9) Which out of the following enzymes cleaves a carbon-carbon bond in the pathway of glycolysis ?

a) Aldolase

b) Glyceraldehyde-3-P dehydrogenase

c) Enolase

d) Phosphoglycerate kinase

e) Phosphoglycerate mutase

10) After a heavy meal, which out of the following allosteric activator would be most effective in increasing the rate of glycolysis ?

a) ATP

b) Citrate

c) Acetyl co A

d) Fr-2,6 bisphosphate

e) 2,3 bisphosphoglycerate.

11) Compared with the resting state a vigorously contracting muscle shows-

a) An increased conversion of pyruvate to lactate

b) Increased oxidation of pyruvate to CO2

c) A decreased concentration of AMP

d) Decreased level of fr-2,6 bisphosphate

e) Decreased ratio of NADH/NAD+

12) A 24 -year-old man presented with symptoms of shortness of breath, weakness and fatigue. His Hemoglobin level was 7G/dl. Red blood cell isolated from the patient showed abnormally low-level of lactate. A deficiency of which of the following enzymes would be the most likely cause for patient’s anemia?

a) Phosphoglucose isomerase

b) Phosphofructokinase

c) Hexokinase

d) Glucokinase

e) Pyruvate kinase.

13) A mixture of sodium fluoride and potassium oxalate is added to sample collected for blood glucose estimation to prevent loss of glucose by anaerobic glycolysis. Fluoride is an inhibitor of glycolysis. Which of the following enzymes is inhibited by fluoride ?

a) Hexokinase

b) Phosphofructokinase

c) Glyceraldehyde-3-P dehydrogenase

d) Lactate dehydrogenase

e) Enolase

14) Oxamate is a competitive inhibitor of which of the following enzymes ?

a) Hexokinase

b) Phosphofructokinase

c) Glyceraldehyde-3-P dehydrogenase

d) Lactate dehydrogenase

e) Pyruvate dehydrogenase

15)  Which out of the following enzymes of glycolysis is inhibited by Arsenate ?

 a) Hexokinase

b) Phosphofructokinase

c) Glyceraldehyde-3-P dehydrogenase

d) Lactate dehydrogenase

e) Pyruvate dehydrogenase

Answers-

1)-e                2)-b                3)-c                 4)-c                 5)-b                6)-b              



7)-d                8)-a                9)-a                10)-d              11)-a              12)-e



13)-e              14)-d              15)-c



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TCA Cycle- Multiple Choice Questions

1) A 24-year-old woman presents with diarrhea, dysphagia, jaundice and white transverse lines on the fingernails (Mee’s lines). The patient is diagnosed with Arsenic poisoning,that inhibits which of the following enzymes of TCA cycle ?

a) Citrate synthase

b) Isocitrate dehydrogenase

c) α-Keto glutarate dehydrogenase complex

d) Succinate dehydrogenase

e) Malate dehydrogenase

2)  A biochemistry graduate student  isolated all enzymes of TCA cycle to produce NADH, oxidation of which of the following substrates in the citric acid cycle is not coupled to the production of NADH ?

a) Succinate

b) Malate

c) α-Keto glutarate

d) Isocitrate

e) Pyruvate.

3) A 3-Year-old boy presents to the pediatric clinic with the symptoms of hypotonia, lactic acidosis, and seizures. After an extensive workup , he is diagnosed with pyruvate dehydrogenase complex deficiency. Which of the following cofactors is not required by this enzyme to convert pyruvate to Acetyl co A ?

a) Thiamine

b) Lipoic acid

c) Pantothenic acid

d) Niacin

e) Ascorbic acid.

4) Which of the following vitamins is required for the synthesis of a cofactor required for the conversion of Succinate to Fumarate?

a) Thiamine

b) Lipoic acid

c) Pantothenic acid

d) Niacin

e) Riboflavin.

5) Pyruvate dehydrogenase complex deficiency is an autosomal recessive disorder and leads to anion gap metabolic acidosis. Which of the following accumulates  to cause metabolic acidosis ?

a) Beta hydroxy butyric acid

b) Acetoacetic acid

c) Fumaric acid

d) Lactic acid

e) Hydrochloric acid.

6) A 3 year-old child presents with a history of recurrent rash upon sun exposure and passage of purple colored urine. The child is diagnosed  with  Congenital Erythropoietic  Porphyria, a disorder of pathway of haem biosynthesis. Which of the following intermediates of TCA cycle is used as a precursor for  haem biosynthesis ?

a) Succinyl co A

b) Acetyl co A

c) Succinate

d) Malate

e) Pyruvate

7) A 16 -year-old male comes to the clinic for a routine sports physical examination. His physical examination is unremarkable except for the skin findings of multiple pale masses which appear to be xanthomas. Xanthomas are generally associated with the underlying hypercholesterolemia. Which of the followings is utilized as a precursor for cholesterol biosynthesis ?

a) Succinyl co A

b) Acetyl co A

c) Succinate

d) Malate

e) Pyruvate.

8) A 2-year-old child was brought to pediatric emergency with convulsions. The child was diagnosed with ammonia intoxication due to some urea cycle disorder. Reduced formation of GABA  is considered to be the most important cause of convulsion due to depletion of glutamate from where it is produced by decarboxylation. Which of the following intermediates of TCA cycle is involved in the formation of Glutamate ?

a) Succinate

b) Malate

c) α-Keto glutarate

d) Isocitrate

e) Pyruvate.

9) In TCA cycle , GTP is produced at one step by substrate level phosphorylation and that is subsequently utilized for Gluconeogenesis. Which of the following enzymes is involved in this process of formation of GTP from GDP ?

a) Succinate Thiokinase

b) Succinate dehydrogenase

c) Citrate synthase

d) Isocitrate dehydrogenase

e) Malate dehydrogenase

10) A  5-year-old child was rushed to pediatric emergency as he accidently consumed Fluoroacetate, a known inhibitor of TCA cycle. Which of the following enzymes is inhibited by  fluoroacetate?

a) Citrate synthase

b) Aconitase

c)  Succinate dehydrogenase

d) Isocitrate dehydrogenase

e) Malate dehydrogenase.

11) Malonate is an inhibitor of-

a) Citrate synthase

b) Aconitase

c)  Succinate dehydrogenase

d) Isocitrate dehydrogenase

e) Malate dehydrogenase.

12) A 56-year- old chronic alcoholic has been  brought in a semiconscious state to the medical emergency. Blood biochemistry reveals hypoglycemia  with blood glucose level of 45 mg/dl. Which of the following intermediates of TCA cycle can be directly converted to phosphoenolpyruvate to trigger the pathway of gluconeogenesis ?

a) Succinate

b) Malate

c) α-Keto glutarate

d) Oxaloacetate

e) Pyruvate.

13) A 78-year-old male is brought to emergency with Acute myocardial infarction. Blood biochemistry reveals lactic acidosis. How much energy yield (ATP) per mol of glucose is expected in such a condition?

a) 32

b)2

c) 34

d) 36

d) 38

14) Which of the following allosteric modulators  is not effective in influencing the rate of TCA cycle ?

a) NADH

b) FADH2

c) Ca++

d) ADP

e) ATP

15)  How many molecules of CO2 are produced per mole of Acetyl co A in TCA Cycle ?

a) 2

b) 1

c) 3

d) 0

e) 4

16) The cytosolic isoform of which of the following TCA cycle enzymes requires NADP+ as a coenzyme, that can further be utilized in the reduced state for reductive biosynthesis?

a) Citrate synthase

b) Aconitase

c)  Succinate dehydrogenase

d) Isocitrate dehydrogenase

e) Malate dehydrogenase.

17) Which of the following intermediates of TCA cycle is depleted  in Type 1 Diabetes mellitus to suppress TCA cycle and to channel excess Acetyl co A towards pathway of ketogenesis ?

a) Succinate

b) Malate

c) α-Keto glutarate

d) Oxaloacetate

e) Pyruvate.

18)- Which of the following enzymes is Thiamine dependent and essential for glucose oxidation in the brain?

a) Pyruvate dehydrogenase complex                  

b) Acetyl co A carboxylase

c) Transaldolase                                              

d) Succinyl-co A Thiokinase

e) Succinate dehydrogenase    

19)-Anaplerotic reactions are those that result in replenishing intermediates in the TCA cycle. Which of the following enzymes catalyzes an anaplerotic reaction?

a) Malate dehydrogenase

b)Pyruvate carboxylase

c) Pyruvate kinase

d) Citrate synthase

e) Succinyl-co A Thiokinase



20) -Which of the following intermediates of TCA cycle cannot be utilized for gluconeogenesis ?

a) Succinate

b) Malate

c) α-Keto glutarate

d) Oxaloacetate

e) Acetyl co A.



Answers-1)-c                     2)-a                        3)-e                        4)-e                        5)-d                        6)-a                      

                7)-b                        8)-c                        9)-a                        10)-b                     11)-c                      12)-d

                13)-b                     14)-b                     15)-a                      16)-d                     17)-d                     18)-a

                19)-b                     20)-e                  











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Gluconeogenesis- Multiple Choice Questions

1)  A 4-month-old boy is being evaluated for seizures, psychomotor retardation, and hypotonia. Work up reveals elevated serum levels of lactate, alanine, pyruvate and keto acids. Based on the clinical presentation,pyruvate carboxylase activity is measured using fibroblasts from a skin biopsy and is found to be markedly decreased. This enzyme is normally used to directly synthesize which of the following molecules ?

a) Pyruvate

b) Oxaloacetate

c) Malate

d) Acetyl co A

e) α- Keto glutarate

2) A 34-year-old woman presents with central obesity, relatively thin extremities and purple stria on her abdomen. Further work up reveals an excessive serum cortisol level and a blood sugar level of 258 mg/dl. Which of the following is the most likely cause of her hyperglycemia ?

a) Excessive consumption of processed carbohydrates

b) A pancreatic adenoma secreting  ACTH and glucagon

c) Cortisol induced inhibition of insulin

d) Glucorticoids cause induction of Phosphoenolpyruvate carboxy kinase gene

e) Increased gluconeogenesis due to increased provision of substrates through fatty acid oxidation.

3) A 56-year-old, obese man complains of polydipsia, polyuria and fatigue. A glucose tolerance test confirms the diagnosis of diabetes. He is placed on Metformin, which works by which of the following mechanisms ?

a) Inhibiting hepatic gluconeogenesis

b) Increasing glucagon level

c) Increasing cellular responsiveness to circulating insulin

d) Stimulating the release or preformed insulin

e) Replacing the need for endogenous insulin

4) An enzyme used in both glycolysis and gluconeogenesis is:

a) 3-phosphoglycerate kinase.

b) Glucose 6-phosphatase

c) Hexokinase

d) Phosphofructokinase-1

e) Pyruvate kinase

5) Which one of the following statements about gluconeogenesis is false?

a) For starting materials, it can use carbon skeletons derived from certain amino acids.

b) It consists entirely of the reactions of glycolysis, operating in the reverse direction.

c) It employs the enzyme glucose 6-phosphatase.

d) It is one of the ways that mammals maintain normal blood glucose levels between meals.

e) It requires metabolic energy (ATP or GTP).

6) All of the following enzymes involved in the flow of carbon from glucose to lactate (glycolysis) are

also involved in the reversal of this flow (gluconeogenesis) except:

a) 3-phosphoglycerate kinase.

b) Aldolase

c) Enolase

d) Phosphofructokinase-1

e) Phosphohexoseisomerase

7) In humans, gluconeogenesis:

a) can result in the conversion of protein into blood glucose.

b) helps to reduce blood glucose after a carbohydrate-rich meal.

c) is activated by the hormone insulin

d) is essential in the conversion of fatty acids to glucose.

e) requires the enzyme hexokinase.

8) Which of the following substrates cannot contribute to net gluconeogenesis in mammalian liver?

a) Alanine

b) Glutamate

c) Palmitate

d) Pyruvate

e) α-Keto glutarate.

9) A 6-year-old boy begins playing soccer in a community league. After his first game of the year, he is brought to see his pediatrician because of his severe muscle cramps and blood in urine. He is subsequently found to be having deficiency of lactate dehydrogenase. This enzyme is important in which of the following conversions ?

a) Pyruvate to Acetyl co A

b) Pyruvate to Oxaloacetate

c) Pyruvate to Alanine

d) Pyruvate to Phosphoenol pyruvate

e) Pyruvate to lactate

10) A new-born infant is found to be having persistent hypoglycemia, despite decreased feeding intervals. The child is also irritable with a moderate degree of hepatomegaly. He is found to have a normal level of muscle fructose 1,6 bisphosphatase but decreased level of liver isoform. Which of the following statement is true of fructose 1,6 bisphosphatase?

a) It is induced by Adenosine mono phosphate (AMP)

b) It is induced by Insulin

c) It is inhibited by Fructose 2,6 bisphosphate

d) It is induced in the fed state

e) It is inhibited during fasting.

11) A 14-year-old  high school girl who is extremely conscious about her appearance has gone a full day fasting to fit in to a dress she intentionally brought a size smaller than her actual size for a dance party. Which of the following organs/tissues contributes to the glucose  that is being synthesized through gluconeogenesis ?

a) Spleen

b) Red blood cells

c) Skeletal muscle

d) Liver

e) Brain

12) An 8 -year-old boy presents with frequent episodes of weakness, accompanied by sweating and feelings of dizziness. Physical examination is remarkable for palpably enlarged liver and kidneys. Blood biochemistry reveals lactic acidemia. The patient is diagnosed with deficiency  of glucose-6-phosphatase, which is normally only expressed in-

a) Liver and muscle

b) Liver and brain

c) Erythrocytes

d) Liver and adipose tissues

e) Liver and kidney.

13)  A 32-year-old body builder has decided to go on a diet consisting of egg whites to ensure only proteins for muscle growth. After a few weeks he experiences  decreased energy and is found to be hypoglycemic. A nutritionist tells the patient that he most likely has the deficiency of vitamin Biotin. Which of the following enzymes is unable to catalyze its step in synthesizing glucose from pyruvate?

a) Pyruvate carboxylase

b) Phospho enol pyruvate carboxy kinase

c) Glucose-6-phosphatase

d) Fr 1,6 bisphosphatase

e) Phosphoglycerate kinase.

14) In an individual at rest, who has fasted for 12 hours, which of the following occurs ?

a) Gluconeogenesis is the major process by which blood glucose is maintained

b) Liver glycogen stores are depleted

c) Glycogen synthase is activated in liver

d) Adenylate cyclase is inactivated in liver

e) Phosphorylase, pyruvate kinase and glycogen synthase are phosphorylated in liver.

15) Which of the following is a common intermediate in the conversion of glycerol and lactate to glucose ?

a) Pyruvate

b) Oxaloacetate

c) Malate

d) Glucose-6-phosphate

e) Phosphoenolpyruvate.

16) In the conversion of pyruvate to glucose during gluconeogenesis,

a) Biotin is required

b) CO2 added in one reaction, appears in the final product

c) Energy is used up in the form of GTP

d) All the reactions take place in the cytosol

e) PDH is the allosteric enzyme used.

17) Which of the following glycolytic enzymes is used in gluconeogenesis ?

a) Glucokinase

b) Phosphofructokinase-1

c) Aldolase B

d) Phosphoglycerate kinase

e) Pyruvate kinase.

18) The conversion of pyruvate to fructose 1,6 bisphosphate by the gluconeogenic pathway involves which of the followings ?

a) Requires lactate dehydrogenase

b) Requires hexokinase

c) Produces 2 ATP and 2GTP

d) Requires 4 ATP and 2 GTP

e) Acetyl co A is not required to activate this pathway.

19) A high ratio of insulin to glucagon can:

a) Promote gluconeogenesis

b) Promote glycogenolysis

c) Found in Type 1 Diabetes Mellitus

d) Occurs during fasting state

e) Promotes synthesis of  Glycogen

20) Which of the followings is a precursor for gluconeogenesis ?

a) Glycogen

b) Glycerol

c) Glucagon

d) Galactose

e) Glucose-1- P.



Answers-  1)-b ,  2)-d,  3)-a,  4)-a,  5)-b,  6)-d,  7)-a,  8)-c,  9)-e,  10)-c,  11)-d,  12)-e,  13)-a,  14)-e,  15)-d,  16)-a ,17)-d,  18)-d,

19)-e,  20)-b.



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Multiple choice Questions- Pentose phosphate pathway

1) Glucose breakdown in certain mammalian and bacterial cells can occur by mechanisms other than classic glycolysis. In most of these, glucose 6-phosphate is oxidized to 6- phosphogluconate, which is then further metabolized by:

a) an aldolase-type split to form glyceric acid and glyceraldehyde 3-phosphate.

b) an aldolase-type split to form glycolic acid and erythrose 4-phosphate.

c) conversion to 1,6-bisphosphogluconate.

d) decarboxylation to produce keto- and aldopentoses

e) oxidation to a six-carbon dicarboxylic acid.

2) Which of the following enzymes acts in the pentose phosphate pathway?

a) 6-phosphogluconate dehydrogenase

b) Aldolase

c) Glycogen phosphorylase

d) Phosphofructokinase-1

e) Pyruvate kinase

3) The oxidation of 3 mol of glucose by the pentose phosphate pathway may result in the production of:

a) 2 mol of pentose, 4 mol of NADPH, and 8 mol of CO2.

b) 3 mol of pentose, 4 mol of NADPH, and 3 mol of CO2.

c) 3 mol of pentose, 6 mol of NADPH, and 3 mol of CO2.

d) 4 mol of pentose, 3 mol of NADPH, and 3 mol of CO2.

e) 4 mol of pentose, 6 mol of NADPH, and 6 mol of CO2.

4) In a tissue that metabolizes glucose via the pentose phosphate pathway, C-1 of glucose would be expected to end up principally in:

a) Carbon dioxide

b) Glycogen

c) Phosphoglycerate

d) Pyruvate

e) Ribulose 5-phosphate

5) The main function of the pentose phosphate pathway is to:

a) give the cell an alternative pathway should glycolysis fail

b) provide a mechanism for the utilization of the carbon skeletons of excess amino acids

c) supply energy

d) supply NADH

e) supply Pentoses and NADPH

6) Which of the following statements about the pentose phosphate pathway is correct?

a) It generates 38 mol of ATP per mole of glucose consumed.

b) It generates 6 moles of CO2 for each mole of glucose consumed

c) It is a reductive pathway; it consumes NADH.

d) It is present in plants, but not in animals.

e) It provides precursors for the synthesis of nucleotides.

7) The reactions of the pentose phosphate pathway using glucose-6 phosphate as the initial substrate are best described by which of the following statements ?

a) They produce 2 moles of NADPH for each mole of CO2 released.

b) They generate 2 moles of adenosine triphosphate per mole of glucose-6-phosphate metabolized to ribulose-5 phosphate.

c) They occur in the matrix of mitochondria.

d) They are not required for the production of NADPH in the mature red blood cells

e) They are required for the  metabolism of glucose in the muscles.

8) In the pentose phosphate pathway, the major products are which of the followings ?

a) Ribulose and ATP

b) Ribulose and NADPH

c) Ribose and NADH

d) Ribose and NAD+

e) Xylulose and ATP

9) Which of the following statements about the oxidative section of the pentose phosphate pathway is correct?

a) The pentose phosphate pathway generates NADH.

b) The pentose phosphate pathway oxidizes NADPH to NADP+

c) The rate-limiting reaction of the pentose phosphate pathway is catalyzed by glucose-6-phosphatase.

d) The pathway supplies ribose-5-phosphate and NADPH in the quantities the cells requires.

e) The pathway is highly active in the fasting state.

10) Which of the following statements about the nonoxidative section of the pentose phosphate pathway is correct?

a) The nonoxidative reactions of the pentose phosphate pathway are not reversible.

b) Transketolase is an enzyme that transfers three-carbon units in the pentose phosphate pathway

c) Transaldolase is an enzyme that transfers two-carbon units in the pentose phosphate pathway

d) Pentoses can provide glycolytic intermediates in this phase of HMP pathway

e) Pentoses can be metabolized to provide NADPH in this phase of HMP pathway.

11) Which of the following statements about the use of the NADPH generated from the pentose phosphate pathway is not correct?

a) NADPH generated from the pentose phosphate pathway is used for steroid synthesis.

b) NADPH generated from the pentose phosphate pathway is used for the regeneration of glutathione to its reduced state.

c) NADPH generated from the pentose phosphate pathway is used for the synthesis of fatty acids

d) NADPH generated from the pentose phosphate pathway can be oxidized in the electron transport chain to provide 38 ATPs

e) NADPH generated from the pentose phosphate pathway is used for the Macrophageal functions.

12) A 19- year-old, African-American male military recruit is about to be sent to Iraq on his assignment. In preparation for his tour of duty, he is given a prophylactic dose of primaquine to prevent malaria. Several days after he develops fatigue and hemolytic anemia. Which of the following enzymes is likely deficient ?

a) Fructokinase

b) Aldolase B

c) Glucose-6-P dehydrogenase

d) Galactokinase

e) Galactosyl Transferase.

13) A 50 -year-old alcoholic male presents with pain, numbness, tingling and weakness in his feet. He is diagnosed with thiamine deficiency. Thiamine and ATP condense together to form   thiamine pyrophosphate, a cofactor important for the enzymes that catalyze oxidative decarboxylation of (α-keto acids) in the TCA cycle and also at one of the steps in pentose phosphate pathway, which out of the following enzymes requires TPP as a coenzyme ?

a) Glucose-6-P dehydrogenase

b) Transaldolase

c) Transketolase

d) 6-P-Gluconate dehydrogenase

e)  Gluconolactone hydrolase.

14) The key regulatory enzyme of HMP pathway is-

a) Glucose-6-P dehydrogenase

b) Transaldolase

c) Transketolase

d) 6-P-Gluconate dehydrogenase

e)  Gluconolactone hydrolase.

15) Xylulose 5-phosphate can be formed from Ribulose 5-phosphate by the action of-

a) Glucose-6-P dehydrogenase

b) Transaldolase

c) Transketolase

d) Phosphopentose epimerase

e)Phosphopentose isomerase.

16)-The pentose phosphate pathway is active in liver, adipose tissue, adrenal cortex, thyroid, erythrocytes, testis, and lactating mammary gland. Why is the pathway less active in skeletal muscle?

a) Muscle tissue contains very small amount of dehydrogenases

b) Muscle tissues do not require NADPH

c) Pentoses the major product of this pathway are not required by muscle tissue

d) Muscle tissue contains very small amount of enzymes of non oxidative phase

e) All of the above.

17) In rapidly dividing cancer cells the need for large amount of ribose is fulfilled by-

a) Highly active Glucose-6-P dehydrogenase

b) Highly active Transaldolase

c) Highly active Transketolase

d) Highly active 6-P-Gluconate dehydrogenase

e) Reversal of non oxidative phase using glycolytic intermediates.



 Answers-        1)-d                2)-a                  3)-c                  4)-a                  5)-e                

                        6)-b                 7)-a                  8)-b                 9)-d                 10)-d

                        11)-d               12)-c                13)-c                14)-a                15)-d

                        16)-a                17)-e



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Glycogen Metabolism- Multiple Choice Questions

1) An infant presents with an enlarged heart, muscle weakness, and hypoventilation. She is diagnosed with glycogen storage disease type II, a disease-causing, abnormal glycogen storage in the heart, skeletal muscle and respiratory  muscles. Glycogen synthase is the regulatory enzyme for glycogen synthesis. It adds glucose residues to the nonreducing ends of a glycogen primer from:

a) Glucose-1-P

b) Glucose-6-P

c) UDP- Glucose

d) UTP

e) ATP.

2) A 30- year-old male presents with severe muscle cramps. He is found to have muscle glycogen phosphorylase deficiency(Mc Ardle’s disease, Glycogen storage type 5).Glycogen phosphorylase degrades glycogen to produce-

a) Glucose

b) Glucose-1-P

c) Glucose-6-P

d) UDP Glucose

e) Glycogen Primer

3) A 15-year-old  type 1 diabetic faints after injecting himself  with insulin. He is administered Glucagon  and rapidly recovers consciousness. Glucagon induces activity of:

a) Glycogen synthase

b) Glycogen phosphorylase

c) Glucokinase

d) Hexokinase

e) UDP Glucose pyrophosphorylase.

4) A 30-year-old presents with intractable vomiting and inability to eat or drink for the past 3 days. His blood glucose level is normal. Which of the following is most important for maintenance of blood glucose ?

a) Liver

b) Heart

c) Skeletal muscle

d) Lysosome

e) Spleen.

5) Shortly after birth, an infant presents with tremors, irritability and seizures. His blood glucose is profoundly low, and he is fed through a nasogastric tube. he is diagnosed with glycogen storage disease type I, a disease that causes excessive build up of liver glycogen, resulting in abnormally low blood glucose level. In glycogen, the linkage at branch points is:

a) α -1,4

b) α-2,3

c) α-1,6

d) β-1,4

e) β-2,3.

6) A 15-year-old male presents with increased thirst, hunger, urination, and weight loss. His fasting blood glucose level is 400 mg/dl and is diagnosed with type 1 diabetes mellitus. What is the reason for this patient’s inability to maintain a normal blood glucose level ?

a) Decreased uptake  of glucose by peripheral cells

b) Abnormal response to glucagon

c) Decreased glucagon to insulin ratio

d) Decreased glucose output by the liver

e) Increased ketone body production.

7) Which enzyme is not present in muscle ?

a) Phosphorylase b

b) Hexokinase

c) Glucose-6-phosphatase

d) Glycogen synthase

e) Lactate dehydrogenase

8) Glycogenolysis is best described by which of the following statements ?

a) It involves enzymes cleaving β, 1-4 glycosidic linkage

b) Requires activation of glycogen synthase

c) Requires a dual action enzyme α-1,4 glycosidase and transferase

d) Uses ATP to produce glucose-1-P

e) Requires inactivation of phosphorylase kinase.

9) Glycogenesis from Glucose-1-P requires which of the followings ?

a) Phosphoglucomutase

b) Uridine triphosphate (UTP)

c) α-1,6 glucosidase

d) Glycogen primer

e) Uridine diphosphate

10) In glycogen, glucose residues form a straight chain via which of the followings-

a) α -1,4 linkages

b) α -1,6 linkages

c) α -1,4 linkages with glycogenin at the non reducing end

d) α -1,6 linkages with UDP glucose at any end

e) straight chain occurs at 3 residues apart

11) In the liver Epinephrine induced glycogenolysis :

a) Requires UDP glucose pyrophosphorylase

b) Requires Phosphoglucomutase

c)Requires inactivation of phosphorylase a

d) Inhibited by c AMP

e) acts upon both liver and muscle cells, similar to glucagon.

12) Glycogen catabolism is best described by which of the following statements-

a) In the brain, it yields glucose for skeletal muscle consumption

b) It requires a debranching enzyme in the erythrocytes

c) It is not a major pathway in the brain

d) It uses phosphorylase for glucose residue cleavage from the reducing end of glycogen in liver

e) It is stimulated by Insulin in liver.

13) During the breakdown of glycogen, free glucose is formed from which of the following ?

a) Glucose residues in α-1,4 glycosidic linkages

b) The reducing end

c) The non reducing end

d) Glucose residues in  α-1,6 glycosidic linkages

e) Hydrolysis of glucose-1-P

14) Which of the following statements explains the synthesis of glycogen directly from D- Glucose ?

a) It does not use glucose-1-P

b) It requires a debranching enzyme

c) It occurs in erythrocytes.

d) It requires UDP-Glucose

e) It requires a glucosyl transferase

15)The degradation of glycogen normally produces which of the followings ?

a) More glucose than Glucose-1-P

b) More Glucose-1-P than Glucose

c) Equal amount of Glucose and Glucose-1-P

d) Neither Glucose nor Glucose-1-P

e) Only Glucose-I-P

16) Which of the following statements about liver phosphorylase kinase is most accurate ?

a) It is present in the inactivated form when epinephrine is released

b) It phosphorylates phosphorylase to make it inactive

c) It is stimulated by c AMP mediated phosphorylation cascade

d) It is not affected by ATP

e) It is phosphorylated in response to Insulin.

17) A newborn is found to have fasting hypoglycemia. The nursery staff begins overnight feeds by nasogastric tube because they find that the child consistently has low blood glucose. A liver biopsy and molecular studies demonstrate an absence of Glycogen synthetase. The normal function of this enzyme is to do which of the followings ?

a) Remove glucose residues one at a time from glycogen in liver

b) Remove glucose residues one at a time from glycogen in muscles

c) Transfer UDP glucose to the non reducing end of glycogen primer

d) Hydrolyze α-1,6 bonds of glycogen

e) Function as a glucosyl 4:6 transferase.

18) A 3-year-old child presents to the pediatrician for failure to thrive. A workup including an ultrasound of his liver shows cirrhosis. A biopsy of liver demonstrates a deficiency of an enzyme involved in glycogen synthesis. Which of the following is the most likely glycogen storage disease ?

a) Type I -Von Gierke’s disease

b)Type II – Pompe’s disease

c) Type III- Cori’s disease

d) Type IV- Andersen’s disease

e) Type V- McArdle disease

19) A new-born is experiencing failure to thrive. On physical examination, organomegaly is appreciated due to accumulation of glycogen in the lysosomes of several organs, including the heart, muscle and liver. A diagnosis of Pompe’s disease is made. Which of the following biochemical deficits are seen in this disorder ?

a) Glycogenin deficiency

b) An α-1,6 glycosidase deficiency

c) A glucose-6-phosphatase deficiency

d) A glycogen phosphorylase deficiency

e) A lysosomal glucosidase deficiency

20) A second year medical student decides to do research in a nutrition laboratory that is studying the effect of caffeine on cellular metabolism. Caffeine inhibits cAMP phosphodiesterase. If  caffeine is added to cells, which of the following enzymes is  phosphorylated and inactivated in liver ?

a) Phosphorylase kinase

b) Calmodulin

c) Phosphorylase

d) Protein kinase A

e) Glycogen synthase

21) A 28-year-old professional cyclist has been training for an opportunity to go for a long race. His coach strongly suggests the intake of carbohydrates after the work out to ensure a  muscle glycogen storage that can endure the 28-day race. The activity of muscle glycogen synthase in resting muscles is increased by the action of which of the followings?

a)Epinephrine

b) Glucagon

c) Insulin

d) Phosphorylation

e) Fasting and starvation.

22) An infant was brought in to the emergency room after her parents witnessed her having seizures. The child’s blood glucose was 28mmol/L. After a thorough workup, a GSD  was suspected, and a muscle biopsy was significant for the accumulation of dextrin, a form of glycogen with branching limited to only a few glucose molecules. Which of the following GSD is most likely the cause of hypoglycemia and subsequent seizures ?

a) Type I -Von Gierke’s disease

b)Type II – Pompe’s disease

c) Type III- Cori’s disease

d) Type IV- Andersen’s disease

e) Type V- McArdle disease



Answers- 1) c,   2)-b,      3)-b,      4)-a,       5)-c,       6)-a,       7)-c,       8)-c,       9)-d        10)-a

                11)-b,    12)-c,     13)-d,    14)-d,    15)-b,    16)-c,     17)-c,     18)-d,    19)-e,    20)-e,

                21)-c,     22)-c.












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amino acids

1. Why are amino acids called as Amino acids?

(Since they have an amino group and an acid group i.e. Carboxyl group which is ionized at the physiological p H and behaves as a proton donor and is thus an acid)

 2- What is meant by primary amino acids?

(Those amino acids which have a genetic information on the DNA for their synthesis are called as Primary or standard amino acids)

3- What is the linkage between the amino acids in a peptide?

(The amino acids are linked together by a peptide bond which is an anhydrous linkage between the amino acids)

4- Name the amino acids which are derived or modified after translation but are not incorporated in to the tissue proteins.

 (Homocysteine, GABA, Argino succinic acid, Ornithine, Citrulline, etc)

5- Define Denaturation

 ( It is the loss of secondary , tertiary or quaternary structure( if present ) of a protein on exposure to heat, UV light, acids, alkalies, heavy metal salts or even by vigorous shaking, the primary structure is left intact)

6-What is meant by a complete protein, give an example of a complete protein?

( A Complete protein contains all the essential amino acids in an appropriate amount  required for growth, repair and maintenance of body weight.  Example -Egg protein)

7- Give an example of a protein with axial ratios >10:1

(Fibrinogen, keratin, collagen )

8-How many amino acids can be accommodated in one turn of alpha helix?

(3.4 amino acids)

 9- What are chaperones?

 (These are the proteins which participate in the proper folding of the proteins)

10- What is the defect in “transmissible spongiform encephalopathies’?

(These are included under the category of Prion’s diseases and are fatal neurodegenerative diseases characterized by spongiform changes, astrocytic gliomas, and neuronal loss resulting from the deposition of insoluble protein aggregates in neural cells. The protein aggregates are formed of misfolded proteins.)

11-What is the difference between a homodimer and a heterodimer?

(Homodimer contains two copies of the same polypeptide chain, while in a heterodimer the polypeptides differ)

12-What are amphipathic helices?

(The alpha helices having predominantly hydrophobic R groups on one side of the axis of the helix and predominantly hydrophilic ones on the other side are called amphipathic helices)

13-All the amino acids except——- have a chiral centre.

 (Glycine)

14-What is meant by isoelectric  p H ?

 ( It is the p H at which amino acid carries no net electrical charge)

15-Proteins contain only D-amino acids, for which a left handed alpha helix is by far the more stable,  thus only left-handed helices are present in proteins. True or false?

 (False –Proteins contain only L-amino acids, for which a right-handed alpha helix is by far the most stable, and only right-handed alpha helices are present in proteins)

16-Give examples of metalloproteins-

( Alcohol dehydrogenase, glutamate dehydrogenase, Xanthine oxidase  etc. are the examples of metalloproteins

17-Give examples of non standard amino acids which are incorporated in to tissue proteins.

( Hydroxy proline, hydroxy lysine )

18– What is meant by zwitterion ?

( It is the form of amino acid present at its isoelectric p H,  both positive  and negative charges are there but the net charge is zero)

19-Name an indole ring containing amino acid-

(Tryptophan

20- Name the peptides which act as gastro intestinal hormones-

( Secretin, pancreozymin and cholecystokinin)

21- Name the amide group containing amino acids

(Asparagine, Glutamine)

22- What are derived proteins ?

(Proteoses, peptones and peptides etc, the product of digestion and denaturation are called as derived proteins )

23- Give two examples of antibiotic peptides

(Polymyxin, Penicillin, etc )

24-What is the difference between cysteine and cystine ?

( Two cystine residues are joined together by a disulfide bridge to from cystine )

25- What are histones?

( Histones are simple proteins which can bind with DNA to form nucleoproteins, generally they are rich in basic amino acids like Arginine and lysine )

26- Which amino acid disrupts the alpha helical structure of the proteins ?

( Proline and hydroxy proline )

27- Name the components of Glutathione

(Glutamic acid, cysteine and glycine )

28- Name two proteins with a quaternary structure

( Immuno globulins, Hemoglobin, CPK , LDH etc )

29- What are brain peptides ?

( Met encephalin and Leuencephalin)

30- Name a Phospho protein

(Casein, Ovovitellin)

31-What is the product formed after decarboxylation of an amino acid ?

( Amines are formed after decarboxylation of amino acids- like Tryptamine, histamine Tyramine etc)

32-Name the sulphur-containing amino acids-

(Cysteine, cystine and Methionine)

33-Choose the aromatic amino acid out of the following-

Arginine, Histidine, lysine and Tyrosine —— (Tyrosine)

34-Choose an amino acid that does not participate in the alpha helical formation-

Methionine, tryptophan, serine, cysteine——

( Tryptophan )

 35- Millon’s reaction is specific for——- ?      

( Tyrosine )

36- Out of the followings which amino acid is not present in the proteins?

β- Alanine, Histidine, Glycine                  

(β- Alanine)

 37- Name a peptide which acts as a smooth muscle relaxant

( Bradykinin)

38-   What is the nature of prosthetic group in Ceruloplasmin ?

(Copper- It is metalloprotein)

 39- What is a nutritionally poor protein ?Give an example-

( A protein which lacks many essential amino acids is called a poor protein, E.g.- Gelatin

 40- Which protein is abundantly present in hair?    

(Keratin )

41-What is the significance of Biuret test?

 ( It is for the detection of proteins and peptides. Dipeptides and amino acids do not give this test positive, more than two peptide bonds are required for this test to be positive )

42- What is the nature of casein, the milk protein?

( It is a Phospho protein- A conjugated protein)

 43- What is the axial ratio in fibrous proteins?

 ( > 10:1)

 44- In proteins the alpha helical and beta pleated sheet structures are examples of-

Primary, secondary or tertiary structure ?          

( Secondary)

 45- Name an Imidazole ring containing amino acid

(Histidine)

46- Name a peptide  hormone which prevents diuresis –

( ADH)

47 What is the basis of using raw egg for heavy metal poisoning ?

( Egg protein binds with heavy metal to form metal proteinate complex, which is water-soluble and is excretable, else heavy protein binds with tissue proteins to cause damage)

48- The tertiary structure of a protein describes sequence of amino acids- true or false ?

( False- Tertiary structure describes the folding of the protein )

49- Give two examples of haemoproteins.

(Hemoglobin, Myoglobin, Cytochromes, Catalase, Peroxidase and Tryptophan Pyrrolase)

50-  In a protein the disulphide bridges can be broken by–

 ( Reduction )


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Chemistry Of Proteins

1- What is the nature of a prosthetic group in a lipoprotein?

 (Lipoprotein is a conjugated protein with lipid as a prosthetic group)

 2- What is the significance of Sakaguchi test?

 (This test is undertaken for the detection of Arginine)

 3- What is the distance traveled per turn in an alpha helix?

 (0-54 nm)

 4- Name an imino acid.

 (Proline, hydroxy proline)

 5-Choose the chromo protein out of the followings-

 Collagen, Keratin, hemoglobin                      

 (Hemoglobin)

 6-Carbonic anhydrase is an example of simple or conjugated protein?

 (It is a conjugated protein, with metal as th prosthetic group)

 7- Name a peptide which acts as an artificial sweetener.

 (Aspartame)

 8- Name the agents which can bring about denaturation of proteins

 (Heat, acids, alkalis, heavy metal salt, UV light, vigorous shaking etc)

 9- Name a tripeptide which acts a reducing agent in the tissues.

 (Glutathione)

 10- Name a peptide which acts as vasoconstrictor

 (Angiotensin-II)

 11- Name the amino acid which is deficient in pulses

 (Methionine)

 12- Choose the odd one out- Collagen, Elastin, Keratin, Histones

 (Histones- The rest three are scleroproteins)

 13- Name two nano peptides

 (Oxytocin, Vasopressin)

 14- Name two globular proteins

 (Hemoglobin, Myoglobin)

 15-Which test should be undertaken for the detection of cysteine in a protein solution?

 (Lead acetate test)

 16-What is the nature of peptide bond- Single, double or partial double bond ?

(Partial double bond)

 17- Out of all the primary amino acids which amino acid gives yellow color on Ninhydrin test?                

 (Proline and hydroxy proline )

 18- Histamine is formed from Histidine by-

 Deamination, decarboxylation or transamination

 (Decarboxylation)

 19- Name two non alpha amino acid

 (GABA, beta Alanine, Delta amino Levulinic acid)

 20- Choose the odd one out-

 Aspartic acid, lysine, Arginine, Cysteine                  

 (Cysteine- Amino acid with uncharged side chain at physiological p H

 21- Choose the odd one out-

Tyrosine, Tryptophan, Threonine                  

 (Tyrosine- non essential Amino acid from the nutritional perspective or threonine if considered non aromatic amino acid)

 22- Name a purely ketogenic amino acid            

 (Leucine)

 23- Name a peptide used as an anticancer drug          

 (Bleomycin)

 24- Name the defense proteins                                    

 (Complement, immunoglobulin)

 25- Choose the odd one out- Silk fibroin, Hemoglobin, Carbonic anhydrase

 (Hemoglobin- The rest are proteins with beta pleated sheet

 26- The proteins with a carbohydrate content > 10 % are called as Mucoproteins- True or false?        

 (True)

 27- The most abundant amino acid in keratin?            

 (Cysteine)

 28- The most abundant amino acid in Collagen—-?    

 (Glycine)

 29- Xanthoproteic test does not specify for—- ?

 Tyrosine, Tryptophan, Serine              

 (Serine)

 30- Give the characteristics of a peptide bond in one line-

 (Rigid, partial double bond, Trans and stable)



31-Name the branched chain amino acids

 (Valine, Leucine, iso Leucine)

 32-Choose the hydrophobic amino acid out of the followings-

 Aspartic acid, Arginine, Serine, Isoleucine

 (Isoleucine)

 33-Which amino acid acts as Methyl group donor?

 (Methionine)

 34- What is the difference between Deamination and Transamination?

(Deamination is the removal of amino group of the amino acid while Transamination is the transfer of amino group from one  donor amino acid to an acceptor keto acid for the formation of a new amino acid)

 35- Out of the 20 amino acids which amino acids participate in the formation of phosphoproteins

 (Serine and Threonine)

 36- Formation of carbamino compound for the transportation of carbon dioxide is a property of amino group, carboxyl group or both groups?

 (Amino group)

 37- Hopkins Cole test is a confirmatory test for which amino acid?

 (Tryptophan)

 38- How many peptide bonds are there in a tripeptide?

 (Two)

 39- The alpha helix is right or left handed?        

 (Right handed)

 40- What is the direction of hydrogen bonds in the beta pleated sheet structure?

 (Perpendicular to the axis)

 41-What is the direction of beta pleated sheets in flavodoxin?

 (Parallel)

 42-Name the most abundant protein in mammals      

 (Collagen)

 43-Name a defect in the primary structure responsible for the causation of a disease

 (Sickle cell disease)

 44-What is the defect in Alzheimer disease?

 (Protein misfolding leading to formation of insoluble protein aggregates)

 45-What is the isoelectric p H of casein?

(4.6)

 46- What is the effect on the solubility of a protein upon denaturation?

 (Solubility decreases upon denaturation)

 47- Name the lipo proteins of biological significance

 (Chylomicrons, VLDL, LDL, HDL)

 48- Which amino acid is lacking in cereals?

 (Cereals lack Lysine)

 49- Which amino acid forms disulphide linkages between two polypeptide chains in oligomeric proteins?                      

 (Cysteine)

 50- Which peptide is used in clinical practice to induce uterine contractions?

 (Oxytocin)


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Chemistry of Proteins

1-Give an example of reversible denaturation

(Denaturation of Ribonuclease by urea)

 2. Give example of a circular peptide.

(Gramicidin S)

 3-What is the difference between Salting in and Salting out?

(Salting in is addition of a pinch of salt to increase the solubility of a protein, while salting out is addition of excess of salt to precipitate it out)

4. Name the proteins containing alpha helical structure predominantly.

(Hemoglobin, Myoglobin etc)

5. Name the super secondary structures

(Greek key, beta meanders, Beta alpha beta)

6. Name the respiratory proteins

(Hemoglobin, Myoglobin, cytochromes)

 7. What is the class of Zein protein?

(Poor protein- it lacks Tryptophan and Lysine)

 8. Name the contractile proteins

( Actin, Myosin, flageller proteins)

 9-What are the features of isoelectric pH?

(Decrease in solubility, electric charge, Electrophoretic migration, loss of biological activity)

 10-What is the basis of protein precipitation by organic solvents?

(Decrease in dielectic constant of the medium)

11-What is the difference between flocculum and coagulum?

(Flocculum is a reversible state of denaturation while coagulum is a an irreversible state of denaturation)

12-What are the forces that stabilize the alpha helical structure?

(Hydrogen and Vander waals forces mainly)

13-What is the basis of cauterization by silver nitrate during surgery to control bleeding?

(Silver nitrate is a heavy metal salt and by causing precipitation of proteins seals the oozing points of the blood vessels)

14-What is meant by a domain?

(Domain is a term used to denote a compact globular functional unit of a protein)

15-Why is Glutathione called a pseudo peptide?

(In glutathione instead of alpha carboxyl group, the gamma carboxyl participates in the peptide bond formation)

16-Covalent forces stabilize the tertiary structure in a protein- True or false?

(False- the non covalent forces stabilize the tertiary structure in a protein)

17- Which tests should be carried out for the detection of Tryptophan in a given solution?

(Xanthoproteic and Hopkins Cole test)

18- Which amino acids contribute towards ionic interactions?

(Positively charged amino acids like Arginine , Lysine and negatively charged amino acids like Aspartic acid and Glutamic acid)

19- Which protein is precipitated by full saturation with Ammonium sulphate?

(Albumin)

20- What is the relationship of amount of salt required and the molecular weight of a protein?

(More the molecular weight and lesser is the amount of salt required by the protein and vice versa)

21-What are the functions of proteins?

(Nutritive, buffering, defense, viscosity, osmotic pressure, enzymes, hormones etc)

22-Name mono amino dicarboxylic acids

 (Aspartic and Glutamic acid)

 23-Name heterocyclic amino acids

 (Tryptophan and Histidine)

 24-Name the 21st and 22 nd amino acid

 (Seleno cysteine and Pyrrolysine)

 25-Which amino acids are involved in forming N- Glycosidic linkages?

 (Asparagine and Glutamine)

26-Name the semi essential amino acid

(Arginine and Histidine)

27-Which amino acid acts as the precursor of vitamin Niacin?

 (Tryptophan)

28-Name the amino acids with a non polar side chain

(Alanine, Valine, Leucine Isoleucine, Methionine, Phenyl Alanine)

29-Which protein structure determines the relationship of amino acids which are 3-4 residues apart ?

 (Tertiary structure)

30-Which test will be negative for a protein lacking tryptophan ?

 (Hopkins cole test)

 31-Name the essential amino acids

( Valine, Leucine, Isoleucine, lysine, Phenylalanine, Methionine and Threonine)

 32-Which amino acid is optically inactive ?

(Glycine)

 33-Which amino acid is abundantly present in prolamines ?

(Proline)

 34-Which protein is mostly found attached to DNA?

(Histone)

 35-Name the amino acids which are both glucogenic as well as ketogenic

(Isoleucine. Phenyl Alanine, Tyrosine and Tryptophan)

35-Name a specific test for the detection of alpha amino acids

(Ninhydrin test)

 36-Name a  specific test for the detection of cysteine

(Lead acetate test)

37-Covalent bond is formed at which level of protein’s structural organization?

(Primary structure)

38-Name the peptide hormones

 (ACTH, TRH, FSH, Glucagon, PTH, ADH, Oxytocin, Secretin, Pancreozymin, Cholecystokinin)

 39-What is the effect on the biological activity of a protein when exposed to UV light ?

 ( It will lose its biological activity since it will be denatured)

 40-Give two examples of protein misfolding causing disease?

 ( Prion’s and Alzheimer disease)

41-What is the class of casein ?

 (Class 1- complete protein)

42-What are the forces that stabilize quaternary structure of a protein ?

 (Mainly non covalent)

 43-Which amino acid acts as the best buffer of the plasma?

 (Histidine)

 44-What will be the product of decarboxylation of Tyrosine?

 (Tyramine)

 45-Why can’t albumin and majority proteins acquire the native configuration upon denaturation?    

 (Chaperones and other proteins assisting proper folding are not there)

 46-What are Beta bends?

 (Short loops to turn the direction of the beta sheets?

 47-What are the forces that stabilize the beta bends?

 (Hydrogen and electrostatic)

 48-Name a peptide to regulate the volume of urine excreted?

 (ADH)

 49-Which protein is present in the tendons and cartilages?

(Collagen)

 50-Name the storage proteins

 Ferritin, ceruloplasmin)





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protein

1-      Haemoglobin and collagen are proteins with diverse functions. Describe how the structures of proteins can be correlated with their functions.

2-      Define protein denaturation. Explain why, when insulin or majority proteins are subjected to denaturation and renaturation conditions, they regain only a few percent of their original activities.

3-      What is the basis of the classification of amino acids? Give one example for each class of amino acids.

4-      What is protein denaturation? Explain the significance of the denaturation-renaturation experiments on ribonuclease.

5-      What are the salient features of an alpha helix? Name the amino acids that destabilize this structure.

6-      Name two modified amino acids found in proteins and state their biological functions.

7-      Discuss fully the primary, secondary, tertiary and quaternary structure of proteins. Illustrate your answer with suitable example

8-      Distinguish between a simple and a conjugated protein. Illustrate your answer with suitable examples.

9-      What are the buffering groups present in a protein at physiological pH? Show how these groups help to contribute to buffering capacity.

10-   Draw the structure of any ammo acids as: (i) zwitterion (ii) cationic form (iii) anionic form

11-   Draw the structure of a dipeptide. Use R to represent the side chain of an amino acid.

12-   Describe the special roles of glycine and proline in protein structure.

13-   What is the stereochemical difference between D-alanine and L-alanine?

14-   What are the main characteristics of globular and fibrous proteins? Give an example of each of these proteins.

15-   Explain how a proline residue in polypeptide chain interrupts the alpha-helical structure.

16-   What are standard or primary amino acids? Give examples of non standard amino acids.

17-   What is iso electric p H ? What are the commercial applications of iso electric p H?

18-   Justify the statement, “Primary structure guides the formation of secondary and tertiary structure”, give example in support of your answer.

19-   What is protein misfolding? Give examples and discuss the clinical significance of protein misfolding.

20-   How is a peptide bond formed between the two amino acids? Discuss the characteristics of a peptide bond.

21-   Enlist the biologically important peptides; Give a brief account of the functions of Glutathione.

22-   Enlist the important functions of amino acids.

23-   What are the various ways by which proteins can be classified? Give examples of each category of proteins.

24-   Compare and contrast the structural features of α helix and β pleated sheets. Give examples of proteins having predominance of these structures.

25-   What is a domain? How is it formed, what kind of forces stabilize its structure?

26-   Give an account of the properties of amino acids, state the clinical significance if any of such reactions.

27-   An 80- year-old male was brought for consultation to  a Medical OPD with the chief complaints of loss of memory and disorientation from the past few months. He was diagnosed with Alzheimer disease. Discuss the biochemical basis, clinical symptoms and the prognosis of this disease.

28-   “Primary structure is guided by information on DNA. A single nucleotide change on DNA can alter the information and thus the sequence of amino acids in a peptide chain with the resultant loss of partial or total functional capacity of the protein”. Comment on the statement.

29-   Enlist the names of the tests performed for detection of specific amino acids in a sample.

30-   Give a brief account of the agents which can bring about protein unfolding? Discuss the biological or clinical aspect of protein denaturation.


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Multiple Choice Questions- Amino acid and protein chemistry

1-A mutation has changed an isoleucine residue of a protein to Glutamic acid, which statement best describes its location in a hydrophilic exterior-

a) On the surface since it is hydrophilic in nature

b) In side the core of the protein since it is hydrophobic in nature

c) Any where inside or outside

d) Inside the core of protein since it has a polar but uncharged side chain

2- Glycine and proline are the most abundant amino acids in the structure of-

a)Hemoglobin

b) Myoglobin

c) Insulin

d) Collagen

3- Some proteins contain additional amino acids that arise by modification of an amino acid already present in a peptide, examples include-

a) 4 -hydroxy proline

b) 5- hydroxy Lysine

c) Gamma Amino Butyric Acid

d) All of the above

4- Choose the incorrect statement out of the followings-

a) Only L amino acids are found in the biological system

b) Glycine is optical inactive

c) Tyrosine is a modified amino acid

d) Seleno cysteine is 21 st amino acid

5- Choose a nano peptide out of the followings-

a) Oxytocin

b) Vasopressin

c) Bradykinin

d) All of the above.

6- Which out of the following amino acids carries a net positive charge at the physiological p H ?

a) Valine

b) Leucine

c) Isoleucine

d) None of the followings.

7- Which out of the following amino acids is a precursor for a mediator of allergies and inflammation?

a) Histidine

b) Tyrosine

c) Phenyl Alanine

d) Tryptophan

8- Mother of a mal nourished child has been instructed to include a complete protein in diet for her child, which out of the followings proteins should be recommended?

a) Pulses

b) Wheat

c) Soy Protein

d) Milk

 9- All of the below mentioned amino acids can participate in hydrogen bonding except one –

a) Serine

b) Cysteine

c) Threonine

d) Valine

10- All of the following amino acids are both glucogenic as well as ketogenic except –

a) Isoleucine

b) Leucine

c) Tyrosine

d) Phenyl alanine

11- Which out of the following amino acid is a precursor of niacin (Vitamin)?

a) Tyrosine

b) Threonine

c) Tryptophan

d) Phenylalanine

12- The greatest buffering capacity at physiological p H would be provided by a protein rich in which of the following amino acids?

a) Serine

b) Cysteine

c) Alanine

d) Histidine

13- Which of the following peptides is cyclic in nature-?

a) Glutathione

b) Gramicidin

c) Met encephalin

d) Leuencephalin

 14- Which out of the followings is not a fibrous protein?

a)Carbonic anhydrase

b) Collagen

c) Fibrinogen

d ) Keratin

15) -Which of the following amino acid is a limiting amino acid in pulses?

a) Leucine

b) Lysine

c) Methionine

d) Glutamine

16)- Which out of the following is not a haemo protein ?



a) Catalase

b) Myeloperoxidase

c) Glutathione peroxidase

d) Aconitase

17- All the below mentioned proteins are metalloproteins except-

a)Carbonic anhydrase

b) Xanthine oxidase

c)  Lactate dehydrogenase

d) Superoxide dismutase                                                                                                      

18- Which out of the following is a peptide antibiotic?

a)Erythromycin

b) Gramicidin

c) Ciprofloxacin

d) Tetracycline

19- Choose the Anticancer peptide out of the followings-

a)Bleomycin

b) Methotrexate

c) Cytosine Arabinoside

d) Dideoxy Inosine

 20- Which of the following amino acids is most compatible with an α- helical structure?

a)Tryptophan

b) Alanine

c) Leucine

d) Proline

21- The highest concentration of cystine can be found in-

a) Melanin

b) Keratin

c) Collagen

d) Myosin

22- In scurvy, which amino acid that is normally part of collagen is not synthesized?

a)Hydroxy Tryptophan

b)Hydroxy Tyrosine

c) Hydroxy Alanine

d) Hydroxy Proline

23- A child with tall stature, loose joints, and detached retinas is found to have a mutation in collagen. Which of the following amino acids is the recurring amino acid most likely to be altered in mutations that distort collagen molecules?

a)Glycine

b) Tyrosine

c) Tryptophan

d) Tyrosine

24- Which one of the following amino acids may be considered a hydrophobic amino acid at physiological p H of 7.4?

a)Isoleucine

b) Arginine

c) Aspartic acid

d) Threonine

25- Which of the characteristics below apply to amino acid Glycine?

a) Optically inactive

b) Hydrophilic, basic and charged

c) Hydrophobic

d) Hydrophilic, acidic and charged

26- Which of the following amino acids in myoglobin, a globular protein, is highly likely to be localized within the interior of the molecule?

a)Arginine

b) Valine

c) Aspartic acid

d) Lysine

 27- Which of the amino acids below is the uncharged derivative of an acidic amino acid?

a)Cystine

b) Tyrosine

c) Glutamine

d) Serine

28-Choose the correct category for milk protein casein out of the followings

a)Nucleoprotein

b) Phospho protein

c) Lipoprotein

d) Glycoprotein





Answers-



1-      a

2-      d

3-      d

4-      c

5-      d

6-      d

7-      a

8-      d

9-      d

10-   b

11-   c

12-   d

13-   b

14-   a

15-   c

16-   d

17-   c

18-   b

19-   a

20-   b

21-   b

22-   d

23-   a

24-   a

25-   a

26-   b

27-   c

28-   b




------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123 Email:ehab10f@gmail.com,ehababoueladab@yahoo.com ------------------------------------------