Viva Questions of Chemistry & Metabolism of Biomolecules

Chemistry & Metabolism: Carbohydrates, Lipids, Amino Acids & Proteins, Nucleotides, Hemoglobin, Integration

Correlation

Q: Cholesterol belongs to which class of lipids? (Topic: Lipids)

A: Derived Lipids

Q: Name the vitamin derived from Cholesterol? (Topic: Lipids)

A: Vitamin D

Q: Deficiency of Vitamin D Leads to? (Topic: Vitamin)

A: Rickets in Children. Osteomalacia in adults

Q: Name the marker enzyme for bone diseases (Rickets & Osteomalacia)? (Topic: Enzymes)

A: Alkaline Phosphatase (ALP)

Q: ALP belongs to which class of enzymes? (Topic: Enzymes)

A: Hydrolase (Class 3 Enzymes)

Q: Name other condition in which ALP acts as a marker enzyme? (Topic: Organ Function Tests)

A: Obstructive jaundice

Q: Name another enzyme which levels parallel with ALP during obstructive jaundice? (Topic: Organ Function Tests)

A: 5’ Nucleotidase


Correlation 

Q: Mention clinical features in patient of phenylketonuria (PKU). (Topic: Amino Acids & Proteins)

A: Mental retardation, hypopigmentation, mousy odour of urine, hypothyroidism.

Q: Mention the biochemical basis of hypopigmentation in PKU. (Topic: Amino Acids & Proteins)

A: Patients of PKU, as they cannot form tyrosine (Due to deficiency of Phenylalanine hydroxylase enzyme), exhibit hypopigmentation.

Q: Mention products of tyrosine. (Topic: Amino Acids & Proteins)

A: Thyroxine, T3, Melanin, Catechol amines- Norepinephrine, Epinephrine, Dopamine

Q: Thyroxine & T3 synthesis requires trace element/mineral? (Topic: Minerals)

A: Iodine

Q: Iodine deficiency leads to? (Topic: Minerals)

A: Goitre (enlargement of thyroid gland), hypothyroidism and myxedema

Q: Mention biochemical picture in primary hypothyroidism. (Topic: Organ Function Test)

A: Decreased T3, Decreased T4, Increased TSH

Q: Mention effect of hypothyroidism on Basal metabolic rate (BMR). (Topic: Nutrition)

A: Decreased BMR


Correlation 

Q: Name the Vitamin whose structure closely resembles to that of monosaccharide. (Topic: Carbohydrates)

A: Vitamin C

Q: Name the disease due to deficiency of Vitamin C. (Topic: Vitamins)

A: Scurvy. Characterized by spongy and sore gums, loose teeth, anemia, swollen joints, fragile blood vessels, decreased immunocompetance, Delayed wound healing

Q: Mention the basis of spongy and bleeding gums in scurvy. (Topic: Extracellular Matrix)

A: Vitamin C helps in Formation of collagen – acts as a coenzyme for the hydroxylation of proline and lysine when procollagen is converted to collagen.

Q: Mention the role of Vitamin C in mineral metabolism. (Topic: Vitamins)

A: Vitamin C Enhances iron absorption (ferrous form); Ferritin formation.

Q: Mention other factors which enhances iron absorption. (Topic: Minerals)

A: Acidity, iron deficiency anemia, alcohol, fructose and cysteine promote iron absorption

Q: Mention the role of iron in Electron transport chain. (Topic: Biological Oxidation)

A: Complex III of ETC: Iron Sulphur protein- Exist Fe3+ (ox) or Fe2+ (red) state.

     Complex V of ETC: Cytochromes: Cytochrome are b, c1, c, a, a3.

Q: Other than cytochromes, mention other hemoproteins. (Topic: Hemoglobin)

A: Hemoglobin, Myoglobin, cytochrome, xanthine oxidase, catalase, tryptophan pyrrolase, peroxidase.

Q: Apart from iron, mention other cofactor for cytochrome oxidase & catalase. (Topic: Minerals)

A: Copper


Correlation 

Q: Mention the Metabolic Significance of HMP Shunt. (Topic: Carbohydrates)

A: Formation of Pentoses & Provision of NADPH

Q: NADPH is a coenzyme of? (Topic: Enzymes)

A: Niacin (Vitamin B3)

Q: Mention Significance NADPH. (Topic: Carbohydrates)

A:

    • Reductive biosynthesis of fatty acids and steroids.
    • Synthesis of amino acids- glutamate dehydrogenase.
    • Free radical scavenging: Antioxidant.
    • Detoxification-hydroxylation. Cytochrome P450
    • Phagocytosis.
    • Integrity of RBC membrane.

Q: What is the End product of Pentose metabolism? (Topic: Nucleotides)

A: Uric Acid

Q: Mention the rate limiting enzyme in HMP Shunt. (Topic: Carbohydrates)

A: G6PD Glucose-6-phosphate dehydrogenase

Q: Mention Clinical Significance of HMP shunt. (Topic: Carbohydrates)

A: G6PD Deficiency Anemia/ Drug induced Hemolytic anemia.

Q: Name the precipitating factors for G6PD Deficiency anemia. (Topic: Carbohydrates)

A: Antimalarial (primaquine), acetanilide (antipyretic), sulfamethooxazole (antibiotic) precipitate the hemolysis- jaundice and severe anemia

Q: G6PD Deficient anemia leads to which type of Jaundice. (Topic: Hemoglobin)

A: Hemolytic

Q: Mention the Result of Van Den Bergh test in Hemolytic Jaundice. (Topic: Organ function Tests)

A: Indirect


Correlation 

Q: Name the pathway of conversation of lactate from muscles into glucose in liver. (Topic: Carbohydrates)

A: Cori’s Cycle

Q: Lactate is end product of which pathway? (Topic: Carbohydrates)

A: Glycolysis under anerobic conditions

Q: Lactic acidosis leads to which type of Acid-base abnormality?  (Topic: Acid-Base Balance)

A: Metabolic Acidosis

Q: Mention Other Causes of Metabolic Acidosis?  (Topic: Acid-Base Balance)

A:  

    • Severe uncontrolled diabetes mellitus
    • Diabetic ketoacidosis (DKA).
    • Starvation ketosis,
    • Lactic acidosis
    • Renal failure

Q: Define ketonuria. Name the test to detect Ketonuria. (Topic: Lipids)

A: Ketonuria: Excretion of ketone bodies in urine; Rothera’s test

Q: Rothera’s Test is positive in? (Topic: Lipids)

A: Prolonged Starvation & uncontrolled DM

Q: Why starvation & uncontrolled diabetes mellitus leads to acidosis? (Topic: Integration)

A: Carbohydrate is either unavailable (starvation) or underutilized (diabetes): Oxaloacetate is unavailable for combining with acetyl CoA Impaired TCA cycle- Acetyl CoA is diverted for Ketone Bodies synthesis.

Q: Mention the organ which adapts to utilize ketone bodies during starvation? (Topic: Integration)

A: Brain

Q: Why brain cannot use fatty acids?  (Topic: Integration)

A: Free Fatty Acids cannot cross Blood-Brain-Barrier


Correlation 

Q: Mention examples of Homopolysaccharides. (Topic: Carbohydrates)

A: Starch, Dextrin, Glycogen, Cellulose, Inulin

Q: Mention Clinical significance of Cellulose. (Topic: Carbohydrates)

A: Not digested by mammals due to lack of enzyme that cleaves β glycosidic bond. Major constituent of dietary fiber.

Q: What is dietary fibre? Enumerate them. (Topic: Nutrition)

A: Complex carbohydrates not digested by human enzymes.

Cellulose, pectins, hemicellulose, lignins, gums, mucilage.

Q: Mention the importance of dietary fibers for diabetic diet. (Topic: Carbohydrates)

A: Improves glucose tolerance, glycemic control and increases sensitivity to insulin.

When carbohydrates combined with fiber, fat & protein: Glycemic index is low. (Example- Ice-cream)

Q: Mention the importance of dietary fibers for diet of coronary heart disease patient. (Topic: Lipids)

A: Dietary fiber: Decrease the absorption of dietary cholesterol- Hypolipidemic effect

Q: Mention functions of Glycogen. (Topic: Carbohydrates)

A: Liver glycogen- Maintain blood glucose levels, between meals.

Muscle Glycogen- fuel reserve for ATP supply during muscle contraction

 


Correlation 

Q: Define Heteropolysachharides. (Topic: Carbohydrates)

A: On hydrolysis of these polysaccharides, they yield a mixture of few monosaccharides or their derivatives. More commonly known as Glycosaminoglycans (GAG).

Q: Name the heteropolysaccharide, which is an Anticoagulant. (Topic: Carbohydrates)

A: Heparin

Q: Mention the relation of heparin with transcription. (Topic: Nucleic acids)

A: Heparin, a glycosaminoglycan binds to RNAP and inhibits the transcription

Q: Mention the Competitive inhibitor, which acts as an anticoagulant. (Topic: Enzymes)

A: Dicumarol- Competitive inhibitor of Vitamin K epoxide reductase

Q: Mention the vitamin, which has active role in blood coagulation.  (Topic: Vitamins)

A: Vitamin K- Coenzyme for the carboxylation of glutamic acid residues

Gamma carboxyglutamate is important in the clotting mechanism

Q: Mention the deficiency manifestation of Vitamin K. (Topic: Vitamins)

A: Blood coagulation is adversely affected, Blood clotting time is increased.

Vitamin K deficiency leads to prolonged coagulation and bleeding.

Q: Mention the phospholipid which helps in coagulation. (Topic: Lipids)

A: Cephalin- Phosphatidyl-ethanolamine

Q: Mention the mineral which has a role in blood coagulation. (Topic: Minerals)

A: Calcium- Factor IV dependent on Ca2+.

Q: Mention the role of Streptokinase in treatment of acute myocardial infarction and thromboembolism. (Topic: Enzymes)

A: Streptokinase is a fibrinolytic (thrombolytic) drug. It forms a complex with plasminogen → converts plasminogen into plasmin → plasmin dissolves fibrin clots.


Correlation 

Q: Mention the supplementary pathway of glycolysis in RBCs, where 2,3 BPG is synthesized. (Topic: Carbohydrates)

A: Rapaport-Leubering cycle

Q: Mention the significance of 2,3 BPG. (Topic: Carbohydrates)

A: Has high affinity for Hb, so reduces Hb affinity with oxygen and unloads more oxygen to tissues. At high altitude, hypoxic conditions, anemia, fetal tissue: 2,3-BPG increases: Enhance the supply of oxygen to tissues.

Q: Mention the effectors which are responsible for right shift of oxygen dissociation curve. (Easy oxygen delivery/ O2 affinity is decreased) (Topic: Hemoglobin)

A: High 2, 3-BPG, High H+, High CO2, High Temperature, HbS

Q: Mention the relation between pH & [H+] ion concentration. (Topic: Acid-Base Balance)

A: pH:  Negative logarithm of [H+] ion concentration.

    • If [H+] is high, the solution is acidic; pH < 7
    • If [H+] is low, the solution is basic or alkaline ; pH > 7

Q: Mention the types of acidosis. (Topic: Acid-Base Balance)

A: Metabolic: due to Loss of HCO3 from the body Respiratory: due to Retention of CO2 (H2CO3)

Q: Mention the causes of Respiratory acidosis. (Topic: Acid-Base Balance)

A: Chronic

    • Depression of respiratory center – drugs opiates or head trauma
    • Paralysis of respiratory or chest muscles
    • Emphysema, asthma, pneumonia, COPD

Causes: Acute

    • ARDS, pneumothorax

Q: Mention the role of Phospholipids in RDS. (Topic: Lipids)

A: Deficiency of lecithin causes- Respiratory distress syndrome in premature infants

Q: Name the heteropolysaccharide, which is a Lubricant and shock absorbent in joints. (Topic: Carbohydrates)

A: Hyaluronic acid

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