Mock Test 6

Mock Test 06: Full Syllabus Mix

45:00

1. Which of the following is a non-reducing sugar? A) Lactose B) Maltose C) Sucrose D) Cellobiose

Ans: C. Sucrose has a glycosidic bond between C1 of glucose and C2 of fructose, hiding both reducing groups.

2. The Henderson-Hasselbalch equation is used to calculate: A) Vmax B) pH of a buffer C) Free energy D) Ionic strength

Ans: B. $pH = pKa + \log([Salt]/[Acid])$.

3. Which enzyme is involved in 'Photorespiration' (C2 Cycle)? A) PEP Carboxylase B) RuBisCO C) Pyruvate kinase D) Hexokinase

Ans: B. RuBisCO acts as an oxygenase during photorespiration.

4. Z-DNA is characterized by: A) Right-handed helix B) Left-handed helix C) 11 bp per turn D) Wider diameter than B-DNA

Ans: B. Z-DNA is a left-handed zig-zag structure.

5. What is the net yield of ATP from 1 molecule of Glucose in Aerobic Respiration (Malate-Aspartate Shuttle)? A) 30 B) 32 C) 36 D) 38

Ans: B. Malate-aspartate yields 32, while Glycerol-phosphate yields 30 (New calculations).

6. Fluorescent recovery after photobleaching (FRAP) is used to study: A) Protein sequence B) Membrane fluidity C) DNA replication D) Cell wall synthesis

Ans: B. FRAP measures the lateral diffusion of lipids/proteins.

7. The precursor for the synthesis of all Steroid hormones is: A) Squalene B) Cholesterol C) Lanosterol D) Mevalonate

Ans: B. Cholesterol is converted to pregnenolone, the lead of steroids.

8. Which of the following amino acids is purely Ketogenic? A) Leucine B) Isoleucine C) Valine D) Alanine

Ans: A. Only Leucine and Lysine are purely ketogenic.

9. Klenow fragment is derived from DNA Polymerase I by removing: A) 3'-5' exonuclease activity B) 5'-3' exonuclease activity C) Polymerase activity D) All activities

Ans: B. Removing the 5'-3' exonuclease domain leaves the Klenow fragment.

10. The 21st amino acid is: A) Hydroxyproline B) Pyrrolysine C) Selenocysteine D) Citrulline

Ans: C. Selenocysteine is encoded by the UGA stop codon in specific contexts.

11. Which cofactor is required by Carbonic Anhydrase? A) $Mg^{2+}$ B) $Zn^{2+}$ C) $Cu^{2+}$ D) $Fe^{2+}$

Ans: B. $Zn^{2+}$ is essential for the catalytic activity of Carbonic Anhydrase.

12. Denaturation of DNA leads to an increase in absorbance at 260nm. This is called: A) Hypochromic effect B) Hyperchromic effect C) Bathochromic shift D) Blue shift

Ans: B. Unstacking of bases increases UV absorption.

13. Which enzyme is a marker for Lysosomes? A) Catalase B) Acid Phosphatase C) Cytochrome oxidase D) Succinate dehydrogenase

Ans: B. Lysosomes contain acid hydrolases.

14. The secondary structure of protein is primarily stabilized by: A) Covalent bonds B) Hydrogen bonds C) Hydrophobic interactions D) Disulfide bridges

Ans: B. H-bonds between backbone C=O and N-H stabilize Alpha helices and Beta sheets.

15. The 'Central Dogma' was proposed by: A) Watson B) Crick C) Nirenberg D) Meselson

Ans: B. Francis Crick proposed it in 1958.

16. The pH at which an amino acid exists as a Zwitterion is called: A) pKa B) pH optimum C) Isoelectric point (pI) D) Equivalence point

Ans: C. Net charge is zero at pI.

17. Gluconeogenesis occurs primarily in the: A) Muscle and Brain B) Liver and Kidney C) Adipose tissue D) Pancreas

Ans: B. Liver is the main site, followed by the kidney cortex.

18. Myoglobin shows what kind of oxygen binding curve? A) Sigmoidal B) Hyperbolic C) Linear D) Bell-shaped

Ans: B. Myoglobin has no cooperativity, thus hyperbolic. Hemoglobin is sigmoidal.

19. Which chromatography separates proteins based on their charge? A) Gel filtration B) Affinity chromatography C) Ion-exchange D) Reverse phase

Ans: C. Uses charged beads (Anion or Cation exchangers).

20. In the Urea cycle, the nitrogen atoms come from: A) Ammonia and Glutamine B) Ammonia and Aspartate C) Urea and CO2 D) Arginine and Ornithine

Ans: B. One N from free $NH_4^+$ and one from the amino group of Aspartate.

21. Which molecule is known as the "Universal Energy Currency"? A) DNA B) Glucose C) ATP D) Acetyl-CoA

Ans: C. Adenosine Triphosphate.

22. Okazaki fragments are joined by: A) DNA Polymerase B) DNA Helicase C) DNA Ligase D) Primase

Ans: C. Ligase seals the nicks in the lagging strand.

23. Which bond is broken during the 'Unzipping' of DNA? A) Phosphodiester B) Hydrogen bonds C) Glycosidic bonds D) Peptide bonds

Ans: B. Helicase breaks the H-bonds between base pairs.

24. The pentose phosphate pathway primarily generates: A) ATP and NADH B) NADPH and Ribose-5-phosphate C) FADH2 and CO2 D) Glucose and Lactate

Ans: B. NADPH for biosyntheses and Ribose for nucleotides.

25. Which enzyme is inhibited by Malonate? A) Isocitrate dehydrogenase B) Aconitase C) Succinate dehydrogenase D) Fumarase

Ans: C. Malonate is a competitive inhibitor of Succinate dehydrogenase.