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1. Which of the following is a reducing sugar
2. The primary structure of a protein refers to:a) The three dimensional folding stabilized by hydrogen bonds b) The sequence of amino acids linked by peptide bonds c) The interaction between multiple polypeptide chains d) The alpha-helix configuration or beta-sheet
3. Which of the following is NOT a function of lipids in living organisms?a) Energy storage b) Structural component of cell membranes c) Catalyzing biochemical reactionsd) Insulation and protection of organs
4. In DNA, the base pairing between adenine and thymine is stabilized by:a) Three hydrogen bonds b) Two hydrogen bonds c) Ionic bonds d) Covalent bonds
5. Which of the following statements about enzymes is INCORRECT?a) Enzymes lower the activation energy of a reaction b) Enzymes are highly specific to their substrates c) Enzymes are consumed during the reaction they catalyze d) Enzymes can function outside a narrow pH and temperature range
6. Which of the following is a characteristic feature of phospholipids?a) They are completely hydrophobic b) They have a hydrophilic head and hydrophobic tailc) They are primarily used for energy storage d) They form micelles in non-polar solvents
7. DNA fingerprinting involves the use of:a) mRNA sequences b) Restriction enzymes and VNTRs c) tRNA molecules d) rRNA sequences
8. Which of the following is an example of a frameshift mutation?a) Substitution of one nucleotide b) Insertion of three nucleotides c) Deletion of one nucleotide d) Inversion of a chromosome segment
9. A point mutation involves:a) Insertion of a nucleotide b) Deletion of a nucleotide c) Change in a single nucleotide d) Inversion of a chromosome segment
10. Which of the following is a feature of the lac operon in E. coli?a) It is an example of positive gene regulation. b) It is always turned on. c) It is regulated by lactose and glucose levels. d) It codes for proteins involved in glycolysis.
11. What is the function of single-strand binding proteins (SSBs) in DNA replication?a) Synthesize new DNA strands b) Prevent reannealing of separated DNA strands c) Remove RNA primers d) Relieve torsional strain
12. During translation in eukaryotes, what is the role of the Shine-Dalgarno sequence?a) It signals the termination of translation. b) It facilitates the binding of the small ribosomal subunit to mRNA.c) It is absent, and the 5′ cap serves a similar purpose. d) It recruits tRNA to the P site of the ribosome.
13. In the lac operon of E. coli, under which condition will transcription occur at the maximum rate?a) High glucose and high lactose b) Low glucose and low lactose c) Low glucose and high lactose d) High glucose and low lactose
14. Which of the following modifications occurs to eukaryotic mRNA Post transcriptionally to ensure stability and translation efficiency?a) Addition of a 5′ cap and a poly-A tail b) Removal of exons by splicing c) Methylation of the promoter region d) Addition of a 5′ poly-A tail
15. In the Meselson-Stahl experiment, after two rounds of replication in a 14N medium starting with fully 15N-labeled DNA, what is the expected composition of DNA molecules?a) All DNA molecules will have both strands labelled with 14N. b) Half will have both strands 15N, and half will have both strands 14N. c) All DNA molecules will have one 15N strand and one 14N strand. d) Half will have one 15N and one 14N strand, and half will have both 14N strands.
16. The DNA strand which is oriented in 5′ → 3′ direction and is not involved in RNA synthesis is calleda) terminator strand b) sense strand c) antisense strand d) template strand.
17. RNA expresses itself througha) peptidyl transferase b) amino acids c) proteins d) carbohydrates.
18. Assertion (A): Cleistogamous flowers produce assured seed-set even in the absence of pollinators. Reason (R): Cleistogamous flowers do not open at all and ensure self-pollination.a) Both A and R are true, and R is the correct explanation of A. b) Both A and R are true, but R is not the correct explanation of A. c) A is true, but R is false. d) A is false, but R is true.
19. Which of the following is responsible for the formation of the pollen tube?a) Generative cellb) Vegetative cellc) Synergidd) Egg cellDeselect Answer
20. The phenomenon of pollen grains germinating on the stigma of the same flower is called:
a) Autogamyb) Geitonogamyc) Xenogamyd) Cleistogamy