Final exam quiz
1. Which of the following is true about operons?
A) They are found in both prokaryotes and eukaryotes.
B) They regulate multiple genes as a single unit in prokaryotes.
C) Operons are turned on by repressors binding to the promoter.
D) Operons cannot respond to environmental changes.
Answer: B) They regulate multiple genes as a single unit in prokaryotes.
2. Which of the following is a prezygotic barrier?
A) Reduced hybrid fertility
B) Mechanical isolation
C) Hybrid inviability
D) Hybrid breakdown
Answer: B) Mechanical isolation
3. During transcription, which enzyme is responsible for synthesizing mRNA?
A) DNA polymerase
B) RNA polymerase
C) Helicase
D) Ligase
Answer: B) RNA polymerase
4. What is the purpose of a 5’ cap and poly-A tail in eukaryotic mRNA?
A) To catalyze DNA replication
B) To stabilize mRNA and aid in translation
C) To splice out introns
D) To stop transcription
Answer: B) To stabilize mRNA and aid in translation
5. How do enzymes speed up chemical reactions?
A) By increasing the activation energy required
B) By lowering the activation energy required
C) By altering the reaction products
D) By breaking down into substrates
Answer: B) By lowering the activation energy required
6. If a woman who is a carrier for color blindness (X-linked recessive) has children with a man who is not colorblind, what is the probability of a colorblind son?
A) 0%
B) 25%
C) 50%
D) 100%
Answer: C) 50%
7. Divergent evolution leads to which type of structures?
A) Analogous
B) Homologous
C) Vestigial
D) None of the above
Answer: B) Homologous
8. Which gene is referred to as the "guardian of the genome" for its role in preventing tumor formation?
A) BRCA1
B) p53
C) MYC
D) RAS
Answer: B) p53
9. What type of bond exists within a water molecule, and what type of bond exists between water molecules?
A) Covalent within; ionic between
B) Ionic within; covalent between
C) Covalent within; hydrogen between
D) Hydrogen within; covalent between
Answer: C) Covalent within; hydrogen between
10. Which of the following describes polygenic inheritance?
A) One gene influences multiple traits.
B) A single trait is influenced by multiple genes.
C) One gene suppresses the effect of another gene.
D) Two different traits are inherited together.
Answer: B) A single trait is influenced by multiple genes.
11. What is the role of the operator in an operon?
A) It is where RNA polymerase binds to start transcription.
B) It binds repressors to regulate transcription.
C) It encodes the structural genes.
D) It serves as a termination sequence for RNA polymerase.
Answer: B) It binds repressors to regulate transcription.
12. What happens during the elongation phase of transcription?
A) RNA polymerase binds to the promoter.
B) The RNA strand is synthesized by complementary base pairing.
C) RNA polymerase detaches at the termination sequence.
D) The mRNA undergoes splicing.
Answer: B) The RNA strand is synthesized by complementary base pairing.
13. Which type of fat contains double bonds?
A) Saturated fats
B) Unsaturated fats
C) Trans fats
D) None of the above
Answer: B) Unsaturated fats
14. What is hydrolysis?
A) The removal of water to form bonds
B) The addition of water to break bonds
C) The process of breaking down DNA strands
D) The synthesis of proteins from amino acids
Answer: B) The addition of water to break bonds
15. How does the pH of a solution change if hydroxide ion concentration increases by 1000-fold?
A) The pH decreases by 3.
B) The pH increases by 3.
C) The pH remains the same.
D) The pH decreases by 1000.
Answer: B) The pH increases by 3.