15. Which of the followings is NOT true for cilia or flagella?
(A)They are involved in cell motility.
(B)They require ATP to work.
(C)They are composed of microfilaments.
(D) They require motor proteins to work.
(E) They are composed of an internal structure called the axoneme.

11. The neurotransmitter released at neuromuscular junctions in vertebrates is (A)acetylcholine. (B)serotonin. (C)epinephrine. (D) GABA. (E) endorphin.

12. The lacteal, a lymphatic vessel in the center of each intestinal villus, functions in digestion by absorbing (A)carbohydrates. (B)proteins. (C)nucleic acids. (D) vitamin C. (E) lipids.

13. Which of the following is a true statement about virus (A) all viruses have capsids and membrane envelope (B)viral RNA genome can be reversely transcribed into DNA by retrovirus (C) RNA viruses can serve as a template for DNA synthesis (D) viruses have lysogenic cycle (E) all of the above

14. Which of the following is not the components of an operon (A)operator. (B)promoter. (C)co-repressor. (D) structural genes. (E) None of above.

16. Which of the following scientist-discoveries is mismatched? (A)Watson and Crick – DNA structure. (B)Griffith – DNA is genetic material. (C)Meselson and Stahl – DNA replication mechanism. (D) Mendel – genetic inheritance. (E) None of above.

17. Which of the following statements best describes DNA polymerase? (A)It is an enzyme required to produce a primer needed for DNA replication. (B) It is an enzyme that catalyzes the addition of nucleotides to the 5′ end of a growing DNA strand. (C) It is an enzyme that catalyzes the addition of nucleotides to the 3′ end of a growing DNA strand. (D) It is an enzyme required to glue pieces of DNA fragments together. (E) It is an enzyme that polymerizes the DNA and keeps the replication fork open.

18. A DNA specimen that contains 30% guanine has ________ thymine. (A)10% (B)20% (C)30% (D) 40% (E) The amount of thymine cannot be determined.

19. Bile is crucial for ______ digestion because of its function in _____. (A)protein, protecting the stomach lining (B)fat, solubilizing glycerol:fatty acid bonds (C)nucleic acids, uncoiling DNA strands (D) fat, emulsification (E) protein, lyophilization

20. Which animal would you predict would have the highest mass-specific metabolic rate? (A)a lizard (B)a squid (C)an elephant (D) a goose (E) a hummingbird 

21. Which structure prevents blood flowing back into the atria during ventricular contractions? (A)atrioventricular valves (B)semilunar valves (C)sinoatrial node (D) carotid blood shunts (E) foramen ovale