複選題

13. Why is ATP an important molecule in metabolism?
(A) Its hydrolysis provides an input of free energy for exergonic reactions.
(B) It provides energy coupling between exergonic and endergonic reactions.
(C) Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy.
(D) Its terminal phosphate bond has higher energy than the other two phosphate bonds.

9. The large surface area in the gut directly facilitates_____.(A) secretion (B) absorption (C) filtration (D) temperature regulation

10. The motor (somatic nervous) system can alter the activities of its targets, the skeletal muscle fibers, because _____.(A) it is electrically coupled by gap junctions to the muscles (B) its signals bind to receptor proteins on the muscles (C) its signals reach the muscles via the blood (D) it is connected to the internal neural network of the muscles

11. Imagine that a woman is in the final week of her pregnancy. Her doctor gives her an injection of oxytocin. The likely result of this is that the pregnant woman would _____.(A) stop secreting prostaglandins from the placenta (B) undergo vigorous contractions of her uterine muscles (C) increase the synthesis and secretion of progesterone (D) be prevented from lactation

12. The force driving simple diffusion is _____, while the energy source for active transport is _____. (A) the concentration gradient； ADP (B) the concentration gradient； ATP (C) transmembrane pumps； electron transport (D) phosphorylated protein carriers； ATP

14. In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve? (A) It allows for an increased rate of glycolysis. (B) It allows for an increased rate of the citric acid cycle. (C) It increases the surface for oxidative phosphorylation. (D) It increases the surface for substrate-level phosphorylation.

15. The beginning of anaphase is indicated by which of the following? (A) Chromatids lose their kinetochores. (B) Cohesin attaches the sister chromatids to each other. (C) Cohesin is cleaved enzymatically. (D) Spindle microtubules begin to polymerize.

16. Which of the following is a true statement about sexual vs. asexual reproduction? (A) Asexual reproduction, but not sexual reproduction, is characteristic of plants and fungi. (B) In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring. (C) In asexual reproduction, offspring are produced by fertilization without meiosis. (D) Asexual reproduction produces only haploid offspring.

17. Which of the following is true of a species that has a chromosome number of 2n = 16? (A) The species is diploid with 32 chromosomes per cell. (B) The species has 16 sets of chromosomes per cell. (C) Each diploid cell has eight homologous pairs. (D) A gamete from this species has four chromosomes.

18. Codons are part of the molecular structure of _____. (A) a protein (B) mRNA (C) tRNA (D) rRNA

19. Which viruses have single-stranded RNA that acts as a template for DNA synthesis? (A) proviruses (B) viroids (C) bacteriophages (D) retroviruses