12. One difference between cancer cells and normal cells is that cancer cells________.
(A)are unable to synthesize DNA
(B)are arrested at the S phase of the cell cycle
(C)continue to divide even when they are tightly packed together
(D) cannot function properly because they are affected by density-dependent inhibition

8. In some cells, there are many different ion electrochemical gradients across the plasma membrane even though there are usually only one or two types of proton pumps present in the membrane. The gradients of the other ions are most likely established by which of the following? (A)co-transport proteins (B) ion channels (C)pores in the plasma membrane (D)passive diffusion across the plasma membrane

9. Which of the following responses is stimulated by cell signaling the formation of biofilms? (A) formation of mating complexes (B) aggregation of bacteria (C)secretion of substances that inhibit the growth of foreign bacteria (D) inhibition of quorum sensing

10. Which of the following reactions produces the majority of the COz released by the complete oxidation of glucose? (A) glycolysis (B)electron transport (C)oxidation of pyruvate to acetyl-CoA (D)the citric acid cycle

複選題11. Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. Which of the following statements best describes a related function they serve in plants? (A)They serve as accessory pigments to increase light absorption. (B) They protect against oxidative damage from excessive light energy. (C)They shield the sensitive chromosomes of the plant from harmful ultraviolet radiation. (D) They reflect orange light and enhance red light absorption by chlorophyll.

13. Meiosis II is similar to mitosis in that_________. (A) sister chromatids separate during anaphase (B) DNA replicates before the division (C) the daughter cells are diploid (D) homologous chromosomes synapse

14. Glucose-6-phosphate debydrogenase deficiency (G6PD) is inherited as an X-linked recessive allele in humans. A woman whose father had GoPD is planning a family with a man who has no history of the disease. What proportion of their sons are expected to have the disease? (A)100% (B) 1/4 (C)1/2 (D) 0

15.DNA strands are antiparallel. Which of the following statements defines "antip (A) The double helix structure of DNA creates nonparallel strands. (B) A 5' to 3' DNA strand is paired with the 3' to 5' DNA strand. (C) Hydrogen bonds between base pairs cause DNA strands to cross. (D) One DNA strand contains bases that complement the bases in the opposite strand. C) 1/2

16. Transcription in eukaryotes requires which of the following molecules in addition to RNA polymerase? (A)anticodons (B)ribosomes and tRNA (C)transcription factors (D) aminoacyl-tRNA synthetase

17. Muscle cells differ from nerve cells mainly because they__________. (A)express different genes (B)contain different genes (C)use different genetic codes (D) have unique ribosomes

18.When attempting to introduce a particular fragment of DNA into the genome cell which of the following methods would be most successful? (A) CRISPR/Cas9 recombination (B) in vitro hybridization of the DNA with the cell's genome (C)infecting the mouse cell with a Ti plasmid (D) RNA-seq followed by genetic profiling