12. In the cell cycle, which of the following occurs during S phase?
(A)separation of sister chromatids
(B)replication of the DNA
(C)spindle formation
(D)condensation of the chromosomes
(E)centrosomes synthesis

8. The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the (A)H+ concentration gradient across the membrane holding ATP synthase. (B)flow of electrons down the electron transport chain. (C)transfer of phosphate to ADP. (D)oxidation of glucose and other organic compounds. (E)electron transmission of photosynthesis.

9. Which of the following sequences correctly represents the flow of electrons during photosynthesis? (A)NADPH→ O2→ CO2 (B)NADPH→ electron transport chain→ O2 (C)H2O→ NADPH→ Calvin cycle (D)H2O→ photosystem I→ photosystem II (E)H2O→ mitochondria→ NADPH

10. In mechanism, photophosphorylation is most similar to _______ (A)carbon fixation. (B)oxidative phosphorylation in cellular respiration. (C)substrate‐level phosphorylation in glycolysis. (D)reduction of NADP+. (E)protein synthesis and modification

11. Which of the following is a true statement? (A)Anabolic pathways build molecules, require energy, and are endergonic. (B)Catabolic pathways build molecules, release energy, and are exergonic. (C)Catabolic pathways break down molecules, require energy, and are exergonic. (D)Anabolic pathways break down molecules, require energy, and are endergonic. (E)The second and third answers are correct.

13. Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle? (A)M (B)G1 (C)G2 (D)S (E)cytokinesis

14. Asexual reproduction __________. (A)is limited to plants (B)requires both meiosis and mitosis (C)leads to a loss of genetic material (D)is limited to single‐cell organisms (E)produces offspring genetically identical to the parent

15. What number and types of chromosomes are found in a human somatic cell? (A)21 autosomes and 2 sex chromosomes (B)22 autosomes and 1 sex chromosome (C)45 autosomes and 1 sex chromosome (D)44 autosomes and 2 sex chromosomes (E)n chromosomes

16. For what purpose(s) might a karyotype be prepared? (A)for prenatal screening, to determine if a fetus has the correct number of chromosomes (B)to determine whether a fetus is male or female (C)to detect the possible presence of chromosomal abnormalities such as deletions, inversions, or translocations (D)The first and second answers are correct. (E)The first three answers are correct.

17. In tigers, a recessive allele of a particular gene causes both an absence of fur pigmentation (a white tiger) and a cross‐eyed condition. If two phenotypically normal tigers that are heterozygous at this locus are mated, what percentage of their offspring will be cross‐eyed? (A)100% (B)10% (C)25% (D)50% (E)75%

18. Which of the following do you expect if an individual is heterozygous for the sickle‐cell trait? (A)they will not develop sickle‐cell disease (B)they will show some symptoms of the disease because the allele that causes sickle‐cell disease is not really recessive (C)they will be more apt to acquire a serious case of malaria (D)they will have full‐blown sickle‐cell disease because the allele is dominant (E)none of the listed choices are correct