13. Which of the following statements regarding gene linkage is correct?
(A) The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
(B) The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%.
(C)All of the traits that Mendel studied—seed color, pod shape, flower color, and others—are due to genes linked on the same chromosome.
(D) Linked genes are found on different chromosomes.
(E)All of the above.

9. Which one of the following statements is NOT true?(A)Intracellular receptors are found in either the cytoplasm or nucleus of target cells.(B) Ligands of intracellular receptors are hydrophobic or small. (C)Most intracellular receptors regulate translation. (D) Intracellular receptors and their ligands form complexes to carry out specific functions. (E)All of the above.

10. In a photosystem, clusters of chlorophyll b, and carotenoid pigments function most like____________.(A) an electrical generator(B) an antenna (C)a propeller on a motorboat (D) a windmill (E)a spring

11. Sex determination in mammals is due to the SRY gene found on the Y chromosome. Which of the following situations could allow a person with an XX karyotype to develop a male phenotype? (A) the loss of the SRY gene from an autosome (B) translocation of SRY to an X chromosome (C)the presence of an extra autosomal chromosome (D) the presence of one normal and one shortened (deleted) X chromosome (E)None of the above.

12. What is the main advantage of the C4 and CAM photosynthesis strategies over the C3 strategy? (A) They help the plant conserve water and synthesize glucose efficiently under hot, dry conditions. (B) They allow the plant to fix carbon more efficiently under conditions of low atmospheric CO2. (C)They allow the plant to fix carbon more efficiently in dim or cool conditions. (D) They make it possible for the plant to use the Calvin cycle at night and during the day. (E)They allow the plant to avoid photorespiration by producing a four-carbon sugar in place of glucose.

14. Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their first child will have albinism? (A) 0 (B) 1/2 (C)1/4 (D) 1 (E)1/16

15. Which one of the following statements is NOT true for signal transduction in the cells? (A) The relay molecules in signaling transduction are often proteins. (B) Many of the relay molecules are protein kinases, and they often act on other protein kinases in the pathway. (C)The activity of a protein regulated by phosphorylation depends on the balance in the cell between active kinases and active phosphatases. (D) Cytoplasmic protein kinases phosphorylate serine or glycine. (E)None of the above.

16. Which of the following statements about independent assortment or segregation is correct? (A) The law of independent assortment describes the behavior of two or more genes relative to one another. (B) The law of segregation describes the behavior of two or more genes relative to one another. (C)The law of independent assortment is accounted for by observations of prophase I of meiosis. (D) The law of segregation is accounted for by anaphase of mitosis. (E)None of the above.

17. It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that________. (A) island forms are descended from mainland forms (B) common environments are inhabited by the same organisms (C)island forms and mainland forms have identical gene pools (D) the island forms and mainland forms are converging (E)None of the above.

18. Genes in chromosomes packed into _______ fiber show the highest transcriptional activity. (A) 10 nm (B) 30 nm (C)supercoiling (D) metaphase chromosome (E)naked DNA

19. Which factor and mechanism regulates population growth in negative feedback manner typically so that population growth may follow the logistic growth model? (A) earth quakes； density-dependent (B) infectious disease； density-dependent (C)competition for resources； density-independent (D) toxic wastes； density-independent (E)toxic wastes； competition for resources