13. Which one of following pathogens has no genetic materials?
(A) a prokaryote
(B)a viroid
(C)a plasmid
(D)a virus
(E) a prion

9. A mutation causes a gene to become overactive, contributing to uncontrolled cell growth. Which term best describes this gene? (A) tumor-suppressor gene (B)oncogene (C)spliced gene (D)alternatively spliced gene (E) malignant gene

10. Which of the following statements about the cell cycle is correct? (A) The cell cycle is a sequence of replications and divisions that produces a new cells. (B)The phases of the cell cycle are G1, S, and M phases. (C)In actively dividing cells, the S and G2 phases are collectively known as interphase. (D)When the S phase of the cell cycle is finished, a cell has twice as many chromatids as the number of chromosomes in the G1 phase. (E) During G2 phase, the cell grows and copies its chromosomes in preparation for cell division.

11. The probability of obtaining a recessive phenotype from self-fertilization of a heterozygous individual is (A)25%(B)50%(C)75%(D)100%(E)12.5%

12. The inheritance pattern where two or more genes do not assort independently because they are close together on the same chromosome is called (A) Mendelian inheritance.(B)epistasis.(C)genomic imprinting.(D)linkage.(E) dominance.

14. What is a homeobox? (A) a cluster of homeotic genes (B)a sequence within a homeotic gene that encodes the DNA-binding portion of a transcription factor (C)the portion of the promoter to which a homeoprotein binds to activate transcription of genes important for development (D)an enhancer region needed for expression of a homeotic gene (E) none of these are correct

15. What nucleic acid is subject to alternative splicing? (A) DNA (B)rRNA (C)pre-mRNA (D)mRNA (E) tRNA

16. Radioactive isotopes are applied to measure the age of fossil, what term describes the time it requires for exactly one-half of a given amount of a radioactive isotope of an element to decay? (A) decay time (B)decay product (C)half-life (D)half-decay (E) useful dating range

17. The phenomenon about exchange of genetic material among different species is called (A) homolgous gene exchange. (B)horizontal gene transfer. (C)exon shuffling. (D)genetic recombination. (E) exon shuffling and or genetic recombination.

18. What phenomenon would countere the conditions for Hardy-Weinberg equilibrium? (A) The population is isolated from other populations. (B)Females select males based on secondary sex traits. (C)The population is large. (D)No genotypes within the population have a reproductive advantage. (E) Genetic drift within the population does not change allele frequencies.

19. If deer is crossed with sheep, the embryos will form but cease development and spontaneously abort. This is an example of (A) a prezygotic mechanism. (B)hybrid inviability. (C)hybrid sterility. (D)hybrid breakdown. (E) spermatic behavior.