Biology Quiz 2

6. Which of the following statements about meiosis is true?

**A. The chromosome number in the resulting cells is halved. B. DNA replication occurs before meiosis I and meiosis II. C. The homologs do not pair during prophase I. D. The daughter cells are genetically identical to the parental cell. E. The chromosome number of the resulting cells is the same as that of the parent cell.

17. True-breeding plants

**A. produce the same offspring when crossed for many generations. B. have no mutations. C. result from a monohybrid cross. D. result from a dihybrid cross. E. result from crossing over during prophase I of meiosis.

14. Chiasmata

A. form during prophase I. B. are sites where sister chromatids can exchange genetic material during meiosis. C. increase genetic variation among the products of meiosis. D. increase genetic variation among the products of mitosis. **E. Both a and c

7. In meiosis II,

A. four genetically identical cells are generated. **B. sister chromatids are separated. C. DNA replication occurs. D. crossing over occurs. E. Both a and b

4. If the ori site on the E. coli chromosome is deleted,

A. nothing will happen. B. replication will start but not be able to continue. **C. replication will not start. D. replication will initiate at another ori site on the chromosome. E. the chromosome will be replicated but the cell will not be able to divide.

20. In a metaphase chromosome, DNA is combined with _______, called _______, to form structures known as _______.

A. proteins; nucleoproteins; centrosomes B. nucleic acids; nucleosomes; histones **C. proteins; histones; nucleosomes D. small molecules; histones; nucleosomes E. proteins; nucleosomes; histones

5. The cross AaBb × AaBb is an example of a _______ cross and the results of such crosses led Mendel to propose what we now call _______.

A. selfcross; law of segregation of genes B. dihybrid cross; law of segregation of genes **C. dihybrid cross; law of independent assortment D. test cross; law of segregation of genes E. test cross; law of independent assortment

15. A fellow student crosses a red flowered plant with a white flowered plant and observes that all of the offspring are red. Flower color is coded by a single gene with two alleles in this plant. What can you conclude from this?

A. the colors of the plants blended together in the offspring B. the red allele is recessive **C. the parents were homozygous for flower color D. this was a dihybrid cross E. the red offspring all had the same genotype.

16. What is the probability that a cross between a true-breeding pea plant with spherical seeds and a true-breeding pea plant with wrinkled seeds will produce F1 progeny with spherical seeds?

A. 1 ⁄ 2 B. 1 ⁄ 4 C. 0 D. 1/8 **E. 1

10. What fraction of offspring of the cross AaBb × AaBb is homozygous for all the dominant alleles, assuming that they are on different chromosomes?

A. 1/4 B. 1/8 **C. 1/16 D. 1/32 E. 1/64

13. Chromosome movement during anaphase is mediated by

A. ATP-dependent molecular motors and shortening of polar microtubules at the centrosome that pull the chromosomes toward the poles. B. cohesin proteins. **C. ATP-dependent molecular motors and shortening of the kinetochore microtubules at the centrosome that pull the chromosomes toward the poles. D. cdk binding to cyclin. E. all of the above

12. Which of the following statements about DNA replication and cytokinesis in Escherichia coli is true?

A. DNA replication occurs in the nucleus. B. Cytokinesis is facilitated by microfilaments of actin and myosin. C. DNA replication occurs during the S phase of the cell cycle. **D. Cell reproduction is initiated by environmental signals, which result in DNA replication, DNA segregation, and cytokinesis. E. The E. coli chromosome is linear.

2. Interphase involves all of the following steps except

A. DNA replication. B. the synthesis of cellular components necessary for mitosis. C. the conservation of energy for later stages of mitosis. **D. the condensation of chromatin. E. All of the above

18. Mendel's Peas: Which of the following is not a characteristic of pea plants (shown) that caused Mendel to choose them for his studies of inheritance? (There's supposed to be a picture but it doesn't help you answer the question)

A. Flower morphology that made controlled cross-pollination possible **B. Prior studies on meiosis in this species C. Existence of true-breeding strains D. Presence of many well-defined, contrasting traits E. Ease of cultivation

11. In a test cross, peas of an unknown genotype are crossed with peas of a known genotype. In this example, smooth peas are the unknown and wrinkled peas are the known (rr). If half of the offspring from that cross are smooth and half are wrinkled, what is the genotype of the unknown plant?

A. Incomplete dominance B. Homozygous dominant: RR C. Homozygous recessive: rr **D. Heterozygous: Rr E. The genotype cannot be determined from the information given.

8. The formation of haploid gametes during meiosis explains

A. Mendel's law of independent assortment. **B. Mendel's law of segregation of alleles. C. dihybrid crosses. D. both a and c E. all of the above

9. Which of the following statements about chromatids is true?

A. They are replicated chromosomes still joined together at the centromere. B. They are identical in mitotic chromosomes. C. They undergo recombination in mitosis. D. They are identical in meiotic chromosomes. **E. Both a and b

19. Control of the Cell Cycle: Which of the following statements about protein signals involved in the control of the cell cycle (shown) is false? (Theres some kind of pie chart)

A. Transition from G1 to S and G2 to M depends on the phosphorylation of certain key proteins by cyclin-dependent kinase or Cdk. B. Cdk's must be bound with a specific cyclin to be active as kinases. C. Cyclins bind transiently to kinase enzymes. D. DNA damage during G1 can result in the cell cycle stopping until it can be repaired. **E. The phosphorylation of retinoblastoma protein effectively inhibits cell division.

3. Cytokinesis: Complete the following sentence about the photomicrograph shown. This is _______ cell, undergoing _______, with the formation of a _______. (Theres supposed to be a picture here)

A. an animal; apoptosis; division furrow B. an animal; cytokinesis; division furrow C. an animal; interkinesis; division furrow **D. a plant; cytokinesis; cell plate E. a plant; cytokinesis; division furrow

1. The difference between asexual and sexual reproduction is that

A. asexual reproduction occurs only in bacteria, whereas sexual reproduction occurs in plants and animals. B. asexual reproduction results from meiosis, whereas sexual reproduction results from mitosis. **C. asexual reproduction results in an organism that is identical to the parent, whereas sexual reproduction results in an organism that is not identical to either parent. D. asexual reproduction results from the fusion of two gametes, whereas sexual reproduction produces clones of the parent organism. E.asexual reproduction occurs only in haplontic organisms, whereas sexual reproduction occurs only in diplontic organisms.