Name:                                              .                                       2003 03 20

 

Read each question carefully. Answer each question. Total = 20

 

1.   Interphase is the stage when                        .

 

a  nothing occurs                       c.  a cell grows and duplicates its DNA

b. spindles are formed               d.   mitosis occurs

2.   After mitosis is completed, the chromosome number in a daughter cell is             the parent’s.         

                                                                 

a. the same as               c.  rearranged compared to

b. one-half                    d.  doubled compared to

3.   Which of the following statements is FALSE when comparing prophase I of  meiosis with prophase of mitosis?

 

a.       The nuclear membrane gradually disappears in both.

b.      Each chromosome is composed of two sister chromatids.

c.       In both, G₂ of the cell cycle has just been completed.

d.      Tetrads (or bivalents) form in both.

 

4.   Match each stage in mitosis with its key event.  (2)

 

               C      metaphase                    A.   sister chromatids  separate

               B       prophase                      B.   chromosomes begin to condense

               D      telophase                      C.   chromosomes align at the equator

               A      anaphase                      D.   daughter nuclei begin to form

 

5.   You are looking in a microscope at a cell, which is described as undergoing cytokinesis. What will confirm that the cell is animal?

 

a.       presence of a cell wall        

b.      presence of a cell plate

c.       presence of a cleavage furrow

d.      presence of a metaphase plate

 

6.   Meiosis            the  parental chromosome number.

 

a. doubles                     c. reduces by half

b. corrupts                    d.  maintains

 

7.   Each chromosome moves away from its homologue during              .

 

a.      Prophase I                          c.  Anaphase I      

b.     Prophase II                        d.  Anaphase II

 

8.   Sister chromatids move apart and end up at opposite poles during               .

 

a.      Prophase I              c.  Prophase II     

b.     Anaphase I             d.  Anaphase II

 

9.   A gamete affected by non-disjunction in Meiosis I would have         .

 

a.      a change from the normal chromosome number

b.     one extra or one missing chromosome

c.      the potential for a genetic disorder

d.     all of the above.

 

10. Which of the following is true of a species with 2N = 20?

 

            a. The species has 20 completely different types of chromosomes.

            b. There are 20 homologous pairs of chromosomes.

            c. During the S phase of the cell cycle, the DNA mass is halved.

            d. A gamete from this species has 10 chromosomes.

 

11.       Which cell may undergo meiosis?

 

a.   bacterium                b.  haploid                    c.  diploid                     d.  sperm

 

 

12. Refer to the following number of chromosomes in the diploid body cells of four organisms.  In each case,

determine the number of chromosomes found in a gamete produced by the organism.

 

Organism/Somatic cell Chromosome #                      Gamete Chromosome #.

 

a.                  Fruit fly (Drosophila melanogaster)                 8                                         4   .

b.                  Corn (Zea mays)                                              20                                     10     .

c.                  Human (Homo sapiens)                                   46                                     23      .

d.                  Horsetail (Equisetum sp.)                                 216                                  108       .

 

13. Trisomy 21 means that an individual has           .

 

a.   21 autosomes instead of 22.            c.   an extra sex chromosome.

b.   a missing chromosome 21               d.   3 copies of  chromosome #21

 

14. The exchange of genetic information occurs              .

 

a.      between sister chromatids               c.   between centromeres         

b.      between non-sister chromatids        d.   between non-homologous chromosomes

 

15. Which of the following is NOT TRUE about synapsis?

a.   Crossing over can take place

b.   Cells after Meiosis I will be identical.

c.   Each chromosome in the tetrad will be attached to one microtubule

d.   It ensures (in general) that each gamete will receive one of each homolog.

 

16. Identify the structures

a, b, d, and e (4).

a chromosome

b cleavage furrow

c. centrioles or centrosome

d. nuclear membrane (fragment)

e. spindle fibre or kinetochore microtubule