BIOL 1201 Study Guide - Quiz Guide: Ploidy, Zygosity, Cytokinesis

You are studying a cell which, before the S phase of the cell cycle, has 8 chromosomes and 2.4 picograms (2.4 × 10¹² grams) of DNA. Complete the following table with the expected number of chromosomes, chromatids, homologous pairs and the amount of DNA in each area or pole of the spindle at each of the stages indicated.

Determine if the following events occur during Mitosis, Meiosis I, Meiosis II, Mitosis and Meiosis, Mitosis and Meiosis I, or Mitosis and Meiosis II. (Answers may be used once, more than once or not at all. Be as accurate as possible with your answer.)

___ 1. The chromosome number is reduced by half.

___ 2. The amount of DNA in the cell is twice the amount of a normal diploid cell in G1.

___ 3. DNA is replicated during S phase.

___ 4. Homologous chromosomes separate.

___ 5. Sister chromatids separate.

___ 6. Chromosomes condense and align along the metaphase plate.

___ 7. Homologous chromosomes align and undergo crossing over.

___ 8. Has one round of division per round of DNA replication.

___ 9. The number of chromatids is equal to the number of chromosomes of a diploid cell in G1.

___ 10. Tetrads align on the metaphase plate.

a. Mitosis and Meiosis I only

b. Both Mitosis and Meiosis

c. Meiosis II only

d. Mitosis and Meiosis II only

e. Mitosis only

f. Meiosis I only

Match the term with its correct definition or explanation.

Chromatin

Homologous Chromosomes

Sister chromatids

Diploid

Interphase

S Phase

Synapsis

Crossing Over

Cell Plate

Cleavage Furrow

A. The exchange of genetic material between homologous chromosomes during meiosis I.

B. The pairing or tight association of homologous chromosomes in meiosis I. Results in the formation of a tetrad.

C. Non-identical copies of the same chromosome. Present in all diploid cells, even before replication. These chromosomes are the same length and contain genes for the same characteristics, but may have different alleles for each gene. D.

The period of the cell cycle that includes G1, S phase, and G2. E. A structure that develops during cytokinesis in plants.

F. Condensed chromosomes.

G. An invagination that develops during cytokinesis in animal cells.

H. When an organism has two copies of every chromosome (2n).

I. Two identical copies of a chromosome. These are only present after DNA replication.

J. The phase of the cell cycle when DNA is replicated.