Cell's Life Questions

1. A cell has one chromosome going into S phase. How many chromosomes does it have in G₁? In G₂?
     
2. Cytokinesis refers to which division, nuclear or cytoplasmic?
     
3. What stages of the cell cycle can be grouped together under the common heading interphase?
     
4. Besides the growth and replication of organelles, what other important events occur during the gap phases?

Cell's Life Answers

1. It has 1 chromosome in G₁, and 1 in G₂, but that chromosome now has 2 chromatids, so double the amount of DNA.
     
2. Cytoplasmic, the physical separation into two identical daughter cells.
     
3. G₁, S, and G₂.
     
4. The sensing of the cell's environment to decide whether it is a good time to divide.

Mitosis vs. Meiosis Questions

1. A diploid cell with 12 chromosomes (6 homologous chromosome pairs) goes through meiosis. How many chromosomes will each daughter cell have when meiosis is completed?
     
2. You found a cool plant species that you know has 10 unique kinds of chromosome, but the one you have found has 2 copies of each chromosome present in G₂ phase. Is this example of the organism haploid or diploid?
     
3. Which division process is important for the creation of eggs and sperm?

Mitosis vs. Meiosis Answers

1. 6. But, even though the total number of chromosomes is reduced by half, the number of types of chromosomes is the same.
     
2. Be careful not to get chromosome and chromatid mixed up here. The organism is diploid. If n = 10 (the number of unique chromosomes the species has), then if there are 2 copies of each, you have 2 × n (the diploid number). A haploid organism would have only one copy of each chromosome (or n).
     
3. Meiosis

Cell Division Questions

1. Which stage of the cell cycle in meiosis is the most different from mitosis?
     
2. Which overall part of meiosis is most like mitosis?
     
3. Do homologous chromosomes pair during mitosis?

Cell Division Answers

1. Prophase I
     
2. Meiosis II; it is when the sister chromatids separate and the homologous chromosomes are no longer present so they cannot align.
     
3. No, during meiosis I.