5.1: Meiosis

Question 1

What are the phases of meiosis I?

Answer 1

• Prophase I-nuclear envelope disappears, fibers form, DNA exists in double chromosome paris made up of sister chromatids, nonsister chromatids exchange genetic information
• Metaphase 1-double chromosomes are still paired, but they are aligned in the center of the cell
• Anaphase 1-the double chromosomes move to opposite sides of the cell
• Telophase 1-nuclear envelope and nucleus is reestablished with half of info that the parent had.

Question 2

What is the role of meiosis I?

Answer 2

To separate the parent information into 2 diploid cells with half the information. Crossing over also occurs, which increases genetic variation.

Question 3

What are the phases of meiosis II?

Answer 3

Prophase II-similar
Metaphase II- similar, but oriented top to bottom instead
Anaphase II- similar, but separate sister chromatids.
Telophase II-similar, but only contain single chromosomes
end with haploid that are all genetically different.

Question 4

What is the role of meiosis II?

Answer 4

To make the cells into four haploid with all different genetic data.

Question 5

Identify three differences between meiosis I and meiosis II,

Answer 5

• the double chromosomes in meiosis I are separated, where as the sister chromatids are separated in meiosis II
• meiosis I results in 2 diploid cells, but meiosis II results in 4 haploid cells
• 2 cells vs 4 cells

Question 6

Identify what part of meiosis results in the reduction of chromosome number.

Answer 6

Cytokinesis after meiosis I leads to half the chromosomes in each cell.

Question 7

What does 2n=6 mean?

Answer 7

That the cell is diploid, meaning it has 6 total chromosome pairs.

Question 8

What does n=3 mean?

Answer 8

The cell is haploid with 3 chromatids.

Question 9

What are the phases of mitosis? Describe each phase.

Answer 9

Prophase- the chromatin condenses into chromosomes and mitotic spindles begin to form, with the nucleolus disappearing.
Metaphase-the spindle is complete and chromosomes are aligned in the middle of the cell.
Anaphase-chromatids of each chromosome are separated and daughter chromosomes are moving to two poles of the cell.
Telophase-daughter nuclei begin to form.

Question 10

Describe the daughter cells resulting from mitosis.

Answer 10

There are two diploid daughter cells that are identical to each other. 2n=4 each.

Question 11

Describe the daughter cells resulting from meiosis.

Answer 11

There are 4 haploid daughter cells that have genetic variation. n=2 each.

Question 12

Identify three similarities between mitosis and meiosis.

Answer 12

• both have PMAT phases
• both are used to help the organism grow and reproduce
• Both involve the dividing of cells

Question 13

Identify three differences between mitosis and meiosis.

Answer 13

• Meiosis results in 4 haploid cells as opposed to two diploid cells.
• Meiosis uses PMAT twice as opposed to just once in mitosis.
• meiosis produces daughter cells that are genetically different (crossing over during prophase I)