Quiz 12: Meiosis

Consider an organism with diploid cells that has 22 chromosomes in each cell (2n=22). How many chromosomes will be in a gamete of that organism?

11

When a cell undergoes mitosis how many cell divisions take place? When a cell undergoes meiosis how many cell divisions take place?

1; 2

When a cell undergoes mitosis, how many daughter cells are produced? When I sell undergoes meiosis how many daughter cells are produced?

2; 4

What is crossing over? Draw a diagram as part of your explanation. When does this event take place?

Crossing over is the exchange of DNA between homologous chromosomes; during prophase 1.

Explain why crossing over produces variation.

Crossing over produces variation because it creates new combinations of genes that were present in either parent.

How is a diploid cell different from a haploid cell?

Diploid cells contain two of each chromosome, whereas haploid cells contain one of each chromosome

In humans we have 46 chromosomes in each somatic cell (that is cells that are not eggs or sperm). Each of these as a pair. For example, you have two copies of chromosome number one. You inherited one from your mother (in the egg cell) and one from your father (in the sperm cell). What we call these pairs of chromosomes?

Homologous chromosomes

During anaphase 1 of meiosis, what is being pulled apart?

Homologs

Explain why independent assortment of homologs produces variation. Draw a diagram as part of your explanation. When does this event take place?

Independent assortment produces variation because there are different resulting gametes depending on how they're arranged at the metaphase plate; occurs during metaphase 1

What makes metaphase one of meiosis different from metaphase of mitosis?

Metaphase 1 of meiosis lines the homologs up, whereas metaphase in mitosis lines the pairs of sister chromatids up.

Draw a cell in G1 phase, in a species where n=2 and 2n=4.

See lecture slides.

In the slide titled "Independent Assortment" why are the chromosomes colored red and blue (what does red and blue represent)?

The red and blue differentiate between chromosomes that came from mom and dad.

During anaphase 2 of meiosis, what is being pulled apart?

The sister chromatids.