Question

college prep
period
u3l10: meiosis vs. mitosis
homework:

1. define homologous chromosome:

1. define crossing over/recombination:

1. what phase does crossing over/recombination occur?

1. describe 2 parts of meiosis that are similar to mitosis.

1. identify whether each process below occurs during mitosis, meiosis, or both.

a. sister chromatids separate
b. haploid cells are formed
c. cell division occurs once
d. homologous chromosomes pair
e. 4 haploid cells are the final result
f. crossing over occurs
g. cell division occurs twice
h. replicated chromosomes line up in the middle of the cell
i. 2 diploid cells are the final result

1. for each process decide whether the cells is a diploid or haploid.

a. does the parent cell in mitosis start as diploid or haploid?
b. are the resulting cells at the end of mitosis diploid or haploid?
c. does the parent cell in meiosis start as diploid or haploid?
d. are the resulting cells at the end of meiosis diploid or haploid?

Explanation:

1. Homologous chromosomes are pairs of chromosomes (one from each parent) that have the same genes at the same loci but may have different alleles.
2. Crossing over (recombination) is the exchange of genetic material between homologous chromosomes during meiosis.
3. Crossing over occurs in prophase I of meiosis.
4. Similarities between meiosis and mitosis: Both involve chromosome replication (interphase) and both have phases like prophase, metaphase, anaphase, and telophase (though meiosis has two rounds of these).

5.

• a. Sister chromatids separate in both mitosis and meiosis (anaphase of mitosis and anaphase II of meiosis).
• b. Haploid cells are formed only in meiosis.
• c. Cell division occurs once in mitosis.
• d. Homologous chromosomes pair only in meiosis (prophase I).
• e. 4 haploid cells are the final result of meiosis.
• f. Crossing over occurs only in meiosis (prophase I).
• g. Cell division occurs twice in meiosis.
• h. Replicated chromosomes line up in the middle of the cell in both (metaphase of mitosis and metaphase I of meiosis).
• i. 2 diploid cells are the final result of mitosis.

6.

• a. The parent cell in mitosis starts as diploid.
• b. The resulting cells at the end of mitosis are diploid.
• c. The parent cell in meiosis starts as diploid.
• d. The resulting cells at the end of meiosis are haploid.

Answer:

1. Homologous chromosomes are pairs of chromosomes (one from each parent) that have the same genes at the same loci but may have different alleles.
2. Crossing over (recombination) is the exchange of genetic material between homologous chromosomes during meiosis.
3. Prophase I of meiosis.
4. Both involve chromosome replication (interphase) and both have phases like prophase, metaphase, anaphase, and telophase (though meiosis has two rounds of these).

5.

• a. both
• b. meiosis
• c. mitosis
• d. meiosis
• e. meiosis
• f. meiosis
• g. meiosis
• h. both
• i. mitosis

6.

• a. diploid
• b. diploid
• c. diploid
• d. haploid