Week 4

What is the purpose of mitosis?

Repairs and produces body cells, making identical cells to replace what was lost.

What is Interphase in the cell cycle?

A phase of growth, DNA replication, and cell functions, making up 90% of the cell cycle.

What happens to chromosomes during DNA replication?

They replicate and are still counted as one chromosome, now with two chromatids.

What is the first step of mitosis?

Prophase, where chromatin condenses into visible chromosomes and spindle fibers start to form.

What does metaphase represent in mitosis?

Chromosomes line up in the middle of the cell as the nucleus is disassembled.

During anaphase, what happens to chromatids?

Chromatids are pulled away to opposite sides of the cell.

What occurs in telophase during mitosis?

Chromatids form nuclei on both sides as the nuclear membrane reforms.

What is cytokinesis?

The final step in mitosis that splits the cytoplasm and completes cell division.

Distinguish between chromosomes and sister chromatids.

Chromosomes are storage units for DNA; sister chromatids are identical copies formed after DNA replication.

What are homologous chromosomes?

Chromosomes that are of the same length and contain the same genes.

What is the function of alleles?

Alternative forms of a gene that result in different DNA.

What happens during meiosis?

It is a type of cell division in germ line cells that produces genetically unidentical gametes.

Why is meiosis important for sexual reproduction?

It creates genetic variation by producing four genetically unidentical gametes.

Describe prophase 1 in meiosis.

Chromosomes thicken, line up with homologous pairs, and may undergo crossing over.

What occurs during metaphase 1 of meiosis?

Chromosomes align in pairs at the middle of the cell.

What is the outcome of telophase 2 in meiosis?

Results in four genetically different cells after cytokinesis.

How do gametes differ from somatic cells?

Gametes are haploid (n=23), while somatic cells are diploid (2n=46).