Lecture 6: Transmission of the genetic code: Meiosis

What is meiosis used for?

To create gametes (eggs and sperm) with half the number of chromosomes.

What is mitosis used for?

To make identical cells for growth and repair.

What is the difference between diploid and haploid?

Diploid (2n) has two sets of chromosomes (46 in humans); Haploid (1n) has one set of chromosomes (23 in humans).

What are homologous chromosomes?

Chromosomes that pair up in meiosis and have the same genes but may have different alleles.

What happens during prophase I of meiosis?

Crossing over occurs and homologous chromosomes pair up.

What is independent assortment?

Chromosomes line up randomly during Metaphase I, creating genetic diversity.

When does a cell become haploid in meiosis?

After Meiosis I, the cell has half the chromosomes.

What happens during crossing over?

Homologous chromosomes exchange genetic material during Prophase I, creating genetic variation.

What is the final outcome of meiosis?

Four genetically diverse haploid gametes.

Compare meiosis and mitosis.

Mitosis involves 1 division to produce 2 identical cells, while meiosis involves 2 divisions to produce 4 unique cells.