Biology Honors Meiosis

What is diploid?

2 sets of chromosomes

What is haploid?

1 set of chromosomes

What are autosomes?

Chromosome pairs 1-22 that are the same in everyone

What are sex chromosomes?

The 23rd pair of chromosomes that determine biological sex. Either XX for female or XY for male.

What is meiosis? What does it do?

The chromosome numbers are cut in half in two division. This creates gametes that allow for genetic variation and makes sure chromosome number is correct in the next generation.

What are gametes? What are examples?

Sex cells that are haploid. Examples are sperm cells and egg cells.

What are gonads? What are examples?

The place in which gametes are created and meiosis occurs. Examples are ovaries and testes.

What is the normal number of chromosomes in a human? How many in a sex cell?

A normal human has 46 chromosomes. Each sex cell has 23 chromosomes.

What is crossing over?

Exchanging of sections of genes between homologs.

What is independent assortment?

The process where chromosomes randomly move to separate poles.

What is random fertilization?

One sperm out of millions will fertilize a single egg.

How many cell divisions are in meiosis?

2 cell divisions

Does crossing over occur in prophase 2?

No, only prophase 1.

What are germ-line cells?

Cells that undergo meiosis to produce gametes.

Are the daughter cells in mitosis genetically different? Meiosis?

The daughter cells in mitosis are genetically similar. The daughter cells in meiosis are genetically different.

Are ending daughter cells in mitosis diploid or haploid? Meiosis?

Daughter cells in mitosis are diploid, while daughter cells in meiosis are haploid.

What does spermatogenesis produce? Oogenesis?

Spermatogenesis produces 4 genetically different sperm cells. Oogenesis produces one ovum (egg cell) and 3 polar bodies.

What is a karyotype?

The layout of an individual’s chromsomes.

How is a karyotype arranged?

Arranged by band pattern and size. Size goes from largest to smallest.

How do sex chromosomes keep the ratio of males/females equal?

There is a 50/50 percent chance that the father will pass down the X or Y chromosome, which determines sex.

Why can’t doctors just remove the extra chromosome in trisomy?

The chromosomes are in every cell of the body.