9-Sexual Reproduction and Meiosis

What type of cell gives rise to gametes?

germ cells

What is the name given to cells that make up a body and are not germ cells nor gametes?

Somatic cells

What is a gamete?

A haploid reproductive cell. Sperm and egg.

What is the name of the cell produced when two haploid gametes fuse?

A zygote.

Are germ cells diploid?

Yes

Are gametes diploid?

No. They are haploid.

What is the process called where two gametes fuse to form a zygote?

Fertilization

In the animal sexual life cycle, what process do germ cells undergo to produce gametes?

Meiosis

In the animal sexual life cycle, what is the name of the process when haploid gametes fuse to form a zygote?

Fertilization

What process does the zygote undergo to produce the cells of a multicellular organism?

Mitosis

Are somatic cells in humans diploid?

Yes

How many cell divisions occur in meiosis?

Two

How many daughter cells are produced when a cell undergoes meiosis?

4

If a diploid cell undergoes meiosis, what will the ploidy of the daughter cells be?

Haploid

What do we call the two cell divisions that occur during meiosis?

Meiosis I

Meiosis II

Does synapsis occur during meiosis I or meiosis II?

Meiosis I

Does crossing over occur in meiosis I or meiosis II?

Meiosis I

Does independent assortment occur during meiosis I or meiosis II?

Meiosis I

When is the chromosome number halved, meiosis I or meiosis II?

Meiosis I

When are the homologous chromosomes separated, meiosis I or meiosis II?

Meiosis I

When are the sister chromatids separated, meiosis I or meiosis II?

Meiosis II

What is the name of the process where the homologous chromosomes pair up and become physically connected?

Synapsis

What is it called when there is an exchange of DNA between two non-sister chromatids in a homologous pair?

Crossing over

When does synapsis occur?

Prophase I of Meiosis I

When does crossing over occur?

Prophase I of Meiosis I

In what phase of Meiosis do pairs of homologous chromosomes align down the center of the cell?

Metaphase I

Independent assortment occurs because of the events of which phase?

Metaphase

How many different alignments are possible during Metaphase I?

2 to the power of n. Where n is equal to the number of pairs of homologous chromosomes.

What gets separated in anaphase I?

Homologous chromosomes

In what phase of meiosis do chromosomes align down the center of the cell?

Metaphase II

Are the 4 daughter cells produces in meiosis genetically indentical?

No.

What are three things that lead to genetic variation in sexually reproducing organisms?

1. Crossing Over

2. Independent Assortment

3. Random Fertilization

What is polyploidy?

Polyploidy is the condition of having extra sets of chromosomes

What is aneuploidy?

Aneuploidy is the condition of either having one or a few extra chromosomes or missing one or a few chromosomes.

What can cause aneuploidy?

Nondisjuction

What is it called when a pair of homologous chromosomes or a pair of sister chromatids do not separate properly during cell division?

Nondisjunction

In what type of aneuploidy does and organism have an extra copy of one chromosome?

Trisomy

In what type of aneuploidy is an organism missing a single chromosome?

Monosomy