Warm-UpDescribe how is mitosis different in prokaryotic versus eukaryotic cells?Hint: go back to the difference between prokaryotes and eukaryotes during replication.

Yesterday’s Picture UNIT

3B

Meiosis UNIT

3C

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UNIT

3CMeiosis

4-chromosome somatic cell with a maternal (m) and a paternal (p)

homologue of each chromosome

2nn = 4

1m

1p

2p 2m

3p

3m 4m

4p

Meiosis starts with a somatic cell (non-gamete) which has a paternal copy and a maternal copy of each chromosome (“homologous” chromosomes).

1m 1p

2p 2m

3p 3m

4m 4p

UNIT

3CMeiosis

4-chromosome somatic cell with a maternal (m) and a paternal (p)

homologue of each chromosome

2nn = 4

1m

1p

2p 2m

3p

3m 4m

4p

Chromosome pairs line up randomly prior to division: homologues can be on either side.

Chromosome pairs line up in the middle of the cell randomly; the maternal

homologue can be either on one side or another for each chromosome.

2nn = 4

Meiosis starts with a somatic cell (non-gamete) which has a paternal copy and a maternal copy of each chromosome (“homologous” chromosomes).

UNIT

3CMeiosis

Chromosome pairs line up randomly prior to division: homologues can be on either side.

Meiosis starts with a somatic cell (non-gamete) which has a paternal copy and a maternal copy of each chromosome (“homologous” chromosomes).

1m 1p

2p 2m3p

3m

4m 4p

1p2m 3m

4p

1m2p3p

4m

Two genetically distinct gametes are born. Each have only four

chromosomes, not paired.

1nn = 4

Cell divides into two, each with of the four chromosomes, but different

combinations of homologues.

2nn = 4

Cell division causes each new cell to have different combinations of chromosomes.

Illustrate how a single somatic cell with 2 chromosomes can generate four genetically distinct gametes by drawing the process of meiosis. (LO 3.9)

CTQ #1UNIT

3C

UNIT

3CMeiosis is a process of producing gametes (sperm and egg).

Meiosis

UNIT

3CMeiosis is a process of producing gametes (sperm and egg).

Meiosis

Purpose: to increase genetic diversity during sexual reproduction.

Maize

UNIT

3CMeiosis is a process of producing gametes (sperm and egg).

Meiosis

How? by:1. Sharing genes with

another individual (sex).

Purpose: to increase genetic diversity during sexual reproduction.

UNIT

3CMeiosis is a process of producing gametes (sperm and egg).

Meiosis

How? by:1. Sharing genes with

another individual (sex).2. Making gametes as

genetically distinct from each other as possible.

Purpose: to increase genetic diversity during sexual reproduction.

I know they don’t look different, but they are!

UNIT

3CMeiosis is a process of producing gametes (sperm and egg).

Meiosis

How? by:1. Sharing genes with

another individual (sex).2. Making gametes as

genetically distinct from each other as possible.

3. Crossing over during meiosis.

Purpose: to increase genetic diversity during sexual reproduction.

UNIT

3CMeiosis

1m 1p

2p 2m

3p 3m

4m 4p

How? by:1. Sharing genes with

another individual (sex).2. Making gametes as

genetically distinct from each other as possible.

3. Crossing over during meiosis.

Purpose: to increase genetic diversity during sexual reproduction.

Crossing over creates even new combinations of maternal-paternal DNA.

UNIT

3CMeiosis

1p2m 3m

4p

1m2p3p

4m

1m 1p

2p 2m

3p 3m

4m 4p

How? by:1. Sharing genes with

another individual (sex).2. Making gametes as

genetically distinct from each other as possible.

3. Crossing over during meiosis.

Purpose: to increase genetic diversity during sexual reproduction.

Crossing over creates even new combinations of maternal-paternal DNA.

Explain how meiosis contributes to increased genetic diversity in a population. (LO 3.10)

CTQ #2UNIT

3C

State two events during meiosis that contribute to increased genetic diversity and describe how they function to increasing variation in a population. (LO 3.28)

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