Biology; Unit 8: Meiosis

Meiosis

1. cell division that results in four daughter cells

2. each with half the number of chromosomes of parent cell

What are the 2 phases of meiosis

1. Meiosis I

2. Meiosis II

What are the 4 phases of meiosis I

1. Prometaphase I

2. Metaphase I

3. Anaphase I

4. Telaphase I

What are the goals of meiosis I (Hint 3 things)

1. crossover + recombine genetic material

2. seperate pairs of chromosomes

3. make 2 daughter cells w/ haploid number of cells

Prometaphase I (Hint 4 main things)

1. nuclear membrane disintegrates (access to DNA)

2. nucleolous disappears

3. chromatins --> condense into chromosomes

4. synapsis + crossing over happen

Synapsis (Hint 2 main things)

1. homologous chromosomes pair up

2. make tetrad

Crossing Over (Hint 3 things)

1. homologous chromosomes wrap around each other

2. exchanges sections of chromatids

3. make new genetic info

Metaphase I (Hint

1. homologous chromosomes = pairs line up down middle of cell

2. law of independent assortment

Law of Independent Assortment

homologous chromosomes line up at random (creates genetic combinations)

Anaphase I (Hint 2 things)

1. homologous chromosomes separate

2. pulled to opposite sides of cell

Telophase I (Hint 3 things)

1. chromosomes reach opposite sides of cell

2. new nuclei start to form

3. cytokinesis occurs

What are the 4 phases of meiosis II

1. Prophase II

2. Metaphase II

3. Anaphase II

4. Telophase II

What are the goals of meiosis II (Hint 2 things)

1. separate the 4 sister chromatids

2. make 4 daughter cels that are HAPLOID in number

Prophase II (Hint 3 things)

1. chromosomes condense

2. nuclear membranes disintegrate

3. NO CROSSING OVER

Metaphase II (Hint 1 thing)

1. chromosomes line up down equator of cells

Anaphase II (Hint 2 things)

1. chromosomes separate

2. pulled to opposite sides of cells

Telophase II (Hint 3 things)

1. chromosomes reach opposite sides of cell

2. 4 new nuclei start to form

3. cytokinesis occurs

4. results in 4 geneticall unique haploid cells

What is the purpose of meiosis

make 4 genticially unique daughter cells (2 parents)

During meiosis is the starting cell haploid or diploid

Diploid

During meiosis is the end cell haploid or diploid

Haploid

Where does meiosis occur

gametes/sex cells

What is meiosis used for

sexual reproduction

What does meiosis make

4 genetically unique HAPLOID cells

True or False: During meiosis chromosome nubers stay the same

False --> chromosomes numbers are cut in half

True or False: Genetic variation forms after meiosis

True --> meiosis makes 4 UNIQUE CELLS

What phase of meiosis makes genetically unique cells +

Meiosis I --> synapsis + crossing over happens (these processes mix up DNA/making them unique)

What's the difference between Meiosis I vs Meiosis II

Meiosis I --> creates 2 genetically different cells

Meiosis II --> copies those cells into 4 same cells as orignal 2

True or False: Meiosis II + Mitosis are similar

True --> both result in copying previous cells