3.3

Question 1

what is meiosis

Answer 1

one diploid cell gives rise to four genetically different haploid cells

Question 2

what happens before meiosis

Answer 2

DNA is copied and each chromosome has 2 chromatids

Question 3

difference between meiosis I and II

Answer 3

meiosis I: homologous chromosomes of a pair are separated

meiosis II: sister chromatids of each chromosomes are separated

Question 4

phases of meiosis I

Answer 4

PROPHASE I
- homologous chromosomes pair condense and form bivalent (synapsis)
- crossing over: exchange of genetic information between homologous chromosomes (forms a temporary junction called chiasma)

METAPHASE I
- spindle microtubules move homologous pairs to equator
- random orientation

ANAPHASE I
- homologous pairs are separated, one chromosome of each pair moves to each pole

TELOPHASE I
- chromosomes decondence
- cytokinesis
- two haploid daughter cells

Question 5

phases of meiosis II

Answer 5

PROPHASE II
- chromosomes condense
- nuclear membrane dissolves
- centrosomes move perpendiculaR to before

METAPHASE II
- spindle microtubules attach to centromere and move the chromosomes to the equator

ANAPHASE II
- spindle microtubules contract and separate sister chromatids to opposite poles

TELOPHASE II
- Chromosomes decondense
- nuclear membrane reforms
- cytokinesis
- four haploid daughter cells