meiosis

Question 1

meiosis

Answer 1

Production of haploid gametes

Question 2

Meiosis I

Answer 2

(reductional division):
* homologs pair up
Crossing Over: Nonsister chromatids exchange DNA segments
tetrad (a group of four chromatids)
chiasmata, X-shaped regions of crossing over
* homologs separate
* resulting in two haploid daughter cells with replicated chromosomes

Question 3

Meiosis II

Answer 3

(equational division):
* sister chromatids separate
* The result is four haploid daughter cells with unreplicated chromosomes

Crossing over in Prophase I increases the possible variation
* Nonsister chromatids exchange DNA segments
* Each pair of chromosomes forms a tetrad
* a group of four chromatids
* chiasmata, X-shaped regions where crossing over occurred

Question 4

Meiosis differs from Mitosis in meiosis l

Answer 4

1. Synapsis and crossing over in prophase I:
   * Homologous chromosomes physically connect and exchange genetic information
2. homologous chromosomes (tetrads) are paired at the metaphase plate instead of individual replicated chromosomes
3. Homologous chromosomes, instead of sister chromatids, separate at anaphase I

Question 5

Variation

Answer 5

the heritable genetic kind, results from:
1. Mutations
2. Behavior of chromosomes during meiosis
* Independent assortment of chromosomes
* each member of a pair of homologous chromosomes separates independently of the members of other pairs so the results are random
3. Crossing over - produces recombinant chromosomes
* homologous portions of two nonsister chromatids trade places
4. Random fertilization

Question 6

2n = the number of combinations possible when chromosomes assort independently into gametes