Meiosis

Question 1

what does meiosis produce

Answer 1

4 genetically different haploid daughter cells

Question 2

what are the two stages of meiosis

Answer 2

meiosis I
meiosis II

Question 3

what is meiosis I

Answer 3

the reduction division when the pairs of homologous chromosomes are separated into two cells which will both be haploid

Question 4

what is meiosis II

Answer 4

second division is similar to mitosis. pairs of chromatids in each daughter cell are separated forming two more cells.
4 haploid daughter cells produced in total

Question 5

prophase 1

Answer 5

same as prophase in mitosis
BUT
homologous chromosomes line up forming bivalents. crossing over also occurs

Question 6

metaphase 1

Answer 6

same as metaphase in mitosis
BUT
homologous pairs assemble along metaphase plate instead of the individual chromosomes. independent assortment also occurs

Question 7

anaphase 1

Answer 7

homologous chromosomes pulled to the opposite poles and the chromatids stay joined to each other. recombinant chromatids are also formed

Question 8

telophase 1

Answer 8

chromosomes assemble at each pole and nuclear membrane reforms. chromosomes recoil. cell undergoes cytokinesis and divides into two new cells
reduction from diploid to haploid is complete

Question 9

prophase 2

Answer 9

chromosomes condense and become visible again.
nuclear envelope breaks down.
spindle formation begins.

Question 10

metaphase 2

Answer 10

individual chromosomes assemble on the metaphase plate.
due to crossing over chromatids not identical so there is IA again and more genetic variation produced

Question 11

anaphase 2

Answer 11

chromatids of the individual chromosomes pulled to opposite poles after division of the centromeres

Question 12

telophase 2

Answer 12

chromatids assemble at the poles
chromosomes uncoil and form chromatin again
nuclear envelope reforms
nucleolus becomes visible
cytokinesis results in 4 daughter cells being formed

Question 13

crossing over

Answer 13

chromosomes are large molecules of DNA and moving them through liquid cytoplasm results in chromatids entangling

Question 14

independent assortment

Answer 14

the orientation of each homologous pair is random and independent of any other pair. the maternal or paternal chromosome can end up facing either pole. IA can result in many different combos of alleles facing the poles resulting in genetic variation

Question 15

recombinant chromatids

Answer 15

sections of DNA on sister chromatids which were entangled during crossing over now break off and re-join sometimes resulting in an exchange of DNA. the points where the chromosomes break off and re-join are called chiasmata. When exchange occurs, this forms recombinant chromatids with genes being exchanged between chromatids. Genetic variation arises from this new combo of alleles as the sister chromatids are now no longer identical.