Meiosis and Recombination

Question 1

Difference between Meiosis and Mitosis

Answer 1

Meiosis is Diploid producing 4 haploid cells. Mitosis is diploid producing 2 diploid cells.

Question 2

In Meiosis, which phase is the phase where all of the cell’s genetic material gets replicated?

Answer 2

S-phase of interphase. Still diploid at this point

Question 3

What happens in G1 of interphase?

Answer 3

Protein and nucleic acid synthesis occuring

Question 4

Which round of meiosis is similar to mitosis

Answer 4

meiosis II

Question 5

Prophase I

Answer 5

homologous pairs line up, forming a tetrad. Allows for recombination. Longest phase, nuclear envelope disappearing. Centrioles migrate to their poles via microtubule organizing centers.

Question 6

Metaphase I

Answer 6

Tetrads line up across the metaphase plate.

Question 7

Anaphase I

Answer 7

Pulling apart homologous sets of chromosomes.

Question 8

Telophase I and Cytokinesis

Answer 8

Each Chromosome actually has 2 copies of genetic info because it was replicated in Interphase. Still considered haploid. 2 haploid cells are produced

Question 9

Meiosis II

Answer 9

Same as Meisosis I except there are no tetrads lining up and pulling apart, it is only sister chromatids. The two haploid cells produced in Meiosis I go through the phase again (similar to mitosis) and produce 4 haploid cells (mitosis produces 2 diploid cells)

Question 10

Nondisjunction

Answer 10

Failure of tetrads to separate during meiosis I or sister chromatids in Meiosis II. Down Syndrome (trisomy 21), Turner syndrome (only X chromosome), Kleinfelters syndrome (extra X)

Question 11

Nondisjunction in MI

Answer 11

two trisomy and two monosomy. monosomy are nonviable offspring. More troublesome than in MII

Question 12

Nondisjunction in MII

Answer 12

1 trisomy, 1 monosomy, 2 normal.

Question 13

Translocation

Answer 13

Movement of a Segment of one chromosome to another non-homologous chromosome (Downs Syndrome- chromosome 21 to 14)

Question 14

Recombination

Answer 14

Adds to genetic diversity, really common. Can have single and double crossover.

Question 15

Linked genes

Answer 15

genes on the same chromosome that probably will not undergo independent assortment. The closer together the chromosome the greater the linkage between genes. The likelihood of recombination increases with distance between genes.