Unit 4, Meiosis

Question 1

How many nuclear divisions are in meiosis? And what characteristics of a cell are produced?

Answer 1

Two nuclear divisions, that creates 4 haploid daughter cells that are genetically different.

Question 2

What is independent segregation?

Answer 2

-homologous pairs line up opposite each other at the equator
-when 4 daughter cells produced there are lots of combinations. Eg) in humans 2^23

Question 3

What is the formula for calculating combinations?

Answer 3

2^n , when n= number of homologous pairs of chromosomes

Question 4

What is crossing over?

Answer 4

-parts of chromatids become twisted, causing part of chromatid to snap
-when broken off it re-combines with other chromatid
-new combination of alleles

Question 5

What is the difference between meiosis and mitosis?

Answer 5

Meiosis- two nuclear divisions, haploid cell, genetic variation
Mitosis-one nuclear division, diploid cell (two chromosome set), genetically identical