Meiosis

Question 1

Discuss how independent assortment affects genetic variation

Answer 1

Independent assortment increases genetic variation when chromosome pairs are separated. This is because each new cell has a new combination of chromosomes.

Question 2

Discuss how crossing over effects genetic variation

Answer 2

The process of crossing over during meiosis reshuffles existing alleles into new combinations which increases genetic variation.

Question 3

Explain the process of independent assortment and when it occurs

Answer 3

The process of independent assortment occurs after crossing over and is where homologous chromosomes line up randomly at the cells equator prior to cell division. Therefore it means only one chromosome from each homologous pair is placed in each gamete.

Question 4

Explain the process of crossing over and when it occurs

Answer 4

Crossing over is when homologous pairs of chromosomes pair up to exchange sections of genetic material during meiosis after DNA replication.

Question 5

Describe genetic variation

Answer 5

Genetic variation is the differences in genetic information between individuals in a population.

Question 6

Discuss how linked genes affect genetic variation

Answer 6

Because of the unlikelihood that linked genes will be separated by crossing over, it means that the final gametes produced by meiosis will have less genetic variation compared to gametes produced by individuals with unlinked genes. Linked genes mean the offspring phenotypes will be similar to the parental generation.

Question 7

Describe linked genes

Answer 7

Linked genes are genes/alleles that are found together on the same chromosome and are therefore more likely to be inherited together.

Question 8

Describe unlinked genes

Answer 8

Unlinked genes are found on different chromosomes or are found far apart on one chromosome and are more likely to be separated by crossing over.

Question 9

Discuss how unlinked genes affect genetic variation

Answer 9

Because crossing over is likely to separate unlinked genes that are found further away from each other on the same chromosome because of distance it means that the unlinked genes create more unique gametes. Hence the offspring will have more phenotypic variation.

Question 10

Explain why linked genes do not independently assort during meiosis

Answer 10

Independent assortment does not separate linked genes. Linked genes occur on the same chromosome and are likely to be inherited together, because they cannot be separated by independent assortment. This is because genes like these found close to each other on the same chromosome are less likely to be separated via crossing over and therefore, will also stay together during independent assortment. This means linked genes are ultimately more likely to stay together and be inherited together.