Question

1.) Describe the differences and similarities of mitosis and meiosis.

2.) Define homologous chromosomes, homologous, synapse, crossing over, reduction division, independent assortment, and synaptonemal complex.

3.) Describe the mechanisms that increase genetic diversity through sexual reproduction.

Answer 1

1. Differences- Mitosis happens in body cells, meiosis happens in sex cells. In mitosis there is one cell division, in meiosis, there are two cell divisions. In mitosis there is no recombination or crossover, in meiosis, there is recombination or crossover. Mitosis produce two diploid daughter cells, meiosis produces four haploid daughter cells. In mitosis daughter cells are identical, in meiosis daughter cells are genetically different.

Similarities- Both create new cells. They follow similar steps. Both begin from one parent cell.

2. Homologous chromosome- For diploid organisms, homologous chromosomes are the chromosome pairs with the same length, banding pattern, centromere position and other. For a pair, each part is being inherited by each parent.

Synapse- Synapse is the cross over of two homologous chromosomes during meiosis.

Crossing over- In meiosis, among homologous chromosomes there is exchange of genes which is called crossing over.

Reduction division- In meiosis, the first cell division where chromosome number is reduced to half (from diploid to haploid) is the reduction division.

Independent assortment- If there are two alleles then the assortment or distribution of alleles in the gametes are independent of each other.

Synaptonemal complex- During meiosis, the protein structure formed at the region of crossing over of homologous chromosome for exchange of genes.

3. The random crossing over between homologous chromosomes during meiosis is the main reason behind genetic diversity through sexual reproduction.