31) Unit 2 - Meiosis

Question 1

what is meiosis

Answer 1

the process whereby 1 diploid gamete mother cell divides into 4 dissimilar haploid gametes

Question 2

Describe the process of meiosis 1

Answer 2

1) The chromosomes coil up and become visible as two sister chromatids joined by a centromere
2) The homologous chromosomes pair up so they are alligned gene by gene to form a bivalent
3) Chiasmata form at random positions between the homologous chromosomes and allow crossing over of sections of DNA between the chromosomes
4) The nuclear membrane breaks down to allow microtubles to attach to the centromeres of the chromosomes at the equator
5) The chromosomes are positioned randomly irrespective to their parental origin. this is called independent assortment
6) The homologous chromosomes are separated by the spindle fibers and are pulled to opposite ends of the cell
7) A nuclear membrane forms around the chromosomes and cytokineses separates the cell into two

Question 3

describe the process of meiosis 2

Answer 3

1) Each cell is haploid as it contains just 1 copy of each homologous chromosome
2) The nuclear membrane breaks down and microtubles bind to the centromere of each sister chromatid at the equator
3) Microtubles shorten and pull the sister chromatids to opposite ends of the cell
4) A nuclear membrane forms around each set of chromosomes and cytokinesis separates the cell in two
5) At the end of meiosis, 4 genetically dissimilar haploid cells have been produced

Question 4

What are the characteristics of a homologous chromosome

Answer 4

• Same size
• Same centromere position
• Same genes at the same loci

Question 5

what processes in meiosis are responsible for the genetic variation

Answer 5

crossing over and independent assortment

Question 6

which genes are more likely to be separated during crossing over?

those that are close together or those that are far apart

Answer 6

further apart