Unit 2 Section 2- Meiosis

Question 1

By what process are gametes formed?

Answer 1

Meiosis

Question 2

What happens during meiosis?

Answer 2

• chromosomes condense and arrange themselves into homologous pairs
• crossing over of chromatids
• homologous pains join to spindle by their centromere at equator
• homologous chromosomes move to opposite poles of the cell and are separated
• sister chromatids separated in second cell division
• 4 genetically different gametes formed

Question 3

How does meiosis contribute to genetic variation?

Answer 3

Independent segregation of homologous chromosomes and crossing over

Question 4

What is crossing over of chromatids?

Answer 4

During meiosis 1 homologous pairs of chromosomes pair up
Chromatids twist around each other and bits of chromatid swap over
They have the same genes but different combinations of alleles.

Question 5

What is independent segregation of homologous chromosomes?

Answer 5

All cells have a combination of maternal and paternal chromosomes
During meiosis different combinations of maternal and paternal chromosomes go u to each cell

Question 6

How is DNA from one generation passed onto the next?

Answer 6

Sperm and egg cell both contain a haploid number of chromosomes, when they fuse they combine their DNA to form a cell with normal diploid number of chromosomes, half of the chromosomes are from the father and half are from the mother