chapter 17: meiosis genetic variation and errors

Question 1

what happens in the bivalent

Answer 1

crossing over

Question 2

sorting chromosomes into new cells after crossing over

Answer 2

1. meiotic spindles attach to chromosomes
2. spindles pull chromosomes to middle of dividing cell in a vertical line on the metaphase plate - assorted randomly
   - the lining up of homologous chromosomes in meiosis 1 determines which grandparents chromosome a gamete receives

Question 3

gene notation - drosophila genetics

Answer 3

• named after mutant phenotypes
• wildtype gets +

Question 4

nondisjunction

Answer 4

• results in gametes with an extra chromosome
• and gametes that are missing a chromosome
• can occur in meiosis 1 or 2
• increases in occurrence with parent age

Question 5

pathogen exposure increases what

Answer 5

rate of sexual reproduction