Meiosis

Question 1

Why does meiosis occur?

Answer 1

To produce 2 haploid cells which have varied gametes for reproduction and variation

Question 2

Name the 4 causes of variation

Answer 2

Crossing over
Random assortment
Random gamete selection
Mutations ( gene and chromosomal )

Question 3

What happens during crossing over ?

Answer 3

Alleles from 1 chromosome switch with alleles from another chromosome

Question 4

After crossing over has occurred, what is the resultant chromatid called ?

Answer 4

Recombinant chromatids

Question 5

The point at which the two alleles cross is called the …

Answer 5

Chiasma

Question 6

Crossing over occurs in which phase ?

Answer 6

Prophase 1

Question 7

What happens during Random Assortment ?

Answer 7

Chromosomes line up randomly at equator

Question 8

Which phase(s) does Random Assortment happen ?

Answer 8

Metaphase 1 And 2

Question 9

Explain Random Gamete Selection

Answer 9

No individual controls which sperm will fertilize which egg

Question 10

What is a mutation?

Answer 10

A spontaneous change in the genetic code

Question 11

Explain a gene point mutation

Answer 11

Error in placing of nucleotides. Addition. Substitution. Deletion. Occurs in Interphase

Question 12

Explain a chromosomal mutation

Answer 12

Caused during meiosis in formation of gametes. Extra or missing chromosome.

Question 13

What causes an extra or missing chromosomes in a chromosomal mutation?

Answer 13

Nondisjunction

Question 14

What will Nondisjunction cause?

Answer 14

Aneuploidy

Question 15

Define Nondisjunction

Answer 15

The failure of homologous chromosomes to separate properly during meiosis

Question 16

When will Nondisjunction occur ?

Answer 16

During gametogenesis

Question 17

Define Aneuploidy

Answer 17

An extra or missing chromosome

Question 18

Why does mitosis occur ?

Answer 18

To produce 2 diploid cells which are identical to the parent cells