Meiosis

Question 1

What does diploid and haploid mean?

Answer 1

diploid - two complete sets of chromosomes one from each parent

haploid is having a single set of unpaired chromosomes

Question 2

What is zygote?

Answer 2

when two gametes, one from each parent, fuse to produce a fertilised egg cell

Question 3

What is a reduction division?

Answer 3

nucleus divides twice to produce four daughter cells - gametes

each gamete contain half of the chromosome from the parent cell

Question 4

What does homologous chromosomes mean?

Answer 4

each nucleus contains matching sets of chromosomes, called homologous chromosomes

each nucleus of the organism’s cells contain two full sets of genes, a pair of genes for each characteristic

Question 5

What are alleles?

Answer 5

different version of the same gene

different alleles of a gene will all have the same locus

Question 6

What is meiosis I?

Answer 6

Meiosis 1 is the first division in the reduction division when the pairs of homologous chromosomes are separated

each intermediate cell will only contain one full set of genes instead of two (haploid)

Question 7

What is meiosis II?

Answer 7

similar to mitosis, the pairs of chromatids in each daughter cell are separated forming two more cells, four daughter haploid cell are produced

Question 8

Which stages of meiosis lead to variation?

Answer 8

Prophase 1:

• bivalents form, crossing over occur
• chaisma occur
• alleles exchanged

Metaphase 1:
-bivalents randomly (independantly) line up on the equator

Metaphase II:
-Independant assortment of chromosomes

Question 9

What other processes lead to variation?

Answer 9

chromosome mutation

non-disjunction

non-sister chromatids

Question 10

What is dis-junction?

Answer 10

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division.