Lesson 19 - Meiosis

Question 1

How is genetic variation created in Meiosis?

Answer 1

1. Crossing over in prophase I.
2. Independent assortment of chromosomes in metaphase I.
3. Independent assortment of chromosomes in metaphase II.
4. Production of haploid gametes that will fuse with the gametes of another organism.

Question 2

Gametes

Answer 2

Sex cells

Question 3

Zygotes

Answer 3

fertilised egg

Question 4

Why is meiosis known as reduction division?

Answer 4

• Contains half a chromosome number of the parent cell - haploid.

Question 5

Homologous Chromosomes:

Answer 5

• Nucleus of the organism’s cells contains two full sets of genes –> a pair of genes for each characteristics.
• Same genes at same loci.
• Centromeres in the same position.

Question 6

Alleles / gene variants

Answer 6

Different versions of the same genes.

Question 7

Stages of meiosis

Answer 7

• Meiosis 1 –>
  - first division is the reduction division when pairs of homologous chromosomes are separated into two cells.
  - Intermediate cells will only contain one full set of genes instead of two, haploid.
• Meiosis 2
  - second division is similar to mitosis and the pairs of chromatids present in each daughter cell are separated, forming two more cells.

      - Four haploid daughter cells are produced in total.

Question 8

Prophase 1

Answer 8

• Chromosomes condense
• Nuclear envelope disintegrates
• Spindle formation begins.
• Homologous chromosomes pair up, forming bivalents.
• Move through lipid cytoplasm and they are brought together –> chromatids entangle. (Crossing over)

Question 9

Metaphase 1

Answer 9

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