Unit 2 - AOS2 - Sexual reproduction

Question 1

Fertilisation

Answer 1

two haploid sex cells unite
- sperm(n) + egg cell(n) = zygote(2n)

“combination of genetic material from sleek and egg cell to form a zygote (single felled embryo)”

(embryo continues to develop and grow through mitosis (2n -> 2n)

Question 2

Genetic variability

Answer 2

shuffling of genetic material

• independent assortment
• crossing over
  -random fertilisation

Question 3

results of meiosis in terms of gametes and type of ploidy

Answer 3

gametes produced in sex organs by meiosis (2n -> n)

gametes = sperm and egg
1 diploid cell -> 4 haploid cells

Question 4

Independent assortment

Answer 4

• During Metaphase I
  “Homologous chromosomes may align to the left of right of the equator with no method.”

Question 5

Crossing over

Answer 5

• During Prophase I to Metaphase I
  ‘Homologous chromosomes (paternal and maternal) line up and can exchange complementary genetic material.
• point of cross = chiasma

Question 6

Advantages of meiosis

Answer 6

• Gametes with many different combinations of parental chromosomes are possible
• Offspring are genetically different from parents and from each other

Question 7

Disadvantages of meiosis

Answer 7

• Energy is required for produce organs for sexual reproduction
• Energy is required to find a mate
• Competition for mates