3.3.2 - Fertilisation In Mammals

Question 1

How Does The Sperm Cell Travel Up The Cervix?

Answer 1

Follows a chemical signal released by the egg cell to reach the uterus.

Question 2

When Does Fertilisation Occur?

Answer 2

When the sperm cell reaches the oviduct.

Question 3

What Is Fertilisation?

Answer 3

The fusion of the nuclei from a male gamete and a female gamete.

Question 4

Describe The Acrosome Reaction

Answer 4

When the acrosome releases digestive enzymes that digest a path through the zona pellucida allowing the sperm to pass through the egg cell membrane.

Question 5

Describe The Cortical Reaction

Answer 5

The chemicals inside the cortical granules cause the zona pellucida to rapidly thicken and harden, preventing any more sperm from entering and ensuring only one sperm cell can fertilise the egg.

Question 6

Describe The Process Of Fertilisation
(6 Points)

Answer 6

~ Acrosome reaction.

~ The egg cell then releases cortical granules from its vesicles into the space between the egg cell membrane and the zona pellucida.

~ Cortical reaction.

~ Nucleus of the sperm cell enters the egg and fuses with the nucleus of the egg cell, forming a zygote.

~ Zygote divides by mitosis, to form 2 new cells and will continue to divide until an embryo is formed.

~ Cell division continues until many of the new cells produced become specialised to perform particular functions and form body tissues.

Question 7

How Many Chromosomes Does A Zygote Have?

Answer 7

46.