1.4 Steps Of Fertilisation In Mammals

Question 0

Stage 1) CONTACT

Answer 0

Sperm come in contact with secondary oocyte

Calcium ions enter sperm head

Stimulates sperm to release Acrosome enzymes

Acrosomal reaction

Question 1

Alkaline semen provides a medium for sperm to swim, also contains hormones called prostaglandins which stimulate contraction of the uterus and oviducts to assist the

Answer 1

Movement of the sperms

Question 2

Stage 2) ACROSOMAL REACTION

Answer 2

Acrosome swells
Cell membrane of sperm fuses with the membrane of Acrosome

Contents flow out
Hydrolytic Enzymes released

Digest zona pellucida

Question 3

Stage 3) ATTACHMENT OF SPERM TO OVUM

Answer 3

Sperm binds to the membrane of the ovum

Question 4

Stage 4)

Answer 4

Fusion of sperm and ovum membrane

Question 5

Stage 5) CORTICAL REACTION

Answer 5

cortical granules move towards the ovum membrane to release their contents into the zona pellucida

Hardens the zona pellucida - prevents polyspermy

Question 6

Stage 6) FERTILISATION

Answer 6

The haploid sperm fuses with the haploid ovum nucleus to form diploid zygote nucleus