Fertilisation Flashcards
summarise fertilisation
fusion of egg and sperm to form zygote
what is the main function of fertilisation?
Combining haploid sets of chromosomes from two parent to form single diploid cell
What is the cell formed during fertilisation called?
Zygote
What is polyspermy?
Multiple spem fertilise the egg
Where does fertilisation generally occur in mammals?
Internally, in moist environment to allow sperm to move
What happens to the sperm once in the egg?
Centriole acting as basal body for flagella produces spindles fibres for first mitotic devision.
Where does sperm enter in the egg in amphibians?
In the animal hemisphere
What are the two hemispheres of the egg called?
Vegetal pole and animal pole
What is the animal pole?
Where the nucleus is, consists of several small cells that divide rapidly
What is the vegetal pole?
Contains large yolky cells that divide very slowly, Thought to develop into extra embryonic membranes
How is the animal/vegetal axis determined?
defined by the placement of the nucleus in the egg, occurs before fertilisation
How is dorsal/ventral axis determined?
By point of sperm entry, cells opposite will eventually become dorsal portion of body
What doe dorsal mean?
the upper side or back of an animal, plant, or organ
What does ventral mean?
the underside of an animal or plant
What does anterior mean?
front of the body/ head
