Part 3: Fertilization Flashcards
(16 cards)
What is fertilization?
sperm cell fuses with egg cell to make zygote
How sperm cell fuses with egg (step 1)
Sperm reaches the egg through female reproductive tract (internal) or near egg (external).
How sperm fuses with a egg (step 2)
Sperm uses enzymes to break through eggs outer layers
How sperm fuses with a egg (step 3)
Sperm receptor proteins bind specifically to egg surface receptors.
How sperm fuses with a egg (step 4)
Once sperm bonds, egg prevents other sperm from entering
How sperm fuses with a egg (step 5)
Sperms nucleus enters egg, combining genetic material to form a diploid zygote.
What is zygote?
Single cell formed right after fertilization
What is embryo?
From fertilization up to 8 weeks - organs begin forming
What is fetus?
From 9 weeks to birth - growth and development of systems
How fraternal twins (dizygotic) form
2 eggs released and fertilized by 2 different sperm.
How identical twins (monozygotic) form
1 egg is fertilized by 1 sperm
What is internal fertilization
Happens inside body.
Less eggs needed, protects embryo
What is external fertilization
Outside body, in water.
Lots of eggs and sperm. Less chance of survival
Viviparous description
Fetus made in womb
Most mammals
Oviparous description
Embryo made outside in an egg.
Birds, reptiles, most fish, insects
Ovoviviparous description
Embryo made inside egg that stays in body till hatches
Ex some sharks, reptiles
