Sexual reproduction Flashcards
(26 cards)
What is internal fertilisation?
This is the union of an egg cell and sperm cell, which occurs inside a woman.
What is external fertilisation?
This is when a sperm cell fertilises an egg cell outside of the female’s body.
What is a gamete?
This is a cell whose nucleus join with another cell to form a new organism.
How many sperm make it to the egg?
Around 36.
How many sperm cells are originally released?
300 million.
What happens to the majority of sperm?
They die because they get trapped/caught in cilia or they might die in acid.
How many chromosomes does each sex cell (sperm or egg) have ?
23.
What is describes as ‘the beginning of a new human’?
Fertilisation-sperm and egg combine to make a zygote.
Whats is sexual reproduction?
When an offspring is created by two parents.
Name 3 features that makes sperm cells suits its function.
- Long tail
- No food store
- Pointy head
- Millions made each day
Name 3 features that makes egg cells suits its function.
-Has a membrane so only 1 sperm can enter.
-Its large.
-Can’t move much.
1 or 2 made per month.
What is amniotic fluid?
A watery substance surrounded around the body, serves as a layer of protection.
What is an amnion?
A bag containing amniotic fluid.
What is a placenta connected to?
Mother’s uterus.
What is waste materials?
Things like carbon dioxide that are waste products of respiration.
What is the name of the zygote when it is 100 cells big?
Blastocyst.
When does the first splitting of identical twins start?
First week.
What happens if the splitting of identical twins occurs earlier?
They develop more independently.
If a cell divides later, what three features do they share?
Amnion, chorion and placenta.
What is another name for non-identical twins?
Fraternal twins.
Can non-identical twins share a placenta.
No, both babies do not share the same features.
Name 6 things that happen when males grow up.
- Testes and penis gets bigger.
- Testes produce sperm.
- Voice breaks.
- Hair growth on face and chest.
- Shoulders get wider.
Name things that both genders have when they grow up.
- Underarm hair.
- Body odour stronger.
- Growth rate increases.
- Mood swings.
- Pubic hair.
Name 6 things that happen when females grow up.
- Breasts develop.
- Hips get wider.
- Ovaries start to release egg cells.
