Unit 2 : Multi-cellular Organisms - Sexual Reproduction Flashcards
What do all living things produce ?
Offspring similar to themselves.
In humans, what are the 2 gametes ?
Sperm and egg.
How many chromosomes do human gametes contain ?
23 = haploid
How many chromosomes do normal body cells contain ?
46 = diploid
What are the features of an egg ? (5)
Large in size. 1 produced per month. Unable to move. Has a large food store. Produce in the ovaries.
What are the feature of a sperm ? (5)
Microscopic. Half a billion produced. Can swim. Has no food store. Produced in the testes.
Where does fertilisation take place in humans ?
In the oviduct.
What does the fertilisation of the human male nucleus & female nucleus produce ?
zygote
What is the function of the urethra ?
Carries sperm out of the body.
What is the function of the sperm duct ?
Carries sperm from the testes.
What is the function of the glands ?
Adds fluid to the sperm.
What is the function of the scrotum ?
Protects the testes.
What is the function of the oviduct ?
Carry egg to the uterus.
What is the function of petals on a flower ?
Attracts insects and other pollinators.
What is the function of the sepals ?
Protects the flower bud.
What is the function of the nectary ?
Produces nectar.
What is the male part of a flower called & what structures are within it ?
Stamen = Anther + filament.
What is the function of the anther ?
Makes pollen grain.
What is the function of the filament ?
Provides support for the anther.
What is the female part of a flower called & what structures are within it?
Carpel = ovary + style + stigma
What is the function of the stigma ?
Traps pollen grain
What is the function of the style ?
Pollen tube travels through here.
What is the function of the ovary ?
Produces ovules.
What are the two process involved in sexual reproduction in plants ?
Pollination and fertilisation.
What are the two types of pollination ?
Cross- pollination & self- pollination
What is cross- pollination ?
The transfer of pollen from the anther of one flower to the stigma of another flower.
What is self- pollination ?
This is when the pollen from the anther of a flower is transferred to the stigma of the same flower.
How can pollination carried out ?
By insects or wind.
Describe the stages of fertilisation ?
The pollen grain germinates on the stigma. The pollen grain grows a pollen tube down through the style towards the ovule. The male gamete (nucleus) travels down the pollen tube to the ovule. The male nucleus fuses with the female nucleus inside the ovule. This is fertilisation. The fertilised ovule becomes a seed and the whole ovary swells up to form a fruit.
