3A Reproduction Flashcards
What is the difference between asexual reproduction and sexual reproduction?
- Asexual reproduction involves mitosis to produce genetically identical copies
- Sexual reproduction involves the combination of sperm and egg cells to create a zygote
What is the difference between a zygote and an embryo?
The zygote is the diploid cell formed from the fusion of a sperm and egg cell, it becomes an embryo after it begins to divide.
1 adavantage and 1 disadvantage of sexual reproduction
Adv - it introduces variation
Disadv- it is slower and produces limited amount of offspring
1 advantage and 1 disadvantage of asexual reproduction
Adv - It produces lots of offspring quickly
Disadv - It does not introduce variation and so all offspring are susceptible to the same environmental pressures as the parents
3 features of insect pollinated plants
- Bright coloured flowers
- Sweet nectar
- Sticky pollen
3 features of wind pollinated plants
- No bright colours
- Stigma exposed to the air
- Light pollen
Describe the process of fertilisation in plants
- Pollen grain lands on the stigma
- Pollen tube begins to grow from the pollen grain into the ovary
- Pollen grain travels down the pollen tube and fertilizes the egg
- Fruit and seeds form from the egg
How can seeds grow before they can photosynthesise?
They use energy stores of starch
Give one natural example of plant cloning
Plant runners from strawberries and spider plants.
Give one artificial example of plant cloning
Tissue cuttings placed in a growth medium
What does oestrogen do?
Builds up uterus linning
Where is oestrogen secreted from?
The ovaries
What hormone does oestrogen inhibit?
follicle stimulating hormone (FSH)
What does progesterone do?
Progesterone maintains the womb lining
Where is progesterone secreted from?
The ovaries
What hormone does progesterone inhibit?
Follicle stimulating hormone (FSH).
Where are eggs produced?
In the ovaries
How are egg cells adapted to their function?
- They are very large cells
- They contain a large cytoplasm for the lots of divisions they undergo
- They have a haploid nucleus
How are sperm cells adapted to their function?
- Acrosome contains enzymes so the sperm can penetrate the egg
- Haploid nucleus
- Tail so that it can swim to the egg
- Lots of mitochondria for energy
What is the purpose of amniotic fluid?
To protect the developing fetus
What is the purpose of the placenta
To allow nutrients and oxygen to pass from the mother to the fetus during development
What role does oestrogen play during puberty
- Increases breast size
- Triggers the development of the uterus
- It causes eggs to mature during the menstrual cycle
What role does testosterone play during puberty?
- Triggers growth and development of the penis and testes
- Causes the voice to deepen
- Triggers the growth of pubic hair
- Increases muscle mass
