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
Give one advantage and one disadvantage of sexual reproduction
Advantage - It introduces variation
Disadvantage - It is slower and produces a limited amount of offspring
Give one advantage and one disadvantage of asexual reproduction
Advantage - It produces lots of offspring quickly
Disadvantage - It does not introduce variation and so all offspring are susceptible to the same environmental pressures as the parents
State 3 features of insect pollinated plants
- Bright coloured flowers
- Sweet nectar
- Sticky pollen
State 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 fertilises 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?
Oestrogen causes the uterus lining to thicken
Where is oestrogen secreted from?
The ovaries
What hormone does oestrogen inhibit?
Oestrogen inhibits follicle stimulating hormone (FSH)
What does progesterone do?
Progesterone maintains the uterus lining
Where is progesterone secreted from?
The ovaries
What hormones do progesterone inhibit?
Progesterone inhibits follicle stimulating hormone (FSH) and luteinising hormone (LH)
What does follicle stimulating hormone (FSH) do?
FSH stimulates the follicle to mature and release oestrogen
What does luteinising hormone (LH) do?
A surge in LH causes the release of an egg from a follicle (ovulation)
Where is FSH secreted from?
The anterior pituitary gland
Where is LH secreted from?
The anterior pituitary gland
Where are eggs produced?
In the ovaries
How are eggs adapted to their function?
- They are very large cells
- They contain a large cytoplasm for the lots of divides they undergo
- They have 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
