Cell Division B1 Flashcards
What kind of reproduction does meiosis involve?
Sexual
What kind of reproduction does mitosis involve
Asexual
What cells does mitosis produce and what are these called?
Mitosis involves the formation of identical cells. Mitosis leads to the formation of two daughter cells that are identical to the original cell. They are known as diploid cells
What do chromosomes carry?
Genes
What are the 3 stages of the cell cycle
- DNA replicates to form copies of each chromosome
- Mitosis takes place: one set of chromosomes is pulled to each end of the cell. The nucleus also divides.
- The cytoplasm and the cell membrane divide to form 2 identical cells
Functions of mitosis
1.essential for growth and development of multicellular organisms (plants and animals)
2. Mitosis takes place when an organism repairs itself (when a broken bone heals)
3. Takes place during asexual reproduction
What are gametes
Female and male sex cells (sperm and egg cells)
How many chromosomes does a human gamete (sex cell) contain
23
Meiosis only takes place in
Reproductive organs (testes) (ovaries)
Explain the stages of meiosis
- All the pairs of chromosomes are copied
- The cell then divides into 2
- These 2 cells divide again forming the gametes. Chromosomes are now single and not paired (23 in humans)
How many gametes does meiosis form from 1 original cell. These gametes are all
4
Genetically different from one another and has different alleles
In sexual reproduction 2 gametes join together, what is this called?
Fertilisation. - full number of chromosomes has now been restored
What happens after fertilisation?
The new egg cell (which has been made from the fertilisation of the 2 gametes )divides by mitosis producing a new clump of identical cells. This is called the embryo.
