11. Cell Reproduction - Mitosis and Meiosis
What is the end result of mitosis?
2 new, identical diploid body cells
How many chromosomes are there in the daughter cells of meiosis?
23
How many chromosomes does a haploid nucleus carry?
23 chromosomes
What is the end result of meiosis?
4 unique haploid reproductive cells
How many chromosomes are there in the daughter cells of mitosis?
46
How many chromosomes does a diploid nucleus carry?
46 chromosomes
What is a diploid nucleus?
A diploid nucleus is the sort of nucleus that a somatic cell has.
Name the female sex cell
A female gamate/sex cell is called the ovum (or egg)
What is duplicated during mitosis or meosis?
A full set of chromosomes is duplicated and then evenly distributed to both daughter cells.
What is a haploid nucleus?
A haploid nucleus is the sort of nucleus that a gamate has. Carrying HALF genetic information. Many will mature into sperms and eggs, the reproductive cell called GAMATES.
What does fertilisation lead to?
A zygote, which is a diploid cell which has two copies of each chromosome, one from the father and one from mother.
Cell Cycle
Damaged, dead and worn out cells can be replaced by growth and division. This works a bit like a washing machine cycle - each stage must be finished completely before the next one is allowed to start.
What is the name of the copied cells?
Daughter cells
How many 'copies' cells are created during Meiosis? What are they called?
During Meiosis, 4 copies are called. 4 haploid cells which are called GAMETES (sex cells i.e. sperm) They have half genetic information each.
What is fertilisation?
Fertilisation is the fusion of a female and male gamate
What is the name of cells whilst in a neutral state
G0 resting phase
What is a gamate?
Gametes are an organism's reproductive cells. They are also referred to as sex cells.
What sort of nucleus do gametes have? How many chromosomes do they have?
Gametes have a haploid nucleus, which has 23 chromosomes. With half UNPAIRED genetic information from mother, half from father.
When does mitosis occur in sex cells?
In fertilised sex cells.
What is the name of the cell before it splits?
Interphase
What is Meiosis?
Meiosis is the coping of sex cells. Formation of Gametes (sex cells) e.g. ova & spermatozoa
What is mitosis?
Mitosis is the copy of NON sex cells. 2 cells identical to the original mother cell are created, called daughter cells.
Why does mitosis occur?
Mitosis occurs for growth and repair of cells. e.g. to maintain the bodies structure.
What sort of cells do not undergo any new mitosis, shortly after birth?
Nerve cells Muscle Cells Egg Cells
describe mitosis process
PROPHASE, nucleus breaks down, releasing DNA META PHASE chromos align in centre of cell ANA PHASE cells go to either side of cell TELOPHASE diapolod nucluar membrane forms Cell splits
describe meiosis process
PROPHASE, nucleus breaks down, releasing DNA META PHASE chromos align in centre of cell and 'cross over' information share chromos seperate onto opposite sides cell is split cell breaks down again into two creating 4 unique HAPLOID CELLS called GAMATES
What is the purpose of meiosis?
Reproductions
What sort of cells undergo continuous mitosis?
Skin cells undergo continuous mitosis
What sort of cells does mitosis usually occur in?
Somatic Cells (non sex cells). 1 division creates 2 identical daughter cells to the original mother cell
What sort of nucleus do somatic cells have after meiosis? How many chromosomes do they have?
Somatic cells have a diploid nucleus, they have 46 chromosomes.
What sort of cells do not undergo mitosis UNLESS repairing minor damage? What is the exception?
The Liver cells. However, major liver damage may present too much damage to be repaired through mitosis.
How many divisions are there during Meiosis?
There are 2 divisions during meiosis.
How many cells are created from 1 division during mitosis?
Two identical daughter cells.
What is a haploid cell?
a cell with a haploid nucleus, containing half genetic information (23 chromos)
Apoptosis
cells self destruct, components are removed by phagocytosis
What is the =fusion of a female and male gamate called?
fertilisation.
Are the cells from meiosis identical?
no, they are different
What happens to the zygote?
the zygote undergoes mitosis, turns into the embryo and then a foetus after 8 weeks.