Reproduction and growth Flashcards
What is mitosis?
Its a type of cell division in which a diploid cell copies itself and finally divides into 2 identical diploid daughter cells. All the daughter cells are identical
How many chromosomes are in a diploid human cell?
46 chromosomes
Explain the process of mitosis?
The cell grows
DNA is copied to form 2 copies of each chromosome. These copies are joined together at a single point
The nuclear membrane breaks down
The chromosomes line up across the centre of the cell
The copies of chromosomes are pulled apart and move to opposite ends of the cell
The cytoplasm and cell membrane divide to form 2 different cells
What are chromatids?
Copies of cell DNA
What is meiosis?
A type of cell division which gives rise to cells that are genetically different.
Where does meiosis take place?
In the sex organs
What are the type of cells formed from meiosis?
Gametes
How many chromosomes are in a haploid human cell?
23 chromosomes
Explain the process of meiosis?
Parent cell grows
DNA replicates to form 2 copies of each chromosome, they are then joined together at a single point (centromere)
nuclear membrane breaks down
Homologous pairs of the chromosomes join together
The pairs exchange sections of dna
They attach to the spindle fibres
They are pulled apart and move to opposite ends of the cell
The cell divides
This process repeats with the new cells
What are sperm?
Sperm have a tail like flagellum that moves through the water
What are egg cells?
Produced monthly in female humans from the ovaries
What is external fertilisation?
In fish, they release the egg and the sperm into the water and the sperm swim through the water to the egg. Occurs outside the body
What is internal fertilisation?
Male animals including birds and mammals release there sperm into the bodies of females. Fertilisation occurs inside the female.
What is fertilisation?
When a haploid sperm cell and a haploid egg cell fuse together to make a diploid cell
What is a zygote?
The first cell that is formed through fertilisation
What is the ovary?
Where the egg cells are formed by meiosis. Produces hormones oestrogen and progesterone
What is the oviduct?
Egg cells travel down this to the uterus. Lined with cilia which move the cell. Site of fertilisation
What is the uterus?
A lining forms in the uterus, where the embryo will implant. The foetus develops in the uterus, which has a thick muscular wall. This contracts during labour
What is the cervix?
Narrow opening to the uterus. This widens during labour, to allow the baby to be born
What is the vagina?
Muscular tube that leads from the cervix to the outside of the womans body
What are the testes?
Where sperm cells are formed by meiosis. Produces the hormone testosterone
What is the sperm duct?
Maturing sperm are transported through this tube
What are the seminal vesicles and prostate gland?
Release liquids into the sperm duct which mixes with the sperm cells to form semen. Provides nutrients for the sperm
What is the Urethra?
Tube inside penis which can transport either urine or semen
