2.1 producing new cells Flashcards
i can identify the part of a cell which controls the process of cell division (mitosis)
nucleus
what is mitosis
Mitosis is the process in which an organism can increase its cell numbers during growth and repair
I can state the meaning of “chromosome complement”
The chromosome complement of an organism means the number of chromosomes that it’s cells contain
Diploid
Two sets of chromosomes found inside a normal body cell
The importance of each daughter cell having the same number of chromosomes as the original parent cell
Daughter cells must have the same number of chromosome as the original parent cell to en-surethey contain a full set of genetic information to be able to function normally
two cells formed at the end of mitosis
daughter cells
chromotids
two identical copies of chromosomes that are formed when a chromosome doubles immediately before the cell undergoes mitosis. The pair of identical chromatids are then held together es by the centromere until they are pulled apart by the spindle fibre
equator
middle zone of the dividing cell. This is where the pairs of chromosome will line up and attach to spindle fibres
spindle fibres
appear in a dividing cell when the nucleus membrane disappears. The spindle fibre are made of proteins and are anchored at opposite ends of the cell. When the spindle fibre contracts they pull the pairs of chromosomal apart and pull the newly formed single chromosomes to the opposite poles
stage 1 of mitosis
Original parent is preparing for mitosis. The chromosomes are undergoing DNA replication and coiling up to become visible
stage 2 of mitosis
each chromosome has now doubled to become two identical pair of chromotids
stage 3
the nucleus membrane disappears and the spindle fibre appears. The double chromosomes migrate to the equator and line up attached to the spindle fibres
stage 4
the spindle fibres start to contract pulling the identical chromatids apart to the opposite poles of the cell
stage 5
The spindle fibres disappear and two new nucleus members appear around each set of chromosomes clustered at opposite poles.
stage 6
the cell cytoplasm starts to divide and two new cells membranes form across the centre of the original cell dividing it completely to form two identical daughter cells