Cells and control Flashcards
Where is genetic material held in a cell?
In Nucleus in form of chromosomes.
Chromosomes = Coiled up lengths of DNA molecules
What happens when a cell divides by mitosis?
It makes two cells that are identical to the original cell.
Nucleus of each cell contains the same number of chromosomes as the original.
When is mitosis used?
For growth and repair
What are the stages of mitosis?
Interphase Prophase Metaphase Anaphase Telophase
What happens during Interphase? (Mitosis)
Dna spread out in long strings
Before division the cell has ri to grow and increase sub cellular structures eg ribosomes
It then duplicates
DNA is copied and it forms X shaped chromosomes
What is prophase? (Mitosis)
Chromosomes get shorted and fatter
Membrane around nucleus breaks down
The chromosomes spread freely in cytoplasm
What happens in metaphase? (Mitosis)
Chromosomes line up at the centre of the cell
What happens in anaphase? (Mitosis)
Cell fibres pull the chromosomes apart
The two parts (arms) of each chromosome go to opposite ends of the cell
What happens in telephase? (Mitosis)
Membranes form around each of the sets of chromosomes
These become the nuclei of the two new cells
Cytoplasm and cell membrane divide to form to separate cells (Cytokinesis)
What are daughter cells?
The product of mitosis
Contains exact same sets of chromosomes
Genetically identical diploid cells
Genetically identical to the parent cell
What is cell differentiation?
The process where a cell changes to become specialised for its job.
How do animals grow?
Cell division (Mitosis)
How do plants grow?
Elongation
Cell division only happens in the tips of roots and shoots
What is cancer?
Uncontrolled cell division
Can be caused by change in one of the genes that controls cell division.
Mass of abnormal cells = Tumour
If the tumour invades and destroys surrounding tissue it’s cancer
What are stem cells?
Stem cells can differentiate into different types of cells
