Chapter 1- Cell Division Flashcards
What is mitosis?
Mitosis is the division of the nucleus in two genetically identical daughter nuclei
What is interphase?:G1?
Growth of cell and increase in number of organelles
Interphase: What is S phase
Replication of chromosomes copies remaining attached to one another
Interphase: What is G2?
Further growth occurs, organelles increase in number, DNA condenses to form visible chromosomes, micro tubules begin to form
What happens after G2?
After interphase and the DNA has replicated, the cell moves into mitosis
What happens during mitosis
During mitosis the replicated chromosomes separate and move to opposite poles of the cell thus providing the same genetic material to each of these locations
What are the 4 phases of mitosis
Prophase, metaphase, anaphase, telophase
What 2 things happens in metaphase
1) all replicated chromosomes (chromatid pairs) align at equator
2) all chromatid pairs have myofibril network attracted to centromere
What 4 things happen in prophase
1) centriole replicates and moves towards ‘poles’ of the cell
2) develops myofibril network (proteins attach to centromere)
3) nuclear membrane breaks down
4) condensation of chromosomes
What 1 thing happens in anaphase
1) myofibril network pulls chromatid pairs apart and moves a set of chromosomes to each ‘pole’
What 4 things happen in telophase?
1) centriole remaining in each new prospective cell
2) nuclear membrane reforming
3) chromosomes de condense
4) breakdown of myofibril network
What happens after mitosis
Cytokinesis
What happens in animal cytokines?
1) the plasma membrane pulls inwards around the equator of the cell to form a cleavage furrow
2) when the cleavage furrow reaches the centre, the cell is pinched apart into two daughter cells
What are cyclins?
Group of proteins that ensure that tasks are performed at the correct time and that the cell only moves onto the next stage of the cycle when it is appropriate
What do tumour suppressor genes produce?
Proteins which inhibit cell devision
mutations to tumour suppressor genes result in?
Uncontrolled cell devision = tumour
What can tumours do?
Grow in size which can cause damage to local tissue and may spread to other parts of the body
How can tumours form?
Because of random changes to the base sequences of genes
What are carcinogens?
What time of tumour are they?
1) Chemicals and agents that cause cancer
2) malignant tumours
What are oncogenes?
Few genes that can become cancer-causing after mutating
In a normal cell oncogenes are involved in the control of the cell cycle and cell devision therefore mutations in then cause what?
Result in uncontrolled cell decision and tumour formation
What is a primary tumour?
When a tumour cell has been formed it divides repeatedly to form Two, then four, then eight cells and so on
What is metastasis?
The movement of cells from a primary tumour to set up secondary tumours in other parts of the body
What else involes mitosis?
Growth, embryonic development, tissue repair and asexual reproduction
