Cells - Mitosis Flashcards
What are 3 uses of mitosis?
Growth of tissues
Repair of damaged tissue
Formation of clones of lymphocytes
Define chromatin
The state of DNA when it isn’t wound up tightly as a chromosome
Define a chromosome
Compact X or I shaped form of chromatin formed during cell division
Define chromatids
The 2 identical arms of an X shaped chromosome
Define centromere
The point at which chromatids are joined
Define homologous chromosomes
2 chromosomes originating from the same parent, containing the same genes but different alleles
Define a centriole
Centriole are organelles that pull chromatids apart during cell division
Define the spindle apparatus
A group of spindle fibres that divides genetic material in a nucleus
What are the 6 stages of the cell cycle
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Describe the interphase
Not strictly part of mitosis
The cell grows and DNA replicates
Chromosomes aren’t visible
Describe the prophase
Chromosomes condense and become visible
Centrioles move to opposite poles of the cell
Spindle apparatus form from spindle fibres at the centriole
Describe metaphase
Nuclear envelope breaks
Chromosomes align along equator of the cell -> pulled by spindle apparatus
Describe anaphase
Centromeres split, allowing chromatids to separate
Chromatids move towards poles, pulled by spindle fibres
Describe telophase
Spindle fibres disperse
Nuclear envelopes reform
Chromosomes decondense
Define cytokinesis
A ring of protein filaments form around equator of cell, which then tightens and splits the cell into 2
How is cell division regulated?
There are checkpoints between each stage of the cell cycle, regulated by control genes
What is the effect of mutated control genes?
Cells dividing uncontrollably -> leading to tumours
Define a benign tumour
Slow growing Doesn’t spread to other parts of the body Not classed as cancer
Define a malignant tumour
Fast growing Often spreads throughout the body Classed as cancer
Name 5 lifestyle changes the can prevent cancer
Smoking
Diet (high fat, low fibre)
Obesity
Physical activity
Sunlight
Name 3 treatments for tumours
Surgery
Radiotherapy
Chemotherapy
Name the 4 types of chemotherapy functions
Blocking enzymes in DNA synthesis
Preventing DNA unwinding
Inhibiting synthesis of new nucleotides
Preventing development of the mitotic spindle
