Cell cycle Flashcards
What is the cell cycle?
series of changes that a cell undergoes from the time it forms until it divides
What are the major phases of the cell cycle?
Interphase
Mitosis
Cytoplasmic division (cytokinesis)
Function of interphase
cellular components duplicate
What happens in mitosis and cytokinesis
cell splits into two
distributing its contents into two daughter cells
What happens in S phase
When genetic material (DNA) replicates
What are the mitosis stages
Prophase
Metaphase
Anaphase
Telophase
What is the restriction checkpoint?
cell chooses to die
remains specialised exit cell cycle
continue in cycle+ divide again
Ensure cellular parts are duplicated and chromosomes are distributed
What is checkpoints?
When proteins interact at certain times in cell cycle- control whether the cell cycle progresses
Cell division in the cell cycle
Stimulation from hormone or growth factors can trigger cell division
If cell division is too frequent a wound cannot replace damaged cells
What causes cancer?
results from changes in genes (mutations)
Alter cell cycle in somatic cells (cells that aren’t sperm/egg)
Characteristics of cancer
Uncontrolled cell division
Cancer cells make telomerase -keeps chromomeres long silences signals that would stop cell division
What is dedifferentiation?
loss of specialised structures and functions of the normal type of cell
What is invasiveness?
ability of cancer cells to break through boundaries that separate cell cycle
What is angiogenesis?
Ability of cancer cells to induce extensions of nearby blood vessels
What is metastasis?
spread of cancer cells to other tissues, through the bloodstream or lymphatic system
What is telomeres
when telomeres shorten to a certain length cell no longer divides
What does the enzyme telomerase do?
keep telomers long in cell types that must continually divide
What are the two types of cell division?
mitosis
meiosis
What is meiosis?
formation of egg/sperm cells
What is mitosis?
Division of the nucleus
What happens in interphase?
Chromosomes are visible as chromatin fibres
Single pair of centriole is present
what happens in prophase?
Chromosomes have condensed
centriole have replicated each pair moves back to opposite end of the cell
Nuclear envelope and nucleolus disappear and spindle fibres
What happens in metaphase?
Chromosomes line up at centriole
What happens in anaphase?
Centromeres are pulled apart by spindle fibres
Chromosomes line up midway between centrioles
