2.2 cell cycle ans mitosis Flashcards
phases of the cell cycle
interphase
mitosis ( PMAT)
cytokinesis
phases of interphase
G1
S phase
G2
what happens in G1
cells grows and new organelles and proteins are made
what happens in s phase
cell replicates DNA
what happens in g2
cells keeps growing
proteins needed for division are made
what happens during mitosis
parent cell divides to produce two genetically identical daughter cells
what is mitosis needed for
growth of multicellular organisms and repair of damaged tissues
phases of mitosis
Prophase
Métaphase
Anaphase
Telophase
structure of chromosomes
- chromosomes are made of two strands (chromatids) joined by a centromere
- two strands on the same chromosome are sister chromatids
what happens during prophase
- chromosomes condense getting shorter and fatter
- centrioles start moving to opposite ends of the cell forming a network of spindle fibres
- nucleur envelope breaks down
what happens during metaphase
- chromosomes line up along the middle of the cell and attach to spindle via centromere
what happens during anaphase
- chromosome dividing separating each pair of sister chromatids
- spindles contract and pull chromatids to opposite ends of the spindle, centromere first
- chromosomes appear v shaped
what happens during telophase
- chromatids reach opposite poles, could and become long and thin again
- called chromosomes again
- nuclear envelope forms around each group of chromosomes so there is now two nuclei
-cytoplasm divides - two genetically identical daughter cells produced
what is a tumour
uncontrolled cell division
how is a tumour formed
mutation in gene that causes cell division
how do you calculate the mitotic index
number of cells with visible chromosomes/total number rid cells observed=mitotic index
