2.6 cell division and cellular organisation Flashcards
(17 cards)
What does ipmatc stand for
interphase, prophase, metaphase, anaphase, telophase, cytokinesis
in G1 and G2 what 2 things can G stand for
Growth or gap
what 4 things are in interphase
G1, G0, S, G2
what happens in G1
Cells grow and new organelles and proteins are made
What happens in G0 (G1 checkpoint)
The cell checks that the chemicals needed for replication are present and for any damage to the DNA before entering the S phase
What happens in S
the cell replicates DNA ready to divide by mitosis
what happens in G2
the cell kepps gorwing and proteins needed for cell division are made
what happens at the G2 checkpoint
the cell checks whether all the DNA has been replicated without any damage. If it has, the cell can enter mitosis
Why is mitosis needed
Growth of muiticellular organisms, repairing of damaged tissues and asexual reproduction
Describe what happens in the prophase
the nuclear envelope breaks down then chromosomes condense, and centrioles start moving to the poles
each chromosome is made of 2 strands joined by…
a centromeere
what are seperate strands of chromosomes called
chromatids
What happens in metaphase
chromosomes become attatched to spindle fibres by the centromere and line up along the equator of the cell. The cell checks that all chromosomes are attatched to the spindle fibres before mitosis continues
What happens in anaphase
centromeres divide, seperating each pair of sister chromatids. motor proteins contract the spindles pulling chromatids to the poles of the cell.
What happens in telophase
Chromatids reach each opposite poles. A nuclear envolope form around each group of chromosomes so there are now two nuclei
what happens in cytokinesis
the cytoplasm divides, in animal cells cleavage furrow forms to divide cell membranes. There are now 2 genetically identicle daughter cells.
Why do cells increase ATP before division
Motor proteins require ATP to recoil the chromatids
