Topic 2- Cell cycle Flashcards
What is the cell cycle?
the regulated sequence of events that occurs between one cell division and the next
What are the 3 stages of the cell cycle
-Interphase
-nuclear division (mitosis)
-cell division (cytokinesis)
The length of the cell cycle is very variable depending on which 3 things?
-environmental conditions
-the cell type
-the organism
The movement from one phase to another is triggered by chemical signals called what?
Cyclins
What happens during interphase
The cell increases in mass and size and carries out its normal cellular functions (eg. synthesising proteins and replicating its DNA ready for mitosis)
What are the 3 phases in interphase
-G1 phase
-S phase
-G2 phase
When is a signal is received telling the cell to divide again?
G1
What happens in the S phase (synthesis)
The DNA in the nucleus replicates (resulting in each chromosome consisting of two identical sister chromatids)
Is the S phase short or long?
Short
What happens during the G1 phase?
Cells make the RNA, enzymes and other proteins required for growth
What happens during the G2 phase?
cell continues to grow and the new DNA that has been synthesised is checked and any errors are usually repaired
Does cell growth stop during the M phase
Yes
What happens during cytokinesis
The whole cell divides and one nucleus moves into each cell to create two genetically identical daughter cells
What does cytokinesis involve in animal cells?
constriction of the cytoplasm
What does cytokinesis involve in plant cells?
A new cell wall is formed
