Stages of mitosis Flashcards
What are the 3 stages of interphase
G1, S and G2
What occurs during G1?
Cellular contents, excluding chromosomes is duplicated
What checks occur at G1?
Size, nutrients, correct growth factors and DNA damage
What is G0?
Cell cycle arrest
What occurs at G0?
Stops cell division, differentiation and specialisation
What occurs at S stage?
Each of the 46 chromosomes are duplicated by the cell
What checks occur at S stage?
If the DNA replicated
What occurs at G2?
The cell ‘double checks’ the duplicated chromosomes for error and making any needed repairs. Microtubules and relevant proteins are made also
What checks occur at G2?
DNA errors and mistakes are repaired
Where do checks occur during mitosis?
At the spindle assembly checkpoint
What checks occur during mitosis?
Are the spindle fibres connected to the chromosomes to move them
What are the types of microtubules involved in mitosis?
Aster, kinetochore and interpolar
What are the 4 stages of mitosis?
Prophase, metaphase, anaphase and telophase
What occurs during prophase?
- Chromatin condenses and becomes visible.
- The chromosomes consist of 2 identical sister chromatids, joined by a centromere.
- Nuclear membrane breaks down.
- Centrioles move to opposite poles of the cell and microtubules start to assemble around centrioles, forming the spindle.
What occurs during metaphase?
- Chromatid pairs attach to spindle microtubules at the centromere.
- Chromatid pairs line up across the cell equator to form the metaphase plate
What occurs during anaphase?
- Centromeres divide
- The sister chromatids are pulled apart by the spindle fibres to opposite ends of the cell
What occurs during telophase?
- The chromatids reach the poles of the spindle so they are now separate and are chromosomes
- The chromosomes unravel and become indistinct.
- The nuclear membrane reforms
How does cell division occur in animal cells?
Many cells divide to allow organisms to grow and repair damaged structures
How does cell division occur in plants?
Only specific areas undergo cell division - the meristem cells - so the shoot and root tails and just under bark so girth can increase
What is cytokinesis?
The splitting of the cytoplasm
What occurs during cytokinesis?
The nucleus has divided and 2 independant cells are formed with each being genetically identical to eachother and the parent cell