Cells - Mitosis and the cell cycle Flashcards
What are the stages of the cell cycle?
Mitosis, interphase and cytokinesis.
What are the stages of mitosis?
Prophase, metaphase, anaphase, telophase.
What happens during prophase?
- Chromosomes condense and become visible.
- Centrosomes move towards opposite poles.
- Spindle fibres begin to emerge.
- Nuclear envelope breaks down.
What happens during metaphase?
- Centromeres reach opposite poles.
- Spindle fibres attach to the chromosomes.
- Chromosomes line up in the centre of the cell.
What happens during anaphase?
- The sister chromatids separate at the centromere.
- Spindle fibres shorten.
- The sister chromatids are pulled to opposite poles by the spindle fibres.
What happens during telophase?
- Chromosomes arrive at opposite poles and begin to decondense.
- The nuclear envelopes begin to reform.
- The spindle fibres break down.
What happens during interphase?
During this stage the cell grows and prepares to divide - chromosomes and some organelles are replicated, chromosomes begin to condense.
What happens during cytokinesis?
The parent and replicated organelles move to opposite poles of the cell, and the cytoplasm divides.
For which processes is mitosis important?
Growth, repair and reproduction.
What is binary fission?
The process through which prokaryotic cells divide.
What is the process of binary fission?
- The circular DNA in the cells replicate and both copies attach to the cell membrane. Plasmids also replicate.
2.The cell membrane grows between the DNA and pinches inward, dividing the cytoplasm in two. - A new cell wall forms, dividing the original cell. The identical daughter cells have one copy of circular DNA and variable numbers of copies of plasmids.
How do viruses replicate?
They inject their nucleic acids into another cell , and the infected host cell replicates the virus particles.
