2-2 All cells arise from other cells Flashcards
1
Q
What are the three stages of the cell cycle?
A
- Mitosis
- Interphase
- Cytokinesis
2
Q
What is mitosis?
A
- To produce identical daughter cells for growth and asexual reproduction.
- Cells produced by mitosis are genetically identical therefore mitosis does not give rise to genetic variation.
- Prophase, Metaphases, Anaphase, Telophase
3
Q
What is interphase?
A
- During this stage the cell grows and then prepares to divide, chromosomes and some organelles are replicated, chromosomes also begin to condense.
4
Q
What is cytokinesis?
A
- During cytokinesis the parent and replicated organelles move to opposite sides of the cell and the cytoplasm divides thus producing two daughter cells.
5
Q
What is mitosis important for?
A
- Growth
- Repair
- Reproduction
6
Q
What happens in prophase?
A
- Spindle fibres appear
- Chromosomes condense
7
Q
What happens in metaphase?
A
- Spindle fibres attach to chromosomes
- Chromosomes align at centre
8
Q
What happens in anaphase?
A
- Centromeres divide
- Sister chromatids move to opposite poles
9
Q
What happens in telophase?
A
- Nuclear membrane reforms
- Chromosomes decondense
- Spindle fibres disappear.
10
Q
What is binary fission?
A
- The process by which prokaryotic cells divide.
11
Q
What are the stages of binary fission?
A
- The circular DNA in the cells replicates and both copies attach to the cell membrane. Plasmids also replicate.
- The cell membrane then begins to grow between the two DNA molecules and begins to pinch inwards, dividing the cytoplasm in two.
- A new cell wall forms between the two DNA molecules dividing the original cell. The identical daughter cells each have a single copy of the circular DNA and a variable number of copies of the plasmids.
12
Q
How do viruses replicate?
A
- As viruses are non-living, they do not undergo cell division.
- Following the injection of their nucleic acids into another cell, the infected host cell replicates the virus particles.
