Cell Division - Mitosis Flashcards
How do eukaryotic cells divide?
mitosis or meiosis
How to prokaryotic cells divide?
binary fission
How do viruses divide?
Viruses do not undergo cell division because they are non-living, they replicate inside host cells.
Inject nucleic acid into the host + the host replicates the virus particles
What are the different stages of the cell cycle?
interphase, prophase, metaphase, anaphase, telophase (cytokinesis)
What happens during interphase?
organelles double
DNA replicates
cell grows
longest stage
what is produced?
What is the purpose of mitosis?
genetically identical daughter cells
diploid cells (2 copies of every chromosome)
growth and repair - eg clonal expansion of B cells
one round of divsion
What happens during prophase?
Chromosomes condense and become visible
Centrioles separate and move to opposite poles of the cell - creating spindle fibres
Nucleolus disappears
What happens during metaphase?
Chromosomes line up along the equator
Spindle fibred attach to centriole of chromatids
What happens during anaphase?
Spindle fibred pull chromatids to opposite poles
Centromere divides in 2 + individual chromatids are pulled to opposite poles (become chromosomes)
This requires ATP; provided by respiration in the mitochondria
What happens during telophase?
Chromosomes at opposite poles become longer and thinner
Spindle fibres disintegrate, the nucleus reforms
Cytokinesis
2 genetically identical cells are formed
How do you calculate the mitotic index?
Mitotic index = number of cells in stage of mitosis/ total number of cells x 100
Describe binary fission.
- Replication of circular DNA and plasmids
- Division of cytoplasm; produces 2 daughter cells, each with a single copy of the circular DNA and a variable number of plasmids
