Cell Cycle Flashcards
How does DNA replicate itself?
SEMI-CONSERVATIVE REPLICATION
Helicase enzymes break hydrogen bonds holding two strands of DNA together
Nucleotides line up next to their corresponding bases by complimentary base paring, Joined together by polymerase enzymes to from polyneucloitides
ligase enzymes join the polyneucloetide chains to from two separate DNA molecules
what is the cell cycle?
sequence of events carried out by every dividing eukaryotic cell
Phase 1?
the cell grows
Phase 2?
growth continues and DNA is replicated
Phase 3?
apparatus for mitosis forms
Phase 1,2 and 3?
Interphase
Mitosis?
The division of the cell to form two diploid daughter cells
Phophase?
DNA in the nucleus condenses into chromosomes.
nuclear Membrane disintegrates
Spindle apparatus is formed (network of microtubules)
Metaphase?
Chromosomes align up the centre of the cell
spindle fibres attach and pull them apart
the chromotids become daughter chromosomes
Anaphase?
spindle fibres shorten, pulling chromosomes to the poles
Telophase?
When two sets of chromosomes reach opposite poles, the nuclei reform around them
Mitokinesis?
the cell membrane pinches and sepperates into two diploid daughter cells
Meiosis?
Cell division to form haploid gametes for sexual reproduction
what occurs during meiosis?
every phase in mitosis the nuclear envelope disintegrates again the cells divide once more this time the chromosomes separate four haploid gametes formed.
How is variation ensured during Meiosis?
Genes recombine randomly
random fusion of gametes
