Cell Division Flashcards
What happens at the G0 phase in the cell cycle?
this phase is variable in length - it is an optional non-replicative phase , many differentiated cells remain in this phase
Its the “Cell cycle arrest phase”
What happens at the G1 phase in the cell cycle?
approx 10 hours, it is a period of cell growth and preparation for cell division - including replication of key components like centrosomes
What happens in the S phase of the cell cycle?
during the S phase - 5-6 hours, the DNA replication occurs
what happens in the G2 phase of the cell cycle?
G2 is 3-4 hours long , it is a short resting phase before cell division occurs where there is ‘double checking ‘ for error in the duplicated chromosome
how many chromosomes do humans have?
23 chromosome pairs
What are the different phases of mitosis?
interphase (G2) , prophase, pro metaphase, metaphase, anaphase, and telophase/cytokinesis
Do the paternal and maternal homologs associate during mitosis/meiosis?
mitosis = no
meiosis = yes
What are the centrosomes?
they are small structures that organise the microtubules for chromosome splitting.
if you chromosomes lack a centromere- what is the result?
the DNA cannot split during mitosis b/c the microtubules will not attach to it
Are the daughter cells in mitosis/meiosis haploid or diploid?
mitosis = diploid
meiosis = haploid (half of the original DNA)
What is ‘independent assortment?’
it is the random segregation of paternal and maternal chromosomes
how is genetic diversity generated in Meiosis 1?
by independent assortment - where the chromosomes line up randomly along the axis and by recombination where parts of the chromosomes swap allowing for the exchange of DNA
What happens if recombination occurs in mitosis?
It’s unusual, but if it happens then there could be loss/gain of DNA
What is a Chiasmata?
It is a ‘crossing over point ‘ where DNA cross with another DNA strand during meiosis - it is also the point that holds homologs together on spindle until Anaphase 1
What is the kinetochore?
it is a protein complex that connects to the centromere and allows the mitotic spindles to bind to it
