Cell Division and Plasma Membrane test Flashcards
what is chromatin?
each portion of DNA
What is chromosome?
Threadlike structure of nuclei acids and proteins carrying DNA stretched out during interphase
What is supercoiling?
A process by which long thin chromatins transform into a short fat chromosome (process by which chromatin wraps around a histone protein)
what is a Chromatid?
one of the two copies of DNA in a chromosome held to the other chromatid by a centromere
what is a centromere
A portion of DNA that does not replicated during the S phase of interphase
What are centriols?
Related to production of spindle fibres 2 centriols = 1 centrosome
Hapliod
A nuclei that has only one pair of homologous chromosomes (Gametes)
Diploid
Pair of chromosomes 2n Somatic.
Equational division
When the nucleus divides so that each chromosome divides into equal longitudinal halves.
What are the stages of mitosis?
Interphase prophase metaphase anaphase early telephase late telephase
What happens in interphase?
Spindle microtubules start growing
Chromosomes are becoming shorter and fatter due to supercoiling
there is a centromere
s phase is where DNA replicates
What happens in prophase?
Spindle microtubules extend to the middle from each pole
each chromosome consist of two identical chromatids formed from DNA
What happens in metaphase?
Nuclear membrane has broken down and chromosomes have moved to the middle
spindle microtubules from both poles are attached to each centromere on opposite sides
NOTE: at the end of metaphase the centromeres replicate and and chromatids separate.
What happens in anaphase?
Centromeres have divided and the chromatids have become chromosomes
spindle microtubules pull genetically identical chromosomes to opposite poles.
What happens in early telephase?
Spindle microtubules break down
chromosomes have reached the poles and the nuclear membrane has formed around them
