mitosis/meiosis Flashcards
prokaryotes divide by
binary fission
what do chromosomes look like in bacteria?
single circular chromosome
how do bacteria replicate their DNA?
from ORI sequence- create double strand- form septum, pinch in, voila! 2 daughter cells
eukaryotes have what kind of chromosomes (shape)
linear
unlike bacteria, chromosomes exist in ___ pairs
homologous
definition mitosis
chromosomal process that ensures each daughter cell gets exact, correct copy of genetic information
at what phase of mitosis do chromosomes become visible in light microscope
prophase
define DNA packing
Positively charged Histone proteins neutralize the negative charge on DNA
what is the beads on a string model?
Octamers of histone “core” proteins (nucleosomes) wrap DNA around themselves, giving it the appearance of “beads on a string”
when would you see the most condensed form of DNA
metaphase, on sister chromatids
what does 30 mm fiber refer to
the arrangement of packed nucleosomes and DNA
when would distinct chromosomes be visible
M phase of mitosis
4 phases of cell cycle
G1, G2 S, M,
what phase are non dividing cells in? can you give an example?
G0. liver cell
Interphase is what 3 phases
G1 + G2 + S
G1
rapid growth and metabolic activity of mitosis
G2
growth and preparation for cell division
S phase
DNA replication and growth
what kind of phase are neurons always in?
G0 - nondividing
what significant event happens in S phase?
synthesis of DNA
describe a replication fork and when you’d find it
in S phase, as you replicate DNA, you go from single strand -> double strand. as this is happening, bidirectionally, you get a replication bubble and fork
Kinetochore
Kinetochore structures (made of proteins) are the attachment sites for microtubules at the centromere regions
telomeres
ends of chromatids/chromosomes
what do you call DNA in the replicated form
‘sister chromatids’
how do you identify chromosomes for a karyotype?
based on their band patterns, gleaned from electrophoresis. line up from largest->smallest
name for non-sex cells
somatic cells
what phase of mitosis is essentially a reverse of prophase
telophase- rebuild nuclear envelope, recondense