Cell cycle and Cell Division (mitosis and meiosis) Flashcards
what is the goal of cell division
partition 2 identical (more-or-less) copies of genetic material between two daughter cells
Difference between prokaryotes and eukaryotes in cell division
binary fission(pros) mitosis (euks)
Why are prokaryotic cells simpler to divide
comparatively simple; only 1 chromosome, so have a relatively easy time sorting daughter chromosomes to daughter cells
why are eukaryotic cells more difficult to divide
longer DNA & multiple chromosomes
what are the steps of binary fission
1) Prokaryote chromosome replicates & cell stretches
2) Produce 2 circular chromosomes at opposite ends of cell
3) Cell membrane stretches & breaks apart → form 2 cells
Each cell has now has 1 full chromosome
4) Randomly distributed cytosol, plasmids, & ribosomes end up in both cells
what are the two methods of asexual reproduction>
binary fission and mitosis
explain loose chromatin
Unwound DNA
Found throughout Interphase
DNA is being used for macromolecule synthesis
explain condensed chromosomes
Tightly packaged DNA
Found only during cell division
DNA is not being used for macromolecule synthesis
why do eurkaryotes do mitosis?
they have a nucleus so dna cannot simply move to either side of the cell
they have multiple chromosomes meaning need to ensure that each daughter cell has exactly 1 copy of each chromosome
chromosomes are formed from what
2 sister chromatids with an identical sequence
where are sister chromatids attached
at the centromere
where to microtubules attach to?
The kinetochore
what is another name for the microtubules that split the sister chromatids
mitotic spindle
What pulls apart the sister chromatids in mitosis
microtubles
where are the two centrosomes?
at opposite poles of the nucleus
what is the centromere?
dna sequence that links sister chromatids
what are the 3 functions of the centromere?
adhesion
kinetochore formation
pairing of homologous pairs
what is the kinetochore?
protein structure that assembles at centromere
what are the functions of the kinetochore?
links chromosome to microtuble polymers from the mitotic spindle
used in mitosis and meiosis
what does the cell cycle include?
Includes DNA replication, cell division & cell growth
What are the 4 phases of the cell cycle?
g1 (gap phase 1)
s (synthesis)
g2 (gap phases 2)
m (mitosis)
explain gap phase 1 (g1)
lasts approx 11h growing performs transcription and translation produces proteins and organelles at a certain phase, s is initiated
explain s phase
lasts approx 8h period of dna replication little growth occurs nucleus contains double the dna once celel has replicated all its dna, g2 is initiated
does protein synthesis occur in s phase
NO not enough space/energy to do both