Cell Division Flashcards
When does RNA, tubulin, and other proteins and energy required for division synthesize?
G2 phase, 2-4 hrs.
When does DNA synthesis/duplication occur? with centrosome duplication?
S phase. 8-10 hours. goes from 2n to 4n.
When does general growth and PROTEIN synthesis occur?
G1 phase. variable in length. generally long.
Name the cyclins responsible for regulating cell cycle and their points of regulation.
Cyclin D and E -> passage past restriction point so from G1 to S.
Cyclin A -> S to G2.
Cyclin B -> G2 to M.
what happens in Werner’s syndrome?
mutation in gene that encodes DNA helicase so cant replicate chromosomes and go through cell cycle. so can’t replace… so have old cells…
what happens in Progeria (Hutchinson Gilford syndrome)?
mutation in IFs that line nuclear envleope and affects ability of cells to divide. so can’t regenerate and child looks very old.
What is the centromere?
region of chromosome, where kinetochore microtubules bind.
what happens in prophase?
chromosomes condense.
kinetochores assemble on centromeres.
Centrosomes (MTOCs) migrate to poles.
Spindle begins to form.
What happens in prometaphase?
Nuclear envelope breaks down.
Microtubules attach to kinetochores. .
Chromosomes begin to migrate
What happens in Metaphase?
Chromosomes maximally condensed and lined up on metaphase plate.
What happens in Anaphase?
Sister chromatids separate.
Cleavage furrow begins to form at late anaphase.
What happens in Telophase?
spindle microtubules begin to depolymerize.
nuclear envelope forms around daughter nuclei.
chromosomes begin to decondense and nucleoli form.
cleavage furrow deepens.
What does Vincristine and Colchicine do? also taxol.
destabilize microtubules so disrupt mitotic spindle formation
What does 5-fluorouracil , methotrexate, and cytosine arabinoside do?
they inhibit DNA synthesis. deprive DNA of nutrients.
meiotic prophase I sub-phases?
Leptotene - chrom condense form long strands.
Zygotene - homolog chrom pair up and form synaptonemal complex -> tetrad or bivalent.
Pachytene - chrom condense more. chiasmata form and cross over occurs between homol. chrom.
Diplotene - chrom condense more. parts decondense for RNA synth.
Diakinesis - chrom condense max. nucleolus and nuclear envel. appear.
