Cell Biology Flashcards
What order does the eukaryote cell cycle go in?
G1 phase, S phase, G2 phase and M (mitotic) phase.
What are the stages of cell division in eukaryotes?
Prophase -> Anaphase -> Metaphase -> Telophase.
What are some pros and cons for studying the cell cycle in embryonic cells?
Pros:
Synchronised cell devisions.
Non-invasive.
Fast.
Cons:
Skips G1 and G2 phases.
Can only study certain model organisms.
What are the pros and cons of manipulating cell cultures with drugs?
Pros:
You can study any organisms cells.
Can study each of the phases independently.
Cons:
Interferes with the cell.
Quite slow.
What are “Conditional mutants” ?
Organisms with mutant alleles that become unstable under certain conditions causing the cell to stop in whichever phase it is in.
CDK’s phosphorylate a lot of things, what are some of them?
Cohesins that cause chromosomes to condence.
Nucleus: cause nucleic envelope breakdown.
Fragmentation of the Golgi body.
Formation of the mitotic spindle.
Cascade effects: kinases turns on a kinase turns on..
What is G-actin and what does it do?
G-actin is monomeric actin that is disassociated from other actin molecules. It binds ATP.
What is F-actin and what does it do?
F-actin is filamentous actin. It is actin when it is polymerised with other actin subunits. It has bound ADP in filament form.
Name the main actin control proteins and their function.
Profillin: Speeds up the formation of F-actin.
Thymosin: Prevents the formation of F-actin.
Formin: Produces linear actin filaments.
ARP2/3: Produces branched networks of actin.
Name the main microtubule control proteins and their function.
Gamma-TuRC: Nucleating ring complex, grows filaments from the centrosome.
Stathmin: Prevents filament assembly, common in human cancers.
Katanin: Severs microtubules
The ARP2/3 complex has what effect on actin?
It nucleates the formation of branched networks at a 70 degree angle with growth occurring on the positive end of the filament. It likes to bind to existing filaments before starting this growth.
Do Microtubules have polarity?
NO.
BUT they do have a plus and a minus end, this is NOT to do with charge.
Alpha tubulin forms the minus end.
Beta tubulin forms the plus end.
What is the difference between Lamellapodia and Phillapodia?
Lamellarpodia are sheet-like extentions of the cell’s outer membrane that pull the cell forward.
Phillapodia are thin finger-like extentions of the cell membrane that allow the cell to move.
What are the two things that determine microfilament growth?
Concentration of G-actin monomers and the Critical concentration.
Critical concentration is the concentration of
G-actin where addition is equal to loss.
What is a “Rams horn arrangement” and how does one occur?
The term Rams horn arrangement is used to describe the curling back of microtubules when they destablise.
This occurs when GDP is bound to the end of the
F-actin and Kinesin-13 (Catastrophe factor) is present.
