m. Lecture (Feb. 10th) Slide Deck Flashcards
a) What are the regulators of the cell cycle events?
b) What are the key regulator subunits of those regulators?
c) what are 2 other regulatory mechs?
a) CDK - cyclin-dependent kinases
b) cyclins
c)
- synthesis/degradation of CDK inhibitors
- activating/inhibitory phosphorylation of CDKs
a) What is the role of positive regulators (cyclin) in the cell cycle?
b) What happens to it when it fulfills its role?
a) sets up the transition from one phase to another in the cell cycle
b) it gets degraded
a) What is the role of negative regulators (surveillance mechs) in the cell cycle?
checkpoints = brakes on cell cylce progression in order to check if events are completed/DNA is damaged (makes sure a transition to the next step doesn’t happen until the prev step is completed)
All of the following stages w/in the eukaryotic cell cycle are part of interphase except
a) G1
b) S
c) G2
d) M
D
Describe the following checkpoints, and indicate which phase transition this occurs
a) spindle assembly
b) chromosome segregation
a) checks to see if all chromosomes are attached to mitotic spindles - metaphase to anaphase
b) check to see if all the chromosomes have reached the opposite poles - anaphase to telophase
using this image indicates the types of CDKs/activity occurring for each
a) G1/S phase
b) S phase
c) mitotic phase
d) APCj/C
What are the 5 things that make it easy to analyse the cell cycle of yeast
- simple - they are unicellular organisms that have synchronized growth
- time efficient - goes through a cell cycle very quickly
- cell cycle morphology - you are able to determine what cell cycle they are in based on their morphology
- haploid - can be grown as haploid which makes gene manipulation easier due to only having to manipulate one gene rather than two
- mutation morphology - you can see when a mutation has taken placed based on their morphology
Match the following
a) S. cerevisiae
b) S. pombe
1. fission
2. budding
a) 2
b) 1
Does this image demonstrate budding or fission?
budding
Does this image demonstrate budding or fission?
Fission
Does this image demonstrate the S. cerevisiae cell cycle or S. pombe?
S. cerevisiae
Does this image demonstrate the S. cerevisiae cell cycle or S. pombe?
S. pombe
What is the advantage of using Xenopus oocytes (frog) to analyze the cell cycle?
b/c their eggs are huge thus easy to visualize
ANS the following wrt Xenopus oocytes
a) Why does the egg arrest at the metaphase of meiosis II?
b) these eggs are known to divide asymmetrically. Explain what this means
c) What happens to the male and female DNA during each cleavage/division
d) How can one analyze the stages?
a) waiting for fertilization
b) produce polar bodies that are discarded
c) they fuse
d) they can artificially fertilize the oocytes and pause the cell cycle at various stages and harvest the molecules that they wish to study
Describe the following methods used to cause cell synchrony in eukaryotes. Indicate which ones are for yeast vs mammals
a) hydroxyurea
b) Nocodazole
c) Mating pheromone
a) a drug of thymidine that inhibits the synthesis of dNTPs causing an arrest in the early S phase preventing replication from occurring - mammals
b) a drug that disrupts the formation of mitotic spindles causing an arrest in prometaphase - both
c) lack of fertilization which causes the arrest at the late G1 phase - yeast
a) What is cell synchrony?
b) How can one cause cell synchrony?
c) what type of cells require this?
a) when all the cells are going through the same stages w/in the cell cycle at the same time
b) by causing an arrest at a certain stage and waiting for all the cells to reach that arrest then washing away the drug that caused the arrest
c) mammalian cells
Describe the role of flow cytometry wrt analyzing the cell cycle
it uses the scattering of lights on each indiv cell to determine certain aspects of the cell (size, morphology) which is then used to determine which cell cycle those cells were in
What is this image showing?
flow cytometry
Match the following to the image. How do you know?
a) undergoing replication
b) unreplicated
c) replicated
a) green = it’s when the cell is going from having 1 copy of DNA to 2 (b/c 1C and 2C)
b) yellow = when the cell has 2 copies of DNA meaning the DNA must have already been replicated (2C)
c) blue = when the cell has 1 copy of DNA meaning the DNA must have yet to be replicated (1C)
a) describe temperature-sensitive (ts) mutations
b) how does one isolate cells that have ts mutations
a) these are mutations that only grow at certain temps
b) grow two identical colonies with a mix of mutants and wildtypes at two different temps and find the difference in the colonies that are able to grow vs not. The mutagens will only grow in one of the temps
what does cdc stand for?
cell division cycle
a) is this S. cerevisiae or S. pombe?
b) What happening in this image?
a) S. cerevisiae
b) a cdc mutation that prevents the cells from undergoing cytokinesis (dividing)
a) is this S. cerevisiae or S. pombe?
b) What happening in this image?
a) S. cerevisiae
b) a cdc mutation that allows the nuclei to duplicate but prevents budding
a) is this S. cerevisiae or S. pombe?
b) What happening in this image?
a) S. pombe
b) the wee mutation that causes the cell to progress through the cell cycle before it has grown properly (smaller cells)
