Cell Cycle Flashcards
3 Steps of Cell Cycle
- Cell Growth/ Chromosome Duplication
- Chromosome Segregation
- Cell Division
cells reproduce by duplicating their contents and dividing in two
cell cycle
4 Phases of Cell Cycle
- G1
- S
- G2
- M
What happens during G1 and G2 (interphase) phases?
cell continues to grow while being monitored
What happens during the S phase?
cell replicates its DNA (synthesis)
What 2 things happen during the M phase?
mitosis and cytokinesis
when the nucleus divides
mitosis
when the cell splits into two/ cytoplasm divides
cytokinesis
A number of checkpoints are accomplished in order to move to next phase of the cell cycle. (T or F)
True
Progression through the cell cycle depends on what?
cyclin-dependent protein kinases (Cdks)
The amount of cyclins stay constant throughout the cell cycle. (T or F)
False, the abundance varies to regulate activity of Cdks
Distinct Cdks associate with different cyclins to trigger the different events of the cell cycle. (T or F)
True
Link the 4 cyclin-Cdk complexes to the cyclin
G1-Cdk : cyclin D
G1/S-Cdk : cyclin E
S-Cdk : cyclin A
M-Cdk : cyclin B
Some Cdk activity is regulated by cyclin degradation. (T or F)
True
For S-Cdk to be active, inhibitory phosphates must be removed. (T or F)
False, for M-Cdk
The activity of a Cdk can be blocked by the binding of a Cdk inhibitor. (T or F)
True
Inhibition of activating phosphatase blocks entry to which phase?
mitosis
Inhibition of APC activation delays exits from which phase?
mitosis
Cdk inhibitors block entry to which phase?
S phase
DNA damage can arrest the cell cycle in G2 phase. (T or F)
False, G1 phase
Describe 2 Steps of the Initiation of DNA Replication
- In G1, Cdc6 binds to ORC loading a pair of DNA helicases to form a pre-replicative complex.
- In S phase, S-Cdk triggers replicative complex to start DNA synthesis at replication fork.
At mitosis, activated M-Cdk indirectly activates more M-Cdk, creating a negative feedback loop. (T or F)
False, a positive feedback loop
5 Steps of Mitosis
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
What happens during interphase? (3)
-cell increases in size
-DNA of chromosomes replicated
-centrosome duplicated
What happens during prophase? (2)
-duplicated chromosomes condense
-mitotic spindle assembles between two centrosomes
Chromosomes in prophase consist of two sister chromatids. (T or F)
True
What happens during prometaphase? (2)
-breakdown of nuclear envelope
-chromosomes attach to spindle microtubules and undergo movement
What happens during metaphase? (2)
-chromosomes align at equator of spindle
-each sister chromatid attaches to opposite spindle pole
What happens during anaphase? (1)
-sister chromatids separate and are pulled to spindle poles (chromosome segregation)
What happens during telophase? (2)
-sets of chromosomes arrive at the poles
-new nuclear envelope reassembles forming two separate nuclei
tie together two adjacent sister chromatids in each duplicated chromosome
cohesins
help coil each sister chromatid into a smaller, more compact structure easier to segregate
condensins
The cytoskeleton plays an essential role in mitosis. (T or F)
True
In what two phases are centrioles replicated?
S and G2 phases
Microtubules don’t move during chromosome segregation. (T or F)
False, they move and rearrange
Where do microtubules attach to on the chromosomes?
the kinetochore
Name the 3 classes on microtubules found in the mitotic apparatus
- Aster
- Kinetochore
- Interpolar
What does APC trigger?
the separation of sister chromatids by promoting the destruction of cohesins
