intro to the cell cycle
during which phase is DNA replicated?
a) G1 phase
b) S phase
c) G2 phase
d) M phase
b) S phase
When a checkpoint isn't passed right away, what issue can arise?
a) the cell will not divide successfully
b) incorrect splicing of protein signal sequences
c) chromosome segregation defects
d) no issues arise
c) chromosome degradation defects
In order, what are the phases of mitosis?
prophase -> metapahse -> anaphase -> telophase -> cytokinesis
Centrioles are composed of ___ fibrils of ___ microtubules.
a) 4, 7
b) 9, 6
c) 10, 3
d) 9, 3
d) 9, 3
when does the nuclear envelope break?
a) between anaphase and cytokinesis
b) between prophase and prometaphase
c) between metaphase and anaphase
d) between prophase and metaphase
b) between prophase and prometaphase
True or false: M phase includes mitosis but excludes cytokinesis
What controls the cell cycle control system?
a) molecular switches
b) specific proteins
c) actin filaments
d) gap junctions
In prophase: replicated chromosomes condense, mitotic spindle assembly requires: centrosome _______ and bipolar spindle _______
a) duplication, assembly
b) duplication, disassembly
c) none of the above
The microtubules connect to ____ at the centrosome.
y-tubulin ring complexes
Which microtubules help position the mitotic spindle?
astral microtubules
Do cells always replicate? Are there exceptions?
No, cells do not always replicate. Some mature cells do not divide at all, some only divide after being given an appropriate stimulus, and some normally divide on an ongoing basis.
the exposed plus end of the microtubule that attaches to the kinetochore protein allows for....
polymerization and depolymerization
what protein helps condense the chromosomes at the beginning of mitosis? (HINT: condense)
condensins
True or false: centrosome duplication starts in G1 phase.
False, it starts in S phase
which microtubules span from the centrosome to the chromatin?
kinetochore microtubules
What's the stage called in which a cell still does its job but is not undergoing any replication or division?
G0 (Gap 0)
in sister chromatid separation, do kinesins move toward the centrosome and dyneins move toward the cell membrane or vice versa?
kinesins to centrosome, dyneins towards cell membrane
During which phase does bipolar mitotic spindle assembly start?
prophase
Does the nuclear envelope breakdown when it is phosphorylated or dephosphorylated?
phosphorylated
which microtubules span from centrosome to the middle?
interpolar microtubules
What are the three major checkpoints in the cell cycle?
1. start
2. G2/M
3. metaphase-to-anaphase transition (aka spindle assembly checkpoint)
_____ marks the end of mitosis.
a) anaphase
b) telophase
c) cytokinesis
d) metaphase
b) telophase
The centrioles of centrosomes are at a ____ degree angle to each other.
a) 60
b) 180
c) 90
d) 45
c) 90
what forms a two dimensional lattice on the inner nuclear membrane to help keep it in place?
the lamin
what do the kinetochore microtubules bind to to pull the sister chromatids apart?
kinetochore proteins