10.3/10.4 Overview of eukaryotic cell cycle Flashcards
cell cycle
-repeated sequence of growth and division
Interphase
- G1
- S
- G2
- each chromosome replicates to produce two sister chromatids
- Time between mitosis(not doing mitosis)
G0
- resting phase
- where mature neurons can spend entire life
- if cell stays in G1 forever(not dividing) it is stuck in G0
*Muscle & Nerve cells are stuck in G0 perminately
G1
- Primary growth and maturation phase
- only comes out of this phase if it wants to divide
- chromosomes are “sticks”
- liver cells can resume G1 in response to injury
When does a cell leave G1?
-If cell is going to divide for;
- growth
- repair
- reproduction(asexual)
S
- Synthesis=S
- Replication of DNA/chromosomes
- produces two sister chromatids by the end of S phase
- when leave S, chromosomes are X’s
G2
- preparation for mitosis
- chromosomes coil tightly using motor proteins
- centrioles replicate, microtubules organize
- centrioles move to opposite poles
M phase
- M= Mitosis & cytokinesis
- subdivided into 5 phases (PMAT)
- Where X chromosomes separate (nuclear division, division of DNA, nucleus)
- separation of sister chromatids into individual chromosomes
Cytokinesis
- where the CELL splits in half
- division of cytoplasm to produce two daughter cells
centromere
- in S phase
- point of constriction
- region on chromosome where two sister chromatids are held together at the kinetochore
kinetochore
-connect centromere to microtubules
chromatids
-stay attached at centromere by cohesin
At the end of S phase, what do chromosomes look like?
- chromosomes change from “sticks” to X’s
- fully extended and uncoiled
The centromere serves as an attachment site for a group of proteins that forms what?
Kinetochore
What type of cells are stuck in G0 permanently?
Muscle and nerve cells
Centrioles
- pair of microtubule organizing centers
- replicated in G2 to produce one for each pole
Kinetochore
-structure that functions as attachment site for microtubule a to separate chromatids
Tubulin
- the protein that forms microtubules
- microtubules synthesized in G2
