Lecture 2- Cell division and apoptosis Flashcards
Where does cell division take place?
-Development -Growth -Repair and maintenance -Cell diseases -Reproduction
What must happen before a cell divide?
1-There must be a reproductive signal 2-There must be growth (the cell double in size) 3-Replication of DNA 4-Chromosome segregation
What is cell cycle?
The period between cell divisions
What are the two main components of cell cycle?
Interphase and mitosis/cytokinesis
In which phase does the majority of cells spends their time?
Interphase
What are the three phases in interphase?
G1, S and G2
Describe G1 phase
In G1 the cell double in size and prepare for DNA replication.
How many chromatid there are in the chromosome in G1 phase?
In G1 phase there’s only one chromatid per chromosome.
What is nuclear envelope?
The double membrane that separates the nuclear content from the cytoplasm.
What are Microtubules?
Dynamic scaffolding poles that form the cytoskeleton and the mitotic spindle.
Which are the two kind of microtubules in the mitotic spindle?
1-Polar Microtubules 2-Kinetochore Microtubules
Describe polar microtubules:
Polar Microtubules form the framework of the spindle and run from one pole to the other.
Describe kinetochore microtubules:
Kinetochore microtubules attach to the kinetochore of the chromosomes.
What is a centrosome?
Centrosomes are organelles located near the nucleus that orientate the spindle apparatus in the right direction.
What’s the function of Restriction?
To activate or arrest the cell cycle. The cell can only progress to the S phase if it has sufficiently grown during the G1 phase.
Describe how the activation/arrest of the cell cycle works at checkpoints:
The cell cycle is controller by CDKs. CDKs phosprylate RB in order to inactivate it. Inactivated RB allows the cell cycle to proceeds.