1.5c - Control of the Cell Flashcards
What do checkpoints do?
control progression through the cell cycle
Checkpoints are…
mechanisms within the cell that assess the condition of the cell during the cell cycle and halt progression to the next phase until certain requirements are met
How are cyclin proteins accumulated?
during cell growth
Cyclin proteins are involved in…
regulating the cell cycle
Cyclins combine with and activate…
cyclin-dependent kinases (CDKs)
Active cyclin-CDK complexes…
phosphorylate proteins that regulate progression through the cycle, if sufficient phosphorylation is reached, progression occurs
At the G1 checkpoint, retinoblastoma protein (rB) acts as…
a tumour suppressor by inhibiting the transcription of genes that code for proteins needed for DNA replication
Phosphorylation by G1 cyclin-CDK…
inhibits the rB, allowing transcription of the genes that code for proteins needed for DNA replication
Cells progress from G1 to…
S phase
At the G2 checkpoint…
the success of DNA replication and any damage to DNA is assessed
DNA damage triggers…
the activation of several proteins including p53 that can stimulate DNA repair, arrest the cell cycle or cause cell death
A metaphase checkpoint…
controls progression from metaphase to anaphase
At the metaphase checkpoint…
progression is halted until the chromosomes are aligned correctly on the metaphase plate and attached to the spindle microtubules
What may cause degenerative disease?
an uncontrolled reduction in the rate of the cell cycle
What may cause tumour formation?
an uncontrolled increase in the rate of the cell cycle
