3 lecture 2 Flashcards
do cells make mistakes
yep
what is an example of a mistake a cell makes
lagging chromosomes
why do chromosomes lag behind
some just take longer than others to separate
what is a euploid cell
have correct number of chromosomes
do lagging chromosomes cause problems
they can
how do lagging chromosomes cause problems
the lagging chromosome will be trapped in the spindles mid zone during anaphase
the trapped chromosome will be trapped and damaged in the process of the cell splitting
is it quick to fix mistakes int he cell
nope
is cell division a controlled process
Cell division is a tightly controlled process
what ensures that there are no mistakes in a cell
Proteins survey the condition of the cell at each step
If a mistake is detected, what happens
normal cells halt at checkpoints and make repairs
what must happen in order for cells to proceed with division
Cell must pass the survey to proceed with cell division
what are the 3 major checkpoints
3 major checkpoints: G1,G2, and metaphase
do the checkpoints have a fixed amount of time that they go on for
checkpoints monitor the processes and impose a delay as needed
what is checked in the g1 checkpoint
is cell division necessary
are growth factors present
is the cell large enough
are suficient nutrients available
what is checked in the s checkpoint
nothing really
what is checked in the g2 checkpoint
what DNA replicated correctly
is the cell large enough
what is checked in the metaphase checkpoint
are all the chromosomes attached to microtubules
what happens if the daughter cells are not the exact same size
daughter cells may not be exactly the same size, so the smaller one will take longer to reach the cell size threshold and and will be in G1 phase for longer
what does Mitosis do
produces two genetically-identical nuclei
what happens if even one chromosome is wrong
chromosome attachment is monitored if even one is wrong, anaphase is delayed
can mistakes happen in healthy cells
yep
what is disease, if mistakes also happen in healthy cells
it is the failure to detect and correct mistakes that lead to disease
what are the 2 origins of cancer
oncogenes
tumour suppressors
what is oncogene
losing control
what are tumour suppressors
losing a checkpoint
cancer is the result of what
defects in checkpoint or repair systems