Week 8 Flashcards
protein kinase
an enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein and making a conformational change
cAMP
low glucose = high cAMP = high transcription
high glucose = low cAMP = no transcription
second messenger
steroid hormone receptors
the steroid hormone binds to the receptor protein and turns into a hormone-receptor complex, then enters the nucleus and acts as a transcription factor to create a new protein
steroid hormones can only pass the plasma membrane because they have a transmembrane protein as their receptor molecule on the cell surface
protein phosphatase
removes the phosphate from a protein
growth factor
need for growing and dividing
g-protein coupled receptors
GDP binds to the receptor, changing it to GTP, and then GTP can bind to the enzyme to get a response where it is changed back to GDP so the process can continue
second messangers
can rapidly diffuse around the cell and bind to proteins to cause a conformational change
s phase
DNA synthesis, DNA is replicated to form sister chromatids
G2 phase
a gap with a checkpoint to ensure DNA synthesis is complete
prophase
chromosomes condense
metaphase
chromosomes align
anaphase
chromosomes move to poles
telophase
nuclei reform
cytokinesis
cell division and separation
diploid cells
have 2 complete sets of chromosomes (2n)
human somatic cells have 23 pairs of homologs; 2n=46
centromere
where the two sister chromatids attach
microtubules
attach at the centromere by a kinetochore on each side of the sister chromatids, pulls sister chromatids apart so there’s the same genetic material in each of the daughter cells
dicentric chromosome
chromosome with two centromeres; causes each centromere to randomly attach to spindles, leading to problems with chromosome segregation (not equal amounts of genes in each daughter cell because the chromatids are randomly broken apart)
G1 checkpoint
checks to make sure DNA was replicated, if the cell passes the checkpoint, it can continue to cell division, if not it stays in the G0 phase
G0 phase
no cell division
M checkpoint
when all chromosomes are correctly attached to poles, anaphase can start where they actually move to the poles
aneuploid cells
when daughter cells do not inherit the correct number of chromosomes, caused when the anaphase checkpoint fails
euploid cells
have the correct number of chromosomes
karyotype
complete complement of chromosomes present in the cell
cyclins
cell cycle is controlled by these regulators
