things i often forget Flashcards
what is the name of the process that results in more than one protein being produced from a single gene
alternative rna splicing
what are the factors that affect the set of proteins expressed by a given cell type
- metabolic activity
- cellular stress
- response to signalling molecules
- diseased vs healthy cells
where are lipids synthesised
smooth endoplasmic reticulum
what is a signal sequence and what does it do
a short stretch of amino acids at one end of the polypeptide
it determines the eventual location of a protein in a cell
what do transmembrane proteins carry
a signal sequence
what does a signal sequence do
it halts translation and directs the ribosome synthesising the protein to dock with the ER forming the RER
where do proteins undergo post translational modification
golgi apparatus
where do secreted proteins get translated
in the rough endoplasmic reticulum
what is the classification of an r group with an amine group
basic
what is the classification of an r group with a carbonyl group
polar
what is the classification of an r group with a hydroxyl group
polar
what is the classification of an r group with a carboxyl group
acidic
what is the classification of an r group with a hydrocarbon group
hydrophobic
what kind of bond results in regions of secondary structure
hydrogen bonding along the backbone
what is an alpha helice
looks similar to the dna double helix shape
what is a beta pleated sheet
really long arrow, no overlap but loops and comes back up and then back down
what is a turn
arrow, flip, arrow
what is a prosthetic group
a non protein unit tightly bound to a protein and necessary for its function
why does a change in pH disrupt the protein structure
as pH changes from the optimum, the normal ionic interactions between charged group ions are lost, which changes the conformation of the protein until it becomes denatured
where do allosteric interactions occur
between spatially distinct sites
why are allosteric interactions of biological importance
the activity of allosteric enzymes can vary greatly with small changes in substrate concentration
what do modulators do
they regulate the activity of the enzyme when they bind to the allosteric site
what do positive modulators do
they increase the enzymes affinity for the substrate
what do negative modulators do
they decrease the enzymes affinity for the substrate
what is meant by cooperativity in binding
changes in binding at one subunit alter the affinity of the remaining subunits
what do protein kinases do
they catalyse the transfer of a phosphate group to other proteins
what do protein phosphotases do
they catalyse the reverse reaction
does adding a phosphate add negative or positive charges
negative