Practice questions Flashcards
In alpha helices, how many AA residues per turn, and how many hydrogen bonds per turn?
3.6 residues per turn, # of H bonds=(total # of AA’s)-4
Where on a titration curve would you expect to find a positively charged glycine?
Low pH
Is the cytoplasm a reducing or oxidizing environment? How and what consequences does this have for protein structure?
Reducing. Several anti-oxidative enzymes are responsible for keeping the cytoplasm free of ROS. Because disulfide bonds are formed through an oxidation reaction, they are unstable in the cytoplasm
What is the sequence of events of A-beta formation?
Cleavage of APP with beta secretase, followed by gamma secretase
Define the max velocity of a Michaelis Menten reaction
Vm=k3[Etotal]
Can double stranded RNA or RNA/DNA hybrids form b-form DNA?
No, the extra hydroxyl group on RNA makes it impossible
What is satellite DNA?
Tandemly repeating, non coding DNA. Forms the main component of centromeres and heterochromatin
What is one of the mechanisms of action of p53 pertaining to the cell cycle?
It up regulates p21 and inhibits the cell cycle
What is uniparental disomy? What type of disorders are these patients at higher risk for?
When a person receives two copies from one parent and none from another.
Higher risk of imprinting disorders
True or false: nonrandom x-activation only targets abnormal x
False, in some instances, nonrandom x-inactivation can target the normal x
Do additional hydrogen bonds or Van der waals forces contribute the most to increased stability of GC pairs over AT?
Van der Waals forces
How does negative supercoiling affect the openness of DNA?
Increases openness for replication/transcription
Is apoptosis the final fate of almost all cells in the body?
No, not all cells die this way
While cells undergoing necrosis often swell and burst, apoptotic cells ______ and _____.
Shrink and condense
What does DNA polymerase alpha do?
Makes the RNA primer
