biochemistry

Question 1

how to recognize redox rxns

Answer 1

Oxidation - gain O or lose H, lose e

Reduction - lose O, gain H, gain e

Question 2

pKa of an amino acid and pH

Answer 2

Basically, when the pH is less (even more acidic) than the pKa of an acidic group, only then will that group be mostly protonated
However, if pH is greater than pKa, the acidic group will be mostly deprotonated

Question 3

pKa of carboxyl of every AA

Answer 3

= 2. Whereas the pKa of every ammonium group is 9

Question 4

pI

Answer 4

the isoelectric point, which is a special pH for every AA where it has a net charge of zero. An uncharged molecule is called a zwitterion
* If the AA only has the 2 groups (COOH and NH2) then just average their pKa to get pI

Question 5

fun fact about proline

Answer 5

due to its NH group lacking a second hydrogen, it has no remaining hydrogen to form an H bond with adjacent AAs in the alpha helix. As such, proline never appears in an alpha helix

Question 6

alpha helices

Answer 6

stabilized by H bonds btw H on the amino and O on the carboxyl.
frequently appear in transmembrane domains because the all the polar groups are bonded to each other.