7.1

Question 1

what are aspartATE and glutamATE mean?

Answer 1

anionic form, DEPROTONATED

the acid form contains the H

Question 2

“His goes both ways”

Answer 2

Lys (K) and Arg (R) are protonated at physiologic pH

His (H) is around the middle; acts as proton acceptor and donor (prevalent in ACTIVE SITES)

Carboxylic is ALWAYS anionic

-NH2 is ALWAYS cationic

Question 3

is tryptophan (Trp) polar or non-polar?

Answer 3

it is NONPOLAR, despite the NH group

Question 4

Nonpolar amino acids

Answer 4

GP
AVILM
FW

Proline (P) is non-polar

Question 5

Polar amino acids

Answer 5

ST NQ

Y with -OH is polar

C is fairly polar

Question 6

9 essential amino acids

Answer 6

K-H-T-V-L-I-F-W-M-P

Lysine
Histidine
Threonine
Valine
Leucine
Isoleucine
Phenylalanine
Tryptophan
Methionine
Proline

Question 7

can amino acids act as acids or bases?

Answer 7

they can BOTH

AMPHOTERIC

Question 8

N-C(-R)-C-N-C(-R)-C

Answer 8

The pattern of N-C-C - N-C-C

Question 9

protease

Answer 9

cuts peptide bond

Question 10

inside of cells is oxidizing or reducing environment?

Answer 10

REDUCING

disulfide bridges found in extracellular polypeptides (antibodies, hormone insulin)

Question 11

4 ways of denaturing

Answer 11

1. UREA (hydrogen bonds = secondary structure)
2. extreme pH (think ceviche)
3. temperature
4. salt concentration

disruption of protein’s SHAPE, not primary structure

Question 12

alpha helices (width, direction)

Answer 12

5 angstroms in width, each AA rises 1.5 angroms
3.6 amino acids per turn

AAs bond CLOSE TO EACH OTHER

GOOD for transmembrane regions (Hydrophobic interior) since hydrogens are bonded, with hydrophobic R groups

Question 13

beta sheet

Answer 13

residues FAR from each other

Question 14

tertiary structure

Answer 14

Van Der Waals = nonpolar side chains

hydrogen bonds between polar side-chains

disulfide bridges

electrostatic interactions between acidic/basic side chains

hydrophobic goes interior, hydrophilic R-groups exposed to water

Question 15

quaternary structure

Answer 15

SEPARATE polypeptides

VdW, hydrogen bonds, disulfide bonds, electrostatic interactions

Question 16

cofactor

Answer 16

metals, small molecules required for activity of enzymes

when organic, called a co-enzyme, which binds to the substrate during catalyzed reaction (example: coenzyme A)

Question 17

covalent modification

Answer 17

kinase phosphorylates serine, threonine, tyrosine covalently (actives/deactivates)

Question 18

zymogen

Answer 18

inactive form of a protein

activated by cleavage by a protease

Question 19

regulation of enzymatic activity

Answer 19

1. covalent modification
2. proteolytic cleavage
3. association with polypeptides
4. allosteric regulation

Question 20

allosteric regulation

Answer 20

NON-COVALENT, REVERSIBLE

alters conformation of the enzyme AT A DISTANCE

OTHER SITES (cooperativity is active sites)

Question 21

cooperativity

Answer 21

sigmoidal

binding of CO2 to hemoglobin STABILIZES TENSE Hb, causes the four binding sites to have lower affinity for oxygen

Question 22

protease

Answer 22

DO NOT REQUIRE ATP TO CLEAVE BOND