Class 3 E1

Question 1

Increasing [S] decreases?

Answer 1

Keq

Question 2

Increasing [P] increases?

Answer 2

Keq

Question 3

The Keq is smaller when you have?

Answer 3

more reactants / substrates, higher denominator.

Question 4

The Keq is larger when you have?

Answer 4

more product, higher numerator.

Question 5

Equilibrium is not when?

Answer 5

S and P are equal.

Question 6

ATP found at higher conc’s in cells vs. ADP. [ATP] >[ADP] when?

Answer 6

Coupled to another rxn.
Gradient of protons across mitochondrial membrane.
Produced through redox-rxns w/ enzymes that use a lot of E.

Question 7

Which of the following is a buffer system?
A. KCl and KOH
B. KCl and KNO3
C. HCl and NaOH
E.	H2O and HF
F.	H3PO4and H2PO3−

Answer 7

H3PO4 and H2PO3-

Question 8

Why can’t a buffer system be made of HCl and NaOH?

Answer 8

they’re not conj. acid and base, both strong acids

Question 9

AA’s make up

Answer 9

proteins.

Question 10

What FG’s do all AA’s contain?

Answer 10

amine

carboxylic acid

Question 11

All 22 AA residues differ in?

Answer 11

side chains.

Question 12

AA aren’t available to H-bond because?

Answer 12

they’re bonded to the next AA in the peptide chain.

Question 13

AA are usually what type of enantiomers?

Answer 13

L

Question 14

AA’s are chiral except for?

Answer 14

glycine.

Question 15

R – groups are

Answer 15

side chains and important FGs.

Question 16

R – groups extend into which part of the enzyme?

Answer 16

binding pocket.

Question 17

R – groups contribute to what type of interactions?

Answer 17

acid-base

protein-protein

Question 18

R – groups form?

Answer 18

dimers.

Question 19

Zwitterion

Answer 19

molecule w/ (-) and (+) charge.

Question 20

AA at neutral pH is an example of a?

Answer 20

zwitterion.

Question 21

AA ionized at a low pH (protonated, + charge) is an example of a?

Answer 21

zwitterion.

Question 22

AA ionized at a high pH (deprotonated- charge) is an example of a?

Answer 22

zwitterion.

Question 23

AA Classification:

Nonpolar (hydrophobic)

Answer 23

alkyl group
aromatic ring
H
fatty acid (hydrophobic and polar end)

Question 24

AA Classification:

Polar (hydrophilic)

Answer 24

acidic: carboxylate ion side chain.
basic: amino side chain
neutral: alcohol thiol, amide side chains.

Question 25

AA Classification: | Can AA's be both polar and nonpolar?

Answer 25

yes, a little bit of each.

Question 26

The 7 AA's with nonpolar side chains?

Answer 26

``` Alanine Valine Leucine Isoleucine Methionine Phenylalanine Tryptophan ```

Question 27

The 2 AA's with polar (-) charged side chains?

Answer 27

Aspartate | Glutamate

Question 28

The 3 AA's with polar (+) charged side chains?

Answer 28

Lysine Arginine Histidine

Question 29

The 5 AA's with polar uncharged side chains?

Answer 29

``` Serine Threonine Glutamine Asparagine Tyrosine ```

Question 30

The 3 AA's that have side chains with unique properties?

Answer 30

Glycine Cysteine Proline

Question 31

Properties of nonpolar side chains?

Answer 31

Hydrophobic Incapable of H-bonding. Aliphatic / aromatic.

Question 32

Properties of polar negatively charged side chains?

Answer 32

Contain a carboxyl group. | Commonly deprotonated at physiological pH.

Question 33

Properties of polar positively charged side chains?

Answer 33

Contain amino groups.

Question 34

Why are Lysine and Arginine positively charged at physiological pH?

Answer 34

Lysine (pKa 10.5) Arginine (pKa 12.5) They're protonated at physiological pH.

Question 35

What happens to Histidine at physiological pH?

Answer 35

pKa of 6.0, partially protonated.

Question 36

Properties of polar uncharged side chains?

Answer 36

Hydrophilic | Not usually ionized at physiological pH.

Question 37

Glycine's unique properties:

Answer 37

Fits into hydrophobic / hydrophilic environment. | Often resides at sites where 2 polypeptides are in close contact.

Question 38

Cysteine's unique properties:

Answer 38

Able to form covalent bond w/ another cysteine to form a disulfide link.

Question 39

Proline's unique properties:

Answer 39

Able to create kinks in polypeptide chains. | Can disrupt ordered secondary structure.

Question 40

AA side chains play a pivotal role in?

Answer 40

protein folding | protein-protein interaction

Question 41

Side chains can be ___ at diff pKa values?

Answer 41

ionized

Question 42

AA have an effect on the overall protein ___ and ___?

Answer 42

structure and function.

Question 43

How would the structure of Threonine be changed at a pH of 2 (acidic pH)

Answer 43

The carboxylic acid group would be protonated. (O-)

Question 44

Peptide Bond

Answer 44

linkage btw 2 AA's, linear polymers of AA's.

Question 45

How is a peptide bond formed?

Answer 45

an amide linkage btw the carboxyl of one AA and the amino of the next AA.

Question 46

Peptide bonds are what type of bond?

Answer 46

recurring.

Question 47

What is removed when a peptide bond is formed and what is the result of that?

Answer 47

a water molecule is removed, resulting in dehydration.

Question 48

What type of bond is a covalent linkage of trans configuration?

Answer 48

a peptide bond.

Question 49

Dipeptides

Answer 49

2 linked AA's.

Question 50

Oligopeptides

Answer 50

4-20 AA's.

Question 51

Polypeptides

Answer 51

20+ peptides linked together.

Question 52

Proteins tend to be more than how many AA's?

Answer 52

100

Question 53

Monomers are single chains of AA folded into?

Answer 53

active protein.

Question 54

AA Modifications

Answer 54

Acetylation Phosphorylation Hydroxylation

Question 55

Acetylation

Answer 55

introduces an acetyl FG. | for a H atom

Question 56

Phosphorylation

Answer 56

rxn w/ a Pi or by transferring a phosphate from another Pi.

Question 57

Hydroxylation

Answer 57

introduces a hydroxyl into an ion or radical | usually by replacing a H atom