1.4&1.5-AminoAcids&Proteins

Question 1

What are the 3 positive AA’s?

Answer 1

HAL! Histidine, Arginine, Lysine

Question 2

What are the 2 Negative AA’s?

Answer 2

GA! Glutamate, Aspartate

Question 3

How large of a change in scale for changing 1 full unit of pH? Ex. pH7 to pH6…

Answer 3

10x differnce. (pH=7 = .0000001mol/L to pH=6 = .000001mol/L)

Question 4

High Ka=?pKa?

Answer 4

High Ka=Low pKa (logarithmic relationship)

Question 5

Low pKa=?pH?

Answer 5

Low pKa=Low pH (strong acid)

Question 6

What is the Henderson-Hasselbalch Equation?

Answer 6

pH= pKa + log [ConjBase] / [Acid]

Question 7

Concerning the HH Eq relationships: what happens to the relationship of pH to pKa if we add base to the solution?

Answer 7

pH > pKa (adding numerator log [A-] / [HA]

Question 8

Concerning the HH Eq relationships: what happens to the relationship of pH to pKa if we add acid to the solution?

Answer 8

pH < pKa (adding to the denominator log [A-] / [HA])

Question 9

What does pKa tell me about how much dissociation has occurred?

Answer 9

pKa = 50% dissociation

Question 10

Where does aspirin (pKa=3.5) get absorbed? Stomach (pH=1.5) or S.I. (pH=6.5)

Answer 10

Stomach (pH 1.5). Here, the aspirin is very associated, so it is not charged, so it can pass the membrane.

Question 11

What % dissociation occurs when you have a 1 pH unit above the pKa?

Answer 11

91% dissociation

Question 12

What % dissociation occurs when you have a 1 pH unit below the pKa?

Answer 12

9.1% dissociation

Question 13

What is the average of the pKa surrounding the zero charge point?

Answer 13

pI-isoelectric point

Question 14

What are the polar and charged (+&-) AAs?

Answer 14

HAL (+) (Histidine, Arginine, Lysine), GA! (-) (Glutamate, Aspartate), and (Polar) St. AG Cystine chapel (Serine, Threonine, Asparagine Glutamine, Cystine)

Question 15

How are amino acids typically read?

Answer 15

N to C

Question 16

What secondary structure is silk an example of?

Answer 16

Beta sheet

Question 17

What category of protein structure incorporates “bends” when a backbone can fold on itself?

Answer 17

Secondary Structure

Question 18

Which protein structure category deals with folding and 3D structure via hydrophobic/plolar/hbonding type interactions?

Answer 18

Tertiary

Question 19

Which structure is defined by having multiple subunits?

Answer 19

Quaternary

Question 20

Fibrous VS Globular: Which is water soluble? Which lacks tertiary structure?

Answer 20

Globular is water soluble. Fibrous is water insoluble and lacks tertiary structure

Question 21

What is the pH of the carboxyl portion of an AA?

Answer 21

2

Question 22

What is the pH of the Amino portion of an AA?

Answer 22

9