1ST SEM (153 - 172)

Question 1

153. Which of the following amino acids have a positively charged side chain at neutral pH?
     Select one or more:
     a. Arginine
     b. Lysine
     c. Glycine
     d. Aspartate
     e. Glutamate

Answer 1

a. Arginine
b. Lysine

Question 2

154 Which of the following amino acids have a negatively charged side chain at neutral pH?
Select one or more:

a. Arginine
b. Alanine
c. Asparagine
d. Aspartate
e. Glutamate

Answer 2

d. Aspartate
e. Glutamate

Question 3

155 Which of the following amino acids have sulfur-containing side chains?

Select one or more:
a. Histidine
b. Cysteine
c. Methionine
d. Proline
e. Valine

Answer 3

b. Cysteine
c. Methionine

Question 4

156 Which amino acid has a guanidine group in its side chain?
Select one:
a. Histidine
b. Lysine
c. Tyrosine
d. Arginine
e. Tryptophan

Answer 4

d. Arginine

Question 5

Which of the following amino acids have four carbon atoms?

Select one or more:
a. Aspartate
b. Threonine
c. Asparagine
d. Proline

Answer 5

a. Aspartate
b. Threonine
c. Asparagine

Question 6

Which of the following amino acids have five carbon atoms? Select one or more:

a. Glutamate
b. Glutamine
c. Histidine
d. Proline
e. Glycine

Answer 6

a. Glutamate
b. Glutamine
d. Proline

Question 7

Which of the following amino acids have six carbon atoms?

Select one or more:
a. Leucine
b. Isoleucine
c. Histidine
d. Proline
e. Glycine

Answer 7

a. Leucine
b. Isoleucine
c. Histidine

Question 8

Which of the following amino acid side chains are nonpolar?

Select one or more:
a. Valine
b. Leucine
c. Asparagine
d. Lysine

Answer 8

a. Valine
b. Leucine

Question 9

Which of the following amino acid side chains are polar?
Select one or more:
a. Glutamine
b. Leucine
c. Asparagine
d. Threonine

Answer 9

a. Glutamine
c. Asparagine
d. Threonine

Question 10

Which of the following amino acid side chains are polar?
Select one or more:

a. Glutamine
b. Leucine
c. Asparagine
d. Threonine

Answer 10

a. Glutamine
c. Asparagine
d. Threonine

Question 11

Pair the amino acids with their character!

1. Proline 2. Arginine 3. Glutamate
   a. neutral b. acidic c. basic

Select one:
a. 1-a, 2-c, 3-b
b. 1-a, 2-b, 3-c
c. 1-b, 2-c, 3-a
d. 1-b, 2-a, 3-c
e. 1-c, 2-a, 3-b

Answer 11

a. 1-a, 2-c, 3-b

Question 12

Pair the amino acids with their character!

1. Glutamine 2. Lysine 3. Aspartate
   a. neutral b. acidic c. basic

Select one:
a. 1-a, 2-b, 3-c
b. 1-a, 2-c, 3-b
c. 1-b, 2-c, 3-a
d. 1-b, 2-a, 3-c
e. 1-c, 2-a, 3-b

Answer 12

b. 1-a, 2-c, 3-b

Question 13

Select the correct statements!

Select one or more:
a. Acidic amino acids have a net negative charge at neutral pH.
b. The isoelectric point of acidic amino acids is at acidic pH.
c. The isoelectric point of the acidic amino acids can be calculated as the average of their three pKa values.
d. Asparagine is an acidic amino acid.

Answer 13

a. Acidic amino acids have a net negative charge at neutral pH.
b. The isoelectric point of acidic amino acids is at acidic pH.

Question 14

Select the correct statements!

Select one or more:
a. Neutral amino acids have no net charge at neutral pH.
b. neutral amino acids have a positive and a negative charge at neutral pH.
c. The isoelectric point of the neutral amino acids can be calculated as the average of their pKa values.
d. Glutamine is a neutral amino acid.

Answer 14

a. Neutral amino acids have no net charge at neutral pH.
b. neutral amino acids have a positive and a negative charge at neutral pH.
c. The isoelectric point of the neutral amino acids can be calculated as the average of their pKa values.
d. Glutamine is a neutral amino acid.

Question 15

Select the correct statements!

Select one:
a. Leucine has two asymmetrical centers.
b. Only D-amino acids can be found in proteins.
c. Natural amino acids are dextrorotatory.
d. Glycine has no chiral center.
e. Proline is not active optically.

Answer 15

d. Glycine has no chiral center.

Question 16

What is the dominant form of Arginine at pH 6.0? (pKa values of Arginine are 2.2, 9.0 and 12.5).

Select one:
a. Two positive and one negative charges
b. One positive and two negative charges
c. One negative and one positive charges
d. One negative charge
e. One positive charge

Answer 16

a. Two positive and one negative charges

Question 17

What is the dominant form of Glutamate at pH 7.0?

(pKa values of Glutamate are 2.2, 5.6 and 9.2).

Select one:
a. One negative charge
b. One negative and one positive charges
c. One positive and two negative charges
d. One positive charge

Answer 17

d. One positive charge

Question 18

What is the dominant form of Histidine at pH 8.0? (pKa values of Histidine are 1.8, 6.0 and 9.2).
Select one:
a. One positive and one negative charges
b. Two negative and one positive charges
c. One negative charge
d. One positive charge

Answer 18

a. One positive and one negative charges

Question 19

What is the dominant form of Glycine at low pH (pH=1)?

Select one:
a. NH2–CH2–COO-
b. NH3+–CH2–COOH
c. NH3+–CH2–COO-
d. NH2–CH2–COOH
e. NH2–CH3+–COO-

Answer 19

b. NH3+–CH2–COOH

Question 20

Select the correct statements!

Select one or more:
a. Glutamate has a negative charge on its side chain at the isoelectric pH.
b. Glutamate has a negative charge on its side chain at neutral pH.
c. Arginine has a positive charge on its side chain at the isoelectric pH.
d. Arginine has a positive charge on its side chain at neutral pH.

Answer 20

b. Glutamate has a negative charge on its side chain at neutral pH.
c. Arginine has a positive charge on its side chain at the isoelectric pH.
d. Arginine has a positive charge on its side chain at neutral pH.

Question 21

172 Lysine at its isoelectric point has….

Select one:
a. a deprotonated a-carboxyl group, a deprotonated–a-amino group and a protonated e-amino group.
b. a deprotonated a-carboxyl group, a protonated a-amino group and a deprotonated e-amino group.
c. a protonated a-carboxyl group, a protonated a-amino group and a deprotonated e-amino group.
d. a protonated a-carboxyl group, a deprotonated a-amino group and a protonated–e-amino group.
e. a deprotonated a-carboxyl group, a deprotonated a-amino group and a deprotonated e-amino group.

Answer 21

a. a deprotonated a-carboxyl group, a deprotonated–a-amino group and a protonated e-amino group.