Amino Acids

Q. What is alpha carbon and alpha hydrogen?

Q.

Calculate the potential of hydrogen electrode in contact with a solution whose pH is 10.

Q.

What is an ortho or para directing group in aromatic ring?

Q. Which of the following compounds can form a zwitter ion?

1. Benzoic acid
2. Acetanilide
3. Aniline
4. Glycine

Q.

QUESTION 14.11

What are the essential and non-essential amino acids? Give two examples of each type.

Q.

How do you explain the amphoteric behaviour of amino acids?

Q.

Describe the term D- and L- configuration used for amino acids with examples.

Q. The reduction potential of hydrogen electrode at pH=7 will be (1) 0 V (2) -0.414 V (3) + 0.414 V (4) 0.72 V

Q.

Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol. Why?

Q.

Which of the following is not an essential amino acid

1. Valine

2. Lysine

3. Histidine

4. Glycine

Q.

Wat is the charge present on sulphate ion?

Q. A tetrapeptide has -COOH group on alanine. This produces glycine (Gly), valine (Val), phenyl alanine (Phe) and alanine (Ala), on complete hydrolysis. For this tetrapeptide, the number of possible sequences (Primary structures) with - NH₂ group attached to a chiral centre is___

Q.

How are the two polypeptide chains in insulin linked together?

Q. The substituents R₁ and R₂ for nine peptides are listed in the table given below. How many of these peptides are positively charged at Ph = 7.0? ___

Q.

Amino acids are classified as acidic, basic or neutrl depending upon the relative number of amino and carboxyl groups in their molucule. Which of the following are acidic?
(a) $\left(C{H}_3\right)CH-\underset{N{H}_2}{\underset{|}{CH}}-COOH$
(b) $HOOC-C{H}_2-C{H}_2-\underset{N{H}_2}{\underset{|}{CH}}-COOH$
(c) $H_{2}N-C{H}_2-C{H}_2-C{H}_2-COOH$
(d) $HOOC-C{H}_2-\underset{N{H}_2}{\underset{|}{CH}}-COOH$

Q. The $p{K}_a$ values for the three ionisable groups $X,Y\text{and}Z$ of glutamic acid are 4.3, 9.7 and 2.2 respectively.

The isoelectric point for the amino acid is:

1. 3.25
2. 4.95
3. 7
4. 5.95

Q.

The ionization constant of chloroacetic acid is 1.35 × 10^–3. What will be the pH of 0.1M acid and its 0.1M sodium salt solution?

Q.

Which of the following is not a basic amino acid?

1. Histidine

2. Lysine

3. Glycine

4. Arginine

Q.

The total number of distinct naturally occurring amino acids obtained by complete acidic hydrolysis of the peptide shown below is___

Q.

Which of the nitrogen of histidine is first protonated ?

1. $\alpha$

2. $Both$

3. $\beta$

4. $None$

Q. Which of the following is/are polar amino acids?

1. Serine
2. Cysteine
3. Leucine
4. Isoleucine

Q. Which of the following $\alpha$ - amino acids is not optically active?

1. Alanine
2. Cysteine
3. Glycine
4. Phenylalanine

Q.

If 20 mL of a 0.1 M NaOH is added to 30 mL of 0.2M CH3COOH (pka=4.74), the pH of the resulting solutiin is

Q.

All common amino acids except one react with cold nitrous acid(HNO₂) and evolve nitrogen gas.

That amino acid is

1. Cysteine
2. Proline
3. None of these
4. Histidine

Q. Protonation of carbonyl group forms a cation with significant charge on the carbon atom

How many of the following carbonyl compounds form an aromatic cation only after protonation?

Q. A carbonyl compound gives a positive iodoform test but does not reduce Tollen's reagent or Fehling's solution. It forms a cyanohydrin with HCN. The compound is:

1. acetaldehyde
2. propionaldehyde
3. acetone
4. None of the above

Q.

Isoelectric point is a

1. Melting point of an amino acid under the influence of electric field

2. Hydrogen ion concentration that does not allow migration of amino acid under electric field

3. Specific temperature

4. Suitable concentration of amino acid

Q. 47. What is the order of enzyme catalysed reaction?

Q. Which of the following metal is required by the enzymes that utilise ATP in phosphate transfer as the cofactor?

1. Ca
2. Mg
3. Be
4. K

Q.

Lysine, $H_{2}N-(C{H}_2{)}_4-\underset{N{H}_2}{\underset{|}{CH}}-COOH$ is ......... .
(a) $\alpha -$ amino acid (b) basic amino acid
(c) amino acid synthesised in body (d) $\beta -$amino acid