Phospholipids are esters of glycerol with

1. one carboxylic acid residue and two phosphate groups

2. three phosphate groups

3. three carboxylic acid residues

4. two carboxylic acid residues and one phosphate groups

Which of the following structures represents the peptide chain ?

1. 

2. 

3. 

4. 

The helical structure of proteins is established by

1. dipeptide bonds

2. hydrogen bonds

3. ether bonds

4. peptide bonds

Which is not a true statement?

1. a-carbon of a-amino acid is asymmetric except glycine

2. All proteins are found in L-form

3. Human body can synthesis all proteins they need

4. At pH = 7 both amino and carboxylic groups exist in ionised form

Which type of amino acid is lysine ?

1. b - amino acid

2. Acidic

3. Basic

4. Neutral

The structure of glycine (amino acid) is ${\mathrm{H}}_3\stackrel{\oplus }{\mathrm{N}}{\mathrm{CH}}_3\stackrel{\mathrm{O}}{\stackrel{\left|\right|}{\mathrm{C}}}{\mathrm{O}}^{⊝}$(zwitter ion). The correct statement among the following is-

1. Glycine, as well as other amino acids are amphoteric.

2. The acidic functional group in amino acids is $-\stackrel{\oplus }{\mathrm{N}}{\mathrm{H}}_3$

3. The basic functional group in acids is $-{\mathrm{CO}}_2^{⊝}$

4. All the statements are correct.

Nitrous acid (HNO₂) converts amino acids into hydroxy acids with retention of configuration.

Estimation of nitrogen gas evolved in the reaction is the basis of Van slyke estimation of amino acids. Which of the following amino acids cannot be analysed by Van slyke method?

Codes :

(1) only I

(2) only II

(3) I and III

(4) I, III, IV

What will be product when glycine, is heated–

(1)
(2)
(3)
(4)

             O
             ll
NH₂-CH-C-NH-CH₂-CO₂H
         l
       CH₃

_{Identify the amino acid obtained by hydrolysis of the above compound :-}

_{1. Glycine}

_{2. Alanine}

_{3. Both (1) and (2)}

_{4. None of the above}

At iso-electric point:

(1) conc. of cation is equal to conc of anion

(2) Net charge is zero.

(3) Maximum conc. of di-polar ion (Zwitterion) will be present

(4) All of the above