Question

26. Which of the following classification does not match the amino acid side chain A) Contains an basic group/ lysine B) It is polar C) Forms disulfide bond/ cysteine D) Forms hydrogen bonds with neighbors/ alanine serine 27. All amino acids found in proteins are L-amino acids EXCEPT the achiral. A) glutamate B) Lysine C) glyeine D) Alamine 28. The plH at which the positive and negative charges of an amino acid balance each ofher is called the A) isotonic point B) isobaric point C) isosbestic point D) isoelectric point 29. Leucine amino acid below shows the ionization state at olH-74. Ater adding a base, its net charge AT pll 12 is A)-1 B)-2 C)+1 D) +2 E)0 не 30. Which of the following does not contribute to the secondary structure? A) hydrogen bond between C O and H-N within the backbone B) intermolecular hydrogen bond between two different backbones, forming sheets C) disulfide bonds D) hydrogen bond between C-O and H-N4 amino acids apart making coils 31. The STRONGEST interaction between one lysine and one glutamate can best be described as A) Hydrophobic interaction B) Covalent disulfide bonding C) Hydrogen bonding D) Formation of a salt bridge 32 A) The sequence of amino acids B) Hydrogen bonding within the polypeptide backbone C) The interaction of protein subunits interface with amino acids of opposite charges D) Intermolecular hydrogen bonds of B-pleated sheet Which of the following contributes to the formation of the quaternary structure of proteins 33. Prosthetic groups are A) Are part of the secondary structures of proteins B) Are not essential for a protein or enzyme to function C) Are non polypeptide organic molecules covalently bound to some proteins D) Are polypeptide organic molecules in a protein

Answer 1

26) correct option is D

Alanine side chain is methyl which cannot form hydrogen bonds. Rest all are true.

27) option C is correct

Glycine is achiral as alpha carbon doesnot have four different substituent i.e. the condition for being chiral.

28) option D is correct

the pH at which positive charge balances negative charges is called isoelectric point.

29) option A is correct

After adding base it will lose its NH_{​​​​​3}^​+ proton. So at pH 12, the net charge will be due to COO^{​​​​-} group. Hence -1 charge.

30) option C is correct

Disulphide bonds are formed in tertiary structure.

31) option D is correct

lysine and glutamate forms a salt bridge.

32) Option C is correct

Interaction of protein subunits interface with amino acids of opposite charges

33) Option C is correct

Prosthetic group are non polypeptide organic molecules bound to protein.