Question

Amino Acids SW C2 9. Which of the following is an L-amino acid? çoo coo coo HẠN |-R HANH, HẠN –H HÀNH R coo B. 10. The following questions refer to the structures A-E below: (a) Which represents the structure of an amino acid at very high pH? (b) Which is a zwitterion? (c) Which represents the structure of an amino acid at very low pH? (d) Which structure/(s) is/are) not possible? R-CH-COOR-CH-COOH R-CH-COOH R-CH-COOR -CH-COO NH2 NH2 *NH NH2 *NH3 D. E. Make sure you can justify your answers if required. 11. Use the following information to draw the structure of the predominant form of L-glutamic acid at physiological pH (pH = 7.4). You may draw a line or condensed structure. pK, (a-COOH) pK, (a-NH3) Amino acidR side chain Glutamic acid -(CH2)2COH PK, (side chain) 4.25 2.19 9.67

Answer 1

Ans 9 : C)

In L amino acids the amino group is present on the left of asymmetric carbon atom in the structure.

Such amino acids tend to rotate the plane polarised light to the counter clockwise direction. These amino acids are used by our cells to produce proteins.

So the structure mentioned in option C is correct.