Which of the following statements are TRUE?

Multiple answers:Multiple answers are accepted for this question

PLEASE SHOW WORK FOR EACH PART AND EXPLAIN WHY EACH ANSWER CHOICE IS WRONG OR RIGHT

a

The tripeptide His-Lys-Glu has a net charge of -2 at pH 8.0.

b

The tripeptide Asp-Asp-Asp has a net charge of -3 at pH 7.0.

c

The tetrapeptide His-His-His-His has a net charge of -1 at pH 7.0.

d

There are 6 possible sequences for a tripeptide containing Arg - His - and Pro.

e

Certain bacteria synthesize cyclic tetrapeptides. The net charge at pH 7.0 of a cyclic tetrapeptide consisting of two Pro and two Tyr is 0.