I cant find these solutions in my textbook or lecture Could

I can\'t find these solutions in my textbook or lecture. Could I get some help...

I. which of the following amino acid would form ionic bond with negatively charged DNA?
a. serine
b. alanine
c. lysine
d. glutamic acid

II. which of the amino acids would be found in the interior of the cell membrane?
a. glutamine
b. valine
c. threonine
d. aspartic acid

III. which of the following amino acid would most likely be involved in hydrogen bonding?
a. phenylalanine
b. isoleucone
c. tryptophan
d. threonine

Solution

Q1. c (Lysine) As Lysine has an extra amino group (-NH₃) in its side chain, its attains a positive charge. Therefore an ionic bond is formed between the positively charged Lysine with the negatively charged DNA.

Q2. b (Valine) The interior of the cell membrane contains hydrophobic amino acids. So among the four options valine is the hydrophobic amino acid.

Q3. d (threonine) As threonine has a free -OH (hydroxyl) group in its side chain, it is involved in forming hydrogen bond with the -NH group of the other amino acid.