Chapter 2 Study Questions

Question 1

You are running your first marathon on a very warm day. You start to sweat heavily and realize that you may be in danger of dehydration. Why is severe dehydration potentially life threatening?

Answer 1

Because water is a solvent for many biomolecules, water is a chemical participant in many biological reactions, it is necessary for buffering ability, water drives hydrophobic interactions

Question 2

Useful pH equations

Answer 2

pH = -log [acid]
pOH = -log [base]
pH + pOH = 14
pH = pKa + log [conjugate base]/[conjugate acid]

Question 3

Provides the least amount steric hindrance in proteins

Answer 3

Glycine

Question 4

Aromatic R group: hydrophobic and neutral at any pH

Answer 4

tryptophan and phenylalanine

Question 5

Saturated hydrocarbon R group; important in hydrophobic interactions

Answer 5

All non-polar AAs except Glycine, proline, and methionine

Question 6

What is the only amino acid have an R group with a pKa near 7; important in the active site of some enzymes.

Answer 6

Histidine

Question 7

What do the amino acids threonine and tyrosine have in common?

Answer 7

They both have OH groups. Are both polar, and are both capable of hydrogen bonding.

Question 8

What makes the amino acid cysteine important? Can methionine perform the same function?

Answer 8

Cysteine is important, because it allows for the formation of disulfide bridges. Methionine cannot perform this same function.

Question 9

What structural property of amino acids permits the measurement of protein concentration by UV light absorption? Which amino acids have this property?

Answer 9

Resonance/Aromaticity. Tryptophan and tyrosine are capable of this property