Protein Structure and Function

Question 1

peptide bond

Answer 1

linkage between an amino group and carboxyl group in an amino acid

Question 2

globular

Answer 2

proteins, including enzymes and carrier proteins, that are water soluble

Question 3

The exterior of a protein is (hydrophobic/hydrophilic)

Answer 3

hydrophilic

Question 4

The interior of a protein is (hydrophobic/hydrophilic)

Answer 4

hydrophobic

Question 5

tyrosine and tryptophan

Answer 5

absorb UV light, can help to determine amounts of purified protein

Question 6

specific activity

Answer 6

the activity per amount of purified protein

Question 7

molten globule

Answer 7

when one or two structural elements are formed with the rest of the protein in an open state, prone to aggregation in this state

Question 8

chaperone

Answer 8

a specialized protein that assist in correct protein folding

Question 9

alpha helix

Answer 9

a secondary structure of proteins, results from hydrogen bonding

Question 10

proline

Answer 10

amino acid with 5-membered ring, strongly disfavored in alpha helix (helix breaker)

Question 11

amphipathic

Answer 11

a molecule that has both hydrophobic and hydrophilic parts (alpha helix)

Question 12

beta-sheet

Answer 12

secondary structure of protein, results from hydrogen bonding between stretches of amino acid residues

Question 13

disordered peptide regions

Answer 13

connects domains of a protein (not a helix or b sheet)

Question 14

gylcine

Answer 14

smallest amino acid, allows protein to form sharp bends

Question 15

fibrous proteins

Answer 15

relatively insoluble, elongated, structural (collagen or elastin)

Question 16

elastin

Answer 16

a fibrous protein found in lungs, extensively cross linked

Question 17

desmosine

Answer 17

a linkage provided by 4 lysine residues, in elastin

Question 18

keratins

Answer 18

in hair and nails, tough fibers rich in cysteine

Question 19

pKa

Answer 19

the pH at which the molecule is 50% in the acid form and 50% in the base form

Question 20

isoelectric point

Answer 20

a certain pH where certain proteins and amino acids are electrically neutral