Chapter 4

Question 1

5 constraints on alpha helix stability

Answer 1

• electrostatic repulsion between residues
• the bulkiness of adjascent R groups
• the interactions of residues spaced by 3-4 residues
• the occurence of proline and glycine
• the interaction of amino acids at each end of the helix

Question 2

parallel beta sheets vs anti parallel beta sheets

Answer 2

• strands run in the same N to C direction

- strands run in opposite

Question 3

what determines tertiary structure

Answer 3

amino acid sequence

Question 4

quaternary structure is what by what

Answer 4

subunits held together by non covalent interactions

Question 5

3 fibrous proteins and 2 globular proteins

Answer 5

• keratin, collagen, silk

- myoglobin, hemoglobin

Question 6

examples and primary structure of keratin

Answer 6

• hair, nails, horns

- contains a seven repeat pattern where positions a and d are hydrophobic

Question 7

the coiled coil of keratin is

Answer 7

two right handed helicies around each other in a left handed fashion

Question 8

the individual units of keratin are

Answer 8

linked together through disulfide bonds

Question 9

collage examples and primary structure

Answer 9

• tendons and skin

- repeats of Gly-Pro-hydroxyprol

Question 10

the coiled coil of collagen is

Answer 10

three left handed helicies around each other in a right handed fashion