Biochem: Proteins

Question 1

Primary structure

Answer 1

• sequence or order of amino acids
• all protein structures are driven from this
  POLYPEPTIDE CHAIN BEING MADE
• linear

Question 2

secondary structure

Answer 2

H-bonds between R-group and another backbone of the a.a (most likely double bonded O on carboxyl)
- alpha helix(coiled)
- beta-pleated sheets (accordion shape)

Question 3

Tertiary structure

Answer 3

local rules of chemistry:
- polar/nonpolar
- opp attract like, charges repel (more H bonding between R-groups)
- cysteine buddies (disulphide bridges stabilizes structure)

Question 4

quaternary structure

Answer 4

different subunits or pieces
- takes place in ER
- helped by chaperone proteins/chaperonins which takes in chain and forces the shape of proteins
OPTIONAL - not all proteins have a quaternary structure

Question 5

what factors create the 3D shape of proteins

Answer 5

1. electrostatics
   - opposites attract
   - like charges repel
   - dipole-dipole attractions (including H-bonds)
   - ionic
2. Likes Dissolves Likes
   - polar & non-polar
3. Cysteine Buddies
   - disulphide bridges

Question 6

Denaturation

Answer 6

anything that disrupts D-D attractions and H-bonds will cause this
- can be caused by hear, acids, ions

Question 7

what are the monomer and polymer in proteins

Answer 7

mono: amino acids
poly: polypeptide chain

Question 8

what are the 2 functional groups on all amino acids

Answer 8

amino, carboxyl

Question 9

what types of amino acids must be digested? why?

Answer 9

8-9-10: body cant make them from other sources so it must be brought in thru diet

Question 10

what bonds join amino acids together?

Answer 10

peptide bonds

Question 11

polypeptides

Answer 11

• long, linear string of amino acids bonded together with peptide bonds
• has N-terminus and C-terminus

Question 12

what determines the order of amino acids

Answer 12

nucleotide sequence in gene

Question 13

what factors can lead to denaturation

Answer 13

• temp
• pH
• salinity/[ion]

Question 14

how is denaturation different from conformational change

Answer 14

denaturation is irreversible, conformational change is not

Question 15

a friend of yours wants to use their choco protein powder to make a “healthy version” of hot choco, by mixing the powder with very hot water. why is this not a good idea?

Answer 15

hot water will denature protein = clumpy drink that nobody wants to drink (stupid question)

Question 16

if a sailor was stranded at sea, although surrounded by water, they cannot drink the salty ocean water. despite having a full supply of protein/energy bars, explain why it would be a bad idea to eat those bars

Answer 16

breaking down proteins requires water (hydrolysis). body cannot afford to lose water

Question 17

why does order of amino acids matter?

Answer 17

properties of R-groups determines behavior/characteristics of amino acids
- polarity, acid base, conformation
- when continuing to form protein structure, the behavior determines shape (form follows function)