Biochemistry Ch1

Question 1

Proteinogenic amino acids

Answer 1

the 20 alpha-amino acids encoded by the human genetic code

Question 2

Which AA is the only one with an R absolute configuration

Answer 2

Cysteine

Question 3

Which AA is the only achiral AA

Answer 3

glycine

Question 4

Peptide bond

Answer 4

specialized form of an amide bond which forms between -COO- group and NH3+ gorup
- Dehydration reaction releasing H2O

Question 5

Peptide terminal ends

Answer 5

N-terminus: amino terminus
C-terminus: carboxy terminus
N to C

Question 6

Primary structure of protein

Answer 6

linear arrangement of AAS

Question 7

Secondary Structure

Answer 7

Local structure of neighboring AA
Alpha-helices
- rodlike structure in which the peptide chain coils clockwise around a central axis
- Carbonyl oxygen atom and amide hydrogen 4 residues down the chain
BETA-PLEATED SHEETS
- peptide chains lie along side one another, forming rows or strands held together by hydrogen bonds between carbonyl oxygen and amide hydrogen on the adjacent
- Ripple to accommodate as many bonds as possible

Question 8

Tertiary Structure

Answer 8

The 3D shape
- determined by hydrophobic and hydrophilic interactions between R groups
- Hydrophobic on interior and hydrophilic N-H and C=O bonds get pulled in by hydrophobic residues
- hydrophilic bonds can then form electrostatic interaction and hydrogen bonds
- Can also be determined by hydrogen bonding and acid base interations

Question 9

Disulfide bonds in tertiary structure

Answer 9

two cystine molecules can oxidize to form cystine creating loops

Question 10

How does protein folding occur

Answer 10

secondary structures form first and then hydrophobic interactions and hydrogen bonds cause the protein to collapse

Question 11

Solvation Layer

Answer 11

When solute dissolves, the nearby solvent molecules form a solvation layer
- not favorable with hydrophobic side chains because water molecules cannot form hydrogen bonds with side chains