Biochemistry: Proteins Flashcards Preview

BIO125 > Biochemistry: Proteins > Flashcards

Flashcards in Biochemistry: Proteins Deck (19):
1

charges on functional groups

(1) help amino acids stay in solution  interact w/ other amino acids or solutes

(2) affect chemical reactivity

2

peptide bond

C – N covalent bond after amino acid condensation
- chain composed of < 50 amino acids linked together

3

peptide bond backbone

(1) R-group orientation

(2) directionality

(3) flexibility

4

protein

polymers made up of amino acids
- many fcns (depends on size & shape)

5

levels of organization (protein structure)

(1) primary structure

(2) secondary structure

(3) tertiary structure

(4) quaternary structure

6

primary structure

unique sequence of amino acids in a protein
- limitless primary structures

fundamental to higher levels of protein structure

7

secondary structure

distinctively shaped sections of proteins that are stabilized by H-bonding
- possible structures
- fcns

8

possible structures of secondary structure

(1) α-helix (alpha-helix) – coiled backbone (spiral shape) stabilized by H-bonding

(2) β-pleated sheet (beta-pleated sheet) – segments of peptide chains bend 180˚ & fold into sheet-like shape by H-bonding

*type depends on primary structure

9

secondary structure fcns

(1) increase stability of molecule

(2) help define shape

10

tertiary structure

overall 3D shape of single polypeptide chain
- result from multiple interactions

11

tertiary structure interactions

(1) H-bonding

(2) hydrophobic interactions

(3) van der Waals interactions

(4) covalent bonding

(5) ionic bonding

12

quaternary structure

overall 3D shape formed from 2+ polypeptide chains (subunits)
- could be identical subunits or not

13

groups of amino acids based on their side chains

(1) nonpolar side chain

(2) polar side chain

(3) uncharged side chain

interactions w/ otro amino acids predictable

14

nonpolar side chain

(1) hydrophobic – lack charged or highly electronegative atoms -> no form H-bonds w/ water

(2) no dissolve -> tend to coalesce in aq. solution

(3) lost proton -> acidic

(4) interact w/ water

15

polar side chain

(1) hydrophilic – readily dissolve in water

(2) took proton -> basic

(3) interact w/ lipids

16

uncharged side chain

(1) highly electronegative oxygen -> polar covalent bond -> uncharged polar

(2) interact w/ lipids

17

prion

(proteinaceous infectious particles) proteins that can be folded into infectious, disease-causing agents

(ie) mad cow disease

18

protein folding characteristics

(1) mostly spontaneous

(2) some proteins require chaperones

(3) some misfolding

19

protein fcns

(1) catalyst

(2) defense - antibiotics

(3) movement - dinein kinesin

(4) signaling - insulin

(5) structure - collagen & microtubules

(6) transport - hemoglobin