Biochem Final part 1

Question 1

Hydrophobic

Answer 1

water-fearing

Question 2

hydrophobic effect

Answer 2

the energetic preference of nonpolar molecular surfaces to interact with other nonpolar molecular surfaces and thereby to displace water molecules from the interacting surfaces

Question 3

Hydrophilic

Answer 3

water-loving

Question 4

Amphoteric

Answer 4

they can react either as acids or bases, depending on the circumstances

Question 5

Isoelectric point

Answer 5

the pH at which the net electric charge is zero

Question 6

zwitterion

Answer 6

a functional group molecule in which at least one has a positive electrical charge and one a negative electrical charge.

Question 7

primary structure

Answer 7

covalent bonds linking amino acid residues in a polypeptide chain

Question 8

secondary structure

Answer 8

recurring structural patterns
-ɑ-helix, β-sheets, β-turn, random coils

Question 9

tertiary structure

Answer 9

3D folding of polypeptide
-determined by amino acid sequence
-hydrogen bonds between nearby amino acid residues
- salt bridges

Question 10

quaternary structure

Answer 10

2+ polypeptide subunits

Question 11

protein domain

Answer 11

part of a polypeptide chain that is independently stable or could undergo movements as a single entity

Question 12

motif

Answer 12

recognizable folding pattern involving 2+ elements of 2° structures & the connection(s)
b-a-b loop or b barrel

Question 13

Intrinsic disorder proteins

Answer 13

-Lack of definable structure
-Often lack a hydrophobic core
-High densities of charged residues (Lys, Arg, Glu) and Pro
-Facilitates protein interactions with multiple binding partners

Question 14

Denaturation

Answer 14

loss of three-dimensional structure sufficient to cause loss of function
- can happen by heat, pH extremes, detergents, strong acids/bases, organic solvents

Question 15

native conformation

Answer 15

the arrangement of all atoms contained in the protein in a conformation that is stable and functional
thermodynamically the most stable, therefore, lowest free energy

Question 16

enzyme

Answer 16

A biomolecule, either protein or RNA, that catalyzes a specific chemical reaction

Question 17

substrate

Answer 17

the molecule that is bound to the active site and acted upon by the enzyme

Question 18

Active site

Answer 18

provides a specific environment in which a given reaction can occur more rapidly

Question 19

allosteric site

Answer 19

an effector binding site within enzymes, distinct from the active site, that
allows molecules to either activate or inhibit (or turn off) enzyme activity

Question 20

Pre-steady state

Answer 20

the initial transient period during which ES builds up

Question 21

steady state

Answer 21

the period during which [ES] and other intermediates remain constant

Question 22

Saturation effect

Answer 22

occurs at Vmax, when virtually all the enzyme is present as the ES complex
- Further increases in [S] do not affect rate

Question 23

Km vs Kcat

Answer 23

Km: Michaelis constant, characteristic of the enzyme and the substrate under s[ecific conditions
Kcat: limiting rate of any enzyme-catalyzed reaction at saturation

Question 24

V0 vs Vmax

Answer 24

V0: initial velocity
Vmax: maximum velocity

Question 25

Stereoisomer

Answer 25

each of two or more compounds with the same molecular formula,
differing only in the spatial arrangement of their atoms

Question 26

enantiomer

Answer 26

stereoisomers that are mirror images

Question 27

diastereomer

Answer 27

stereoisomers that are not enantiomers (D (OH to the right) and L(OH to the left))

Question 28

aldose

Answer 28

sugar with the carbonyl group is at the end of the carbon chain (in an aldehyde group)

Question 29

Hemiacetal (/hemiketal)

Answer 29

Ring formation that occurs because aldehyde and ketone groups react reversibly with hydroxyl groups in an aqueous solution

Question 30

ketose

Answer 30

sugar with the carbonyl group is at any other position (in a ketone group)

Question 31

acetal (/ketal)

Answer 31

Glycoside formation: hemiacetals and hemiketals react with alcohols to form the corresponding acetal and metal - no OH instead two OR groups

Question 32

pyranose

Answer 32

six-membered rings are pyranoses ex: fructose (monosaccharide cyclization)

Question 33

furanose

Answer 33

Five-membered rings are called furanoses

Question 34

Anomer (alpha and beta)

Answer 34

The two possible diastereomers that form because of cyclization
are called anomers; up (above ring, β) or down (below ring, ɑ)