FINAL - CH 4

Question 1

oligopeptides

Answer 1

Short polypeptides less than 40 amino acids in length

Question 2

Enantiomers

Answer 2

Molecules that are non-superimposable mirror images of one another

Able to rotate light (optically active)

Question 3

Most AA’s are _____ besides ____

Answer 3

Chiral

Glycine

Question 4

Each AA has a ____ and ____ form

Answer 4

D and L

L are used to build proteins/only found in humans

Question 5

the only amino acid that can form disulfide bonds

Answer 5

Cysteine - stabilizes 3D structure

Question 6

Isoelectric Point

Answer 6

pH at which the amino acid is neutral

Question 7

Electrically neutral molecule with positive (amino) and negative (carboxyl groups)

Answer 7

Zwitterion

Question 8

Average molecular weight if an AA

Answer 8

110 g/mol OR dalton

Question 9

How to find PI if there are two Pka’s

Answer 9

Take average

Question 10

How to find PI if there are 3 Pka’s

Answer 10

Draw the structure starting form fully protonated to fully deprotonated.. take the average of the two Pka’s where the molecule is neutral

Question 11

Pka is the pH where:

Answer 11

half the molecules of an amino acid in solution have side chains that are charged. Half are uncharged

Question 12

stimulates water resorption by kidneys and

increases blood pressure

Answer 12

Vasopressin

Question 13

stimulates uterine contractions during childbirth – induces labor

Answer 13

Oxytocin

Question 14

the angle of rotation around the N-Cα

Answer 14

phi (φ)

Question 15

the angle of rotation around the Cα–C

Answer 15

psi (Ψ)

Question 16

Secondary structures

Answer 16

β strands

α helices

β turns

Question 17

α helices

Answer 17

Right handed

Stabilized by hydrogen bonding

Has 3.6 residues per turn

Question 18

H bonding and alpha helices

Answer 18

N + 4 rule

Question 19

α helices have ______ H bonding

Answer 19

Intrastranded

Question 20

The most common location for an α-helix

Answer 20

along the outside of the protein, with one side of helix facing the solution and the other side facing the hydrophobic interior

Question 21

β turns

Answer 21

Connect two β strands in antiparallel β sheet

Question 22

β sheets have ______ H bonding

Answer 22

Interstranded

Question 23

β strands can interact in two ways to form a pleated sheet: _____________

Answer 23

parallel and antiparallel

Question 24

Antiparallel β sheets H bonds

Answer 24

More narrow and more stable

Question 25

Parallel β sheets H bonds

Answer 25

Equally spaced, H bonds are at an angle

Question 26

_____ is made from β sheets

Answer 26

Silk

Question 27

Beta Turns

Answer 27

Type I: Turn with the carbonyl oxygen inward Type II: Turn with the carbonyl oxygen facing outward

Question 28

_______ Observed in tertiary | structure

Answer 28

Disulfide bonds

Question 29

First protein structure determined

Answer 29

Myoglobin Largely α helical in structure

Question 30

Tertiary structures protein folds

Answer 30

``` Four helix bundle fold Greek key fold Rossmann fold TIM barrel fold (also called an α/β barrel) FERM domain fold ```

Question 31

Homodimer

Answer 31

Simplest quaternary structure Contains two identical protein subunits

Question 32

Heterodimer

Answer 32

Contains subunits from different gene products

Question 33

Hemoglobin

Answer 33

Has four polypeptide chains, non-covalently bound Mostly α-helical NO beta strands

Question 34

Fibrous Proteins

Answer 34

Keratin Silk Collagen

Question 35

Collagen Consists of ____________________

Answer 35

three intertwined left-handed helices

Question 36

Globular Proteins

Answer 36

Spherical proteins that consist of multi subunit protein complexes EX: immunoglobulins

Question 37

Most abundant protein in the human body

Answer 37

Collagen

Question 38

Four major classes of structures

Answer 38

Predominately α helices Predominately β heet α /β combined Mixed α & β

Question 39

3 models for protien folding

Answer 39

Hydrophobic collapse Nucleation model Framework model

Question 40

Chaperone Proteins

Answer 40

Proteins that facilitate the formation of stable 3D | structures

Question 41

Chaperone Proteins Functions:

Answer 41

Help newly synthesized proteins fold properly Rescue misfolded proteins Disrupt protein aggregates

Question 42

Two types of chaperone proteins

Answer 42

Clamp type (HSP 70) Chamber type (GroEL-GroES protein complex)

Question 43

Both types of chaperones bind to misfolded proteins and use _______ to facilitate correct folding

Answer 43

ATP hydrolysis

Question 44

GroEL has _____ subunits

Answer 44

14

Question 45

pH < Pka

Answer 45

Protonation

Question 46

pH > Pka

Answer 46

Deprotonation

Question 47

Tm

Answer 47

Transition curve mid point - half of proteins are unfolded | Tm is on X axis

Question 48

Alzheimers disease

Answer 48

caused by the aggregation of Aβ peptides Aggregates are referred to as β-amyloid plaques

Question 49

bps per turn in B DNA

Answer 49

10.5 bp/turn

Question 50

bps per turn in A DNA

Answer 50

11 bp/turn

Question 51

bps per turn in Z DNA

Answer 51

12 bp/turn

Question 52

The isoelectric point is where:

Answer 52

AA has no charge

Question 53

_____ is not found in Alpha helices

Answer 53

Proline

Question 54

Angles in beta sheet

Answer 54

+psi | -phi

Question 55

Angles in alpha helix

Answer 55

- psi | - phi