old exam 1

Question 1

O2 binding triggers a conformational change in hemoglobin (T/F)

Answer 1

True

Question 2

Positive Cooperativity is when the first binding event increases affinity at remaining sites (T/F)

Answer 2

True - hemoglobin triggers change

Question 3

Negative cooperativity is when the first binding event reduces aaffinity at remaining sites (T/F)

Answer 3

True - decreases the strength and closes the binding site for something else

Question 4

CO2 is toxic to humans because

Answer 4

It binds to Fe atom in hemoglobin and prevents binding of O2

Question 5

The lock and key model describes conformational changes in both the protein and the ligand when the ligand binds to the protein (T/F)

Answer 5

False - certain things can bind to certain proteins

Question 6

beta sheet is quaternary structure (T/F)

Answer 6

False - its secondary

Question 7

Proteins can be denatured by extremes of pH (T/F)

Answer 7

True

Question 8

Independently stable part of a protein is called a domain (T/F)

Answer 8

True

Question 9

O2 dissolves easily in water (T/F)

Answer 9

False

Question 10

Anfinsens ribonuclease refolding experiment showed that the amino acid sequence determines the native confirmation (T/F)

Answer 10

True

Question 11

In globular protein would Pro and Gly be found more in Beta or alpha

Answer 11

Beta turn

Question 12

Calculate pH pf a solution of weak acid when molar ratio of proton acceptor to donor is 100:1 and pKa is 4.

Answer 12

pH= 6

Question 13

Long range strong interactions between permanently charged groups

Answer 13

electrostatic interactions

Question 14

a leucine sidechain interacting with a valine sidechain in the protein interior

Answer 14

hydrophobic effect

Question 15

interaction of N-H and C–O of the peptide bond leads to local regular structures such as alpha and beta

Answer 15

hydrogen bonds

Question 16

causes amphipathic lipids to spontaneously form

Answer 16

hydrophobic effect

Question 17

interaction of water molecules in ice

Answer 17

hydrogen bonds

Question 18

weak interactions between all atoms regardless of polarity

Answer 18

Van der Waals

Question 19

3 pKas / peaks

Answer 19

Aspartate

Question 20

What is pKa of the amino group in Aspartate

Answer 20

9.6

Question 21

weak acid curve (not steep)

Answer 21

acetic acid

Question 22

What is the pH range where acetic acid is a good buffer

Answer 22

3.8-5.2

Question 23

Strong acid curve (steep)

Answer 23

HCl

Question 24

All of the following are considered weak except: Hydrogen bonds/hydrophobic interactions/ ionic bonds/ peptide bonds/ van der waal forces

Answer 24

Peptide bonds (peptide and covalent bonds are stronger than others)

Question 25

The variable region of the primary antibody binds to

Answer 25

an epitope in the antigen in our protein sample

Question 26

The variable region of the secondary antibody binds to

Answer 26

the constant region of the primary antibody

Question 27

the purple color that develops on our blot is due to a molecule that is

Answer 27

the product of an enzyme covalently bound to the secondary antibody

Question 28

which lane contains pure protein (Daltons)

Answer 28

3 (clear sheet)

Question 29

what is molecular weight

Answer 29

21,500

Question 30

Which bonds are planar in polypetide backbone

Answer 30

C-N bonds (nothing with alpha helixes)

Question 31

fibrous protein with alpha-helices with many disulfide bonds

Answer 31

keratin

Question 32

fibrous protein with non-covalently held beta sheets

Answer 32

silk

Question 33

globular protein

Answer 33

myoglobin

Question 34

conjugate base

Answer 34

HCO3-

Question 35

CO32-

Answer 35

proton acceptor

Question 36

pH @ 7.0

Answer 36

HCO3-