Exam 1/practice 1 - 2

Front 1

For a given reaction, the value of delta H is 15 kJ/mol and the value of delta S is 51 J, above what temperature will this reaction be spontaneous

Back 1

21 C

Front 2

which of the proteins contain ATP binding sites? out of myosin, kinesin, tublin, actin, and collagen

Back 2

myosin, kinesin, and actin

Front 3

highly active muscle generates lactic acid by respiration so fast that blood passing through the muscle actually experiences a drop in pH from 7.4 to 7.2, under these conditions, would hemoglobin release more or less oxygen than it does at pH 7.4

Back 3

release more oxygen

Front 4

the pH of a 0.1M solution of sodium acetate would be basic or neutral or acidic

Back 4

basic, becasue of the acetate ion reacts with water to form acetic acid and OH-

Front 5

___ is exceptionally soluble in water due to the formation of hydrogen bonds....oxygen, benzene, NaCl, ethanol, or sodium palmitate

Back 5

ethanol//??????

Front 6

a rigid planar structure conssiting of about 40% double bond character is characteristic of a beta sheet alpha helix tertiary structure peptide link alpha loop

Back 6

peptide link

Front 7

the arrangement of the regular structural elements adn the 3-d positions of atoms in the protein are considered part of primary struct,ure, regular secondary structure, tertiary structure, quaternary structure

Back 7

tertiary structure

Front 8

which of the following amino acids is most likely to be found on the exterior, membrane contracting, surface of an integral membrane protein?
Gly Gln Glu Ala Asp

Back 8

Ala

Front 9

wha tis the hydrophobic effect?

Back 9

it is an entropic effect, caused by the desire of water molecules to increase their entropy by excluding hydrophobic groups, which they must otherwise surround with highly ordered structures (called clathrates)

Front 10

which of the following is not a ligand for the porphyrin ring Fe2+ ion in oxymyoglobin
His E7 (his resdue above the porphyrin ring), Oxygen, His F8 (below Porphyrin ring), Nitrogen atoms

Back 10

His E7

Front 11

the absence of 2, 3BPG causes hemoglobin's affinity for oxygen to

Back 11

increase

Front 12

in two homologous proteins, which residue is most likely to replace a GLy residue as a conservative substitution? Trp, Ile, Met, Asp, Lys

Back 12

Asp

Front 13

what would the net charge on the following peptide at physiological pH? Arg, Lys, SP, Val, Tyr

Back 13

+1

Front 14

Which one of these characteristics is not true for the alpha helix?
it is right handed, a hydrogen bond forms between the carbonyl oxygen of the nth amino acid residue and the -NH group of the N + 4 amino acid residue, proline is typically not found in the alpha helix, there are 3.6 amino acids per turn, there is a requirement for glycine every third amino acid residue

Back 14

There is a require ment for glycine every third amino acid residue

Front 15

a sample of the amino acid tyrosine is barely soluble in water. would a polypeptide containing only Tyr residues, poly(tyr) be more or less soluble, assuming the total number of Tyr residues is the same in both cases?

Back 15

the polypeptide would be less soluble

Front 16

proteins can be unfolded or denatured by agents that alter the balance of weak noncovalent forces that maintain the native conformation. how would the following agents cause a protein to denature?
a) amphiphilic detergents b) reducing agents

Back 16

amphiphilic would disrupt internal hydophobic interactions of tertiary structure
reducing agents would disrupt disulfide bonds

Front 17

Ile-Gln-Glu_Val_Glu-Arg-Asp

Trp-Gln-Glu-Tyr-Gly-Arg-Asp

in which protein would these be found? collagen, keratin, actin, tubulin, myosin

Back 17

keratin

Front 18

of these two peptides, which would be more likely to appear in the protein specificied in the question?

Back 18

peptide A

Front 19

At a CO2 partial pressure of 5 torr, the p50 value for hemoglobin is 15 torr. when the CO2 partial pressure is 80 torr the p50 value for hemoglobin is 40 torr. As the concentration of CO2 increases, how does this affect the affinity of hemoglobin Hb for oxygen

Back 19

as pCo2 increases, the affinity of Hb for O2 decreases?

Front 20

urea dissolves readily in water. the beaker containing the dissolved compound is cold to the touch. what conclusions can you make about the sign of the H change and the S change

Back 20

-S, +H

Front 21

rank the solubilities of the following amino acids in water at pH 7: W, R, S, V, T

Back 21

W<V<T<S<R

Front 22

Based on the following Tm values, what can be said about these two DNA molecules, Strand A = 80, Strand B = 100 celsius?

Back 22

A has higher percentage of adenine, strand B has higher percentage cytosine, Strand B has stronger stacking interactions

Front 23

what explains the attractive forces between hydrophobic molecules in an aqueous solution?

Back 23

there is no increase in attractive forces between nonpolar molecules in an aqueous enviornment

Front 24

which of the following fibers is correctly paired with the protein that forms the fiber?
microfilaments: actin
microtubule: tubulin
extracellular support fibers: collagen
intermediate filaments: keratin

Back 24

all of the above

Front 25

what is the pH of a solution tat contains one part acetic acid and three parts sodium acetate? the pK for acetic acid is 4.76

Back 25

5.24

Front 26

which of the following represents an increase in entropy: ice freezing, traffic congestion on highway, dismissal of class when bell rings, sewing garment, filing papers

Back 26

dismissal of class

Front 27

for a globular protein that is found in the cytosol, __ would most likely be found in the proteins interior while ___ would most likely be found on the surface
Val, Phe, Leu, Ile, Ser, Thr, His

Back 27

Leu interior, Ser on the srface

Front 28

Do Chargaff's rules apply to RNA as well as DNA?

Back 28

yes

Front 29

what is the net charge of the heptapeptide His-Ala-Cys-Asp-Ser-Glu-Asn at pH 7?

Back 29

-2

Front 30

what would be the resulting pH if one drop (.05ml) of 1M HCl was added to one liter of pure water?

Back 30

4.3

Front 31

what is the fractional saturation of myoglobin (p50 = 2.8 torr_ of yoglobin when pO2 = 15 torr?

Back 31

0.84

Front 32

which of the following is an example of a conservative amino acid substitution?
Ile - Leu, Ser - Glu, Phe - Tyr, Asp-Gln, Arg-Cys

Back 32

Ile-Leu

Front 33

which of the following methods of amino acid sequence determination requires an unmodified amino terminus? mass spectroscopy, ion exchange, SDS-PAGE, edman sequencing, xray crystallography

Back 33

Edman sequencing

Front 34

the pK of CH3CH2NH3+ is 10.7. would the pK of FCH2CH2NH3+ be higher or lower?

Back 34

loerw

Front 35

which of the following processes are involved in gene expression? replication, transcription, translation

Back 35

transcription and translatoin

Front 36

you are involved in the purification of protein X with a pI of 6.0 using a buffer with a pH of 7.5. what type of resin would you choose to ensure initial binding of protein X?
DEAE pK 10; CM pK 4

Back 36

DEAE pK 10

Front 37

if the following mixture of proteins was applied to a size-exclusion chromatography column, what would be the order of elution?
myoglobin 17.7, hemoglobin 64.5, lysozyme 14.3, triose phosphate isomerase 57.4

Back 37

hemoglobin 64.5, triose phosphate isomerase 57.4, myoglobin 17.7, lysozyme 14.3

(largest to smallest)

Front 38

a plot of the binding of oxygen to myoglobin as a function of pO2 gives a __ shape, a similar plot for hemoglobin gives a ___ shape.
sigmoidal, hypoerbolic, exponential

Back 38

hypoerbolic, sigmoidal

Front 39

which allosteric effector has the greatest ability to stabilize the deoxy state of hemoglobin? BPG, CO2, O2, H+

Back 39

BPG

Front 40

each kinesin head contains a binding site for __ and a binding site for ____
tubulim, GTP, another kinesin molecule, myosin, ATP,

Back 40

tubulin and ATP

Front 41

which of the biopolymers is correctly paired with its major function?
protein: information encoding
mucleic acids: energy storage
lipids: information encoding
polysaccharide: energy storage

Back 41

polysaccharide: energy storage

Front 42

if phosphate buffer pK 6.82 was formulated such that its pH was 7.3, it would be best suited to buffer against ___. if instead it was formulated such that its pH was 6.3 it would be best suited to buffer against ____ (acid or base)

Back 42

acid; base

Front 43

at pH __ the pentapeptide Ala-Glu-His-Val-Cys would contain two positively charged groups and one negatively charged group

Back 43

3.5

Front 44

would DNA binding proteins be more likely to associated with the major or the minor groove?

Back 44

major groove

Front 45

which of the following statements regarding RNA is false?
the ribose in RNA contains an O atom that the ribose in DNA lacks
RNA does not form a 2-stranded double helix like DNA
Since RNA does not form a double helix, it tends to be linear in shape
RNA can form Watson-Crick base pairs with DNA

Back 45

since RNA does not form a double helix, it tends to be linear in shape

Front 46

in a muscle cell, what is the name for the bundles of myosin tails/

Back 46

thick filaments

Front 47

which of the following molecules contains the most oxidized form of carbon/
acetaldehyde, ethanol, acetic acid, ethylene, carbon dioxide

Back 47

carbon dioxide

Front 48

Which of the following amino acids has a thiol group in its side chain? Ser, Asn, Cys, Tyr, Met

Back 48

Cys

Front 49

THe replication of DNA is made possible by the presence of __ strands in the double helix of DNA.
antiparallel, hydreogen bonded, complementary, genomic

Back 49

complementary

Front 50

at physiological pH, all amino acids have at least __ charged groups

Back 50

2

Front 51

which of the following is an example of the hydrophobic effect?
the lipid membrane of cells and organelles
protein folding that places hydrophobic amino aicds in the interior of the protein
the separation of salad dressing
oil sheens seen on the ocean following an oil spill

Back 51

all of the above

Front 52

which of the two proteins below has a longr neck region?
myosin, keratin, kinesin, collagen, actin

Back 52

myosin

Front 53

what term describes the process of converting the information found in DNA into the sequence of a protein? replication, transcription, translation, expression

Back 53

expression

Front 54

which of the following assembles by association of multiple protofilaments?
myosin, actin, tubulin, keratin, collagen

Back 54

tubulin

Front 55

the tertiary structures of myoglobin , alpha hemoglobin and beta hemoglobin are nearly identical and are therefore nearly identical in primary structure, T/F

Back 55

FALSE

Front 56

What bonding interactions are broken during DNA denaturation? covalent, hydrogen, vanderwaals

Back 56

hydrogen and vanderwaals

Front 57

which of the following is the most abundant structural element in the human body
N, C, O, P

Back 57

Carbon

Front 58

Heme is considered a
catalyst, prothetic group, coenzyme, cofactor

Back 58

prothetic group

Front 59

What is a simple statement of Chargraffs rule

Back 59

A+G = C+T

Front 60

which rna molecules are involved in the process of translation?

Back 60

mRNA, tRNA and rRNA

Front 61

the higher the dielectic constant, the more ___the compound
(polar, negatively charged, positively charged, nonpolar, oxidized)

Back 61

polar

Front 62

The Bohr effect describes a lowered oxygen affinity of Hb when the pH _____

Back 62

decreases

Front 63

what level of protein structure is characterized by the three dimensional structure of an entire polypeptide including all amino acid side chains?

Back 63

tertiary

Front 64

a protein that consists of a single polypeptide chain will lack which level of protein structure?

Back 64

quaternary

Front 65

the most important buffering system for maintaining proper blood pH is
the charges on the amino acids
the bicarbonate buffer system of CO2 carbonic acid and bicarbonate
phosphate groups of serum phosphoproteins

Back 65

the bicarbonate buffer system of CO2, carbonic acid, and bicarbonate

Front 66

which of the following would be a proper designation of the deoxy position on DNA?
3'(prime), 3, 2'(prime), 2, 1

Back 66

2'prime

Front 67

which of the following would have the lowest melting point?
NH3, CH4, H2O

Back 67

CH4

Front 68

what is the conjugate acid of H2PO4-?

Back 68

H3PO4

Front 69

which of the 20 standard aminio acids is optically inactive?

Back 69

GLy

Front 70

At a pH above its pKa, the phenolic group of tyrosine is ________
pronated, neutral, positively charged, deporonated, negatively charged

Back 70

deprotonated and negatively charged

Front 71

which amino acid is critical for crosslinking of keratin fibers?

Back 71

Cys

Front 72

alpha helices and beta sheets comprise ___ structure

Back 72

secondary

Front 73

bone and tendons contain ___while hair and nails contain ____

Back 73

collagen, keratin

Front 74

which of the following amino acids has a nonpolar side chain?
Ser, Val, Lys, Asn

Back 74

Val

Front 75

Which of the following would be the strongest acid?
formic acid pK 3.75
succinic acid, a diprotic acid with pK 4.21 and 5.64
acetic acid pK 4.76
ammonium ion pK 9.25

Back 75

formic acid pK 3.75