Biochem Exam 1

Front 1

What are the basic amino acids?

Back 1

H, R, K

Front 2

Where is Carboxyglutamate?

Back 2

In blood-clotting Proteins

Front 3

Which is not a property of water?

Adhesion

Cohesion

High Boiling Point

Low surface tension

good solvent

Back 3

Low surface Tension

Front 4

*blank* are cell structure(s) common to all animal, plant and bacterial cells

mitochondria

ribosomes

nucleus

cell membrane

b and d

Back 4

B (ribosomes) and D (cell membrane)

Front 5

*blank* predominate in nature. All amino acids have a least one chiral center except *blank*

D-amino acids: Glycine

L-amino acids: Alanine

L-amino acids: Glycine

D-amino acids: Alanine

Back 5

L-amino acids: glycine

Front 6

The amino acids that absorb at infrared wavelengths are ________. The three amino acids that absorb UV light are______.

Nonpolar amino acids; F, Y, and W.

Nonpolar amino acids; P, R, and T.

all amino acids; T, Y, and P.

all amino acids; F, Y, and W.

all amino acids; Nonpolar amino acids

Back 6

all amino acids; F, Y, and W.

Front 7

Edman reagent...

Back 7

reacts with the N-terminal of a protein or amino acid

Front 8

Lactic Acid with a Ka of 1.38 x 10-4 is titrated with 0.3 equivalents of a strong base. What is the pH?

Back 8

3.49

Front 9

What molecules make up the backbone of DNA?

Back 9

deoxyribose & phosphate

Front 10

Hemoglobin is ____ to pH and contains ____ binding sites for oxygen.

not sensitive, 1

sensitive, 1

sensitive, 4

not sensitive, 4

None of the above

Back 10

sensitive, 4

Front 11

Which method of protein purification relies heavily on protein - ligand binding?

SDS - Polyacrlamide Gel Electrophoresis

Ion Exchange Chromatography

Affinity Chromatography

Gel Filtration Chromatography

2-D Gel Electrophoresis

Back 11

Affinity Chromatography

Front 12

Which of the following do proteins not function as?

Enzymes.

Regulatory molecules.

Transport molecules.

Storage molecules.

None, proteins can function as all of the above.

Back 12

None, proteins can function as all of the above.

Front 13

Weak forces that influence structure and behavior of biomolecules include:

van der Waals interactions

Ionic interactions

Hydrogen bonds

Hydrophobic interactions

All of the above.

Back 13

All the above

Front 14

All of the following statements about water are true EXCEPT:

Water has a high dielectric constant

Water has a bent structure, making it polar

Water forms hydrogen bonds with polar solutes

Water is more dense as a solid than a liquid

Water participates in hydrophobic interactions, excluding nonpolar substances

Back 14

Water is more dense as a solid than a liquid

Front 15

All of the following amino acids are nonpolar EXCEPT:

Trp

Tyr

Leu

Val

Phe

Back 15

Tyr

Front 16

All amino acids isolated from proteins have four different groups attached to the alpha-carbon except:

Tyrosine

Glycine

Valine

Leucine

Glutamate

Back 16

Glycine

Front 17

What is the most abundant protein found in mammals?

Back 17

Collagen

Front 18

Which of the following peptides is composed of total polar amino acids (using one letter abbreviations)?

GACYNS

DEKRH

GAVLIMWF

QNYCTS

PQHFNR

Back 18

QNYCTS

Front 19

Peptide bond formation results in the release of what?

Back 19

Water

Front 20

Amino Acids contain a central tetrahedral carbon, containing an alpha carbon and which groups (R=side chain)?

Back 20

R,H, H3N+, COO-

Front 21

What method of protein purification separates by size only?

Back 21

Gel Filtration Chromatography

Front 22

Which level of protein structure contains an alpha helix and a beta sheet?

Back 22

Secondary

Front 23

`What type of protein that was considered not playing a role in gene expression is now found to control gene expression?

Back 23

Structural Proteins such as histone protein

Front 24

What type of bonds often occur on the protein surface?

Back 24

Hydrogen Bonds

Front 25

Which angles can result in favorable parameters for β- Sheets?

phi=0, ψ=0

phi=0, ψ=180

phi=180, ψ=0

all of the above

none of the above

Back 25

None of the above

Front 26

What type of structure describes the sequence of an amino acid?

Back 26

1 (Primary)

Front 27

Which of the following is a true statement about a virus?

it is not a free-living organism

it is a free-living organism

they contain nucleic acids encapsulated in a protein coat

both a and c

both b and c

Back 27

both a and c

Front 28

All of the following are true about biomolecules EXCEPT:

all biomolecules are organic and contain carbon

all biomolecules contain ionic bonds between each carbon

they are produced by living organisms

amino acids and vitamins are both examples of biomolecules

none of them are true

Back 28

all biomolecules contain ionic bonds between each carbon

Front 29

Which of the following statements describes Ka:

the negative logarithm of the hydrogen ion concentration (– log10[H+])

pH at which 50% ionized and 50% unionized

the acid dissociation constant, a quantitative measure of the strength of an acid in solution.

None are true

All are true

Back 29

the acid dissociation constant, a quantitative measure of the strength of an acid in solution.

Front 30

Carbonic anhydrase is more active at pH 8.5 than it is at pH 7.Precisely what is favored at the higher pH that causes this?

Deprotonation of water

protonation of water

Molecular autoionization

both a and c

both b and c

Back 30

Deprotonation of water

Front 31

Which of the following are the 3 basic Amino Acids?

GAV

LIM

STC

DEC

HRK

Back 31

HRK

Front 32

Which rare amino acid is found in blood clotting proteins?

Back 32

Carboxyglutamate

Front 33

Which noncovalent interaction is the strongest?

Back 33

Hydrophobic

Front 34

Proteins are commonly purified by all the following except:

Gas Chromotograp

Gel Filtration Chromotography

Ion Exchange Chromotography

SDS-Polyacrylamide Gel Electrophoresis

"Salt-in" and "Salt-out"

Back 34

Gas Chromotograp

Front 35

The two amino acids, ________and _________ contain a sulfur atom, except only _________ is polar, which can undergo oxidation to form disulfide bonds.

Back 35

C and M: C

Front 36

What are the advantages of acid hydrolysis for amino acid analysis of a protein?

Back 36

The process is fast

Front 37

Which type of structures do amino acids have?

Back 37

Tetrahedral

Front 38

The degree of dissociation, when regarding the acid-base properties of amino acids, depends on the ______ of the medium

Back 38

pH

Front 39

Which of the following amino acids always starts protein synthesis?

Val

Pro

Met

Cys

Ala

Back 39

Met

Front 40

Which of the following represents a change in configuration rather than conformation?

Free rotation in the carbon-carbon single bond of 1,2-dichloroethane

D-Glucose and L-Glucose

Partial rotation around a peptide bond between two amino acids

All of the above

None of the above

Back 40

D-Glucose and L-Glucose

Front 41

Over 50% of common cancers are associated with damage to a protein, p53. This protein is:

Back 41

A suppressor

Front 42

Of the following statements, which is incorrect?

amino acids contain a central tetrahedra carbon atom.

D-amino acids predominate in nature.

amino acids are weak polyprotic acids, which denote more than one proton per molecule.

amino acids can join via peptide bonds.

L-amino acids predominate in nature.

Back 42

D-amino acids predominate in nature.

Front 43

The ___ is a quantative measure of the strength of an acid in acid-base reactions.

Back 43

Acid Dissociation constant

Front 44

The overall 3D architecture of a protein is generally referred to as its ____

Back 44

Conformation

Front 45

A protein covalently associated with a carbohydrate group is known as a

Back 45

Glycoprotein

Front 46

The angle about the C(alpha)-N bond and the angle about the C(alpha)-Co bond are denoted the following symbols:

Back 46

Phi and Psi

Front 47

The secondary structure of a protein is mainly stabilized by

Back 47

Hydrogen bonding

Front 48

What type of molecular interaction is the most important in the formation of membranes?

Back 48

Hydrophobic interations

Front 49

In an alpha helix of a polypeptide chain, the amino acid ______ is considered a helix breaker because it fixes the Ca-N-C bond angle.

Back 49

Pro

Front 50

Proteins often consist of two or more monomer subunits. if a protein is made of two identical subunits it is called:

Back 50

Homodimer

Front 51

what amino acid is likely found in beta turns?

Back 51

Gly

Front 52

Aprox. how many residues apart is a turn in the alpha helix?

Back 52

3.5

Front 53

What amino acid is not a part of the non polar group?

Back 53

R

Front 54

An electrostatic interaction might occur within a protein between which of the following amino acid pairs at typical physiological pH?

Ser/Asn

Asp/Glu

Arg/Cys

Lys/Asp

Val/Ile

Back 54

Lys/Asp

Front 55

The resonance structure which forms the "amide plane" contains which atoms?

Back 55

Ca-NH-CO-Ca

Front 56

The amino acid residue most likely to be found in a beta turn is:

Back 56

Glycine

Front 57

Why should the core of the globular and membrane proteins consist almost entirely of a-helix and b-sheets?

Back 57

Highly polar N-H and C=O moieties of the peptide backbone must be neutralized in the hydrophobic core of the protein

Front 58

Arrange the steps involved in folding of globular proteins into a proper sequence.

A. "Molten globule" formation of assembled domains.

B. Formation of domains through cooperative aggregation of folding nuclei.

C. Adjustment in the conformation of domains.

D. Rapid and reversible formation of local secondary structure.

E. Final protein monomer formation.

Back 58

D, B, A, C, E

Front 59

lipoprotein are biochemical assembly that contains both proteins and lipids, bound to the proteins. what is the major function of these types of proteins?

Back 59

Allow fats to move through the water inside and outside cells

Front 60

Rate the following types of bonds in length from the shortest to longest: Single, double, peptide

Back 60

Double, peptide, single

Front 61

Which of the following ψ,φ angle combinations are unfavored in peptide formation?

i. φ = 0°, ψ = 180°

ii. φ = 180°, ψ = 0°

iii. φ = 0°, ψ = 0°

Back 61

All of them

Front 62

The following statements are true regarding the protein Hemoglobin, EXCEPT:

Sickle cell anemia is due to a genetic abnormality which alters the primary structure of Hemoglobin

Amino acid #6 in a normal Hemoglobin protein is Valine

The primary structure of a protein is its unique sequence of amino acids

Hemoglobin is a globular protein with 4 polypeptides which interact at the quarternary structure level

renaturation will cause a protein to fold into its normal protein structure

Back 62

Amino acid #6 in a normal Hemoglobin protein is Valine

Front 63

The following are true of disulfide bridges except:

occur between 2 thiol groups which are present the R groups of the amino acid cysteine

can occur between two cysteine groups, a sulfur-containing amino acid

can occur between 2 methionine residues, a sulfur-containing amino acid

are an example of tertiary structure folding

can be formed by an oxidation reaction of two thiol groups

Back 63

can occur between 2 methionine residues, a sulfur-containing amino acid

Front 64

All of the following are advantages which drive quarternary structure folding, EXCEPT:

stability (reduction of surface to volume ratio)

genetic economy and efficiency

bringing catalytic sites together

cooperativity

increased binding sites due to increased folding

Back 64

increased binding sites due to increased folding

Front 65

Secondary, tertiary and quaternary structures of proteins are formed and stabilized by:

Back 65

Weak forces

Front 66

Which statement is false?

Peptide chains, composed of L-amino acids, have a tendency to under go a right hand twist

Proteins are typically either mostly hydrophobic or mostly hydrophilic

Protein stability arises partially from intramolecular H bonds.

Only A and B

All of the above

Back 66

Proteins are typically either mostly hydrophobic or mostly hydrophilic

Front 67

Elements of secondary structure in proteins include:

All protein structures are based on the amide plane

The amide or peptide bond planes are joined by the tetrahedral bonds of the alpha-carbon

The resonance stabilization energy of the planar structure is 88 kJ/mol

All of the above

None of the above.

Back 67

All of the above

Front 68

What interactions give life to proteins?

Hydrogen Bonds

Van Der Waals forces

Ionic Bonds

Hydrophobic interactions

All of the above

Back 68

All of the above

Front 69

Which of the following are true statements regarding three-dimensional protein structures?

Structure depends on sequence and on weak, noncovalent forces

Motion enables function

Structures of globular proteins are marginally stable

Marginal stability facilitates motion

All of the above

Back 69

All of the above

Front 70

List the different forces in order of their strength (from largest to smallest)

Back 70

Hydrophobic interactions, Ionic bonds, Hydrogen bonds, Van der Waals

Front 71

List all the Basic Amino Acids

Back 71

Lysine (Lys, K), Histidine (His, H), Arginine (Arg, R)

Basically, he Lykes the History of Argentina

Front 72

List all the Acidic Amino Acids

Back 72

Aspartic Acid (Asp, D), Glutamic Acid (Glu, E)

Acidic foods cannot make youAspiring but Glumy.

Front 73

List the Polar Amino Acids

Back 73

Serine (Ser, S), Threonine (Thr, T), Cysteine (Cys, C), Tyrosine (Tyr, Y), Asparagine (Asn, N), Glutamine (Gln, Q)

Polar bear can Throw your CystorTyring and Serve you with modified acidic foods

Front 74

List the Non-polar Amino acids

Back 74

Glycine (Gly, G), Alanine (Ala, A), Valine (Val, V), Leucine (Leu, L), Isoleucine (Ile, I), Methionine (Met, M), Tryptophan (Trp, W), Phenylalanine (Phe, F), Proline (Pro, P)