biochem chapter 1

Which of the following is the most abundant element in the human body?

1. nitrogen

2. carbon

3. oxygen

4. phosphorus

5. none of the above

oxygen

1. amine and carboxylic acid

2. amine, ketone, and carboxylic acid

3. amine, amide, and carboxylic acid

4. alcohol, amine, amide, and carboxylic acid

5. none of the above are correct

amine, amide, and carboxylic acid

1. -52 kJ/mol

2. -10 kJ/mol

3. 10 kj/mol

4. 52 kj/mol

5. none of the above

-10 kJ/mol

Which of the following is a major difference between eukaryotic and prokaryotic cells?

1. eukaryotic cells contain a nucleus, prokaryotic cells do not

2. eukaryotic cells contain organelles, prokaryotic cells do not

3. eukaryotic cells are much larger than prokaryotic cells

4. eukaryotic cells often form multicellular organisms, prokaryotic cells do not

5. all of the above

all of the above

Which of the following correctly identifies the progression from individual molecules to a functioning multicellular organism?

1. molecules, organelle, organ, cell, organism

2. molecules, cell, organ, organelle, organism

3. molecules, organelle, cell, organ, organism

4. molecules, cell, organelle, organ, organism

5. molecules, organ, organelle, cell, organism

molecules, organelle, cell, organ, organism

Change in enthalpy (delta H) is best defined as

1. the sum of heat absorbed and work done

2. the heat content of a system

3. the pressure change at constant temperature

4. the measure of disorder in a system

5. none of the above

the heat content of a system

B

An endergonic reaction with a _ delta H _ and a _ delta S can be changed into an exergonic reaction by decreasing the temperature

1. negative, positive

2. positive, positive

3. positive, negative

4. negative, negative

negative, negative

1. spontaneous and endergonic

2. spontaneous and exergonic

3. nonspontaneous and endergonic

4. nonspontaneous and exergonic

5. none of the above

spontaneous and exergonic

in a water molecule, hydrogens are partially _ ; oxygens are partially _

1. negative, negative

2. negative, positive

3. positive, positive

4. positive, negative

5. none of the above

positive, negative

the strongest non-covalent interactions are _

1. hydrogen bonds

2. LDF

3. van der waals

4. dipole dipole

5. ionic interactions

ionic interactions

Which of the following explains the interactions that occur between the atoms of water molecules and the ions that form when sodium chloride dissolves in water?

1. hydrogens interact with the sodium ion, oxygens interact with the chloride ion

2. hydrogens interact with the chloride ion, oxygens interact with the sodium ion

3. hydrogens interact with the sodium ion and the chloride ion

4. oxygens interact with the sodium ion and the chloride ion

5. none of the above

hydrogens interact with the chloride ion, oxygens interact with the sodium ion

Which of the following explains the attractive forces between hydrophobic molecules in an aqueous solution?

1. in an aqueous environment, LDF between hydrophobic molecules become stronger

2. In an aqueous environment, LDF between hydrophobic molecules and water become stronger

3. since nonpolar molecules do not form hydrogen bonds with hydrogen bonds with water, they can form hydrogen bonds with other nonpolar molecules

4. there is no increase in attractive forces between nonpolar molecules in an aqueous environment

5. none of the above

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

Which of the following is an example of an amphipathic molecule?

1. adenine, a base found in nucleic acids

2. glucose, a monosaccharide

3. serine, an amino acid

4. palmitic acid, a fatty acid

5. none of the above

palmitic acid, a fatty acid

Fatty acid anions most commonly assemble into _ in an aqueous solution

1. lipid bilayers

2. solvent-filled vesicles

3. micelles

4. liposomes

5. none of the above

micelles

Which of the following is true regarding hydrophobic interactions between nonpolar molecules or groups?

1. they depend on strong permanent dipoles in the nonpolar molecules

2. they result from the tendency to maximize water’s contact with nonpolar molecules

3. they are the result of strong attractions between nonpolar regions

4. they require the presence of surrounding water molecules

5. they are the result of strong repulsion between water and nonpolar regions

they require the presence of surrounding water molecules

What would be the resulting pH if one ml of 1.0 M NaOH was added to one liter of pure water (assume pH 7.0)?

1. 11

2. 7.3

3. 1

4. 13

5. 3

11

1. HPO4 2-

2. H2PO4

3. H3PO4

4. PO4 3-

5. none of the above

H3PO4

Hydrophobic interactions between nonpolar molecules _

1. depend on strong permanent dipoles in the nonpolar molecules

2. are the result of strong attractions between nonpolar molecules

3. require the presence of surrounding water molecules

4. are the result of strong repulsion between water and nonpolar molecules

5. result from the tendency of water to maximize contact with nonpolar molecules

require the presence of surrounding water molecules

Which of the following is a characteristic of Chargaff’s rules?

1. A+T = C+G

2. A+G = C+T

3. A+G = C+U

4. all organisms have identical amounts of all four nucleotides

5. none of the above

A+G = C+T

What type of bond is made between nucleotides?

1. ester

2. phosphate ester

3. phosphodiester

4. glycosidic

5. none of the above

phosphodiester

If instead of four different bases in DNA and RNA there were six, what is the minimum size of a codon to encode the 20 amino acids commonly found in proteins?

1. 1

2. 2

3. 3

4. 4

5. cannot be determined

2

The presence of _ approximately one in every 1000 base pairs is what makes each individual human genome genetically unique

1. horizontal genes

2. transposable elements

3. single nucleotide polymorphisms

4. homologous genes

5. orphan genes

single nucleotide polymorphisms

The triplet code allows many amino acids to be specified by more than one codon. Such a code is said to be _

degenerate

An open reading frame is defined by

a start and stop codon

Which of the following bases pairs with guanine?

E

Which of the following bases is not present in RNA?

D

Nucleotides contain one or more phosphate groups that are usually attached to the __

1. C-3’ or C-5’ atoms

2. C-3 or C-3’ atoms

3. C-5 or N-3 atoms

4. C-1’ or N-3 atoms

5. none of the above

C-3’ or C-5’ atoms

Mutations leading to changes that can be inherited by the next generation have to be introduced at the _ level

1. mRNA

2. protein

3. DNA

4. tRNA

5. rRNA

DNA

When a peptide bond forms a(n) _ reacts with a carboxylate group

1. amide

2. amine

3. alcohol

4. ester

5. none of these choices

amine

At a pH above its pKA, the R-group of Asp is _

1. protonated and neutral

2. protonated and positively charged

3. deprotonated and neutral

4. deprotonated and negatively charged

5. none of these choices

deprotonated and negatively charged

Disulfide bonds form between two residues of which amino acid?

1. Met

2. Ser

3. Cys

4. Thr

5. Asn

Cys

What is the net charge of the pentapeptide Ala-Cys-Ser-Glu-Asn at pH 7?

1. -2

2. -1

3. 0

4. +1

5. none of these choices

-1

Since there are 20 standard amino acids, the number of possible linear polypeptides of length N can be expressed as _

20^N

Which of the following best describes the peptide backbone in B-sheet?

highly extended

antiparallel B-sheet

The side chain of serine could interact with the side chain of _ using an _

1. Val; hydrophobic interaction

2. His; hydrogen bond

3. Gln; hydrophobic interaction

4. Asn; electrostatic interaction

5. none of these choices

His; hydrogen bond

Molecular chaperones assist proteins in the formation of _

1. aggregates

2. tertiary structure

3. peptide bonds

4. primary structure

5. none of these choices

tertiary structure

Given pKa values of 2.3 and 9.7, what is the pI of alanine?

1. 12

2. 7.4

3. 6

4. 4.2

5. none of these choices

6

Heme is considered a _

1. catalyst

2. prosthetic group

3. coenzyme

4. cofactor

5. none of the above

prosthetic group

The individual hemoglobin subunits and myoglobin share similar _ structure but have rather different _ structure

1. secondary and tertiary; primary

2. secondary; tertiary

3. primary; tertiary

4. primary and secondary; tertiary

5. primary; secondary

secondary and tertiary; primary

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

1. hyperbolic; sigmoidal

2. sigmoidal; sigmoidal

3. hyperbolic; hyperbolic

4. hyperbolic; exponential

5. sigmoidal; hyperbolic

hyperbolic; sigmoidal

Which of the following best explains the ability for carbon monoxide (CO) to bind to hemoglobin (Hb) despite the relatively low concentrations of CO?

CO binds to Hb about 250 times more strongly than oxygen

Hemoglobin S, the variant responsible for the misshapen red blood cells characteristic of the disease sickle-cell anemia, is potentially advantageous to heterozygotes because it confers some level of resistance to the disease _

malaria

When a cell moves along a surface, actin _ occurs at the leading edge while _ occurs at the trailing edge

1. polymerization, depolymerization

2. depolymerization, polymerization

3. denaturation, renaturation

4. renaturation, denaturation

5. none of the above

polymerization; depolymerization

The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called _

cooperativity

The helical structure of collagen contains:

1. three right-handed helices wound around each other in a right-handed triple helix

2. three right-handed helices wound around each other in a left-handed triple helix

3. three left-handed helices wound around each other in a left-handed triple helix

4. three left-handed helices wound around each other in a right-handed triple helix

5. none of the above

three left-handed helices wound around each other in a right-handed triple helix

Which of the following correctly describes the sequence of events in the myosin-actin cycle?

1. myosin release from actin, ATP binds to myosin, myosin binds to another actin subunit, release of Pi and ADP, stretched myosin returns to original conformation

2. ATP binds to myosin, myosin release from actin, myosin binds to another actin subunit, stretched myosin returns to original conformation, release of Pi and ADP

3. ATP binds to myosin, myosin release from actin, myosin binds to another actin subunit, release of Pi and ADP, stretched myosin returns to original conformation

4. myosin release from actin, myosin binds to another actin subunit, ATP binds to myosin, stretched myosin returns to original conformation, release of Pi and ADP

5. myosin release from actin, ATP binds to myosin, myosin binds to another actin subunit, stretched myosin returns to original conformation, release of Pi and ADP

ATP binds to myosin, myosin release from actin, myosin binds to another actin subunit, release of Pi and ADP, stretched myosin returns to original conformation

Which of the following correctly describes the sequence of events in the kinesin reaction cycle? For simplicity, the two heads are referred to as head 1 and head 2. Head 1 starts as the leading head.

1. ATP binds to head 1, head 2 swings forward, ADP release from head 2, ATP hydrolysis in head 1, head 2 binds to tubulin, head 1 releases tubulin

2. none of the above

3. ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ADP releases from head 2, ATP hydrolysis in head 1, head 1 releases tubulin

4. head 1 releases tubulin, ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ADP release from head 2, ATP hydrolysis in head 1

5. ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ATP hydrolysis in head 1, ADP release from head 2, head 1 releases tubulin

ATP binds to head 1, head 2 swings forward, head 2 binds to tubulin, ADP releases from head 2, ATP hydrolysis in head 1, head 1 releases tubulin

Which of the following biopolymers is correctly paired with the bond that forms between the monomers?

1. protein; ester bond

2. polysaccharide; glycosidic bond

3. DNA; phosphate bond

4. RNA; phosphate bond

5. all of the above

polysaccharide; glycosidic bond

Which of the following elements are found in simple carbohydrates?

1. carbon, hydrogen, and oxygen

2. carbon, hydrogen, oxygen, and nitrogen

3. carbon, hydrogen, oxygen and phosphorus

4. carbon, hydrogen, oxygen and sulfur

5. none of the above

carbon, hydrogen, and oxygen

If a reaction at 37 degrees Celsius has a delta H of 23 kJ/mol and a delta S of 337 kJ/Kmol, what is the delta G for the reaction?

1. 65 kJ/mol

2. -47 kJ/mol

3. 18 kJ/mol

4. -81 kJ/mol

5. none of the above

-81 kJ/mol

1. -52 kJ.mol

2. -10 kJ/mol

3. 10 kJ/mol

4. 52 kJ/mol

5. none of the above

-10 kJ/mol

Photosynthetic organisms use energy from the sun to reduce _ to _

1. formaldehyde; ethanol

2. CO2; ethanol

3. CO2; carbohydrates

4. CO2; oxygen

5. none of the above

CO2; carbohydrates

The similarity of one organism to another (for example a bacteria versus a human) is most easily done by comparing which biopolymer?

1. nucleic acids

2. polysaccharides

3. proteins

4. lipids

5. all of the above

nucleic acids

The second law of thermodynamics states _

that spontaneous processes are characterized by the overall conversion of order to disorder

Calculate the delta G for a reaction with delta H = 20 kJ/mol and delta S=20 J/Kmol that is carried out at 27 degrees C.

1. 14 J/mol

2. 140 J/mol

3. 1,400 J/mol

4. 14,000 J/mol

5. none of the above

14,000 J/mol

hydrogen bonds within liquid water are _

1. ion-induced dipole interactions

2. attractions between the protons of the oxygen nuclei

3. dipole-dipole interactions

4. attractions between the H+ and OH- ions of the liquid

5. attractions between two oxygen atoms

dipole-dipole interactions

What is the C-terminal amino acid in the pentapeptide Val-Leu-Arg-Ser-Gly?

1. Arg

2. Leu

3. Ser

4. Gly

5. Val

Gly

Which of the following amino acids contains a side chain that is polar and uncharged from pH 1-13

1. Tyr

2. Phe

3. Ile

4. Gln

5. Asp

Gln

Which of the following is generally absent from an alpha helix?

1. Trp

2. Ser

3. Ile

4. Pro

5. none of these choices

Pro

Lysine can form a salt bridge by interacting with the side chain of:

1. Glu

2. Ser

3. Asn

4. Gly

5. Pro

Glu

If the following mixture of proteins was applied to a size-exclusion chromatography column, what would be the order of elution? Proteins with molecular weights: myoglobin (17.7 kDa), hemoglobin (64.5 kDa), lysozyme (14.3 kDa), and triose phosphate isomerase (57.4 kDA)

1. lysozyme, myoglobin, triose phosphate isomerase, hemoglobin

2. triose phosphate isomerase, hemoglobin, lysozyme, myoglobin

3. hemoglobin, myoglobin, lysozyme, triose phosphate isomerase

4. hemoglobin, triose phosphate isomerase, myoglobin, lysozyme

5. cannot be determined

hemoglobin, triose phosphate isomerase, myoglobin, lysozyme

A technique for determining protein structure where the protein is in solution is:

1. NMR spectroscopy

2. X-ray crystallography

3. electron crystallography

4. mass spectrometry

5. none of these choices

NMR spectroscopy

Noncovalent forces that stabilize protein structure include all of the following except:

1. the hydrophobic effect

2. hydrogen bonding

3. disulfide bridges

4. salt bridges

5. electrostatic interactions with metal ions

disulfide bridges

The two peptides shown in the diagram below are linked through:

1. a hydrogen bond

2. an ester linkage

3. a glycosidic bond

4. a disulfide bond

5. a peptide bond

a disulfide bond

Which of the following explains the conversion of hemoglobin subunits from deoxy to oxy state?

1. all four subunits switch simultaneously

2. each subunit switches only upon oxygen binding to the particular subunit

3. both alpha subunits simultaneously switch first followed by both B subunits

4. both B subunits simultaneously switch first followed by both alpha subunits

5. none of the above

all four subunits switch simultaneously

Which allosteric effector has the greatest ability to stabilize the deoxy state of hemoglobin?

1. BPG

2. CO2

3. O2

4. H+

5. all of the above have equal ability

BPG

Which of the following details the nucleotide-binding site when tubulin dimers assemble into microtubules?

1. both alpha and beta sites are bound to GTP

2. the alpha site is bound to GDP, the B site is bound to GTP

3. both alpha and B sites are bound to GDP

4. the alpha site is bound to GTP, the beta site is unoccupied following GTP hydrolysis and release of GDP

5. the alpha site is bound to GTP, the B site is bound to GDP

the alpha site is bound to GTP; the beta site is bound to GDP

Which amino acid is critical for crosslinking of keratin fibers?

Cys

Which amino acid is critical for crosslinking of collagen fibers?

Lys

Which of the following represents the longest distance traveled by a kinesin-vesicle complex?

1. movement of a mitochondria in a cardiac cell

2. movement of a neurotransmitter vesicle down the axon of a nerve cell

3. movement of a lipid-filled vesicle within an intestinal cell

4. none of the above

5. movement of a glucose filled vesicle to the membrane of a liver cell

movement of a neurotransmitter vesicle down the axon of a nerve cell

an exergonic process:

1. occurs without the addition of free energy

2. will have more products than reactants at equilibrium

3. all of the above

4. is spontaneous

5. has a delta G < 0

all of the above

entropy is used to measure

randomness

A gaseous mixture of hydrogen, water, ammonia, and methane can produce which of the biomolecules when exposed to an electrical discharge (such as lightning)

amino acids

The biological classification system categorizes organisms into which of the following domains:

1. bacteria, eukarya, prokarya

2. bacteria and eukarya

3. prokarya and eukarya

4. archaea and eukarya

5. bacteria, archaea, and eukarya

bacteria, archaea, and eukarya

A reaction with a _ delta H and a _ delta S will never be spontaneous

positive, negative

Nucleoside triphosphates carry energy in the form of

1. amide linkages

2. glycosidic bonds

3. phosphoester bonds

4. phosphoanhydride bonds

5. hydrogen bonds

phosphoanhydride bonds

In living organisms, genetic information is most often stored in the form of _

deoxyribonucleic acid

The DNA strand that serves as the template for the synthesis of RNA is often called the _

1. messenger strand

2. coding strand

3. transfer strand

4. noncoding strand

5. transcription strand

noncoding strand

Which of the following correctly describes the B-DNA double helix?

1. antiparallel strands

2. right-handed helix

3. base pairs are located in the center of the helix

4. one helical rotation has a rise of 3.4 nm

5. all of the above

all of the above

The coenzymes known as NAD+, FAD, and coenzyme A all contain a derivative of _

1. thymidine

2. guanosine

3. cytidine

4. adenosine

5. uridine

adenosine

In aqueous solution, globules of up to several thousand amphiphillic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center are called _

micelles

In an aqueous solution, if the [OH-] is 3.0×10^-5 M, what is the [H+]?

1. 7.0×10^-9

2. 7.0×10^-2

3. 3.3×10^-3

4. 3.3×10^-10

5. none of the above

3.3×10^-10

Which of the following could be used to formulate 100 mls of a .10 M acetate buffer (pK=4.76) at pH 5 if you start with 64 mls of .10 M sodium acetate

1. 3.6 mls of 1 M HCl

2. 34 mls of .10 M NaOH

3. 34 mls of .10 M HCl

4. 3.6 mls of 1 M NaOH

5. 36 mls of .10 M acetic acid

3.6 mls of .10 M acetic acid

Considering the energetics of transferring nonpolar molecules from water to a nonpolar solvent, the factor T delta S is generally _, causing delta G to be _

1. negligible; either positive or negative

2. negative, negative

3. positive, positive

4. positive, negative

positive, negative

Which of the following molecules would be prevented from readily crossing a lipid bilayer?

1. glucose

2. sodium ions

3. potassium ions

4. water

5. all of the above

all of the above

If the pK values for phosphoric acid are 2.15, 6.82, and 12.38, _ would predominate at pH 5 while _ would predominate at pH 10

1. H3PO4, HPO4 2-

2. H3PO4; PO4 3-

3. H2PO4 - ; HPO4 2-

4. H3PO4; H2PO4-

5. H2PO4- ; PO4 3-

H2PO4-; HPO4 2-

If a 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:

1. base; acid

2. acid; base

3. acid; acid

4. a buffer with a pH that far from the pK would not be an effective buffer

5. base; base

acid; base

During vigorous exercise, hydrogen ions are produced within cells as a result of increased metabolism. what component of the intracellular buffer would increase as a result of the increased H+ production?

1. H3PO4

2. H2PO4-

3. PO4 3-

4. HPO4 2-

5. none of the above

H2PO4-

urea is a water-soluble product of nitrogen metabolism. how many hydrogen bonds can one urea molecule donate to surrounding water molecules?

1. 4

2. 2

3. 3

4. 5

5. 6

4

In DNA, the ribose derivative lacks an _ on carbon _

1. amine; 3

2. none of the above

3. alcohol; 2

4. alcohol; 3

5. amine; 2

alcohol; 2

What type of bond is made between nucleotides?

phosphodiester

Which term describes the process of converting the information found in DNA into the sequence of a protein?

1. transcription

2. translation

3. expression

4. replication

5. none of the above

expression

The replication of DNA is made possible by the presence of _ strands in the double helix of DNA

1. genomic

2. complementary

3. antiparallel

4. none of the above

5. hydrogen bonded

complementary

Bacteria and archaea typically have fewer than _ genes while plants and animals typically have greater than _ genes

1. 1,000; 5,000

2. 10,000; 500,000

3. 5,000; 10,000

4. 200; 1,000

5. 500; 2,500

5,000 ; 10,000

In humans, approximately _% of the genome encodes proteins

1.5

Nucleotides play a central role in living organisms because

1. they mediate transport of energy within the cell

2. they are involved in intracellular signaling

3. all of the above

4. they function as building blocks for nucelic acids

5. they are involved in oxidation-reduction reactions

all of the above

Which of the following explains how cell division is blocked by drugs that prevent proper microtubule function?

1. division of organelles between daughter cells requires organelle movement along microtubules

2. chromosome separate along a microtubule spindle

3. none of the above

4. production of new membranes for organelles and nucleus requires microtubules

5. the condensation of chromatin requires a microtubule skeleton

chromosomes separate along a microtubule spindle

During the formation of microfilaments, which of the following occurs?

1. F-actin polymerizes, becoming G-actin

2. none of the above

3. ATP hydrolysis is catalyzed by F-actin

4. polymerization proceeds quickly at first, then slows after about ten actin monomers have polymerized

5. ATP binds to F-actin

ATP hydrolysis is catalyzed by F-actin