Biochemsitry Test Bank

110 terms by xoxoCarrie

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What is true about naturally occurring monosaccharides?
A) The L-isomers predominate
B) The L and D-isomers occur in equal ratios
C) The D-isomers predominate
D) The ratio of L and D-isomers varies widely depending on the sucrose

C) The D-isomers predominate

Pyranose rings are usually most stable when a ring adopts a _____ conformation with the bulkiest ring substituents in _______ positions.
A) boat; equatorial
B) chair; equatorial
C) chair; axial
D) boat; axial

B) chair; equatorial

Polysaccharide structure can be varied by difference in
A) the kind(s) of sugars in each polysaccharides
B) the presence of branching
C) chain length (number of sugars in each polysaccharides)
D) All of the above

D) All of the above

Chitin is
A) composed of linear fibrils like cellulose
B) composed of N-acetylglucosamine subunits
C) found in fungi cell walls
D) found in insect and crustacean shells
E) All of the above

E) All of the above

The large number of possible oligosaccharide structures in glycoproteins is limited in cells by the kinds of enzymes available for their synthesis
T or F

True

Enzymatic lengthening and degradation of glycogen occurs only at the non-reducing ends
T or F

True

In solution only one anomeric form of a monosaccharide will be present
T or F

False

The simplest adolse is the chiral molecule glyceraldehyde
T or F

True

Most of the carbohydrates on earth are produced by photosynthesis in plants
T or F

True

DNA could be referred to as a glycoside
T or F

True

The sugar derivative found in DNA is an oxidized form of ribose
T or F

False

Which parameter has the greatest correlation to reaction rate?
A) Gibb's free energy
B) enthalpy
C) Activation energy
D) Entropy
E) None of the above

C) Activation energy

An enzyme works well as a catalyst at a pH of 7.2. It is found that catalytic activity is significantly less at a pH of 8.4. Which could likely cause the decrease in activity?
A) The protein has been degraded into its amino acids at pH 8.4
B) The protonation state of amino acids involved in the catalytic mechanism has changed
C) The protein has changed shape due to a change in charge
D) Both B and C
E) All of the above

D) Both B and C

For a weak acid with a pKa=6.5, the effective buffering range is usually considered to be:
A) pH 5.5 to pH 7.5
B) pH 6.4 to pH 6.6
C) dependent on the molarity of the acid
D) pH 6 to pH 7
E) B and C

A) pH 5.5 to pH 7.5

The pKas of isoleucine's α-carboxyl group and α-amino group are 2.3 and 9.8, respectively. Calculate the isoelectric point.
A) 6.0
B) 9.8
C) 2.3
D) The isoelectric point cannot be calculated without the pKa value for the side chain

A) 6.0

The R group of an amino acid determines if it is
A) charged or uncharged
B) an acid or a base
C) polar or non-polar
D) hydrophillic or hydrophobic
E) All of the above

E) All of the above

Proteins segments which fold first can promote the folding of other sections of the protein into the native conformation by a process known as:
A) cooperativity
B) renaturation
C) stabilization
D) disulfide bridge formation
E) hydrophobic interaction

A) cooperativity

Histidine has pKa values of 1.8, 6.0 (R group) and 9.3. At pH 8.0, the net charge on histidine is
A) neutral (uncharged)
B) negative
C) positive
D) Insufficient information to tell

A) Neutral (uncharged)

Prokaryotes are valuable tools for biochemists because
A) E. coli is well-studied and typical of prokaryotes
B) many of their chromosomes are sequenced
C) they contain as many genes as eukaryotic cells
D) they are not very diverse organisms
E) All of the above

B) many of their chromosomes are sequenced

The self-ionization of water is ______
A) a termolecular reaction involving the simultaneous collision of H₂O, H⁺, and OH⁻
B) a unimolecular dissociation of a single water molecule to H⁺ and OH⁻
C) a result of hydrophobic interactions
D) a bimolecular reaction between two water molecules to yield H₃O⁺ and OH⁻

D) a bimolecular reaction between two water molecules to yield H₃O⁺ and OH⁻

Loops and turns in proteins are:
A) stretches of non-repeating three dimensional structures in proteins
B) regions that let a polypeptide chain fold back on itself
C) regions causing direction change in the polypeptide backbone
D) All of the above

D) All of the above

Which is not true about β-sheets?
A) the side-chains of all amino acids point to the same side of the sheet
B) in antiparallel sheets the hydrogen bonds between adjacent strands are nearly perpendicular to the backbones of the strands
C) The polypeptide chains in the sheet are nearly fully extended
D) the range of phi and psi angles is broader than for those in the α-helix

A) the side-chains of all amino acids point to the same side of the sheet

Two weak acids, A and B, have pKa values of 4 and 6, respectively. Which statement is true?
A) for solutions of equal concentration, acid B will have a lower pH
B) Acid A dissociates to a greater extent in water than acid B
C) Acid A is more likely to be a polyprotic acid than acid B
D) B is the conjugate base of A
E) the equivalence point of acid A is higher than that of acid B

B) Acid A dissociates to a greater extent in water than acid B

Some ions such as thiocyanate that are poorly solvated in water and can enhance the solubility of nonpolar compounds in water by disordering the water molecules are called:
A) hydrophobic ions
B) chaotropes
C) azeotropes
D) zeolytes

B) chaotropes

A protein that contains more isoleucine, phenylalanine and leucine than asparagine, lysine, and arginine is most likely:
A) hydrophobic
B) hydrophilic
C) neutral
D) low on the hydropathy index scale

A) hydrophobic

Many proteins have multiple subunites because
A) they are more stable and flexible in movement
B) an active site is shared by different subunits
C) different combinations can perform different functions
D) All of the above
E) A and C

D) all of the above

Tyrosine and tryptophan are less hydrophobic than phenylalanine because:
A) phenylalanine has no polar group in the side chain
B) tyrosine and tryptophan have smaller R groups
C) phenylalanine has an indole group
D) phenylalanine is a phenol
E) All of the above

A) phenylalanine has no polar group in the side chain

Which of these noncovalent forces in biological systems is usually the strongest?
A) hydrogen bonds
B) Van der Walls forces
C) Hydrophobic interactions
D) London dispersion forces

A) hydrogen bonds

The Tm of a protein is temperature at which it
A) is half denatured
B) is completely denatured
C) liquifies
D) resists denaturation

A) is half denatured

The pH of human blood is primarily maintained at 7.4 by:
A) ATP
B) carbon dioxide-carbonic acid buffer systems
C) a bicarbonate buffer system
D) B and C
E) A, B, and C

D) B and C

A dipeptide forms when a functional ______ group of one amino acid reacts with the functional _____ group of another amino acid to form a _______bond
A) carboxylate, amino, double
B) amino, carboxylate, phosphate
C) carboxylate, amino, enzyme
D) amino, carboxylate, peptide

D) amino, carboxylate, peptide

What information can be gained by comparing the sequences of proteins that have the same or similar function in different species?
A) to determine sequences that are conserved among species since they are likely to be important to the function and stability of the proteins
B) to locate highly variable residues which contribute little to the structure and function of the protein
C) to determine evolutionary relationships and relatedness of species
D) All of the above

D) all of the above

Concentrations of some proteins cannot be estimated by UV spectrophotometry because they are:
A) low in protein
B) low in tryptophan and tyrosine
C) low in glycine and valine
D) high in aromatic amino acids

B) low in tryptophan and tyrosine

The distribution of amino acids in a protein often cannot be determined precisely by acid hydrolysis. Why?
A) the amine groups on lysine and arginine neutralize much of the acid?
B) the side chain of phenylalanine is almost totally destroyed by acid hydrolysis
C) the side chains of asparagine and glutamine are also hydrolyzed
D) All of the above

C) the side chains of asparagine and glutamine are also hydrolyzed

Which is true about the side chains of residues in an α-helix?
A) They point toward the center of the helix
B) they hydrogen bond extensively with each other
C) they extend radially outward from the helix axis
D) the extend above or below the pleats

C) they extend radially outward from the helix axis

The oxygen atom of water is nucleophilic because:
A) it has a negative oxidation number
B) it has two unshared pair of electrons
C) it carries a partial positive charge
D) it seeks electron-rich molecules
E) All of the above

B) it has two unshared pair of electrons

A change from one conformation of a molecule to another involves ________?
A) breaking and reforming of covalent bonds
B) rotation about bonds only
C) inversion about a center of symmetry
D) any of the above

B) rotation about bonds only

If human blood is not maintained at close to pH=7.4, a person can develop
A) acidosis
B) alkalosis
C) diabetes
D) both A and B
E) None of the above

D) Both A and B

Tertiary structure of proteins describe:
A) bringing amino acids far apart in primary structure close together
B) polypeptide folding
C) disulfide bridges
D) stabilizing protein structure by non-covalent interaction
E) all of the above

E) all of the above

The lock-and-key theory described the action of
A) enzymes as keys that fit different chemicals
B) substrates as keys that fit in different enzymes
C) substrates as locks that fit different enzymes
D) enzymes as locks that fit other enzymes

B) substrates as keys that fit different enzymes

An ideal α-helix has a pitch of 0.54 nm and rise of 0.15 nm. What is the length along the helix for a segment of an ideal α-helix that contains 30 amino acids?
A) 4.50 nm
B) 16.20 nm
C) 55.5 nm
D) 200 nm

A) 4.50 nm

A spontaneous chemical reaction always has a ______ change.
A) positive entropy
B) positive enthalpy
C) positive Gibb's free energy
D) negative Gibb's free energy
E) negative enthalpy

D) negative Gibb's free energy

Disulfide bridges can form in proteins
A) between two cystine residues in proteins
B) between any two methionines or cyteines
C) only between cysteine residues side-by-side in the protein sequence
D) between cysteine residues that are close in three-dimensional space, but not necessarily close in the primary structure

D) between cysteine residues that are close in three-dimensional space, but not necessarily close in the primary structure

Why is it important that the enzymes in lysosomes are more active at acidic pH than at neutral pH?
A) since lysosomes are primarily found in the stomach acid of mammals, their pH dependence allows for maximum efficiency for the digestion of foodstuffs
B) it prevents them from accidentally degrading the macromolecules in the cytosol
C) it maximizes the interaction with their substrates which are always bases
D) It prevents their diffusion out of the lysosomes
E) it allows for regulation of their uptake by the mitochondria.

B) it prevents them from accidentally degrading the macromolecules in the cytosol

What is the purpose of treating a protein with 2-mercaptoethanol?
A) to cleave disulfide bonds
B) to derivatize any free sulhydryl groups to prevent them from reforming disulfide bonds
C) to derivatize any N-terminal amino acid during Edman degradation
D) to hydrolyze the protein into its amino acids

A) to cleave the disulfide bonds

What is true about the rotation about bonds in a protein backbone?
A) the rotation is free about all bonds in the backbone, except for the bond between the nitrogen and the alpha carbon in proline residues
B) all bonds in the backbone have restricted rotation and partial double-bond character
C) the rotation is free only about the peptide bond. the other bonds are restricted by steric hindrance and the presence of proline residues
D) the bond between the carbonyl carbon and nitrogen is restricted. other bonds are free to rotate depending only on steric hindrance or the presence of proline residues

D) the bond between the carbonyl carbon and nitrogen is restricted. other bonds are free to rotate depending only on steric hindrance or the presence of proline residues

Which statement is false about a globular protein that performs its biological function as a single independent polypeptide chain?
A) non-covalent forces are the primary source of stability for the secondary and tertiary structure
B) its tertiary structure is likely stabilized by the interaction of amino acid side chains in non-neighboring regions of the polypeptide chain
C) it likely has extensive quaternary structure to maintain its globular shape
D) it could contain α-helices that are stabilized by hydrogen bonding

C) it likely has extensive quaternary structure to maintain its globular shape

At the midpoint of a titration curve
A) the concentration of a conjugate base is equal to the concentration of a conjugate acid
B) the ability of the solution to buffer is best
C) the pH equals the pKa
D) All of the above
E) A and B only

D) all of the above

The main property of myoglobin and hemoglobin that makes them an efficient system for oxygen delivery from lungs to muscles is:
A) Hydrophobicity
B) cooperativity
C) different binding affinities for oxygen
D) movement of the protein shapes
E) all of the above

C) different binding affinities for oxygen

Amino acids with non-ionizable side chains are zwitterions when they are _______.
A) in any solution
B) at physiological pH, pH-7.4
C) in alkaline solutions only
D) in acidic solutions only
E) All of the above

B) at physiological pH, pH=7.4

Nearly all peptide bonds are in the trans configuration because
A) trans peptide bonds are stronger
B) cis peptide bonds are weaker
C) cis peptide bonds prevent R groups from interacting
D) trans peptide bonds minimize steric hindrance of R groups

D) trans peptide bonds minimize steric hindrance of R groups

Which linkage(s) occur extensively in nucleotides
A) ether
B) phosphoanhydride
C) phosphate ester
D) amide
E) both B and C

E) both B and C

The abundance of water in the cells and tissues helps to minimize temperature fluctuations. This is due to what property of water?
A) density
B) specific heat
C) viscosity
D) boiling point

B) Specific Heat

T or F
All cells have kept the same general patterns of metabolism, a very similar genetic code and the same monomers or residues

True

T or F
Diffusion is an adequate means of distributing nutrients in prokaryotic cytoplasm because they have more surface area than volume compared to most eukaryotes

True

T or F
The mitochondria and Golgi apparatus are two organelles which originated from bacteria and were incorporated into eukaryotic cells via symbiosis

False

Proteins in biological membranes may be:
A) spanning the membrane
B) porous
C) attached to the membrane surface
D) all of the above
E) B and C only

D) all of the above

The bulk of aerobic metabolism in eukaryotic cells takes place in:
A) the endoplasmic reticulum
B) the nucleus
C) the mitochondria
D) peroxisomes
E) the golgi apparatus

C) the mitochondria

Which three cellular components are present in both prokaryotes and eukaryotes?
A) ribosomes, cholorplasts, mitochondria
B) nucleus, ribosomes, RNA
C) RNA, DNA, ribosomes
D) endoplasmic reticulum, DNA, RNA
E) mitochondria, DNA, RNA

C) RNA, DNA, ribosomes

Which of the following developed during the evolution of eukaryotic cells from prokaryotic cells?
A) DNA
B) the cell membrane
C) nuclear membrane
D) ribosomes
E) proteins

C) nuclear membrane

What is the only cell in the human body that is capable of motility and possesses a flagellum?
A) lymphocytes
B) red blood cells
C) muscle cells
D) sperm cells
E) nerve cells

D) sperm cells

Loops and turns in proteins are:
A) stretches of non-repeating three dimensional structures in proteins
B) regions that let a polypeptide chain fold back on itself
C) regions causing direction change in the polypeptide backbone
D) All of the above

D) all of the above

Which demonstrates that the primary structure of a protein determines its tertiary structure?
A) How the disulfide bonds hold it into the correct shape
B) Proteins refold when the amino acid sequence is the same as in the native conformation
C) proteins can refold even when the amino acid sequence is changed
D) chaotropic agents cannot denature the native conformation
E) All of the above

B) proteins refold when the amino acid sequence is the same as in the native conformation

Which statement is not true about the peptide bond?
A) the peptide bond has partial double-bond character
B) the peptide bond is longer than the typical carbon-nitrogen bond
C) the carbonyl oxygen and the amide hydrogen are most often in a trans configuration with respect to one another
D) rotation is restricted about the peptide bond

B) the peptide bond is longer than the typical carbon-nitrogen bond

Structural proteins that typically assemble into large cables or threads to provide mechanical support to cells or organisms are classified as ______ proteins
A) globular
B) fibrous
C) enzyme
D) β-Strand

B) fibrous

Proteins with alpha helix regions called leucine zippers are
A) part of pairs of helices that are wrapped around each other
B) often found in DNA binding proteins
C) amphipathic helices
D) All of the above

D) all of the above

NMR is often used for the determination of the _____ proteins
A) molecular weight
B) tertiary structure
C) isoelectric point
D) pKa

B) tertiary structure

The distance along a helix axis for one complete turn is called the ______
A)axial distance
B) pitch
C) screw length
D) rise

B) pitch

In a multienzyme complex the process of directly transferring a product of one reaction to the next active site without allowing it to enter the bulk solvent is termed ______
A) the sequential mode
B) a ping-pong reaction
C) metabolite channeling
D) the activity pathway

C) metabolite channeling

Which statement is false about covalent modification?
A) it is slightly slower than allosteric regulation
B) it is reversible
C) it usually uses the same enzyme for activation and inactivation
D) All of the above

C) it usually uses the same enzyme for activation and inactivation

The "T" state refers to the _______.
A) denatured form of the enzyme
B) inactive conformation of the enzyme
C) form of the enzyme without the modulator bound at the regulatory site
D) transition state of the product

B) inactive conformation of the enzyme

Which are correlated with allosteric enzymes that do not follow typical Michaelis-Menten kinetics?
A) Sigmoidal curves of velocity where S is varied
B) Cooperative binding of the substrate
C) changes in conformation of the enzyme when S binds
D) All of the above

D) all of the above

In ______ inhibition the inhibitor binds at a site other than the active site, but alters the active site to prevent binding the normal substrate.
A) uncompetitive
B) noncompetitive
C) irreversible
D) classical competitive
E) non-classical competitive

E) non-classical competitive

In a ping-pong reaction which does not occur?
A) the enzyme covalently binds a portion of the first substrate
B) the enzyme is permanently converted to an altered form by the first substrate
C) A group is transferred from one substrate to another
D) one product is released before a second substrate is bound

B) the enzyme is permanently converted to an altered form by the first substrate

The Km values for enzyme reactions such as A + B → C + D
A) can be determined for one substrate and not the other
B) do not indicate the efficiency of the enzyme
C) can be determined by holding one (A or B) at high concentration while varying the concentration of the other substrate
D) cannot be determined using the Lineweaver-Burk plot analysis

C) can be determined by holding one (A or B) at high concentration while varying the concentration of the other substrate

Which mode(s) of catalysis is/are classified as chemical effects?
1. transition state stabilization
2. acid-base catalysis
3. covalent catalysis
4. proximity effect
A) 1,2, and 3
B) 3 only
C) 2 and 3
D) All of them

C) 2 and 3

A detailed description of a chemical reaction in terms of the molecular atomic or subatomic events is called the reaction ______.
A) motif
B) pathway
C) mechanism
D) primary sequence

C) mechanism

Which substrate is a product of glycolysis, a precursor of gluconeogenesis, and a precursor of the citric acid cycle?
A) Coenzyme A
B) Pyruvate
C) Glucose
D) ATP

B) pyruvate

Under what situation might lactic acidosis occur?
A) oxygen supply to tissues is inadequate
B) transport of glucose into cells is accelerated
C) PFK-1 is over-activated
D) Lactate dehydrogenase is inactive

A) oxygen supply to tissues is inadequate

In the liver, ______ has a main use for maintaining blood glucose, but it can also be used to synthesize glycogen, or enter the pentose phosphate pathway to synthesize ribose-5-phosphate.
A) glucose-1,6-bisphospate
B) glucose-1-phosphate
C) fructose-6-phosphate
D) glucose-6-phosphate

D) glucose-6-phosphate

For a step in a reaction pathway to serve as a control point it should be _____
A) far from equilibrium
B) endergonic
C) irreversible
D) Both A and C
E) All of the above

D) both a and c

Which is not involved in signal transduction?
A) inositol-phosphlipid pathway
B) adenylyl cyclase pathway
C) receptor tyrosine kinases
D) glycolytic pathway

D) glycolytic pathway

Cellulose is not highly branched because it:
A) does not have a polysaccharide backbone
B) does not have α(1→6) linkages
C) is insoluble in water
D) does not have β(1→4) linkages

B) does not have α(1→6) linkages

Adipocytes contain fat droplets which serve to provide an animal with
A) increased cell volume
B) insulation
C) chemical energy
D) A and B
E) B and C

E) B and C

The hydrolysis of ATP to ADP has a ∆G°' of -30 kJ/mol. If in an E. coli cell the concentrations of ATP, ADP and inorganic phosphate are 7.90 mM, 1.04 mM, and 7.90 mM, respectively, which statement is true about the hydrolysis of ATP in the cell?
A) Hydrolysis can proceed spontaneously
B) The hydrolysis is being allosterically controlled
C) The formation of ATP from ADP is occuring more rapidly than the hydrolysis
D) The hydrolysis is at equilibrium

A) Hydrolysis can proceed spontaneously

Fatty acid synthesis occurs in the ____, while fatty acid breakdown occurs in the _____
A) mitochondria, cytosol
B) goligi apparatus, cytosol
C) cytosol, nucleus
D) cytosol, mitochondria

D) cytosol, mitochondria

The degradation of which class of biochemicals does not significantly contribute to the release of energy to the cells?
A) nucleic acids
B) proteins
C) carbohydrates
D) lipids

A) nucleic acids

In signal transduction what is an effector enzyme?
A) an integral membrane protein that changes conformation upon binding of a ligand to a cell surface receptor
B) a protein bound on the interior of a cell membrane that generates a second messenger
C) protein bound on the exterior surface of a cell and is the receptor site for a ligand
D) a small molecule that diffuses within a cell and carries a signal to its ultimate destination

B) a protein bound on the interior of a cell membrane that generates a second messenger

The evolution of biochemical pathways can be studied by
A) comparing pathways in many diverse bacteria
B) isolating pathway enzymes from different individuals
C) comparing linear and circular pathways
D) comparing pathways in closely related species

A) comparing pathways in many diverse bacteria

The ultimate product of complete oxidation of carbohydrates is _____
A) pyruvate
B) acetyl CoA
C) carbon dioxide
D) acetate ion

C) carbon dioxide

In the adenyl cyclase signaling pathway the second messenger(s) is(are) _______
A) protein kinase A
B) cyclic AMP and cyclic GMP
C) ATP and GTP
D) AMP

B) cyclic AMP and cyclic GMP

Triacylglycerols cannot form lipid bilayers because they:
A) have polar heads
B) cannot associate with cholesterol
C) do not have polar heads
D) have hydrophobic tails
E) cannot engage in hyrophobic interactions

C) do not have polar heads

Bacteria that degrade oil at great depths in offshore waters have most likely evolved new pathways and ______ by modifying existing ones.
A) cofactors
B) duplicate factors
C) DNA
D) enzymes

D) enzymes

Mutant organisms can be helpful in the study of metabolism because
A) the structures of enzymes may be deduced
B) there may be an indication of a natural role for an enzyme
C) there may be accumulations of products prior to defective enzymes
D) one can compare the mutant to a non-mutant organisms
E) all of the above

E) all of the above

Which of the following is not a factor contributing to the large free energy hydrolysis of ATP?
A) complexes with Mg²⁺ or Mn²⁺ ions
B) electrical shielding of products of hydrolysis
C) better stability of products than ATP itself
D) better solvation of products than ATP itself
E) Electrostatic repulsion of oxygen atoms

A) complexes with Mg²⁺ or Mn²⁺ ions

A distinct set of metabolic reactions is called a reaction _______
A) cycle
B) mechanism
C) pathway
D) network

C) pathway

Which does not apply to dihyroxyacetone?
A) triose
B) ketose
C) water-soluble
D) chiral

D) chiral

They glycolytic pathway oxidizes glucose to two molecules of pyruvate and also produces a net of two molecules of ATP. ATP allosterically inhibits the enzyme, PFK-1, that catalyzes the third step of glycolysis. This is an example of _______
A) competitive inhibition
B) feedback inhibition
C) feed-forward activation
D) negative cooperativity

B) feedback inhibition

Amylose differs from amylopectin in that amylose
A) forms a helix and no branch points
B) is highly branched and amylopectin is not
C) has more glucose residues than amylopectin
D) has different monomers than amylopectin

A) forms a helix and no branch points

A fatty acid designated as 20:0 is _______, while one that is designated 20:3 D5,8,11 is ______
A) simple, complex
B) monounsaturated, polyunsaturated
C) complex, simple
D) saturated, unsaturated
E) unsaturated, saturated

D) saturated, unsaturated

Which does not apply to the diffusion of O₂, CO₂, and small hydrophobic molecules across a membrane?
A) the transport is saturable
B) diffusion is driven by the concentration gradient across the membrane
C) the diffusion is spontaneous and there is a decrease in free energy as diffusion occurs
D) membrane proteins are not needed for the diffusion process

A) the transport is saturable

If glucose supplies the anomeric carbon atom in a glycosidic link, the resulting compound is classified as a ______
A) glucosamine
B) glucoside
C) glycoside
D) glycan

B) glucoside

Cholesterol is converted to cholesterol esters for _____ in cells and are _____ (more, less) hydrophobic than glycerophospholipids
A) storage, more
B) storage, less
C) transport more
D) transport, less
E) synthesis, more

A) storage, more

When a sugar polymer is analyzed and found to have equal portions of reducing and non-reducing ends, it is likely that
A) it is branched, but not very highly
B) it shows directionality
C) some of the internal glycosidic bonds are in equilibrium with open chain forms
D) it is branched
E) it is linear

E) it is linear

Consider the synthesis of a biopolymer in which the addition of successive monomers occurs by the same kind of reaction(s). The synthesis of the polymer is a ______ pathway
A) linear
B) branched
C) spiral
D) cyclic

C) spiral

Determination of the tertiary structure of a membrane protein finds that he outer surface is composed primarily of hyrophobic residues. Which conclusion is most likely from this observation?
A) it is a lipid-anchored membrane protein
B) the protein can undergo transverse diffusion
C) the protein must be involved in passive transport
D) it is an integral protein

D) it is an integral protein

When red-blood cells are treated extensively with protease most membrane proteins are broken down into small peptides. However, some proteins are very resistant to this treatment. If cleavage by protease is the only type of reaction that occurs in this treatment, how is this explained?
A) they are integral (intrinsic) proteins
B) they contain at least 2 disulfide bonds
C) they are peripheral proteins
D) they are lipid-anchored membrane proteins

A) they are integral (intrinsic) membrane proteins

Eicosanoids participate in a variety of physiological responses and are derived from
A) cholesterol
B) arachidonic acid
C) isoprene
D) waxes

B) arachidonic acid

Which statement is false about the sugar units in DNA
A) it is an epimer of glucose
B) it has a D-configuration
C) they are cyclic in DNA
D) it is a deoxy form of ribose

A) it is an epimer of glucose

What is the role of cholesterol in animal cell membranes?
A) broadens the temperature range of optimum membrane fluidity
B) aids in the transport of small hydrophobic molecules across the membrane
C) is a receptor site for hormones on the surface of membranes.
D) blocks the association of the fatty acyl chains of phospholipids at high temperature

A) broadens the temperature range of optimum membrane fluidity

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