Biochem Final

What is the delta G for conversion of glucose to glucose-6-phosphate, at 37 C, where Keq of the reaction is 780 (R= 8.315 J/mol)? A)-17 B)-889.7 C)+17 D)-889 E)+17000

A)-17 kj.mol

Dissolved solutes alter some physical (colligative) properties of the solvent water because they change the: A)concentration of the water B)hydrogen bonding of the water C)ionic bonding of the water D)pH of the water E)temperature of the water

A)concentration of the water

Of the 20 standard amino acids, only ___________ is not optically active. The reason is that its side chain ___________. A) alanine; is a simple methyl group B) glycine; is a hydrogen atom C) glycine; is unbranched D) lysine; contains only nitrogen E) proline; forms a covalent bond with the amino group

B) glycine; is a hydrogen atom

If you were to magnify a cell 10,000 fold, how big would it appear assuming you are viewing a bacterial cell of 10 um in diameter? A)100nm B)100mm C)10mm D)1m E)100cm

B)100mm

Which of the following is not a glycerophospholipid? A)Cardiolipin B)Ceramide C)Phosphatidylcholine D)Phosphatidylserine E)Phosphatidylethanolamine

B)Ceramide

Identify the functional group in the shaded region: A) phosphoryl B) phosphoketone C) phosphoanhydride D) diphosphate E) none of the above

C) Phosphoanhydride.

To possess optical activity, a compound must be: A) a carbohydrate B) a hexose C) asymmetric D) colored E) none of the above

C) asymmetric.

Fatty acids are a component of A)carotenes. B)diphytanylethers. C)sterols. D)monogalactosyldiacylglycerol. E)All of the above.

D)monogalactosyldiacylglycerol.

Sphingosine is not a component of: A)gangliosides. B)cerebrosides. C)ceramide. D)sphingomyelin. E)cardiolipin.

E)cardiolipin.

which of the following proteins spans from the Z disk to the M line and plays an important role in preventing overextension of muscle? a)paramyosin b)Titin c)Nebulin d)vimentin e)calmodulin

b)Titin

How many more hydrogen ions does a 1 L solution at pH 3 have than a 1 L solution at pH 5? a) 20X b) 1000X c) 100X d) 10X e) 200X

c) 100X

Which of the following solutions has the highest OH- concentration? a) saliva (pH = 6.5) b) lemon juice (pH = 2) c) vinegar (pH = 3) d) baking soda solution (pH = 9) e) sea water (pH = 7.8)

d) baking soda solution (pH=9)

What will the initial reaction velocity of an enzymatic reaction be when the (s) is equal to 0.5Km? a)1 b)0.75 c)0.50 d)0.33 E)1.5

d)0.33 V0=Vmax(S)/Km+(S)

To which major subclass of proteases does chymotrypsin belong? a)it is not a protease b)cysteine proteases c)aspartyl proteases d)serine proteases E)metalloproteases

d)serine proteases

If the average density of E. coli cells is 1.1x10^3 g/L, what is the approximate mass of a single cell that is 2 um in length and 0.8 um in diameter (hint: volume of a cylinder is pir^2h)? A) 1pg (picogram) B) 1ug (microgram) C) 1mg (milligram) D) 1ng (nanogram) E) none of the above

A) 1 pg (picogram).

The amino group of glycine, which has a pKa of 9.6, can exist either in the protonated form (NH3+) or as the free base (NH2). In which of the following pH values can glycine continue to be effective as a buffer due to its amino group? A) 10.3 B) 8.0 C) 11.6 D) 7.0 E) None of the above

A) 10.3

Hundreds of kJ/mol of energy is required to break one of the following bonds: A) C-C B) H-bond C) hydrophobic interaction D) ionic interaction E) van der Waals interaction

A) Carbon -carbon bond

Which of the following pairs of bonds within a peptide backbone show free rotation around both bonds? A) Ca—C and N—Ca B) C=O and N—C C) C=O and N—Ca D) N—C and Ca—C E) N—Ca and N—C

A) Ca—C and N—Ca

Enzymes are biological catalysts that enhance the rate of a reaction by: A) decreasing the activation energy B) decreasing the amount of free energy released C) increasing the amount of energy D) increasing the amount of free energy released E) increasing the energy of transition state

A) Decreasing the activation energy.

Which of the following statements concerning the process of spontaneous folding of proteins is false? A) It may be an essentially random process. B) It may be defective in some human diseases. C) It may involve a gradually decreasing range of conformational species. D) It may involve initial formation of a highly compact state. E) It may involve initial formation of local secondary structure.

A) It may be an essentially random process.

In the diagram below, the plane drawn behind the peptide bond indicates the: A) absence of rotation around the C—N bond because of its partial double-bond character. B) plane of rotation around the C—N bond. C) region of steric hindrance determined by the large C=O group. D) region of the peptide bond that contributes to a Ramachandran plot. E) theoretical space between -180 and +180 degrees that can be occupied by the and angles in the peptide bond.

A) absence of rotation around the C—N bond because of its partial double-bond character.

All of the amino acids that are found in proteins, except for proline, contain a(n): A) amino group. B) carbonyl group. C) carboxyl group. D) ester group. E) thiol group.

A) amino group.

Prosthetic groups in the class of proteins known as glycoproteins are composed of: A) carbohydrates. B) flavin nucleotides. C) lipids. D) metals . E) phosphates.

A) carbohydrates.

Proteins often have regions that show specific, coherent patterns of folding or function. These regions are called: A) domains. B) oligomers. C) peptides. D) sites. E) subunits.

A) domains.

The double-reciprocal transformation of the Michaelis-Menten equation, also called the Lineweaver-Burk plot, is given by 1/V0 = Km /(Vmax[S]) + 1/Vmax. To determine Km from a double-reciprocal plot, you would: A) multiply the reciprocal of the x-axis intercept by −1. B) multiply the reciprocal of the y-axis intercept by −1. C) take the reciprocal of the x-axis intercept. D) take the reciprocal of the y-axis intercept. E) take the x-axis intercept where V0 = 1/2 Vmax.

A) multiply the reciprocal of the x-axis intercept by −1.

Based on Chargaff's rules, which of the following are possible base compositions for double-stranded DNA? A)5%A, 45%G, 45%C, 5%T, 0%U B)20%A, 20%G, 20%C, 20%T, 20%U C)35%A, 15%G, 35%C, 15%T, 0%U D)All of the above E)None of the above

A)5%A, 45%G, 45%C, 5%T, 0%U

A biochemist has 100 mL of a 0.1 M solution of a weak acid with a pKa of 6.3. She adds 6.0 mL of 1.0 M HCl, which changes the pH to 5.7. What was the pH of the original solution? A)6.9 B)5.3 C)7.0 D)6.3 E)none of the above

A)6.9

Which of the following statements about sterols is true? A)All sterols share a fused-ring structure with four rings. B)Sterols are found in the membranes of all living cells. C)Sterols are soluble in water, but less so in organic solvents such as chloroform. D)Cholesterol is the principal sterol in fungi. E)The principal sterol of animal cells is ergosterol.

A)All sterols share a fused-ring structure with four rings.

Which of the following best describes the cholesterol molecule? A)Amphipathic B)Nonpolar, charged C)Polar, charged D)Nonpolar, uncharged E)Polar, uncharged

A)Amphipathic

A true statement about hydrophobic interactions is that they: A)Are the driving force in the formation of micelles of amphipathic compounds in water. B)do not contribue to the structure of water-soluble proteins C)have bonding energies of approximately 20-40 kJ per M D)involve the ability of water to denature proteins E)primarily involve the effect of polar solutes on the entropy of aqueous systems

A)Are the driving force in the formation of micelles of amphipathic compounds in water.

Transition state analogs are compounds that resemble the transition state for a chemical reaction, but are stable molecules, unlike the transition state. What statement should be true about the transition state analog? A)It should bind very tightly to the enzyme B)It should bind very weakly to the enzyme C)It forms a covalent bond when it binds to the enzyme D)It should cause a conformational change in the protein E)It should serve as a general acid group in catalysis

A)It should bind very tightly to the enzyme

Which of the following answers is not true? A)Phospholipase B1 hydrolyzes the fatty acid from the 2-position on the glycerol backbone. B)Phospholipase D hydrolyzes just the head group from the phospho-glycerol backbone. C)Phospholipase C hydrolyzes the complete phospho-head group from the glycerol backbone. D) Phospholipase A1 hydrolyzes the fatty acid from the 1-position on the glycerol backbone.

A)Phospholipase B1 hydrolyzes the fatty acid from the 2-position on the glycerol backbone.

Which one of the following statements about membranes is true? A)Sterol lipids are common in human cell plasma membranes. B)Sterol lipids are common in bacterial plasma membranes. C)Sterol lipids are common in plant cell plasma membranes. D)The plasma membranes of all cell types within a particular organism have basically the same lipid and protein composition. E)Most plasma membranes contain more than 70% proteins.

A)Sterol lipids are common in human cell plasma membranes.

Which of the following is not true of sterols? A)Sterols are commonly found in bacterial membranes. B)Sterols have a structure that includes four fused rings. C)Sterols are more common in plasma membranes than in intracellular membranes (mitochondria, lysosomes, etc.). D)Serols are precursors of steroid hormones. E)Cholesterol is a sterol that is commonly found in mammals.

A)Sterols are commonly found in bacterial membranes.

Which of the following tags is not used to study protein function? A)Synteny tag B)Gal4p DNA binding domain C)Tandem affinity purification (TAP) D)Gal4p activation domain E)Green fluorescent protein (GFP)

A)Synteny tag

Which regard to the structure below, which of the following statements is false? A)the monosaccharide units are a furanose and a pyranose B)the structure is a reducing sugar C)one of the monosaccharide unit can undergo oxidation upon ring-opening D)both monosaccharide units are pyranoses E)the linkage between the two monosaccharide units is a beta 1-4 linkage

A)The monosaccharide units are a furanose and a pyranose.

In the laboratory, recombinant plasmids are commonly introduced into bacterial cells by: A)transformation by heat shock of the cells incubated with plasmid DNA in the presence of CaCl2. B)infection with a bacteriophage that carries the plasmid. C)electrophoresis by a gentle low-voltage gradient draws the DNA into the cell. D)microinjection. E)mixing plasmids with an extract of broken cells.

A)transformation by heat shock of the cells incubated with plasmid DNA in the presence of CaCl2.

Which of the following statements about oligomeric proteins is false? A) A subunit may be similar to other proteins. B) All subunits must be identical. C) Many have regulatory roles. D) Some oligomeric proteins can further associate into large fibers. E) Some subunits may have nonprotein prosthetic groups

B) All subunits must be identical.

Energy requiring metabolic pathways that yield complex molecules from simpler precursors are: A) amphibolic B) anabolic C) autotrophic D) catabolic E) heterotrophic

B) Anabolic.

On the reaction coordinate diagram shown below, the overall free-energy change (delta G) for the uncatalyzed reaction A to B describes the reaction as: A) endergonic B) exergonic C) endothermic D) exothermic E) cannot be described based not eh diagram

B) Exergonic

Hyaluronic acid is a ___ that is found in the fluid of joints where it forms a viscous lubricating fluid. A) chitin B) glycosaminoglycan C) glycoside D) peptidoglycan E) nodulation factor

B) Glycosaminoglycan.

Phosphoric acid is tribasic, with pKa's of 2.14, 6.86, and 12.4. The ionic form that predominates at pH 3.2 is: A)H3PO4 B)H2PO4- C)HPO4 2- D)PO4 3- E)None of the above

B) H2PO4-

Which of the following refers to particularly stable arrangements of amino acid residues in a protein that give rise to recurring patterns? A) Primary structure B) Secondary structure C) Tertiary structure D) Quaternary structure E) None of the above

B) Secondary structure

The four covalent bonds in methane (CH4) are arranged around carbon to give which one of the following geometries? A) linear B) tetrahedral C) trigonal bipyramidal D) triogonal planar E) trigonal pyramidal

B) Tetrahedral

For amino acids with neutral R groups, at any pH below the pI of the amino acid, the population of amino acids in solution will have: A) a net negative charge. B) a net positive charge. C) no charged groups. D) no net charge. E) positive and negative charges in equal concentration.

B) a net positive charge.

The functional differences, as well as differences in three-dimensional structures, between two different enzymes from E. coli result directly from their different: A) affinities for ATP. B) amino acid sequences. C) roles in DNA metabolism. D) roles in the metabolism of E. coli. E) secondary structures.

B) amino acid sequences.

Which group of single-celled microorganisms has many members found growing in extreme environments? a) Bacteria b) Archaea c) Eukaryotes d) Heterotrophs e) None of the above

B) archaea

In an alpha helix, the R groups on the amino acid residues: A) alternate between the outside and the inside of the helix. B) are found on the outside of the helix spiral. C) cause only right-handed helices to form. D) generate the hydrogen bonds that form the helix. E) stack within the interior of the helix.

B) are found on the outside of the helix spiral.

The formation of a peptide bond between two amino acids is an example of a(n) ______________ reaction. A) cleavage B) condensation C) group transfer D) isomerization E) oxidation reduction

B) condensation

To determine the isoelectric point of a protein, first establish that a gel: A) contains a denaturing detergent that can distribute uniform negative charges over the protein's surface. B) exhibits a stable pH gradient when ampholytes become distributed in an electric field. C) is washed with an antibody specific to the protein of interest. D) neutralizes all ionic groups on a protein by titrating them with strong bases. E) relates the unknown protein to a series of protein markers with known molecular weights, Mr.

B) exhibits a stable pH gradient when ampholytes become distributed in an electric field.

The three-dimensional conformation of a protein may be strongly influenced by amino acid residues that are very far apart in sequence. This relationship is in contrast to secondary structure, where the amino acid residues are: A) always side by side. B) generally near each other in sequence. C) invariably restricted to about 7 of the 20 standard amino acids. D) often on different polypeptide strands. E) usually near the polypeptide chain's amino terminus or carboxyl terminus.

B) generally near each other in sequence.

In a mixture of the five proteins listed below, which should elute second in size-exclusion (gel- filtration) chromatography? A) cytochrome c Mr = 13,000 B) immunoglobulin G Mr = 145,000 C) ribonuclease A Mr = 13,700 D) RNA polymerase Mr = 450,000 E) serum albumin Mr = 68,500 B

B) immunoglobulin G Mr = 145,000

When oxygen binds to a heme-containing protein, the two open coordination bonds of Fe2+ are occupied by: A) one O atom and one amino acid atom. B) one O2 molecule and one amino acid atom. C) one O2 molecule and one heme atom. D) two O atoms. E) two O2 molecules.

B) one O2 molecule and one amino acid atom.

Pauling and Corey's studies of the peptide bond showed that: A) at pH 7, many different peptide bond conformations are equally probable. B) peptide bonds are essentially planar, with no rotation about the C—N axis. C) peptide bonds in proteins are unusual, and unlike those in small model compounds. D) peptide bond structure is extraordinarily complex.

B) peptide bonds are essentially planar, with no rotation about the C—N axis.

Which is the proper definition of equilibrium, with respect to a biochemical reaction? A) The forward reaction is favored over the reverse reaction, and it proceeds. B) There is no net change in reactant and product concentrations. C) There is a constant rate at which reactant is converted to product. D) The free-energy change for the reaction is negative. E) The entropy of the reaction is negative and the enthalpy of the reaction is positive.

B) there is no net change in reactant and product concentrations

Purines have ____ ring(s), (each) containing _____ nitrogen(s), whereas pyrimidines have _____ ring(s), (each) containing _____ nitrogens. A)1; 2; 1; 2 B)2; 2; 1; 2 C)2; 1; 1; 2 D)1; 1; 1; 1 E)2; 2; 1; 1

B)2; 2; 1; 2

Neuroglobin is a member of the globin family found in neurons. It is a monomeric protein that helps protect the brain from hypoxia (low O2). Identify the correct statement(s) about neuroglobin below. a) It binds O2 with a hyperbolic binding curve. b) It binds O2 with a sigmoidal binding curve. c) It binds O2 with higher affinity than hemoglobin. d) It binds O2 with lower affinity than hemoglobin A) C AND D B)A and C C)A and D D)B and C E)B and D

B)A and C

Why would a lab technician choose a bacterial artificial chromosome for cloning a gene, rather than a plasmid? A)Because work on the gene will only be performed in a cell-free system, one without the genomic DNA required for cloning. B)Because the insert to be cloned is very large. C)Because the DNA insert is from genomic DNA and not plasmid DNA. D)Because the gene insert will eventually be used to transform cells, meaning incorporate the gene into genomic DNA. E)Because bacterial DNA will be used to make many copies of the gene (i.e., clone it).

B)Because the insert to be cloned is very large.

Which of the following is true of sphingolipids? A)They always contain glycerol and fatty acids. B)Cerebrosides and gangliosides are sphingolipids. C)They contain two esterified fatty acids. D)Phosphatidylcholine is a typical sphingolipid. E)They may be charged, but are never amphipathic

B)Cerebrosides and gangliosides are sphingolipids.

Which of the following statements about the polymerase chain reaction (PCR) is false? A)The technique is sufficiently sensitive that DNA sequences can be amplified from a single animal or human hair. B)DNA amplification is linear in magnitude. C)The boundaries of the amplified DNA segment are determined by the synthetic oligonucleotides used to prime DNA synthesis. D)Newly synthesized DNA must be heat-denatured before the next round of DNA synthesis begins. E)DNA amplified by PCR can be cloned.

B)DNA amplification is linear in magnitude.

Which of the following is not a consequence of partial hydrogenation of vegetable oils? A)Increased risk of cardiovascular disease upon consumption by humans B)Lower melting temperature C)Conversion of some cis double bonds to trans double bonds D)Reduction of some cis double bonds to single bonds E)Longer shelf life

B)Lower melting temperature

When double-stranded DNA is heated at neutral pH, which change does not occur? A)The absorption of ultraviolet (260 nm) light increases. B)The covalent N-glycosidic bond between the base and the pentose breaks. C)The viscosity of the solution decreases. D)The hydrogen bonds between A and T break. E)The helical structure unwinds.

B)The covalent N-glycosidic bond between the base and the pentose breaks.

The nucleic acid bases: A)are relatively hydrophilic. B)are roughly planar. C)absorb ultraviolet light maximally at 280 nm. D)can all stably base-pair with one another. E)are all about the same size.

B)are roughly planar.

Biological waxes are all: A)triesters of glycerol and palmitic acid. B)esters of single fatty acids with long-chain alcohols. C)triesters of glycerol and three long chain saturated fatty acids. D)sphingolipids. E)None of the above

B)esters of single fatty acids with long-chain alcohols.

The experiment of Avery, MacLeod, and McCarty in which nonvirulent bacteria were made virulent by transformation was significant because it showed that: A)bacteria can undergo transformation. B)genes are composed of DNA only. C)mice are more susceptible to pneumonia than are humans. D)pneumonia can be cured by transformation. E)virulence is determine genetically.

B)genes are composed of DNA only

Triple-helical DNA structures can result from Hoogsteen (non Watson-Crick) interactions. These interactions are primarily: A)hydrophobic interactions involving the bases. B)hydrogen bonds involving the bases. C)covalent bonds involving deoxyribose. D)covalent bonds involving the bases. E)hydrogen bonds involving deoxyribose.

B)hydrogen bonds involving the bases.

A convenient cloning vector with which to introduce foreign DNA into E. coli is a(n) A)messenger RNA. B)plasmid. C)E. coli chromosome. D)yeast ARS sequence. E)yeast transposable element

B)plasmid.

Non-steroidal anti-inflammatory drugs (NSAIDS) like aspirin and ibuprofen act by blocking production of: A)biological waxes B)prostaglandins C)sphingolipids D)vitamin D E)none of the above

B)prostaglandins

In DNA sequencing by the Sanger (dideoxy) method: A)radioactive dideoxy ATP is included in each of four reaction mixtures before enzymatic synthesis of complementary strands. B)the role of the dideoxy CTP is to occasionally terminate enzymatic synthesis of DNA where Gs occur in the template strands. C)thedideoxynucleotides must be present at high levels to obtain long stretches of DNA sequence. D)the template DNA strand is radioactive. E)specific enzymes are used to cut the newly synthesized DNA into small pieces, which are then separated by electrophoresis.

B)the role of the dideoxy CTP is to occasionally terminate enzymatic synthesis of DNA where Gs occur in the template strands.

The following data were obtained in a study of an enzyme known to follow Michaelis-Menten kinetics: (μmol/min) (mmol/L) ———————— 217 0.8 325 2 433 4 488 6 647 1,000 ————————————— The Km for this enzyme is approximately: A) 1 mM. B) 1,000 mM. C) 2 mM. D) 4 mM. E) 6 mM.

C) 2 mM.

Roughly how many amino acids are there in one turn of an Alpha helix? A) 1 B) 2.8 C) 3.6 D) 4.2 E) 10

C) 3.6

Which of the following statements is false? A) glycogen: branched homopolysaccharide of glucose B) starch: mixture of two homopolysaccharides of glucose C) agar: mixture of heteropolyssacharides containing modified glucose units D) chitin: linear homopolysaccharide of N-acetylglucosamine E) cellulose: branched homopolysaccharide of glucose

C) Agar: mixture of heteropolysaccharides containing modified glucose units

Use the terms a) chemoautotrophs, b) chemoheterotrophs, c) photoautotrophs, and d) photoheterotrophs and identify the answer that correctly finishes the statement: Carnivores are ___ and herbivores are ___. A) b,c B) b,d C) b,b D) a,b E) a,a

C) B, B

Following complete hydrolysis of a sample of glycogen and a sample of cellulose, which of the following must be true? A) the glycogen sample is more soluble than the cellulose sample B) the cellulose sample is more soluble than the glycogen sample C) Both samples consist of a mixture of alpha-d-glucose and beta-d-glucose D)The glycogen sample has a higher ratio of alpha-d-glucose than the cellulose sample E) the cellulose sample contains only beta-d-glucose

C) Both samples consist of a mixture of alpha- d glucose and beta-d-glucose

Which of the following techniques can be used to isolate nucleus from ribosomes? A) electrophoresis B) X-ray crystallography C) differential centrifugation D) Tissue homogenization E) electron microscopy

C) Differential centrifugation.

The reference compound for naming D and L isomers of sugars is: A) fructose B) glucose C) glyceraldehyde D) ribose E) sucrose

C) Glyceraldehyde

In a conjugated protein, a prosthetic group is: A) a fibrous region of a globular protein. B) a nonidentical subunit of a protein with many identical subunits. C) a part of the protein that is not composed of amino acids. D) a subunit of an oligomeric protein. E) synonymous with "protomer." Peptides and proteins

C) a part of the protein that is not composed of amino acids.

Which of the following statements about the structure of chymotrypsin is ture? a)C is made up of 3 peptides held together by 5 inter disulfide bonds b)C is synthesized as a zymogen called trypinogen c)a serine residue is a key active-site residue in the enzyme d)all E)none

C) a serine residue is a key active-site residue in the enzyme

Adenine binding to thymine in DNA is an example of which of the following? a) Ionic interactions b) Covalent bonding c) Complementarity d) Transcription e) A racemic mixture

C) complementarity

An average protein will not be denatured by: A) a detergent such as sodium dodecyl sulfate. B) heating to 90°C. C) heating below TM D) pH 10. E) urea.

C) heating below TM

The chirality of an amino acid results from the fact that its alpha carbon: A) has no net charge. B) is a carboxylic acid. C) is bonded to four different chemical groups. D) is in the L absolute configuration in naturally occurring proteins. E) is symmetric.

C) is bonded to four different chemical groups.

At pH 7.0, converting a proline to hydroxyproline, will have what effect on the overall charge of the protein containing it? A) it will become more negative B) it will become more positive. C) it will stay the same. D) there is not enough information to answer the question. E) the answer depends on the salt concentration.

C) it will stay the same.

Oxidation and reduction are important cellular processes that sustain life. What group of organisms oxidize inorganic molecules, such as elemental sulfur and nitrate, for fuels? A) Chemotrophs B) Autotrophs C) Lithotrophs D) Phototrophs E) Heterotrophs

C) lithotrophs

Two amino acids of the standard 20 contain sulfur atoms. They are: A) cysteine and serine. B) cysteine and threonine. C) methionine and cysteine D) methionine and serine E) threonine and serine.

C) methionine and cysteine

An octapeptide composed of four repeating glycylalanyl units has: A) one free amino group on an alanyl residue. B) one free amino group on an alanyl residue and one free carboxyl group on a glycyl residue. C) one free amino group on a glycyl residue and one free carboxyl group on an alanyl residue. D) two free amino and two free carboxyl groups. E) two free carboxyl groups, both on glycyl residues.

C) one free amino group on a glycyl residue and one free carboxyl group on an alanyl residue.

One method used to prevent disulfide bond interference with protein sequencing procedures is: A) cleaving proteins with proteases that specifically recognize disulfide bonds. B) protecting the disulfide bridge against spontaneous reduction to cysteinyl sulfhydryl groups. C) reducing disulfide bridges and preventing their re-formation by further modifying the —SH groups. D) removing cystines from protein sequences by proteolytic cleavage. E) sequencing proteins that do not contain cysteinyl residues.

C) reducing disulfide bridges and preventing their re-formation by further modifying the —SH groups.

At the isoelectric pH of a tetrapeptide: A) only the amino and carboxyl termini contribute charge. B) the amino and carboxyl termini are not charged. C) the total net charge is zero. D) there are four ionic charges. E) two internal amino acids of the tetrapeptide cannot have ionizable R groups.

C) the total net charge is zero.

The ribonucleotide polymer (5')GTGATCAAGC(3') could only form a double-stranded structure with: A)(5')CACUAGUUCG(3') B)(5')CACTAGTTCG(3'). C)(5')GCTTGATCAC(3'). D)(5')GCCTAGTTUG(3') E)(5')CACUTTCGCCC(3'

C)(5')GCTTGATCAC(3').

Some effort has been made to extract DNA from fossilized dinosaur bones that have been buried for many millions of years in arid climates. In what form is this DNA most likely to be found? A)Completely denatured B)Tetraplex C)A D)B E)Z

C)A

What name is given to the nucleotide found in DNA and not in RNA? A)Uracil B)Uridylate C)Deoxythymidylate D)Thymidine E)Deoxythymidine

C)Deoxythymidylate

Which of the following is not needed to build a cDNA library? A)dNTPs B)mRNA C)Genomic DNA D)DNA polymerase E)Reverse transcriptase

C)Genomic DNA

Which of these statements about the composition of biological membranes is false? A)The ratio of lipid to protein varies widely among cell types in a single organism. B)The plasma membranes of the cells of vertebrate animals contain more cholesterol than the mitochondrial membranes. C)In a given eukaryotic cell type (e.g., a hepatocyte), all intracellular membranes have essentially the same complement of lipids and proteins. D)The carbohydrate found in membranes is virtually all part of either glycolipids or glycoproteins. E)Triacylglycerols are not commonly found in membranes.

C)In a given eukaryotic cell type (e.g., a hepatocyte), all intracellular membranes have essentially the same complement of lipids and proteins.

What function is served by the major groove in DNA? A)It is a region of DNA that can form a hybrid duplex with DNA of another species. B)It is a region of denatured DNA to which restriction endonucleases bind. C)It Is a binding site for regulatory proteins. D)It is the binding site for ethidium bromide. E)It is the site of guanine tetraplex formation.

C)It Is a binding site for regulatory proteins.

A new plasmid can be purchased from a major supplier who claims it has the largest polylinker available. What is unique about this new plasmid? A)It is possible to incorporate more inserts than any other plasmid. B)There are more endonuclease sites than any other plasmid. C)It is the largest plasmid available based on base pair size. D)The plasmid can accept the longest DNA sequence insert compared to any other plasmid. E)It has the largest number of maintenance genes of any available plasmid.

C)It is the largest plasmid available based on base pair size.

Which of the following statements about hemoglobin and oxygen is INCORRECT? A)The binding of oxygen to a subunit of hemoglobin in the tense state triggers a conformational change to the relaxed state. B)Oxygen binds to the iron atoms of the hemes in hemoglobin. C)Oxygen has a higher affinity for hemoglobin in the tense state. D)Hemoglobin binds oxygen efficiently in the lungs and releases it in tissues. E)None of these statements are true.

C)Oxygen has a higher affinity for hemoglobin in the tense state.

Sanger sequencing was performed on DNA from chloroplasts of a new plant species discovered in the rain forest of Puerto Rico. The X-ray film showed bands in the A, C, and T lanes, but the G lane was blank. What is the most likely explanation for this unexpected result? A)Different template DNA was added to the reaction tube. B)All 4 ddNTPs were added to that tube. C)ddG was not added to the reaction tube. D)The template DNA contained no C. E)The template DNA contained no G.

C)ddG was not added to the reaction tube.

Compounds that generate nitrous acid (such as nitrites, nitrates, and nitrosamines) change DNA molecules by: A)depurination. B)formation of thymine dimers. C)deamination of bases. D)breakage of phosphodiester bonds. E)transformation of A to T.

C)deamination of bases.

What key feature of DNA polymerase allows PCR to be conveniently performed? A)it is a Taq polymerase that can work at very low temperatures. B)it allows hybridization of DNA with oligonucleotide primers at high temperatures. C)it is heat stable and is not denatured by repeated heating and cooling of the PCR reaction D)it is a DNA ligase used in PCR based cloning that can work at high temperatures E)All of the above

C)it is heat stable and is not denatured by repeated heating and cooling of the PCR reaction

The phosphodiester bonds that link adjacent nucleotides in both RNA and DNA: A)always link A with T and G with C. B)are uncharged at neutral pH. C)join the 3' hydroxyl of one nucleotide to the 5' hydroxyl of the next. D)form between the planar rings of adjacent bases. E)are susceptible to alkaline hydrolysis.

C)join the 3' hydroxyl of one nucleotide to the 5' hydroxyl of the next.

Certain restriction enzymes produce cohesive (sticky) ends. This means that they: A)make ends that can anneal to cohesive ends generated by any other restriction enzyme. B)cut in regions of high GC content, leaving ends that can form more hydrogen bonds than ends of high AT content. C)make a staggered double-strand cut, leaving ends with a few nucleotides of single-stranded DNA protruding. D)stick tightly to the ends of the DNA they have cut. E)cut both DNA strands at the same base pair.

C)make a staggered double-strand cut, leaving ends with a few nucleotides of single-stranded DNA protruding.

Silk Fibroin is strong because of: A)covalent crosslinks between adjacent strands B)covalent cross links between stacked sheets C)the peptide backbone of antiparallel beta strands are fully extended D)R-groups in the stacked pleated sheets allow for longitudinal sliding E)silk is not strong, only flexible

C)the peptide backbone of antiparallel beta strands are fully extended

Which of the following is not an appropriate description for van der Waals interactions? A) they involve dipole-dipole interactions B)their strength depends on the distance between the two interacting atoms C)they are highly specific D)an individual van der Waals interaction does not contribute significantly to the stability of a protein E)they can involve hydrophobic amino acids

C)they are highly specific

The aqueous solution with the lowest pH is: A) 0.01 M HCl B) 0.1 M acetic acid (pKa = 4.86) C) 0.1 M formic acid (pKa = 3.75) D) 0.1 M HCl E) 10^-12 M NaOH

D) 0.1 M HCL

The aqueous solution with the highest pH is: The aqueous solution with the highest pH is: A) 1 M HCl B) 1 M NH3 (pKa = 9.25) C) 0.5 M NaHCO3 (pKa = 3.77) D) 0.1 M NaOH E) 0.001 M NaOH

D) 0.1 M NaOH.

A compound has a pKa of 7.4. To 100 mL of a 1.0 M solution of this compound at pH 8.0 is added 30 mL of 1.0 M hydrochloric acid. The resulting solution is pH: A) 6.5 B) 6.8 C) 7.2 D) 7.4 E) 7.5

D) 7.4

Why is it logical for sugars to be added to only one end of amylopectin or glycogen, making them excellent molecules for glucose storage? A) because the other end of the molecule is anchored to a membrane with a lipid B) because it is the reducing end, and a reduction reaction is the mechanism for adding the sugar C) because is has the hemiacetal carbon, the one carbon to which more sugars can be attached D) because there are many nonreducing ends on one molecule, allowing rapid glucose storage and release E) because that end has the number 6 carbon, the one used to make the (alpha -> 6) linkage

D) Because there are many nonreducing ends on one molecule, allowing rapid glucose storage and release.

Which of the following statements does not define configuration or conformation correctly? A) configuration denotes the spatial arrangement of the atoms of a molecule that is conferred by the presence of double bonds around which there is no freedom of rotation B) conformation refers to the spatial arrangement of substituent groups that are free to assume different positions in space because of the freedom of bond rotation C) configuration is conferred by the presence of chiral centers, which gives rise to stereoisomers. D) conformational changes require breaking of covalent bonds E) configurational isomers can only be interconverted by temporarily breaking covalent bonds

D) Conformational changes require breaking covalent bonds.

Which of the following statements is false? A) cytoskeleton is made up of proteins B) actin contributes to cellular movement C) intermediate filaments participate in intracellular organization D) cytoskeleton is a rigid structure in the cell E) cytoskeleton consists of microtubules

D) Cytoskeleton is a rigid structure in the cell.

Stereoisomers that are non superimposable mirror images of each other are known as: A) anomers B) cis-trans isomers C) diastereoisomers D) enantiomers E) geometric isomers

D) Enantiomers

Which is a list of organelles? A) Mitochondria, Chromatin, ER B) Peroxisomes, lysosomes, plasma membrane C) Proteasomes, peroxisomes, lysosomes D) mitochondria, ER, peroxisomes E) All of the above

D) Mitochondria, endoplasmic reticulum, peroxisomes.

Which of the following is not known to be involved in the process of assisted folding of proteins? A) Chaperonins B) Disulfide interchange C) Heat shock proteins D) Peptide bond condensation E) Peptide bond isomerization

D) Peptide bond condensation

Consider an acetate buffer, initially at the same pH as its pKa (4.76). When sodium hydroxide (NaOH) is mixed with this buffer, the: A) pH remains constant B)pH rises more than if an equal amount of NaOH is added to an acetate buffer initially at pH 6.67 C) pH rises more than if an equal amount of NaOH is added to unbuttered water at pH 4.76 D) ratio of acetic acid to sodium acetate in the buffer falls E) sodium acetate formed precipitates because it is less soluble than acetic acid

D) Ratio of acetic acid to sodium acetate in the buffer falls.

The α-keratin chains indicated by the diagram below have undergone one chemical step. To alter the shape of the α-keratin chains—as in hair waving—what subsequent steps are required? A) Chemical oxidation and then shape remodeling B) Chemical reduction and then chemical oxidation C) Chemical reduction and then shape remodeling D) Shape remodeling and then chemical oxidation E) Shape remodeling and then chemical reduction

D) Shape remodeling and then chemical oxidation

A D-amino acid would interrupt an alpha helix made of L-amino acids. Another naturally occurring hindrance to the formation of an alpha helix is the presence of: A) a negatively charged Arg residue. B) a nonpolar residue near the carboxyl terminus. C) a positively charged Lys residue. D) a Pro residue. E) two Ala residues side by side.

D) a Pro residue.

The amino acid substitution of Val for Glu in Hemoglobin S results in aggregation of the protein because of ___________ interactions between molecules. A) covalent B) disulfide C) hydrogen bonding D) hydrophobic E) ionic

D) hydrophobic

Which organelle is found in both plant and animal cells? A) Starch granule B)Chloroplast C) Plasmodesmata D) Mitochondria E)Glyoxysome

D) mitochondria

All of the following are considered "weak" interactions in proteins, except: A) hydrogen bonds. B) hydrophobic interactions. C) ionic bonds. D) peptide bonds. E) van der Waals forces.

D) peptide bonds.

In an aqueous solution, protein conformation is determined by two major factors. One is the formation of the maximum number of hydrogen bonds. The other is the: A) formation of the maximum number of hydrophilic interactions. B) maximization of ionic interactions. C) minimization of entropy by the formation of a water solvent shell around the protein. D) placement of hydrophobic amino acid residues within the interior of the protein. E) placement of polar amino acid residues around the exterior of the protein.

D) placement of hydrophobic amino acid residues within the interior of the protein.

The structural classification of proteins (based on motifs) is based primarily on their: A) amino acid sequence. B) evolutionary relationships. C) function. D) secondary structure content and arrangement. E) subunit content and arrangement.

D) secondary structure content and arrangement.

Thr and/or Leu residues tend to disrupt an helix when they occur next to each other in a protein because: A) an amino acids like Thr is highly hydrophobic. B) covalent interactions may occur between the Thr side chains. C) electrostatic repulsion occurs between the Thr side chains. D) steric hindrance occurs between the bulky Thr side chains. E) the R group of Thr can form a hydrogen bond.

D) steric hindrance occurs between the bulky Thr side chains.

Kendrew's studies of the globular myoglobin structure demonstrated that: A) "corners" between a-helical regions invariably lacked proline residue. B) highly polar or charged amino acid residues tended to be located interiorally. C) myoglobin was completely different from hemoglobin, as expected. D) the structure was very compact, with virtually no internal space available for water. E) the a helix predicted by Pauling and Corey was not found in myoglobin.

D) the structure was very compact, with virtually no internal space available for water.

Which fatty acid has the higher melting temperature. A)16:0 B)20:4 delta 8,11,14,17 C)18:1 delta9 D)20:0 E)18:2 delta9,12

D)20:0

The size of the DNA region specifically recognized by type II restriction enzymes is typically: A)10 to 15 base pairs. B)200 to 300 base pairs. C)about the size of an average gene. D)4 to 6 base pairs. E)50 to 60 base pairs.

D)4 to 6 base pairs.

Which of the following descriptions is false A)A bacteriophage l cloning can package only DNAs of a certain size B)Up to about 23,000 base pairs of the l genome are nonessential C)Bacteriophage cloning requires DNA ligase D)Bacteriophages are bacteria with single stranded linear DNA E)None of the above

D)Bacteriophages are bacteria with single stranded linear DNA

Which of these statements about hydrogen bonds is not true? A)H bonds account for the anomalously high BP of water B)In liquid water, the average water molecule forms H bonds with 3 or 4 other water molecules C)individual H bonds are much weaker than covalent D)Individual hydrogen bonds in liquid water exist for many seconds and sometimes for minutes. E)The strength of a H bond depends on the linearity of the three atoms involved in the bond

D)Individual hydrogen bonds in liquid water exist for many seconds and sometimes for minutes.

Lysozyme has antibacterial properties. How does it affect bacteria? A)it hydrolzes N-glycosidic bonds in peripheral plasma membrane glycoproteins B)it acts as a deb ranching enzyme for cytoplasmic glycoproteins C)it dominates hyaluronic acid in the plasma membrane D)It hydrolyzes polysaccharide chains of peptidoglycans in the bacterial cell wall. E)None of the above

D)It hydrolyzes polysaccharide chains of peptidoglycans in the bacterial cell wall.

Which of the following statements is false with regard to melting of ice? A)the enthalpy change for making and breaking bonds during melting of ice is positive B)Melting of ice is spontaneous and the free energy change for it to occur must be negative C)entropy increases during melting as molecules move from crystal to random structure D)Melting requires heat energy and therefore the reaction is endergonic process. E)Energetics of melting of ice and evaporation of water are similar

D)Melting requires heat energy and therefore the reaction is endergonic process.

Which of the following statements regarding plasmid-cloning vectors is correct? A)Plasmids do not need to contain genes that confer resistance to antibiotics. B)Circular plasmids do not require an origin of replication to be propagated in E. coli C)Foreign DNA fragments up to 45,000 base pairs can be cloned in a typical plasmid. D)The copy number of plasmids may vary from a few to several hundred. E)Plasmid vectors must carry promoters for inserted gene fragments.

D)The copy number of plasmids may vary from a few to several hundred.

A graduate student carefully heated DNA to about 80C and then prepared it for electron microscopy. She observed a number of small open loops of DNA. What conclusion did she correctly make from her observation? A)The denatured DNA is the site of genes, of coding regions, and the annealed DNA is the site of non-coding DNA. B)The open loops are plasmids, and the annealed DNA is genomic. C)The open loops contain denatured DNA that is being transcribed. D)The open loops contain DNA with a high A-T content. E)The open loops contain DNA mutations

D)The open loops contain DNA with a high A-T content.

A solution of DNA is heated slowly until the tm is reached. Which of the following observation is inaccurate A)Separated single-stranded DNA may anneal at a temperatures lower than Tm B)The viscosity of the DNA decreases C)The regions with higher content of A-T base pairs may appear as "bubbles" D)Tm for DNA molecule is independent of pH and ionic strength of the solution E)Approximately 50% of the DNA is double helical

D)Tm for DNA molecule is independent of pH and ionic strength of the solution

The "energy carrier" ATP is an example of a(n): A)peptide B)ribonucleotide C)deoxyribonucleoside triphosphate D)ribonucleoside triphosphate E)di-nucleotide

D)ribonucleoside triphosphate

Which of the following statements about hydrogen bonding in glycogen and cellulose is true? A) Glycogen forms more internal H-bonds than cellulose B) Extensive internal hydrogen bonding makes cellulose more water soluble than glycogen C) Extensive H-bonding with water makes cellulose more water soluble than glycogen D) Glycogen primarily forms H-bonds within a single chain E) The H-bonding in cellulose favors a helical conformation

E) The hydrogen bonding in cellulose favors a helical conformation

The major reason that antiparallel beta-stranded protein structures are more stable than parallel beta-stranded structures is that the latter: A) are in a slightly less extended configuration than antiparallel strands. B) do not have as many disulfide crosslinks between adjacent strands. C) do not stack in sheets as well as antiparallel strands. D) have fewer lateral hydrogen bonds than antiparallel strands. E) have weaker hydrogen bonds laterally between adjacent strands

E) have weaker hydrogen bonds laterally between adjacent strands

By adding SDS (sodium dodecyl sulfate) during the electrophoresis of proteins, it is possible to: A) determine a protein's isoelectric point. B) determine an enzyme's specific activity. C) determine the amino acid composition of the protein. D) preserve a protein's native structure and biological activity. E) separate proteins exclusively on the basis of molecular weight.

E) separate proteins exclusively on the basis of molecular weight.

Which of the following statements concerning fatty acids is correct? A)Fatty acids all contain one or more double bonds. B)Fatty acids are strongly hydrophilic. C)Fatty acids are a constituent of sterols. D)Phosphatidic acid is a common fatty acid. E)A fatty acid is the precursor of prostaglandins.

E)A fatty acid is the precursor of prostaglandins.

Which of the following is not a nucleotide? A)Coenzyme A B)FADH2 C)ATP D)Anti-cytidine monophosphate E)All of the above are nucleotides.

E)All of the above are nucleotides.

Which of the following molecules or substances contain, or are derived from, fatty acids? A)Beeswax B)Prostaglandins C)Sphingolipids D)Triacylglycerols E)All of the above contain or are derived from fatty acids.

E)All of the above contain or are derived from fatty acids.

Which of the following statement is true for reducing sugars? A)Oxidation of glucose under alkaline conditions is the basis for Fehling's reaction B)the enzyme glucose oxidase catalyzes the conversion of glucose to Gluconolactone C)peroxidase converts hydrogen peroxide to water D)in the hemiacetal form, C-1 of glucose cannot be oxidized by complexed Cu2+ E)All of the above

E)All of the above.

In "mixed inhibition" which kinetic parameter is unchanged? a)vmax b)Km c)vmax/Et d)Kcat/Km E)All of these

E)All of these

Why would a lab technician choose a bacterial artificial chromosome for cloning a gene, rather than a plasmid? A)Because work on the gene will only be performed in a cell-free system, one without the genomic DNA required for cloning. B)Because the gene insert will eventually be used to transform cells, meaning incorporate the gene into genomic DNA. C)Because bacterial DNA will be used to make many copies of the gene (i.e., clone it). D)Because the DNA insert is from genomic DNA and not plasmid DNA. E)Because the insert to be cloned is very large.

E)Because the insert to be cloned is very large.

Which of these is a general feature of the lipid bilayer in all biological membranes? A)The polar head groups face inward toward the inside of the bilayer. B)Polar, but uncharged, compounds readily diffuse across the bilayer. C)The bilayer is stabilized by covalent bonds between neighboring phospholipid molecules. D)Individual lipid molecules in one face (monolayer) of the bilayer readily diffuse (flip-flop) to the other monolayer. E)Individual lipid molecules are free to diffuse laterally in the surface of the bilayer.

E)Individual lipid molecules are free to diffuse laterally in the surface of the bilayer.

Intact lysosomes contain 0.1 M KCl and 0.05 M NaCl. When isolating lysosomes what concentration of osmotic is needed to prevent swelling and lysis (R is 8.315 J/mol and temperature 25 C)? a)0.26 b)3.00 c)1.05 d)1.00 e)none of the above

E)None of the above

The pH of a sample of soda you drank is 9.4, while lemonade is pH 4.4. The soda has: A)5 time higher H than the lemonade B)10000 times higher than the lemonade C)5 times lower H than the lemonade D)10,000 times lower than the lemonade E)None of the above

E)None of the above.

A gene for flower color in a wild south African lily was also found in a hybrid orchid only grown in Tokyo, Japan. Both genes control flower color and the genes have a 68% sequence homology. What is the proper term to describe them? A)Analogs B)Mutants C)Proteomes D)Paralogs E)Orthologs

E)Orthologs

Which of the following contains an ether-linked alkyl group? A)Gangliosides B)Sphingomyelin C)Cerebrosides D)Phosphatidyl serine E)Platelet-activating factor

E)Platelet-activating factor

Which of the following statements about membrane lipids is true? A)Triacylglycerols are the principal components of erythrocyte membranes. B)Glycerophospholipids contain fatty acids linked to glycerol through amide bonds. C)Glycerophospholipids are found only in the membranes of plant cells. D)Lecithin (phosphatidylcholine), which is used as an emulsifier in margarine and chocolate, is a sphingolipid. E)Some sphingolipids include oligosaccharides in their structure.

E)Some sphingolipids include oligosaccharides in their structure.

What could be learned by performing a yeast 2-hybrid assay using cadherin from neural cells and a newly described transmembrane protein from skeletal muscle? A)A plasmid made with the genes for these two proteins can be expressed in two different yeast strains. B)Yeast cells contain the genes for these two proteins. C)The DNA for cadherin forms hybrid duplexes with DNA for the new protein. D)Yeast cells can be used as expression vectors for both proteins. E)These proteins can interact with each other.

E)These proteins can interact with each other.

Why are two different restriction endonucleases used in DNA recombination? A)Each is specific for a sequence found on one of the two strands of DNA. B)To cut both phosphodiester bonds and hydrogen bonds. C)One is specific for purines, and one is specific for pyrmidines. D)One is required to produce the open plasmid and the other produces the insert. E)To permit proper orientation of the DNA insert into the plasmid.

E)To permit proper orientation of the DNA insert into the plasmid.

The difference between a ribonucleotide and a deoxyribonucleotide is: A)a ribonucleotide has an extra -OH at C-4. B)a deoxyribonucleotide has an -H instead of an -OH at C-3. C)a ribonucleotide has more structural flexibility than deoxyribonucleotide. D)a ribonucleotide is a pyranose, deoxyribonucleotide is a furanose. E)a deoxyribonucleotide has an -H instead of an -OH at C-2.

E)a deoxyribonucleotide has an -H instead of an -OH at C-2.

The E. coli recombinant plasmid pBR322 has been widely utilized in genetic engineering experiments. pBR322 has all of the following features except: A)resistance to two different antibiotics, which permits rapid screening for recombinant plasmids containing foreign DNA. B)a replication origin, which permits it to replicate autonomously. C)a number of conveniently located recognition sites for restriction enzymes. D)small overall size, which facilitates entry of the plasmid into host cells. E)a number of palindromic sequences near the EcoRI site, which permit the plasmid to assume a conformation that protects newly inserted DNA from nuclease degradation.

E)a number of palindromic sequences near the EcoRI site, which permit the plasmid to assume a conformation that protects newly inserted DNA from nuclease degradation.

Which of the following statements is false? A)gram positive bacteria cells do not have an outer membrane B)gram negative bacteria cells have a thin peptidoglycan layer C)archaea have a thick peptidoglycan layer D)cyanobacteria are gram negative E)archaea cells do not have an outermsmbrane

E)archaea cells do not have an outermsmbrane

Identify the molecule(s) derived from sterols. A)Phosphatidylglycerol B)Arachidonic acid C)Prostaglandins D)Gangliosides E)brassinolide

E)brassinolide

Which enzyme has the highest catalytic efficiency a)enzyme D km=25microM, Vmax 100mM/min b)enzyme B km= 50 microM, vmax 1000mM/min c)enzyme C km=2.5mM, vmax 100mM/min d)Enzyme E km-2.5 microM, vmax 100 microM/min E)enzyme A km-2.5 microM, vmax 100mM/min

E)enzyme A km-2.5 microM, vmax 100mM/min

Which of the following statements is incorrect regarding chymotrypsin? a)C active site is composed of a catalytic of Ser, His, ASP b)the rate of C-catalyzed cleavage exhibits a bell shaped, pH rate profile c)its mechanism of action inclues a covalent acyl-enzyme intermediate d)it catalyzes the hydrolysis of polypeptieds, small esters, and amides E)its mechanism of action includes a direct attack of water on the peptide

E)its mechanism of action includes a direct attack of water on the peptide

An example of a glycerophospholipid that is involved in cell signaling is: A)vitamin A (retinol). B)ceramide. C)testosterone. D)arachidonic acid. E)phosphatidylinositol.

E)phosphatidylinositol.

Proteostasis is the cellular process by which: A)proteins are synthesized B)proteins are folded C)proteins are modified D)proteins are degraded E)protein levels are maintained

E)protein levels are maintained

When a bacterium such as E. coli is shifted from a warmer growth temperature to a cooler growth temperature, it compensates by: A)increasing its metabolic rate to generate more heat. B)putting longer-chain fatty acids into its membranes. C)synthesizing thicker membranes to insulate the cell. D)shifting from aerobic to anaerobic metabolism. E)putting more unsaturated fatty acids into its membranes

E)putting more unsaturated fatty acids into its membranes

For the oligoribonucleotide pACGUAC A)the nucleotide at the 3' end has a phosphate at its 3' hydroxyl. B)the nucleotide at the 5' end is a pyrimidine. C)the nucleotide at the 3' end is a purine. D)the nucleotide at the 5' end has a 5' hydroxyl. E)the nucleotide at the 5' end has a phosphate on its 5' hydroxyl.

E)the nucleotide at the 5' end has a phosphate on its 5' hydroxyl.

Identify the protein indicated by an arrow in the figure below. A) glypican B) integrens C) syndecan D) peptidoglycan E) none of the above

Glypican

What is the pH of a 0.1 mM solution of hydrochloric acid at 37 C? a) 4 b) Cannot be determined with the information provided c) 0.1 d)3 e) 1

a) 4

A compound has a pKa of 7.4. To 100 mL of a 1.0 M solution of this compound at pH 8.0 is added 30 mL of 1.0 M hydrochloric acid. The resulting solution is pH: a) 7.4. b) 7.5. c) 7.2 d) 6.8. e) 6.5.

a) 7.4

What name is given to monosaccharides that differ in configuration about the anomeric carbon atom? a) Anomers b) Epimers c) Enantiomers d) Isomers e) Glycosides

a) anomers

Why is it logical for sugars to be added to only one end of amylopectin or glycogen, making them excellent molecules for glucose storage? a) Because there are many nonreducing ends on one molecule, allowing rapid glucose storage and release. b) Because it has the hemiacetal carbon, the one carbon to which more sugars can be attached. c) Because that end has the number 6 carbon, the one used to make the (alpha 1 -> 6) linkage. d) Because it is the reducing end, and a reduction reaction is the mechanism for adding the sugar. e) Because the other end of the molecule is anchored to a membrane with a lipid.

a) because there are many nonreducing ends on one molecule, allowing rapid glucose storage and release

The functional group shown is a(n) ________. a) hemiketal b) acetal c) hemiacetal d) carboxylic acid e)ketal

a) hemiketal

Which of the following is a heteropolysaccharides a) Hyaluronate b) Chitin c) Cellulose d) Glycogen e) Starch

a) hyaluronate

A laboratory is studying the binding properties of a glycoprotein on the plasma membrane. What amino acids should they analyze for the presence of branched heteropolysaccharides? a) Ser, Thr, and Asn b) Ser, Thr, and Tyr c) Lys, His, and Arg d) Trp, Tyr, and Phe e) Asp and Glu

a) ser, thr, and asn

Derivation of the MM equation requires an assumption of a "Steady state". This means what? a) the ES complex formation is very rapid relative to product formation b)the Km will be = to ½ Vmax c)the rate of the reaction reaches a constant value at high (s) d)there is no product present when the reaction begins E)the (s) effectively doesn't change

a) the ES complex formation is very rapid relative to product formation

According to the Michaelis-menten equation, what is the V/vmax ratio when (s)=4km? a)0.8 b)0.4 c)1.25 d)1.6 E)2.5

a)0.8

Which of the following Correctly identifies the sequence of events that occurs during muscle contraction? 1.myosin head attaches to an actin filament and Pi is released 2. ATP binds to myosin, disrupting the actin-myosin interaction 3. ATP is hydrolyzed and a conformation change moves the myosin head 4. The tail of the myosin is pulled toward the Z disk and ADP is released. a)2,3,1,4, b)2,1,3,4, c)4,2,1,3, d)3,2,4,1, e)2,3,4,1,

a)2,3,1,4,

A plasmid that is present in a small copy number in the bacterial cell and allows it to carry a larger fragment of cloned DNA than a regular plasmid is a)a bacterial artificial chromosome (BAC) b)a eukaryotic expression vector c)an yeast artificial chromosome (YAC) d)A bacteriophage e)None of the above

a)a bacterial artificial chromosome (BAC)

In the drawing below, the structures indicated by A and B are ____ and _____. a)actin, myosin thick filaments b)the myosin head, myosin thick filaments c)tropomyosin, troposin d)myosin thick filaments, actin filaments e)none of the above

a)actin, myosin thick filaments

Which of the following statements is true regarding hexokinase? a)hexokinase cant phosphorylate xylose although it can bind to it b)water is excluded from the active site of the enzyme c)all of the above d)for hexokinase, specificity is observed in the formation of the ES E)the only catalytic strategy used by hexokinase is that of induced fit

a)hexokinase cant phosphorylate xylose although it can bind to it

How do monoclonal antibodies differ from polyclonal antibodies? a)monoclonal antibodies are produced in cultured B cells b)polyclonal antibodies all bind to the same antigen site of a protein c)only the first two answers are correctmonoclonal antibodies bind to only one protein d)monoclonal antibodies bind to only one protein e)polyclonal antibodies are produced from identical B lymphocytes

a)monoclonal antibodies are produced in cultured B cells

Which of the following statements about the tense and relaxed conformation of hemoglobin is FALSE? a)o2 has a higher affinity for hemoglobin in the tense state b)the tense state is stabilized by a greater number of ion pairs than the relaxed state c)binding of o2 to a hemoglobin subunit in the tense state triggers a change in conformation to the relaxed state d)o2 can bind to hemoglobin in either the tense or relaxed conformation e)2,3BPG binding stabilizes T-state of hemoglobin

a)o2 has a higher affinity for hemoglobin in the tense state

Which of the following statements is ture regarding the kinetic properties of allosteric enzymes? a)the kenetic behavior of allosteric enzymes generally reflects cooperative interaction between multiple protein subunits b)plots of V0 vs. (S) in allosteric enzymes usually produce a hyperbolic saturation curve, typical of nonregulatory enzymes c)allosteric enzymes have a Km value d)allosteric enzymes do not exhibit saturation with the substrate when (s) is sufficient. E)none of the above

a)the kenetic behavior of allosteric enzymes generally reflects cooperative interaction between multiple protein subunits

Phosphoric acid is tribasic, with pKa of 2.14, 6.86, and 12.4. The ionic form that predominates at pH 3.2 is a) H3PO4. b) H2PO4(-) c) none of the above. d) PO4(3-) e) HPO4(2-)

b) H2PO4(-)

Which of the following is a reflection of the total energy change in a chemical reaction, a measure of the number and kinds of bonds that are made and broken? A) _G B) _H C) _S D) _E E) _T

b) _H

Chitin is a) found in insect and crustacean shells. b) All of the above. c) composed of N-acetylglucosamine subunits. d) found in fungi cell walls. e) composed of linear fibrils like cellulose.

b) all of the above

Which one of the following has the cellular components arranged in order of increasing size? a) Amino acid < protein < mitochondrion < ribosome b) Amino acid < protein < ribosome < mitochondrion c) Amino acid < ribosome < protein < mitochondrion d) Protein < amino acid < mitochondrion < ribosome e) Protein < ribosome < mitochondrion < amino acid

b) amino acid< protein< ribosome< mitochondrian

How are D and L assigned for carbohydrates? a) All naturally occurring carbohydrates are assigned D. All synthetic carbohydrates are assigned L. b) By examining the position of the hydroxyl group on the next-to-last carbon in the Fischer projection (D has hydroxyl on the right; L has hydroxyl on the left.) c) The aldoses are all D. The ketoses are all L. d) By matching to the R/S conventions (D=R; L=S) e) It is based on the optical rotation (D = dextrorotatory; L = levorotatory).

b) by examining the position of the hydroxyl group on the next-to-last carbon in the Fischer projection (D has hydroxyl on the right; L has hydroxyl on the left)

Which of the following atoms does not commonly form hydrogen bonds between or within biological molecules? a) All four atoms above commonly form hydrogen bonds. b) Carbon c) Oxygen d) Hydrogen e) Nitrogen

b) carbon

The structure of D-arabinose is shown below. How many stereoisomers are possible for this molecule (including the one shown)? a) Six b) Eight c) Four d)One e)Zero

b) eight

The structures of D-ribose and D-arabinose are shown below. These two molecules are a) carbomers b) epimers c) tautomers d) enantiomers e) anomers

b) epimers

What two weak interactions are most important in the formation of a cluster of lipid molecules in an aqueous solution? a) Hydrogen and ionic b) Hydrogen and hydrophobic c) Hydrophobic and van der Waal�s d) Ionic and van der Waal�s e) Ionic and hydrophobic

b) hydrogen and hydrophobic

What chemical feature determines if a sugar is an aldose or a ketose? a) The direction of rotation of polarized light b) The position of the carbonyl carbon c)The number of chiral carbons d) If the enantiomers resemble either glyceraldehyde or dihydroxyacetone e) If the epimers differ in configuration around one carbon or more than one carbon

b) the position of the carbonyl carbon

What function do enzymes actually perform in biochemical reactions? a) They increase the equilibrium of reactions. b) They increase the rate of reactions, but not the equilibrium. c) They increase the activation energy of reactions, causing them to be favorable, thermodynamically. d) They cause products to have higher free energy than reactants e) They facilitate the transformation of free energy into transition state energy.

b) they increase the rate of reactions, but not the equilibrium

What is the actual function of a buffer system such as acetate / acetic acid? a) To ensure that the solution has no free H+ or OH- within a specific range b) To keep the solution within one pH unit of the pKa c) To maintain the solution at the pKa d) To maintain the solution at neutral pH e) To maintain a constant pH in the event the concentration of an acid or alkali increases

b) to keep the solution within one pH unit of the pKa

If an uncatalyzed reaction occurs at a rate 2.5 x 10^-2 s^-1, and the enzyme catalyzed reaction occurs at a rate of 5.0 x 10^7 s^-1, what is the rate enhancement for this raction? a)2000000 b)200000 c)20000 d)100000 E)10000

b)200000

Which of the following stements is false regarding the binding of 2,3 BPG to hemoglobin? a)it is an example of heterotropic allosteric modulation b)BPG blood levels decrease in individuals shortly after they move from sea level to high altitudes c)BPG binds to hemoglobin in the cavity between the _ subunits in the T state d)it reduces the affinity of hemoglobin for oxygen e)foetus has low sensitivity to BPG

b)BPG blood levels decrease in individuals shortly after they move from sea level to high altitudes

which of the following statements regarding the effect of pH on o2 binding to hemoglobin is ture? a)o2 and H+ are bound at the same site in hemoglobin b)both o2 and h+ are bound by hemoglobin but with inverse affinity c)when the o2 concentration is low, hemoglobin bind 02 and release protons D)when the o2 concentration is high, h+ is bound and o2 is released e) none of the above

b)both o2 and h+ are bound by hemoglobin but with inverse affinity

Hydrolytic enzymes often have low activity at high pH and low activity at low pH, but have their greatest activity at neutral pH. Without a catalyst, present, hydrolysis is more rapid at high and low pH and very slow at neutral pH. How would you explain this apparent contradiction. a)all enzymes are only stable at neutral pH b)enzymes employ both general A-B groups that are in their optimal protonation state at neutral pH c)metal ions are required for the enzyme catalyzed reaction, and metal ions will only bind at neutral pH. d)in enzyme catalysis, water is not required as a nucleophile, so pH doesn't matter E)hydrolysis requires the presence of both OH- and H+ ions

b)enzymes employ both general A-B groups that are in their optimal protonation state at neutral pH

What effect does a competitive inhibitor have on Km and Vmax values? a)it changes the vmax, not the km b)it changes the km, not the vmax c)it changes both km and vmax d)it has no effect on these E)none are ture

b)it changes the km, not the vmax

A reaction with a _______ generates more product than substrate at equilibrium. a)large, + delta G b)large. - delta G c)delta G of 0 d)k'eq of 1 E)none of the above

b)large. - delta G

Which type of catalysis uses only H+ and OH- ions present in water? a)Metal ion catalysis b)specific acid-base catalysis c)covalent catalysis d)general acid-base catalysis e)none of the above

b)specific acid-base catalysis

Leghemoglobin is an oxygen-binding protein in root nodules that contain bacteria which fix atmospheric nitrogen. Which of the following is ture if leghemoglobin is like myoglobin, not hemoglobin? a)There are four oxygen binding sites b)the o2 binding curve is hyperbolic c)there is cooperative oxygen binding d)the o2 binding curve is sigmoidal e)o2 binding changes the heme configuration from T to R

b)the o2 binding curve is hyperbolic

The dimensions of living cells are limited, on the lower end by the minimum number of biomolecules necessary for function, and on the upper end by the rate of diffusion of solutes such as oxygen. Except for highly elongated cells, they usually have lengths and diameters in the range of: a) 0.1 μm to 10 μm. b) 0.3 μm to 30 μm. c) 0.3 μm to 100 μm. d)1 μm to 100 μm. e) 1 μm to 300 μm.

c) 0.3 to 100

Which of following is an anomeric pair? a) alpha-D-glucose and beta-L-glucose b) D-glucose and D-fructose c) alpha-D-glucose and beta-D-glucose d)D-glucose and L-glucose e)D-glucose and L-fructose

c) alpha-D-glucose and beta-D-glucose

Adding table sugar to iced tea and stirring it results in which of the following? a) An increase in enthalpy as heat moves into the sugar b)A decrease in free energy due to broken weak interactions between sugar molecules c) An increase in entropy as the sugar dissolves d)An increase in free energy because there is no longer a solvation layer around the sugar crystal e) A negative value for _S because the solute is more random

c) an increase in entropy as the sugar dissolves

Why are chitin and cellulose hydrophobic, and essentially insoluble in an aqueous media? a) Because there are no enzymes that can break the beta linkages. b)They form many inter and intramolecular hydrogen bonds forming a ridgid structure. c)Because beta-glycosidic linkages are nonpolar and alpha linkages are polar. d) Because the linear polymer cannot make hydrogen bonds. e) Polymers of these molecules pack so tightly together that there is no geometric space left for water.

c) because beta-glycosidic linkages are nonpolar and alpha linkages are polar

Which of the following is not a reason that it is difficult to study oligosaccharide composition from biological systems? a) There are no specific glycosidase enzymes that can be used to selectively digest oligosaccharides. b) Oligosaccharides are often branched. c) Oligosaccharides have too much conformational flexibility. d) Oligosaccharides have a variety of linkages (e.g., _1 -> 6 or _1 -> 4). e) Oligosaccharides often have a high negative charge density.

c) oligosaccharides have too much conformational flexibility

When a region of DNA must be repaired by removing and replacing some of the nucleotides, what ensures that the new nucleotides are in the correct sequence? a) DNA cannot be repaired and this explains why mutations occur. b) Specific enzymes bind the correct nucleotides. c) The new nucleotides base pair accurately with those on the complementary strand. d) The repair enzyme recognizes the removed nucleotide and brings in an identical one to replace it. e) The three-dimensional structure determines the order of nucleotides.

c) the new nucleotides base pair accurately with those on the complementary strand

Which of the following properties of water does not contribute to the fitness of the aqueous environment for living organisms? a) High heat of vaporization b) High specific heat c) the very low molecular weight of water d) Cohesion of liquid water due to hydrogen bonding e) The density of water is greater than the density of ice

c) the very low molecular weight of water

Which is the proper definition of equilibrium, with respect to a biochemical reaction? a) The entropy of the reaction is negative and the enthalpy of the reaction is positive. b) The free-energy change for the reaction is negative. c) There is no net change in reactant and product concentrations. d) The forward reaction is favored over the reverse reaction, and it proceeds. e) There is a constant rate at which reactant is converted to product.

c) there is no net change in reactant and product concentrations

If Vmax=100mM/Ml-sec and Km=8mM, what is the velovity of the reaction when (s)=12mM? a)300mM/mL-sec b)50 c)60 d)600 E)12.5

c)60

Elisa is a very useful technique for quantifying specific proteins in a complex mixture. One of the components used in ELISA is a secondary antibody attached to the enzyme Horseradish peroxidase (HRP). What is the purpose of the HRP is this assay? a)HRP is a colored enzyme, so when it binds you can see it b)HRP is the antigen to which the primary and secondary antibodies bind c)HRP is an enzyme that can convert certain colorless substates into colored products d)HRP protects the complex against hydrogen peroxide mediated degradation e)None of the above

c)HRP is an enzyme that can convert certain colorless substates into colored products

Amino acid residues commonly found in the middle of Beta true are? a)Ala and Gly b)hydrophobic c)Pro and Gly d)those with ionized R groups e)Two Cys

c)Pro and Gly

The hydrolysis of ATP by actin serves what function? a)power muscle contraction b)generates a membrane potential c)assembles actin filaments d)the first three choices are all correct e)only the first two are correct

c)assembles actin filaments

To serve as an effective regulatory mechanism, phosphorylation must: a)lead to enzyme activation b)lead to enzyme inhibition c)be reversible d)occure on a serine, but not a threonine E)all

c)be reversible

What contributes to CO being responsible for more than half of yearly deaths due to poisoning? a)it is present in the atmosphere at dangerously high levels b)it has approximently 1000x greater affinity for hemoglobin than oxygen c)hemoglobin bound to CO does not efficiently release O2 in the tissues d)CO is not toxic to humans e)all of the above

c)hemoglobin bound to CO does not efficiently release O2 in the tissues

Which of the following forms a hydrogen bond with O2, but it not one of the 6 coordination bonds with heme? a)His F8, the proximal His residue b)A nitrogen atom in the protoporphyrin ring c)his E7, the distal his residue d)Iron e)Phe CD1, which is at the same plane as the protporphrin ring

c)his E7, the distal his residue

There are two binding sites for acetylcholine on its receptor. What would be the shape of a hill plot if there was cooperativity of binding? a)Hyperbolic b)linear c)sigmoidal, with a sharp change in slope d)tow sigmoidal area linked together, one for each binding event e)two sigmoidal lines, one higher than the other on the graph

c)sigmoidal, with a sharp change in slope

At a (s) that is greater than the Km for the reaction, which is ture? a)Velocity is <Km b)velocity is < ½ vmax c)velocity is >1/2 vmax d) velocity is >km E)velocity is ½ vmax

c)velocity is >1/2 vmax

Examine the Fischer projection below. How is this carbohydrate classified? a) D enantiomer; aldohexose. b) Carbohydrates are not classified based on stereoisomerism c) D enantiomer; ketopentose. d) L enantiomer; ketopentose. e) L enantiomer; aldopentose.

d) L enantiomer; ketopentose

You want to maintain pH = 7.0 for an enzyme-catalyzed reaction that will produce hydrogen ions along with the desired product. At equal concentrations, which weak acid, if any, will serve as the better buffer for the reaction: Acid A, with pKa = 6.5 or Acid B, with pKa = 7.5? a) Both are equally effective. b) None of the above c) Acid B d) Acid A e) Water is as good as either of the acids available.

d) acid A

Hydrophobic interactions make important energetic contributions to: a) enzyme-substrate interactions. b) binding of a hormone to its receptor protein. c) membrane structure. d) All of the above are true. e) three-dimensional folding of a polypeptide chain.

d) all of the above are true

Which of the following statements about starch and glycogen is false? a) Glycogen is more extensively branched than starch. b) Amylose is unbranched; amylopectin and glycogen contain many (a1 � 6) branches. c) Both are homopolymers of glucose. d) Both serve primarily as structural elements in cell walls. e) Both starch and glycogen are stored intracellularly as insoluble granules.

d) both serve primarily as structural elements in cell walls

According to Oparin's theory for the origin of life, the prebiotic atmosphere: a) already contained some primitive RNA molecules. b) basically was very similar to the atmosphere of today. c) contained many amino acids. d) had an abundance of methane, ammonia, and water. e) was rich in oxygen.

d) had an abundance of methane, ammonia, and water

Which of the following is true about the properties of aqueous solutions? a)The pH can be calculated by adding 7 to the value of the pOH. b) A pH change from 5.0 to 6.0 reflects an increase in the hydroxide ion concentration ([OH-]) of 20%. c) Charged molecules are generally insoluble in water. d) Hydrogen bonds form readily in aqueous solutions. e) A pH change from 8.0 to 6.0 reflects a decrease in the proton concentration ([H+]) by a factor of 100.

d) hydrogen bonds form readily in aqueous solutions

What term is given to carbohydrates linked at their anomeric carbons? a) Glycans b) Anomers c) Glycosides d) Non-reducing sugars e) Hemiketals

d) non-reducing sugars

Which of the following conditions would cause red blood cells to burst due to excess water passing through the plasma membrane? a) Placing them in a solution of amphipathic molecules b) Adding a charged solute, such as NaCl c) Placing them in a solution of higher osmolarity than is present within the cells d)Placing them in a hypotonic solution e) Adding an isotonic solution to the cell suspension

d) placing them in a hypotonic solution

The catalog of all proteins functioning in a cell is the: a) metabolome. b) proteasome. c) lysosome. d) proteome. e) genome.

d) proteome

You have two bottles, each of which contains a white, crystalline substance. Your lab director tells you that one contains lactose and the other sucrose. Your job is to determine which bottle contains which sugar. Which procedure would you use? a) React each with bromine (Br2) water. Only sucrose will react. b) Test both for solubility in water. Sucrose is very soluble; lactose is only minimally soluble. c) There is no test to resolve sucrose from lactose because they are same. d) Test for the ability to reduce Ag+. Only lactose will react. e) Dissolve each in water and record the pH. Lactose is far more acidic than sucrose.

d) test for the ability to reduce Ag+. only lactose will react

Water dissociation can be represented by an equilibrium expression. What term from that expression is missing from the ion product of water? a) R, the Gas Constant b) A term containing a log value c) T, the temperature of the reaction d) The concentration of water e) The concentration of H+

d) the concentration of water

When two carbohydrates are epimers: a) they rotate plane-polarized light in the same direction b) they differ in length by one carbon. c) one is a pyranose, the other a furanose. d) they differ only in the configuration around one carbon atom. e) one is an aldose, the other a ketose.

d) they differ only in the configuration around one carbon atom

What effect does the binding of CO2 and H+ to hemoglobin in the peripheral tissues have on the body? a)the tense from of hemoglobin is stabilized by the binding of CO2 and H+ b)binding of H+ to hemoglobin serves as a buffer to regulate the pH of peripheral tissues c)it facilitates the release of O2 in the peripheral tissues d)All of the above

d)All of the above

The ________ immune system destroys host cells infected by viruses and also destroys some parasites and foreign tissues and relies on______ for he immune response. a)Cellular, B lymphocytes b)humoral, B lymphocytes c)humoral, T lymphocyes d)Cellular, T lymphocytes e)None of the above

d)Cellular, T lymphocytes

During muscle contration: a)sarcomeres become progressively shorter b)thick and thin filaments slide past each other c)Z disks in neighboring I bands draw closer together d)all of the above e)none of the above

d)all of the above

If Hb and Mb both had the same P50, but Hb bound O2 with positive cooperativity, what can we say about the two proteins? a)at PO2 above P50, hb and Mb have the same___ b)at po2 below p50, hb has a higher ---than Mb c)at PO2 equal to p50, hb has a higher—than Mb d)at po2 above p50, hb has a higher—than Mb e)po2 about p50, hb has a lower—than Mb

d)at po2 above p50, hb has a higher—than Mb

Which of the following does not play a role in stabilizing the interaction between an antibody and its antigen? a)hydrogen bonds b)van der waals interaction c)ionic interaction d)covalent bonds e)non-covalent

d)covalent bonds

The particular chemical group or groups in a macromolecule to which a given antibody binds is best defined as the: a)hapten b)receptor c)antigen d)epitope e)protogen

d)epitope

Which stement about P50 for myoglobin is Not True? a)it is numerically equal to the equilibrium constant for the oxygen dissociation b)it is a measure of the affinity of myoglobin for oxygen c)it Is defined as that oxygen partial pressure at which half of the oxygen binding sites are occupided d)if __ >p50, then myoglobin is less than 50% saturated with oxygen e)all of these are ture

d)if __ >p50, then myoglobin is less than 50% saturated with oxygen

What is the definition of Km, the michaelis constant? a)The rate at which enzyme is turning substrate into product at 1/2 Vmax b)the V0 at 1/2 maximal (s) c)the number of molecules of substrate converted to product per sec d)the concentration of substrate at which the enzyme is operating at half is Vmax e)The V0 of the enzyme when (S)<<Km

d)the concentration of substrate at which the enzyme is operating at half is Vmax

The amide bond in a protein has a - DG of hydrolysis under physiological conditions in the cell. The peptide bond is thermodynamically unstable ,yet proetins do not fall apart. Why? a)in the cell, proteins arnt exposed to H2O, so hydrolysis cant occur b)the proteins do just rapidly fall apart, the cell just makes more c)the high concentration of free AA in the cell shifts the equilibrium of the hydrolysis d)the transition state energy for hydrolysis is very high, so the rate of hydrolysis is low E)other enzymes in the cell protect the amide bonds

d)the transition state energy for hydrolysis is very high, so the rate of hydrolysis is low

Molecules that differ in configuration can be all of the following, except: A) stereoisomers. B) cis-trans isomers. C) chiral centers that are mirror images of each other. D) enantiomers. E) chiral centers that can be interchanged by rotation of a single bond.

e

Which O-glycosidic bond is commonly found in amylose, amylopectin and glycogen? a) (beta 1 -> 4) b) (alpha 1 -> 6) c) (alpha 1 ->3) d)(beta 1 -> 6) e) (alpha 1 -> 4)

e) (alpha 1-> 4)

Which of the following gases are nonpolar and are very poorly soluble in water? a) None of the above b) NO c) H2S d) NH3 e) CO2

e) CO2

Cellulose is not highly branched because it a) does not have beta 1->4 linkages. b) All the choices are correct c) is insoluble in water. d) does not have a polysaccharide backbones e)does not have alpha 1->6 linkages.

e) does not have alpha 1-> 6 linkages

In what area of the titration curve for carbonic acid (H2CO3) is the molecule fully deprotonated? a) At the second pKa value, given there are two deprotonations b) Far left c) At the center, at the pKa d) In the area about 1 pH unit higher than the pKa e) Far right

e) far right

The pH of a sample of blood is 7.4, while gastric juice is pH 1.4. The blood sample has: a) 6 times lower [H+] than the gastric juice. b) 6000 times lower [H+] than the gastric juice. c) 0.189 times the [H+] as the gastric juice. d) 5.29 times lower [H+] than the gastric juice. e) one million times lower [H+] than the gastric juice.

e) one million times lower [H+] than the gastric juice

The enzyme fumarase catalyzes the reversible hydration of fumaric acid to l-malate, but it will not catalyze the hydration of maleic acid, the cis isomer of fumaric acid. This is an example of: a) biological activity. b) chiral activity. c) racemization. d) stereoisomerization. e)stereospecificity.

e) stereospecificity

I need to calculate the pH of a weak acid. I know the concentration of the acid and its conjugate base, and my solution is at 30 C. What else do I need? a) All that is needed has been given. b) The free-energy change for release of the H+ c) The total H+ concentration (i.e., free and bound to the acid) d) Kd for H+ of the acid e) The pKa of the acid

e) the pKa of the acid

The three-dimensional structure of a protein is determined primarily by: a) electrostatic guidance from nucleic acid structure. b) how many amino acids are in the protein. c) hydrophobic interaction with lipids that provide a folding framework. d) modification during interactions with ribosomes. e) the sequence of amino acids in the protein.

e) the sequence of amino acids in the protein

Which of the following classes of immuoglobulins is the first to be made by B lymphocytes and the major antibody to be produced in the early states of a primary immune response? a)IgA b)IgE c)IgG d)IgH e)IgM

e)IgM

Hemoglobin can assist with blood buffering. Which of the following does not contribute to buffering through hemoglobin and the bohr effect? a)the action of carbonic anhydrase b)H+ binding to various His Residues c)formation of bicarbonate from carbon dioxide d)heme decreases affinity for oxygen as both carbon dioxide and H+ increase e)binding H+ on carbamino-terminal residues of hemoglobin

e)binding H+ on carbamino-terminal residues of hemoglobin