Exams
Which of the following correctly represents a protein backbone? A. -Ca-C-N-Ca-C-N- B. -N-Ca-N-C-N-Ca- C. -C-N-Ca-N-C-N- D. -C-Ca-N-C-Ca-N-
A. -Ca-C-N-Ca-C-N-
In an α-helix, the R groups on the amino acid residues: A. are found on the outside of the helix spiral. B. alternate between inside and outside of the helix. C. cause only right-handed helices to form. D. generate the hydrogen bonds that form the helix.
A. Are found on the outside of the helix spiral.
Which of the following statements about motifs is false? A. β barrels can be made from a combination of β-strands and α-helices B. proteins are classified as α, β or α/β. C. A Greek key motif is composed of 4 consecutive β-strands that fold to form an antiparallel β-sheet. D. motifs are combinations of secondary structures.
A. Beta barrels can be made from a combination of B-strands and a-helices.
The first step in sequencing a protein is: A. break the disulfide bonds between polypeptide chains B. send labeled amino acid off for chromatography C. treat with trifluoroacetic acid (TCA) D. react with edman's reagent
A. Break the disulfide bonds between polypeptide chains
Which of the following statements about oxygen bound to myoglobin is correct? A. It is the sixth coordination link to the heme iron B. forces alpha helices to convert to beta sheets C. oxidizes the histidine in the F helix D. causes reversible oxidation of Fe (II) to Fe (III)
A. It is the sixth coordination link to the heme iron.
Why are hydrogen bonds so important to biochemistry? A. There are several which add up to significant contributions of strength B. They are the strongest covalent bond C. Every molecule participates in them D. They don't require electrons
A. There are several which add up to significant contributions of strength.
Which of the following statements about molecular chaperones is false? A. They bind misfolded proteins via electrostatic interactions B. some act during protein transportation. C. some act during protein synthesis to prevent improper folding D. they can help shuttle proteins across membranes and prevent improper aggregation
A. They bind misfolded proteins via electrostatic interactions.
Which amino acid has a side chain pKa of 10.46? A. Tyr B. Cys C. Phe D. Lys
A. Tyr
What is the net charge of gly at pH 7.0? Assume the pKa of -NH3+ is 9.2 and pKa of -COOH is 2.1. A. +1 B. 0 C. +2 D. -1
B. 0
Calculation the pH of a solution made by diluting 30 mL of 2.5 M HCL in water to a final volume of 1000 mL pH = -log[H+] Ka = [H+][A-]/[HA] pH = pKa + log ( [A-]/ [HA] ) A. 0.012 B. 1.12 C. 7.5 D. 4.77
B. 1.12
Calculate the pH of a solution that contains 3 times as many moles of HA as A- and has a pKa of 4.76 pH = -log[H+] Ka = [H+][A-]/[HA] pH = pKa + log ( [A-]/ [HA] ) A. 3.08 B. 4.28 C. 5.23 D. 5.11
B. 4.28
Which pH is closest to neutral pH? A. 8.7 B. 6.7 C. 7.7 D. 5.7
B. 6.7
A strong acid ionizes __________________ while a weak acid ionized ________________. A. Partially, completely B. Completely, partially C. Into OH- and a salt ion, into H+ and a salt ion D. Less than 10 %, more than 10 %
B. Completely, partially
Which amino acid has a side chain pKa of 8.37? A. Tyr B. Cys C. His D. Met
B. Cys
The following reaction is nonspontaneous when it occurs at 300 K. The S for the reaction is -75 J mol-1 K-1 and the H is -15,000 J mol-1. Does the temperature need to be increased or decreased to make the reaction spontaneous? A. Increased B. Decreased
B. Decreased
What is denaturation? A. Loss of polypeptide sequence B. Disruption in the structure C. Cleavage of polypeptide sequence (polypeptide is cut) D. Impure polypeptide samples
B. Disruption in the structure
The amino acid composition is more important than the sequence of amino acids. A. True B. False
B. False
Which of the following organelles is responsible for coordination protein movement? A. Peroxisomes B. Golgi complex C. Nucleus D. Ribosomes
B. Golgi complex
Which of the following statements describes an important difference between hemoglobin (Hb) and myoglobin (Mb)? A. Each chain in Hb contains a heme prosthetic group B. Hb is a heterotetramer containing 2 alpha and 2 beta chains C. Hb does not bind CO D. Hb binds oxygen more tightly than Mb E. The polypeptide chains of Hb are folded mostly into α-helices
B. Hb is a heterotetramer containing 2 alpha and 2 beta chains.
The center of globular proteins is composed of non-polar residues due to the A. van der Waals interactions B. hydrophobic effect C. favorable electrostatic interactions D. hydrogen bonds
B. Hydrophobic effect.
When OH- is added to a buffer, what happens to the concentration of the conjugate base (A-)? A. Not enough information B. Increases C. Remains the same D. Decreases
B. Increases
Which of the following amino acids has a sulfur in the R group? A. Leu B. Met C. Pro D. Val
B. Met
A reaction is spontaneous when Gibbs free energy (G) is A. Equal to 0 B. Negative C. Not enough information D. Positive
B. Negative
In cation exchange chromatography, the resin is: A. Neutral B. Negatively charged C. Hydrophobic D. Positively charged
B. Negatively charged
Define primary structure A. Small, recognizable structures B. Multiple polypeptide chains folded together C. Amino acid sequence D. All structures of polypeptide folded together
C. Amino acid sequence
Hydronium ion is formed when A. A water molecule is deprotonated B. A hydroxide molecule accepts a proton C. An additional proton is accepted by a water molecule D. A sodium molecule accepts a proton
C. An additional proton is accepted by a water molecule.
Which of the following amino acids is not capable of forming an isopeptide bond? A. Lys B. Glu C. Gln D. Asp
C. Gln
Which of the following interactions is most responsible for the maintenance of protein secondary structure? A. Hydrophobic interactions B. van der Waals forces C. Hydrogen bonds D. Disulfide cross-links E. Salt bridge
C. Hydrogen Bonds
Which of the following functional groups has a positive formal charge? A. Phosphoryl group B. Carboyxlate C. Imino group D. Carboxyl group
C. Imino group
Aggregation of non-polar molecules in an aqueous solution _______________ net entropy of the system. A. Not enough information B. Decreases C. Increases D. Does not change
C. Increases
The pH at which a polypeptide carries no charge is called: A. ½ equivalence point B. pKa C. Isoelectric point D. No-charge point
C. Isoelectric point
A new peptide was sequenced after digestion with Theromlysin and Elastase . Using the following peptides, determine what the N terminal amino acid is Elastase 1. Glu 2. Leu-Ser 3. Pro-Trp-Tyr-Gly-Val 4. Arg-Asp-Gly-Ile-Gly Thermolysin 1. Trp 2. Tyr 3. Gly-Val-Glu 4. Ile-Gly-Pro 5. Leu-Ser-Arg-Asp-Gly A. Ile B. Gly C. Leu D. Glu
C. Leu
Which of the following statements about structure is true? A. all globular proteins have quaternary structure B. all fibrous proteins have quaternary structure. C. only proteins with more than one subunit have quaternary structure D. Only proteins with two or more globular domains have quaternary structure
C. Only proteins with more than one subunit have quaternary structure
Monosaccharides are the monomers that make up which biological polymer? A. Proteins B. Nucleotides C. Polysaccharides D. Polypeptides
C. Polysaccharides
In a protein, which amino acid is considered the most conformationally restricted? A. Gly B. His C. Pro D. Gln
C. Pro
Which of the following organelles are responsible for synthesizing proteins? A. Golgi complex B. Nuclear envelope C. Ribosomes D. Mitochondrion
C. Ribosomes
Which level of structure is defined as local spatial arrangements of the protein backbone? A. quaternary structure B. primary structure C. secondary structure D. tertiary structure
C. Secondary structure
A reaction that occurs without input of additional energy from outside the system is called A. Nonspontaneous B. Enthalpic C. Spontaneous D. Entropic
C. Spontaneous
A protein is least soluble when: A. pH < pI B. pH > pI C. pH = pI
C. pH = pI
Which side chain below is aspartic acid? A. -CH2SH B. -CH2CH2COOH C. -CH2 CH2CH2CH2NH2 D. -CH2COOH
D. -CH2COOH
Which of the following R groups below is alanine? A. -CH2(CH3)2 B. -H C. -CH2CH3 D. -CH3
D. -CH3
What is the net charge of histidine at pH 7.0? Assume the pKa of -NH3+ is 9.2 and pKa of -COOH is 2.1. A. +2 B. -1 C. +1 D. 0
D. 0
What is the number of moles of A- needed to make a buffer that has a pH of 8.70, a pKa of 8.30 and has 0.1 moles of HA. pH = -log[H+] Ka = [H+][A-]/[HA] pH = pKa + log ( [A-]/ [HA] ) A. 1.2 moles A- B. 0.3 moles A- C. 0.1 moles A- D. 0.25 moles A-
D. 0.25 moles A-
At what molar ratio of [A-] to [HA] is the pH equal to the pKa? A. 0.5 [A-] to 1 [HA] B. 1 [A-] to 2 [HA] C. 2 [A-] to 1 [HA] D. 1 [A-] to 1 [HA]
D. 1 [A-] to 1 [HA]
Consider that a hydrogen bond requires a weekly acidic donor and a weakly basic acceptor, how many donors and acceptors, respectively, does 1 water molecule have? A. 1 donor, 2 acceptors B. 2 donors, 1 acceptor C. 1 donor, 1 acceptor D. 2 donors, 2 acceptors
D. 2 donors, 2 acceptors
What is the biochemical definition of steady state conditions? A.32 C and pH 7 B. 38 C and pH 7 C. 25 C and pH 5.7 D. 25 C and pH 7
D. 25 C and pH 7
How does fetal hemoglobin (Hb F) differ from normal adult hemoglobin (Hb A)? A. Hb F has a greater affinity for CO. B. Hb F has a greater tendency to associate in the deoxygenated state. C. An alpha chain lysine residue in Hb A is replaced with a neutral amino acid in Hb F. D. A histidine residue in Hb A is replaced with a neutral amino acid in Hb F.
D. A histidine residue in Hb A is replaced with a neutral amino acid in Hb F.
Which of the following statements about conversion from T to R state is incorrect? A. BPG binding is reduced by a factor of 100 fold. B. Movement of the proximal histidine pulls several other residues in the F helix along with it. C. The iron atom moves into the plane of the protoporphyrin IX ring. D. A smaller central cavity is formed when subunits displace
D. A smaller central vanity is formed when subunits displace.
Which pair of amino acids below would interact through electrostatic interactions at pH 7.0? A. Lys & Arg B. Gly & Lys C. Arg & Gln D. Glu & Lys
D. Glu & Lys
Water organized around a substance is called a __________. A. Water cage B. Water log C. Water layer D. Hydration shell
D. Hydration shell
Which of the following statements about fibrous proteins is false? A. each strand of the protein chain in collagen is a left-handed helix. B. collagen sequence has uncommon amino acids that are derived after protein synthesis C. keratin has a pseudo repeat sequence of a-b-c-d-e-f-g where a and d are non-polar residues D. keratin is a triple helix with individual right-handed helices and left-handed coiled helices.
D. Keratin is a triple helix with individual right-handed helices and left-handed coiled helices.
Which of the following amino acid combinations will have the least ability to stabilize tertiary structure? A. Cys and Glu B. Glu and Lys C. Ile and Val D. Lys and Arg
D. Lys and Arg
Hyper variable region has the sequence Ala-Leu-Gly-Asn-Ile. What property would you expect an antigen to have for favorable binding at pH 7. A. positively charged B. polar C. negatively charged D. non-polar
D. Non-Polar
When the pH is below the pKa, the functional group will always be A. charged B. neutral C. deprotonated D. protonated
D. Protonated
What would be the result if a protein was treated with a chaotropic agent? A. the stability would increase due to hydrophobic collapse. B. Non-polar portions of the protein would solubilize and force a 'refolding' C. Alterations to the formal charges of the side chains would force the protein to adopt a random coil structure. D. The protein would denature, and the non-polar portions would become more soluble
D. The protein would denature, and the non-polar portions would become more soluble.
Which of the following statements about heme properties is correct? A. The fifth coordination position of the Fe+2 is occupied by the distal histidine residue. B. The heme iron is oxidized as it binds O2. C. The heme in sickle cell hemoglobin is unable to bind O2. D. In deoxyhemoglobin, the sixth coordination position of heme is occupied by water. E. Fe has six coordination positions, four of which are occupied by the nitrogen atoms of the porphyrin ring.
E. Fe has six coordination positions, four of which are occupied by the nitrogen atoms of the porphyrin ring.
Which of the following forces does not contribute to protein stability. A. hydrophilic affect B. electrostatic interactions C. disulfide bonds D. metal ions
A. Hydrophilic affect
Which of the following is not a change in hemoglobin that occurs due to the binding of molecular oxygen? A. The heme moves into the hydrophobic pocket of hemoglobin B. Fe(II) moves into the plane of heme C. the F helix is pulled by movement of the Fe(II) cause a shift in its position within the subunit D. the interface between protomers (α1β1 and α2β2) shifts
A. The heme moves into the hydrophobic pocket of hemoglobin.
A peptide bond is formed by a ____ reaction between two amino acids. A. Claisen B. Hydrolysis C. Condensation D. Hydrogenation
C. Condensation
What is the net charge of lysine at pH 11.0? Assume the pKa of -NH3+ is 9.2 and pKa of -COOH is 2.1. A. 0 B. +1 C. +2 D. -1
D. -1
A test that is highly specific for a target protein is called A. Chromatography B. Spectroscopy C. Electrophoresis D. Assay
D. Assay
Which of the following statements about secondary structures is true? A. it is not possible to substitute amino acids without disrupting the function of the protein. B. loops and turns which connect secondary structures usually occur in the center of the protein. C. Nonpolar residues are only found near the N and C terminus of the protein. D. Coils are unique and irregular structures and are considered a type of secondary structure.
D. Coils are unique and irregular structures and are considered a type of secondary structure.
Calculate the mL of a o.1 M HA and 0.1 M A- needed to make a buffer with a final volume of 0.1 L, a final concentration of 0.1 M, and a pH 6.7. The pKa of the buffer is 7.21 pH = -log[H+] Ka = [H+][A-]/[HA] pH = pKa + log ( [A-]/ [HA] ) A. 24 mL A- and 76 mL HA B. 2.4 mL A- and 97.6 mL HA C. Correct Answer is not listed D. 76 mL A- and 24 mL HA E. 97.6 mL HA and 2.4 mL A-
A. 24 mL A- and 76 mL HA
What is the pI of gly? Assume the pKa of -NH3+ is 2.1 and pKa of -COOH is 9.2. A. 3.09 B. 2.92 C. 5.65 D. 4.09
C. 5.65
An atom or group responsible for a compound's color is called a A. Resin B. Ion C. Assay D. Chromophore
D. Chromophore
Match the amino acid with the side chain location: Interior, surface, interior or surface Met His Asn
Met: Interior His: Surface Asn: Surface or interior
Which of the following is not one of the four major levels of protein structure? A. domain structure B. secondary structure C. primary structure D. quaternary structure E. tertiary structure
A. Domain structure
Which of the following polypeptides is least likely to form a beta strand? A. Ser-Glu-Asp-Asn-Phe-Gly-Ala-Pro-Lys-Ser-Ile-Leu-Trp B. Gln-Lys-Ala-Ser-Val-Glu-Met-Ala-Val-Arg-Asn-Ser-Gly C. Cys-Arg-Ala-Gly-Asn-Arg-Lys-Ile-Val-Leu-Glu-Thr-Tyr
A. Ser-Glu-Asp-Asn-Phe-Gly-Ala-Pro-Lys-Ser-Ile-Leu-Trp
Which of the statements about dialysis is true? A. It is the movement of something from low to high concentration B. It is the movement of water and solutes across a a membrane C. It is the movement of only water across the membrane D. It is the movement of only solutes across a membrane
B. It is the movement of water and solutes across a membrane.
Which of the following statements about water is false? A. It interacts via hydrogen bonds B. Water is a non-polar molecule C. It is a bent molecular geometry D. It is a tetrahedral electron geometry
B. Water is a non-polar molecule.
There is a limited size of polypeptides that are observed in biological organism. Which of the following is not a reason why this is observed? A. Beyond 1000 residues, more likely to have errors and efficiency is lost B. All of these are reasons for limited polypeptide size C. Characteristics of proteins are only dependent on amino acid composition favoring smaller polypeptides D. There is a minimum of 40 amino acids needed for discrete, stable folding
C. Characteristics of proteins are only dependent on amino acid composition favoring smaller polypeptides.
Mass spectrometry can help in protein sequencing by measuring: A. measuring the mass of the polypeptide B. measuring the charge to flight ratio C. the mass to charge ratio (m/z) D. measuring the electrospray ionization
C. The mass to charge ratio (m/z)
How many PKA's does the tripeptide valine-histidine-tryptophan have A. 2 B. 1 C. 4 D. 3
D. 3
IgG is one the of the five classes of antibodies. What is their subunit composition? A. 2 heavy chains and 2 light chains B. 4 heavy chains and 4 light chains C. 2 heavy chains and 4 light chains D. 4 heavy chains and 2 light chains
A. 2 heavy chains and 2 light chains
What is the pI of the dipeptide tyr-pro? Assume the pKa of -NH3+ is 2.1 and pKa of -COOH is 9.2. A. 5.97 B. 10.48 C. 9.32 D. 3.49
A. 5.97
Which of the following peptide segments is most likely to form an α helix? A. -Phe-Arg-Lys-Trp-Lys-Gln-His- B. -Met-Glu-Ile-Val-Trp-Lys-Leu-Ala- C. -Phe-Tyr-His-Pro-Glu-Gln-Lys- D. -Gly-Cys-Val-Leu-Ile-Gly-Trp-
B. -Met-Glu-Ile-Val-Trp-Lys-Leu-Ala-
Which of the following correctly describes why antiparallel B sheets are more stable than parallel B sheets? A. R groups are more favorably positioned in antiparallel sheets compared to parallel B. the backbone of antiparallel sheets are more rigid than the backbone of parallel sheets C. additional stabilization occurs from the alignment of the carboyxl terminus of one B sheet with the amino terminus of the neighboring B sheet D. the hydrogen bonding distance and angles are optimal
D. The hydrogen bonding distance and angles are optimal.
Which of the options below is a naturally occurring constraint on the formation of a β-strand? A. a Pro residue B. a positively charged Lys residue C. two nonpolar residues side by side D. negatively charged Arg residue
A. A Pro residue
Proteins are made from which monomer? A. Amino acids B. Monosaccharides C. Nucleotides D. Nucleic acids
A. Amino acids
Micelles are formed from A. Amphiiphilic compounds with a single nonpolar tail B. Amphiphilic compounds with two nonpolar tails C. Hydrophobic small molecules D. Hydrophilic small molecules
A. Amphiphilic compounds with a single non-polar tail.
Which type of amino acids have absorbance that can be used to quantify them? A. Aromatic B. Charged C. Hydrophilic D. Hydrophobic
A. Aromatic
A new peptide was digested using glutamyl peptidase (cleaves C side of Glu) and Elastase (cleaves C side of Val and Ala). The following peptides were generated: Glutamyl peptidase: 1. His-Ala-Lys-Pro-Glu 2. Arg-Val-Ile-Phe-Trp-Glu 3. Val-His-Tyr-Glu Elastase: 1. His-Ala 2. His-Tyr-Glu 3. Ile-Phe-Trp-Glu-Val 4. Lys-Pro-Glu-Arg-Val A. His-Ala-Lys-Pro-Glu-Arg-Val-Ile-Phe-Trp-Glu-Val-His-Tyr-Glu B. Trp-Glu-Val-His Tyr-Glu-His-Ala-Lys-Pro-Glu-Arg-Val-Ile-Phe- C. Not enough information to solve D. Arg-Val-Ile-Phe-Trp-Glu-Val-His- is-Ala-Lys-Pro-Glu-Tyr-Glu
A. His-Ala-Lys-Pro-Glu-Arg-Val-Ile-Phe-Trp-Glu-Val-His-Tyr-Glu
Which of the following statements about hemoglobin conformations is false? A. the T state of hemoglobin has a higher affinity for O2 B. the R state of hemoglobin has higher affinity for O2 C. the T state of hemoglobin is deoxyhemoglobin D. the R state of hemoglobin is oxyhemoglobin
A. The T state of hemoglobin has a higher affinity for O2.
As the concentration of {H+] in solution increases, which of the following statements are true? Select all that apply A. The concentration of [OH-] decreases B. The concentration of [OH-] increases C. The pH increases D. The pH decreases
A. The concentration of [OH-] decreases & D. the pH decreases
Under which of the following conditions will hemoglobin bind less oxygen? A. The oxygen pressure increases from 500 mm to 1000 mm B. The pH increases from 7.0 to 7.2 C. The BPG is removed D. The concentration of carbon dioxide increases
D. The concentration of carbon dioxide increases.
Proteins are eluted from ion exchange columns by the addition of A. High concentration substrate solution B. High salt concentration solution C. Changing the temperature of the column D. Low salt concentration solution
B. High salt concentration solution
Sickle cell hemoglobin differs from normal hemoglobin by a Val on the B-chain in place of a Glu. What would be the best procedure for separating the two forms of hemoglobin in the lab? A. gel-filtration chromatography B. ion exchange chromatography C. salting out procedures D. differential centrifugation
B. Ion exchange chromatography
Under which of the following conditions would hemoglobin have the highest affinity for oxygen? A. High bisphosphoglycerate and low pH B. Low bisphosphoglycerate and high pH C. Low bisphosphoglycerate and low pH D. Low bisphosphoglycerate and low pH and high CO
B. Low biphosphoglycerate and high pH
The pressure that must be applied to equalize the flow of water across a membrane in both directions is called A. Reverse pressure B. Osmotic pressure C. Flow pressure D. Osmond pressure
B. Osmotic pressure
Which statement correctly describes oxygen binding to hemoglobin? A. The binding of the first oxygen molecule has no effect on the binding of the remaining three oxygen molecules E. Each successive oxygen bound makes the remaining sites less likely to bind oxygen B. The binding of the first oxygen molecule enhances the binding of the other three oxygen molecules C. Each of the four oxygens bind with equal facility D. The binding of the first oxygen molecule makes the binding of the other three oxygen molecules more difficult
B. The binding of the first oxygen molecule enhances the binding of the other three oxygen molecules.
Consider a mutant hemoglobin that has a hill coefficient of 1 and p50 value that is lower than normal hemoglobin. Choose the statement below that best describes the two proteins. A. there is a cooperative interaction between oxygen binding sites in both the hypothetical and normal hemoglobin B. the hypothetical hemoglobin has a greater oxygen affinity than normal hemoglobin C. the oxygen binding curve for the hypothetical hemoglobin is hyperbolic, and the curve for the normal hemoglobin is sigmoidal. D. the two hemoglobin would be able to deliver the same amount of oxygen to the tissues.
B. The hypothetical hemoglobin has a greater oxygen affinity than normal hemoglobin. C. The oxygen binding curve for the hypothetical hemoglobin is hyperbolic, and the curve for the normal hemoglobin is sigmoidal.
A reaction has a H of -2,100 and a S of -45 J K-1 mol-1 at 298 K. Which of the following statements about the reaction is true? G = H - TS G = -RTlnKeq G = G+RTlnKeq Keq = [products]/[reactants] R = 8.314 J mol-1 K-1 A. The reaction is at equilibrium (delta G = 0) B. The reaction is nonspontaneous C. The reaction will be spontaneous at hotter temperatures D. The reaction is spontaneous
B. The reaction in non spontaneous.
Which of the following statements correctly describes the β-sheet? A. amino acid side chains are located above the sheet in parallel configuration B. the sheets have a pleated edge on appearance (zigzag like) C. amino acid side chains are located below the sheet in parallel configuration D. the sheets are antiparallel when buried in the center of the protein and antiparallel when on the surface
B. The sheets have a pleated edge on appearance (zigzag like).
What is the actual free energy change for the reaction X+Y Z occurring at 300 K, when [X] = 100 mM, [Y] = 50 mM and [Z] = 25 mM? The standard change in free energy for the reaction is -17,000 J mol-1. G = H - TS G = -RTlnKeq G = G+RTlnKeq Keq = [products]/[reactants] R = 8.314 J mol-1 K-1 A. -21,014 J mol^-1 B. - 11, 722 J mole^-1 C. -12,986 J mol^-1 D. - 1,986 J mol^-1
C. -12,986 J/mol
What is the equilibrium constant for a reaction that has a standard change in free energy of 65 J mol-1 and happens at 273 K? G = H - TS G = -RTlnKeq G = G+RTlnKeq Keq = [products]/[reactants] R = 8.314 J mol-1 K-1 A. 1.97 B. 0.029 C. 0.97 D. 1.03
C. 0.97
Which of the following is part of the general structure of alpha amino acids? A. R group B. Alpha carbon C. All of the above D. Alpha amino group E. Carboxyl group F. Hydrogen
C. All of the above
Which statement about 3° structure determination is false? A. NMR spectroscopy is only applicable for proteins under 100 kDa in size. B. In X-ray crystallography, the structure is elucidated from electron scattering patterns C. X-ray crystallography requires samples be dried in crystals which can be difficult D. Cryo-EM is most suitable for measuring very small proteins.
D. Cryo-EM is most suitable for measuring very small portions.
The _______________ law of thermodynamics states that energy is neither created nor destroyed. A. Third law of thermodynamics B. Fundamental C. Second D. First
D. First
What does it mean when scientists say organisms are open systems? A. They use enzymes to slow down increases in B. Small molecules can enter and exit organisms as needed C. They cannot contain any energy D. They are never at equilibrium
D. They are never at equilibrium.