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Building Blocks Chapter 1-5

Terms in this set (118)

All amino acids are formed by the amination of _____________
A. Sugars
B. Keto acids
C. Short-chain fatty acids
D. Esters
B.
Which amino acid is formed on a t-RNA?
A. Tryptophan
B. Selenocysteine
C. Methionine
D. Alanine
B.
All amino acids have an R group. What is the significance of the R?
A. Each of the 21 amino acids has a unique R group
B. Proline and glycine are the only amino acids without an R group
C. All R groups have charge
D. Not all R groups are bound to the alpha carbon
A.
At neutral pH, all amino acids are _____________
A. Uncharged, and non-reactive
B. Deprotonated at the carboxylic acid
C. Protonated at the amine group
D. Zwitterionic, with both the amine and carboxylic acids charged
D.
Of the following amino acids, whose R group has charge?
A. Leucine, valine, tryptophan
B. Arginine, glycine, isoleucine
C. Methionine, cysteine, alanine
D. Arginine, lysine, glutamate
D.
Which of the following amino acids does not have chirality?
A. Alanine
B. Cysteine
C. Glycine
D. Proline
C.
Which are branched chain amino acids?
A. Methionine, cysteine, alanine
B. Tyrosine, tryptophan, phenylalanine
C. Serine, glycine, threonine
D. Isoleucine, leucine, valine
D.
Which amino acids' R groups are basic?
A. Aspartate and glutamate
B. Lysine, arginine and histidine
C. Isoleucine, leucine and valine
D. Cysteine, methionine and selenocysteine
B.
Which amino acids have aromatic R groups?
A. Phenylalanine, tryptophan and tyrosine
B. Arginine, histidine and lysine
C. Alanine, glycine and proline
D. Serine, threonine and tyrosine
A.
The major use of methionine is in
A. Protein synthesis
B. Forming cysteine through the transulfuration pathway so it is a non-essential amino acid
C. Adenylylation of methionine by ATP to form S'adenosylmethionine
D. Formation of polyamines
C.
The unique amino acid found in the elastin protein is
A. Ornithine
B. S'Adenosylmethionine
C. Desmosine
D. Carboxyglutamic acid
C.
What statement best describes the pathway that forms Selenocysteine?
A. A swap of selenide for sulfur in the R group of cysteine
B. Selenide adds the seleno group to a seryl-tRNA, forming selnocystyl-tRNA, that is then added to growing peptide chain
C. Seleno group is added to cystyl residue as post-transcriptional modification
D. A protein seryl group residue in a protein has a seleno group added as a post- transcriptional modification to form selenocystyl residue
B.
The uncommon amino acid ornithine
A. Is found at the first amino acid at the N terminal of a protein
B. Causes loss of beta sheet in protein
C. Is the starting substrate of the Urea Cycle
D. Exclusively found in alpha helix proteins
C.
The isoelectric point (pI) of a non-polar amino acid is the pH where
A. It has maximum charge
B. It is strongly acidic
C. It is strongly basic
D. Both amine and carboxylic acids are charged and the amino acid has zero net charge
D.
Alanine has a pK1 and a pK2 while lysine has a pK1, pK2 and a pKR. Why?
A. The R group of alanine is acidic
B. The R group of lysine is neutral
C. The R group of alanine is non-polar while lysine has a charged R group
D. Both alanine and lysine have neutral R groups
C.
What amino acids have pKR in the acid range?
A. Isoleucine and leucine
B. Glutamate and aspartate
C. Arginine and lysine
D. Asparagine and glutamine
B.
Of the amino acids in protein, how many do not ionize?
A. 10
B. All
C. None
D. 13
D.
Where are the polar amino acids found in protein?
A. In the interior of globular protein structure
B. On the surface of the globular protein to interact with water
C. In the active site of enzymes, binding site of receptors
D. Answers B & C
D.
What functional group of the amino acid molecule dictates the chemical properties of each amino individual acid?
A. The amine group
B. The R group
C. Carboxylic acid group
D. Both the carboxylic acid and amine group
B.
Which major metabolic pathway is a source of amino acid precursors?
A. Glycolysis
B. Pentose phosphate pathway
C. TCA Cycle
D. All of the above
D.
The three-dimensional structure of a protein depends on
A. Specific gene codes
B. Random binding of amino acids into a peptide chain
C. What amino acids are numerous and available
D. The ribosome, selecting the amino acid order
A.
In quaternary structure identical peptides are called?
A. Isopeptides
B. Heteropeptides
C. Homodimers
D. Hetrodimers
C.
What are secondary peptide structures?
A. Extended chains and beta pleated sheets
B. Random coils and extended regions
C. Extended chains and alpha helix
D. Alpha helix and beta pleated sheets
D.
Why is the peptide bond planar?
A. Because there's no possible rotation around bonds between N and C atoms
B. Because rotation only happens around atoms bonded to alpha C
C. Because the carboxylic acid cannot rotate
D. Because of the resonant double bond between the C of the carbonyl group and the N of the peptide bond
D.
All amino acids in a peptide are trans to each other EXCEPT (it can be either cis or trans)
A. Glycine
B. Alanine
C. Proline
D. Serine
C.
In the peptide chain the R groups
A. Are always cis of each other
B. Are always trans of each other
C. Can be either cis of trans
D. Are long stretches of cis, then alternate to trans
B.
Which of the following is true about a peptide bond
A. Because of its resonance the N has a partial positive charge
B. Because of its resonance the N has a partial negative charge
C. Because of its resonance the N has no charge
D. Depends on the pKR for what charge the N has
A.
Whether a Φ or ψ is favored can be found on a
A. RicTic plot
B. Linweaver-Burk plot
C. Ramachandran plot
D. Arrhenius plot
C.
Which amino acid is considered an alpha helix 'breaker'?
A. Serine
B. Glycine
C. Tryptophan
D. Arginine
B.
Interaction of N-H and C=O of the peptide bond leads to local regular structures such as
A. Extended chains
B. All secondary structures
C. Charged outer surface
D. Alpha helix and beta sheets
D.
What is present in the core of the long axis of an alpha helix?
A. Water molecules
B. Carbonyl groups
C. Amino groups
D. Empty space
D.
Which pair of amino acids are strong alpha-helix formers?
A. Serine and lysine
B. Alanine and leucine
C. Alanine and cysteine
D. Tryptophan and tyrosine
B.
In beta pleated sheet peptide chains, H bonds between parallel strands are
A. Not formed
B. Weaker, 1 Kcal/mol
C. Stronger, 3 Kcal/mol
D. Energetically the same as H bonds in anti-parallel strands
B.
What is the orientation of the R groups of amino acids in beta sheets?
A. Perpendicular to the axis and trans to each other
B. Perpendicular to the axis and cis to each other
C. Lateral to the axis and trans to each other
D. Lateral to the axis and cis to each other
A.
What amino acids are most commonly present in beta turns?
A. Proline and glycine
B. Serine and glycine
C. Serine and threonine
D. Proline and serine
A.
The beta turn is composed of four amino acid residues. Where does the H bond form in the beta turn?
A. Between the CO of the first amino acid residue hydrogen bonds with the NH group of n+3 residues from it
B. Between the CO of the first amino acid residue hydrogen bonds with the NH group of n+4 residues from it
C. Between the CO of the second amino acid residue hydrogen bonds with the NH group of n+4 residues from it
D. Between the CO of the second amino acid residue hydrogen bonds with the NH group of n+6 residues from it
A.
The native configuration of a protein is
A. The lowest entropy state but highest energy state when folded
B. The highest entropy state and lowest energy state when folded
C. The lowest entropy state and lowest energy state when folded
D. The native folding of protein is not affected by entropy and energy states
C.
What bonds hold a peptide in tertiary structure?
A. Covalent bonds, salt bridges and disulfide bonds
B. Salt bridges and disulfide bonds
C. Hydrophobic interactions and hydrogen bonds
D. Answers B & C
D.
The HV region of an antibody has an important feature, which enhances its effectiveness in resolving an infection. Which is it?
A. There are two HV regions on an antibody molecule
B. They are made of a heavy and light chain
C. Both HV chains are followed by a constant region of the peptide chain
D. The HV region shows great variation in amino acid sequence forming stronger binding sites for binding antigen
D.
If two proteins share a secondary a structural motif, then it can be assumed
A. They have similar function
B. Nothing in regards to their secondary structural similarities
C. These are functionally identical regions
D. They belong to the same family of proteins
B.
What can be said about the enthalpy and entropy of a properly folded protein?
A. Entropy decreases as enthalpy increases
B. Both entropy and enthalpy decrease
C. As enthalpy decease entropy stays the same
D. Neither enthalpy nor entropy are affected
B.
Transporters belong to three distinct families depending on the direction of the substance transported. These are
A. Anyporter, antiporter and retroporter
B. Retroporter, symporter, antiporter
C. Forwardporter, backporter, dualporter
D. Uniporter, symporter, antiporter
D.
In the human body, muscles move due to
A. The interaction of actin and myosin proteins
B. The interaction of immunoglobulin and fibronectin
C. The interactions of the three strands of collagen
D. Answers A and C
A.
In signal transduction pathways, a chemical message binds to the receptor and it causes a cytosolic G protein bound to the receptor to
A. Bind to the enzyme protein kinase A and activate binding to target proteins
B. Bind to protein kinase A and produce cAMP from ATP
C. Bind to adenylate cyclase and produce cAMP from ATP
D. Activate the release of calcium ions
C.
How does hemoglobin (Hb) differ from myoglobin (Mb)?
A. Mb has a lower affinity for O2
B. Hb has Fe3+ while Mb has Fe2+
C. Hb has quaternary structure, Mb has tertiary structure
D. Both Hb and Mb carry O2 in blood
C.
How do enzymes speed up the reaction?
A. By the formation of product, favoring the transition state
B. By increasing the number of side products formed
C. By speeding up the binding of the substrate
D. By raising the activation energy needed
A.
Which of the following is true regarding enzymes?
A. They are needed in large amounts
B. They catalyze exergonic and endergonic reactions
C. They increase the energy of activation of the reaction
D. Their effectiveness as catalysts is independent of temperature
B.
Substrate binds to the active site through
A. Ionic bonds
B. Covalent bonds
C. Non-covalent interactions
D. Hydrophobic interactions
C.
The binding energy of the enzyme for the substrate
A. Raises the energy needed for the reaction to occur
B. Has no effect on the reaction of substrate to form product
C. Lowers the energy requirement for the reaction to occur
D. It helps the substrate bind to the active site, but then is lost from the complex of substrate and enzyme
C.
During a catalyzed reaction, which energy is the lowest?
A. ΔH of the formation
B. ΔE of the activation
C. ΔG of the free energy
D. Total ΔH
B.
When ΔG is negative, which of the following is true?
A. The reaction is non-spontaneous and Keq=1
B. The reaction is non-spontaneous and Keq=0
C. The reaction is spontaneous and Keq<<1
D. The reaction is spontaneous and Keq>>1
D.
During an exergonic reaction
A. the energy of the product is always greater than the substrate
B. the energy of the product is always the same as the substrate
C. the energy of the product is always less than the substrate
D. it depends on the reaction
C.
In an endothermic reaction, which of the following are true?
A. ΔH of the reaction is positive and the product has less energy than the reactants
B. ΔH=0 and the energy of the reactants and products are the same conserving energy
C. ΔH of the reaction is positive and the energy of the product is greater than the reactant
D. ΔH of the reaction is negative and the energy of the product is less than the reactant
C.
What is the function of co-enzymes?
A. They are part of the reaction along with the substrate and aid the active site forming the transition molecule
B. They stabilize the enzyme structure
C. They bind to the substrate to aid binding to the active site
D. They aid the enzyme stabilizing the product
A.
The reaction that takes place in the hexokinase active site is considered to be an example of induced fit. Why?
A. Because hexokinase only binds glucose
B. Because hexokinase binds several 6 carbon sugars
C. Because hexokinase only binds straight chains
D. Because hexokinase binds both organic and inorganic residues
B.
Hexokinase phosphorylates numerous 6-carbon hexose sugars, but the reaction is linked to the hydrolysis of ATP and requires Mg2+. Which statement describes this reaction accurately?
A. The hydrolysis of ATP is exothermic and has a negative ΔG and drives the phosphorylation of the hexose sugar, and the Mg2+ binds the phosphate group being added to the hexose
B. The hydrolysis of ATP is endothermic and the Mg2+ binds to the protein to the change it shapes
C. The role of the Mg2+ is to stop water from inferring with the reaction and ATP binds to add the phosphate group to the hexose and the ΔG is zero for this reaction
D. The Mg2+ binds to the ATP to stop it from phosphorylating the enzyme, and the ATP hydrolysis has a negative ΔG
A.
GAP dehydrogenase forms 1,3BPG with a ΔG0' = +6.3 kJ/mol. Why does this endothermic reaction occur?
A. The reduction of NAD to NADH drives the reaction
B. The second reaction, where phosphoglycerate kinase is ΔG0' = -18.8 kJ/mol forms an ATP which drives the GAP dehydrogenase reaction
C. High concentrations of GAP from the splitting of Fr 1,6 BP
D. The elimination of water from the active site
B.
Which statement is true about the nature of Brønsted-Lowry acids and bases?
A. The acid donates an H+ and the base accepts an OH-
B. The acid donates the OH- that the base accepts
C. The acid accepts the H+ and the base donates the H+, forming a conjugate acid base pair
D. The acid donates the H+ and the base accepts the H+, forming a conjugate acid base pair
D.
How does Lewis change the Brønsted-Lowry definition of acids and bases?
A. Lewis acids accept electrons and are halogens in biological systems
B. Lewis acids accept electrons while bases donate electrons, and in biological systems the acids are ions such as Mg2+ and Zn2+
C. Lewis acids also donate H+ but a larger group of ions accept the H+ to form a base
D. Lewis acids donate electrons and the base accepts OH-
B.
The rate of an enzyme-catalyzed reaction depends on
A. The slow step in the mechanism
B. The concentration of transition state formed
C. The energy need to form the transition state
D. The concentration of product formed
A.
In metallo-catalysis, the metal is found
A. Bound to the substrate
B. Transient in the active site
C. Covalently bound to the protein
D. Bound to the co-enzyme
C.
Which kinetic value is experimentally determined?
A. Km
B. Kcat
C. Turnover number
D. Vmax
D.
The ratio Kcat/Km is
A. Represents the affinity of the enzyme for substrate
B. The rate of transition state formation
C. The constant that measures catalytic efficiency
D. Determines how tightly enzyme binds substrate
C.
Competitive inhibition affects which kinetic value?
A. Km
B. Vmax
C. The ratio Kcat/Km
D. Kcat
A.
A Hill plot
A. is used to show inhibition
B. is another way of determining Vmax and Km
C. is used to determine the Kcat
D. shows co-operativity in binding of substrate
D.
If [S] < Km, then V = ?
A. is 2 Vmax
B. is < 0.5 Vmax
C. is > 0.5 Vmax
D. equals Vmax
B.
Which of the following is a (are) disaccharide(s)? (select all that apply)
A. Sucrose
B. Glucose
C. Fructose
D. Lactose
A, D
What is the molecular formula for glucose?
A.
CH3OH
B.
C6H12O6
C.
C12H22O11
D.
C6H12O5
B.
Which of the following molecules is a carbohydrate?
A.
C3H7O2N
B.
C13H26O2
C.
C6H12O6
D.
C6H12O12
C.
Which of the following is not considered a polysaccharide?
A. starch
B. glycogen
C. maltose
D. cellulose
C.
To possess optical activity, a chemical compound must be
A. a hexose
B. aromatic
C. symmetric
D. asymmetric
D.
Which of the following characterizes an asymmetric carbon?
A. It has four identical groups attached to it
B. It has four different groups attached to it
C. It has at least one carboxyl and one amino group attached to it
D. It has two heavy groups on one side and two light groups on the other
B.
At equilibrium in solution, d-glucose consists of a mixture of its anomers. Which statement most accurately describes the solution?
A. The solution consists of approximately equal amounts of the alpha- and beta-anomers
B. The straight-chain form is present in high concentration
C. The alpha-anomer is more stable and is slightly preferred over the b-anomer
D. The beta-anomer predominates over the alpha-anomer by a ratio of approximately 2:1
D.
Fill in the blank:
The transformation of a monosaccharide into its ________ occurs easily and does not require the assistance of a catalyst.
anomer
How many anomeric carbons are present in a fructose molecule?
A. None
B. 1
C. 2
D. 4
B.
Glucose and galactose are
A. epimers
B. anomers
C. enantiomers
D. diastereoisomers
A.
Chemical compounds that have the same structural formula but differ in configuration around one carbon atom are called
A. optical isomers
B. stereoisomers
C. anomers
D. epimers
D.
The typical cyclical structure of glucose is α and β D-
A. Chondroitin
B. Glucoside
C. Glucosamine
D. Glucopyranose
D.
When the linear form of glucose cyclizes, the product is
A. an anhydride
B. a glycoside
C. hemiacetal
D. lactose
C.
Which of the following pairs is interconverted in the process of mutarotation?
A. D-glucose and D-fructose
B. D-glucose and D-galactose
C. D-glucose and L-glucose
D. α-D-glucose and β-D-glucose
D.
Which of the following sugars is not a reducing sugar?
A. Glucose
B. Ribose
C. Sucrose
D. Galactose
C.
Which of the following is a monosaccharide? (select all that apply)
A. Galactose
B. Maltose
C. Sucrose
D. Glyceraldehyde
A, D
Maltose is composed of
A. glucose and glucose
B. glucose and galactose
C. glucose and fructose
D. glucose and sucrose
A
Reduction of glucose leads to the formation of
A. gluconic acid
B. glucitol
C. glucoside
D. glucosamine
C.
Which of the following statements is false?
A. Sucrose is a disaccharide
B. Sucrose is a reducing sugar
C. Sucrose can be digested by invertase
D. Fructose is a component of sucrose
B.
Reaction of glucose with alcohol yields
A. sugar acids
B. glycoside bonds
C. disaccharides
D. None of the above
B.
Hydrolysis of sucrose by the enzyme sucrase yields
A. glucose only
B. glucose and maltose
C. glucose and fructose
D. glucose and galactose
C.
Among the following, which is the sweetest sugar?
A. sucrose
B. fructose
C. saccharin
D. aspartame
B.
The hydrolysis of lactose yields
A. glucose only
B. glucose and fructose
C. glucose and galactose
D. galactose and fructose
C.
Salivary amylase hydrolyses which of the following bonds?
A. α-(1→4) glycosidic linkages
B. α-(1→6) glycosidic linkages
C. β-(1→4) glycosidic linkages
D. β-(1→6) glycosidic linkages
A.
Which of the following polysaccharides cannot be digested by mammalian salivary, gastric, or pancreatic enzymes?
A. cellulose
B. amylopectin
C. amylose
D. glycogen
A.
Carbohydrates are stored in the body principally as
A. glucose
B. sucrose
C. glycogen
D. glycosaminoglycans
C.
All these compounds are glucose polymers except:
A. glycogen
B. inulin
C. cellulose
D. starch
B.
A polysaccharide formed by beta1—>4 glycoside linkage is:
A. starch
B. dextrin
C. glycogen
D. cellulose
D.
A disaccharide produced through hydrolysis of starch is
A. sucrose
B. lactose
C. maltose
D. theralose
C.
Among the following, which is a structural polysaccharide?
A. glycogen
B. pectin
C. starch
D. inulin
B.
Chitin is a polymer of
A. N-acetyl D-glucosamine with α-(1→4) linkage
B. N-acetyl D-glucosamine with β-(1→4) linkage
C. N-acetyl D-galactosamine with α-(1→4) linkage
D. N-acetyl D-galactosamine with β-(1→4) linkage
B.
O- linked polysaccharides are attached to which of the following amino acids?
A. glycine
B. serine
C. tryptophan
D. aspargine
B.
In glycoproteins, the carbohydrate moiety is always attached through the following amino acid residues
A. asparagine, serine, or threonine
B. aspartate or glutamate
C. glycine, alanine, or aspartate
D. tryptophan, aspartate, or cysteine
A.
The biochemical property of lectins that is the basis for most of their biological effects is their ability to bind to
A. amphipathic molecules
B. hydrophobic molecules
C. specific lipids
D. specific oligosaccharides
D.
Which of the following is a dominant feature of the outer membrane of the cell wall of gram negative bacteria?
A. amylose
B. cellulose
C. lipopolysaccharides
D. lipoproteins
C.
What term best describes a metabolic pathway that use simple precursors and energy to produce complex molecules?
A. Anabolism
B. Catabolism
C. Metabolism
D. All of the above
A.
Which of the following molecules are typically oxidized in catabolic reactions?
A. Enzyme and coenzymes
B. Carbohydrates and fats
C. Vitamins and coenzymes
D. Nucleotides and flavins
B.
Select the option that accurately completes the following statements. The role of NAD+ is to __________ electrons in metabolic pathways while the role of NADH is to _________ electrons. In general, nicotinamide adenine dinucleotide is referred to as an electron _________.
A. donate.....accept....generator
B. donate....accept....carrier
C. accept...donate....carrier
D. accept...donate....generator
C.
What is a common way in which enzymatic pathways are regulated to optimize the amount of product formed and substrate consumed?
A. Substrate control
B. Metabolic control
C. Enzyme control
D. Allosteric control
D.
The NADH that is produced by glycolysis under anaerobic conditions is regenerated to NAD+ by the conversion of
A. lactate to pyruvate
B. phosphoenolpyruvate to pyruvate
C. pyruvate to lactate
D. glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate
E. None of the above
C.
In eukaryotes, the enzymes that catalyze the reactions of glycolysis are located in:
A. the cell nucleus
B. the endoplasmic reticulum
C. the mitochondria
D. the lysosomes
E. the cytosol
E.
During glycolysis, the steps between glucose entering the cell and the initial formation of two three-carbon molecules:
A. consume two ATP and two NADH molecules
B. consume two ATP molecules
C. produce two ADP and two NAD molecules
D. produce two ATP and two NADH molecules
E. consume two NADH molecules
B.
The committed step in glycolysis is
A. glucose + ATP leads to glucose 6-phosphate
B. glucose 6-phosphate leads to fructose 6-phosphate
C. fructose 6-phosphate + ATP leads to fructose 1,6-bisphosphate
D. fructose 1,6-bisphosphate leads to dihydroxyacetonephosphate + glyceraldehyde 3-phosphate
E. glucose 6-phosphate leads to glucose 1-phosphate
C.
In general, the higher the intensity of exercise, the greater the proportional contribution of:
A. Aerobic energy production
B. Anaerobic energy production
C. The TCA cycle (Krebs' cycle) to the production of ATP
D. The electron transfer chain to the production of ATP
E. Fat oxidation
.B
All of these compounds are intermediates of glycolysis except
A. Glycerol 6-phosphate
B. Fructose 6-phosphate
C. Fructose 1,6-bisphosphate
D. Glucose 6-phosphate
E. Glyceraldehyde 3-phosphate
A.
Which of the following liver enzymes, absent from other tissues, gives the liver an advantage over other cells in taking up glucose after a meal?
A. Hexokinase
B. Aldolase
C. Enolase
D. Glucokinase
E. Glucose 6-phosphatase
D.
Sodium fluoride inhibits glycolysis by affecting
A. Phosphatase
B. Phosphorylase
C. Amylase
D. Enolase
E. Hexokinase
D.
Starting with glyceraldehyde 3-phosphate and synthesizing one molecule of pyruvate, the net yield of ATP and NADH would be which of the following?
A. 1 ATP, 4 NADH
B. 1 ATP, 2 NADH
C. 2 ATP, 1 NADH
D. 2 ATP, 2 NADH
E. 1 ATP, 1 NADH
C.
Which of the following metabolic conversions is considered to be the major control point of glycolysis?
A. Glucose to glucose-6-phosphate
B. 2-phosphoglyerate to phosphoenolpyruvate
C. Fructose-6-phosphate to fructose-1,6-bisphosphate
D. pyruvate to lactate
C.
Why does the glycolytic pathway continue in the direction of glucose catabolism?
A. There are three irreversible reactions along the glycolytic pathway that prevent the reformation of free glucose
B. High levels of ATP keep the pathway going in a forward direction
C. All of the enzymes of glycolysis function in one direction
D. All of the above
A.
Which of the following is responsible for decreasing blood glucose levels?
A. Glycolysis
B. Insulin
C. GLUT2
D. All of the above
D.
Which of the following enzymes is involved with regulating the glycolytic pathway?
A. Enolase
B. Pyruvate kinase
C. Triose phosphate isomerase
D. Phosphoglycerate mutase
B.
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