ALL Flashcards

1
Q
  1. The central dogma of molecular biology describes how:
A

B. the message contained in the DNA is transcribed to mRNA and translated to protein.

Example sentence: The central dogma explains the flow of genetic information from DNA to protein.

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2
Q
  1. The function of a protein is determined by its:
A

A. three-dimensional shape.

Example sentence: A protein’s function is closely related to its unique three-dimensional structure.

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3
Q
  1. The sequence of what in a protein determines how it folds?
A

B. Amino acids.

Example sentence: The specific sequence of amino acids in a protein dictates its final folded structure.

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4
Q
  1. Why might a biochemist make a particular protein in the laboratory?
A

D. All the above.

Example sentence: Biochemists may produce proteins for various purposes such as research, medical applications, or industrial use.

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5
Q
  1. Proteins are polymers of:
A

D. amino acids linked together by peptide covalent bonds.

Example sentence: Proteins are composed of long chains of amino acids connected by peptide bonds.

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6
Q
  1. What level(s) of protein structure(s) are stabilized with PRIMARILY hydrogen bonds?
A

B. Secondary.

Example sentence: Secondary protein structures, like alpha helices and beta sheets, are mainly stabilized by hydrogen bonds.

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7
Q
  1. Which statement regarding hydrogen bonds is INCORRECT?
A

D. Hydrogen bonds stabilize the primary sequence of amino acids.

Example sentence: Hydrogen bonds play a crucial role in maintaining the secondary and tertiary structures of proteins.

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8
Q
  1. Which statement about protein secondary structure is CORRECT?
A

C. Turns, loops and coils connect beta strands and alpha helices together.

Example sentence: Secondary protein structures are connected by turns, loops, and coils.

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9
Q
  1. In proteins, supersecondary structures are:
A

B. structural features that have more than one secondary structural element.

Example sentence: Supersecondary structures are combinations of secondary structural elements in proteins.

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10
Q
  1. Which forms of the alpha-amino and alpha-carboxyl groups of alanine are most likely to occur at very high pH (for the free amino acid)?
A

B. NH2 and COO-.

Example sentence: At high pH, the amino and carboxyl groups of alanine are likely to be in their deprotonated forms.

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11
Q
  1. The amino acid pictured below:
A

A. is likely to be found in the hydrophobic core of a protein.

Example sentence: Hydrophobic amino acids are often located in the interior of proteins.

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12
Q
  1. Which one of the following statements about the amino acid (cysteine, at neutral pH) shown below is CORRECT?
A

D. It can be involved in forming a type of post-translational modification called disulfide bonds.

Example sentence: Cysteine residues can form disulfide bonds, a common post-translational modification.

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13
Q
  1. Amino acid side chain modification such as:
A

A. phosphorylation is commonly used to control enzyme activity, like an ON/OFF switch.

Example sentence: Phosphorylation of amino acid side chains can regulate enzyme activity.

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14
Q
  1. An alpha helix in a protein contains:
A

C. 3.6 amino acids per turn, does not normally contain proline and is often polar on one side and non-polar on the other side.

Example sentence: Alpha helices exhibit a characteristic structure with specific amino acid patterns.

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15
Q
  1. Which statement about beta turns is INCORRECT?
A

B. They connect individual polypeptides.

Example sentence: Beta turns facilitate changes in protein directionality within the same polypeptide chain.

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16
Q
  1. EDHWVNQYSAIT is an amino acid sequence that can form an alpha helix. Which residues are involved in forming a hydrogen bond with residue Q (underlined)?
A

D. H and T.

Example sentence: Specific amino acid residues in a sequence can interact through hydrogen bonding to stabilize protein structures.

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17
Q
  1. The four main classifications of amino acids, based on the properties of their side chains, are:
A

A. non-polar, polar uncharged, polar positively charged, polar negatively charged.

Example sentence: Amino acids can be categorized into different groups based on the nature of their side chains.

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18
Q
  1. The peptide bond in proteins is:
A

A. planar.

Example sentence: Peptide bonds exhibit a planar configuration due to partial double bond character.

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19
Q
  1. Which one of the following statements about protein structure is INCORRECT?
A

A. Beta-sheets are stabilized by hydrogen bonds between carbonyl oxygens and amino hydrogens from amino acids that are next to each other on the same beta-strand.

Example sentence: Beta-sheets are primarily stabilized by hydrogen bonds between adjacent strands, not within the same strand.

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20
Q
  1. What is the main driving force in protein folding?
A

C. Hydrophobic core formation.

Example sentence: The burial of hydrophobic residues drives the folding of proteins into their native structures.

21
Q
  1. An enzyme catalyzed reaction:
A

B. has a lower activation energy than the equivalent uncatalyzed reaction.

Example sentence: Enzymes lower the activation energy required for chemical reactions to occur.

22
Q
  1. Which statement about the role of enzymes in cellular metabolism is INCORRECT?
A

B. Enzymes ensure that all chemical reactions are at equilibrium.

Example sentence: Enzymes catalyze reactions in cells without altering the equilibrium state.

23
Q
  1. Pyridoxal phosphate (PLP) is present in the active site of glycogen phosphorylase, where it acts as a(n):
A

C. Coenzyme.

Example sentence: Pyridoxal phosphate functions as a coenzyme in the active site of certain enzymes.

24
Q
  1. What enables enzymes to bind to substrates very selectively?
A

A. The 3D geometry and chemical properties of the active site.

Example sentence: Enzymes exhibit specificity in substrate binding due to the unique features of their active sites.

25
25. Which effect below does NOT contribute to enzymatic catalysis?
B. Irreversible binding of substrates to the active site. ## Footnote Example sentence: Irreversible binding of substrates would hinder enzymatic turnover and catalysis.
26
26. Enzymes usually bind BEST to:
C. the transition state of the reaction catalyzed. ## Footnote Example sentence: Enzymes exhibit high affinity for the transition state of the reaction they catalyze.
27
27. The active site of an enzyme:
C. includes amino acid sidechains that specifically bind substrate through multiple weak interactions. ## Footnote Example sentence: The active site of an enzyme contains residues that interact with the substrate through various non-covalent interactions.
28
28. Vmax is the maximum rate of reaction an enzyme can catalyze when:
A. saturated with substrate. ## Footnote Example sentence: Vmax represents the maximum rate of an enzyme-catalyzed reaction under conditions of substrate saturation.
29
29. In enzyme kinetics, a progress curve:
B. shows the appearance of product or disappearance of substrate, over time. ## Footnote Example sentence: Progress curves in enzyme kinetics provide information on the rate of product formation or substrate consumption.
30
30. Which one of the following statements about enzyme kinetics is INCORRECT?
B. The Vmax of a reaction will not change if more enzyme is added. ## Footnote Example sentence: Increasing enzyme concentration can raise the Vmax of a reaction due to enhanced catalytic efficiency.
31
31. A Lineweaver-Burk plot for an enzyme-catalyzed reaction is shown below. The point labeled (y) on the plot corresponds to:
C. -1/Km ## Footnote Example sentence: In a Lineweaver-Burk plot, the y-intercept corresponds to the reciprocal of Vmax.
32
32. Below is a plot that shows an enzymatic reaction with and without an inhibitor. The inhibitor used in the experiment above is a:
B. competitive inhibitor because it increases KM. ## Footnote Example sentence: Competitive inhibitors compete with the substrate by binding to the active site and raising the apparent KM.
33
33. An enzyme-catalyzed reaction in the presence of a competitive inhibitor:
D. can achieve the same Vmax as the uninhibited enzyme if given enough substrate. ## Footnote Example sentence: Competitive inhibitors can be overcome by providing higher substrate concentrations to reach the same maximum reaction rate.
34
34. In the presence of a non-competitive inhibitor, Vmax
35
labeled (y) on the plot corresponds to:
C. Vmax. ## Footnote Example sentence: The point labeled (y) on the plot corresponds to the maximum velocity of the reaction.
36
Below is a plot that shows an enzymatic reaction with and without an inhibitor. The inhibitor used in the experiment above is a:
B. competitive inhibitor because it increases KM. ## Footnote No additional information.
37
An enzyme-catalyzed reaction in the presence of a competitive inhibitor:
D. can achieve the same Vmax as the uninhibited enzyme if given enough substrate. ## Footnote No additional information.
38
In the presence of a non-competitive inhibitor, Vmax will:
D. decrease, while KM will remain unchanged. ## Footnote No additional information.
39
Which statement about the glycogen phosphorylase enzyme is INCORRECT:
B. Glycogen phosphorylase is activated by directly binding to insulin. ## Footnote No additional information.
40
Myoglobin:
A. can bind one oxygen molecule. ## Footnote No additional information.
41
Proteins that show cooperativity:
C. Favour the R-state at high [S] (substrate concentration). ## Footnote No additional information.
42
The T-state of hemoglobin is stabilized by:
A. Binding of bisphosphoglycerate (BPG) between subunits. ## Footnote No additional information.
43
Hemoglobin displays a sigmoidal oxygen binding curve because the binding of oxygen:
C. to one subunit can change the conformation of the other subunits. ## Footnote No additional information.
44
2,3-bisphosphoglycerate (BPG):
D. binds allosterically to stabilize the T-state of hemoglobin. ## Footnote No additional information.
45
What connects allosteric control and cooperativity?
A. Both give rise to a sigmoidal activity curve. ## Footnote No additional information.
46
Which of the following is a chemical substance that activates a receptor?
A. Agonist. ## Footnote No additional information.
47
Which of the following is a chemical substance that prevents the activation of a receptor by an agonist?
A. Antagonist. ## Footnote No additional information.
48
Fill in the blank with the best option: Antagonist is to receptor as _______ is to enzyme.
A. Inhibitor. ## Footnote No additional information.