FREE AND STUDY GAMES ABOUT BIOCHEM EXAM

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FREE AND STUDY GAMES ABOUT BIOCHEM 1/2 EXAM

QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -196 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation Question 1: How many residues are included in one turn of an alpha-helix structure?

Answer:

3.6 Question 2: In sickle-cell anemia, the gene coding for the beta-chain of hemoglobin shows-

Answer:

A missense mutation leading to a substitution of Glu to Val Question 3: Exo-peptidases:

Answer:

Cleave the Peptide bonds non-specifically, in a progressive way, from polypeptide ends Question 4: This question relates to the general mechanism described in the illustration: in the mechanism of trypsin, which amino acid plays the role of "B"?

Answer:

Histidine 57

Question 5: Contractile Proteins

Answer:

Can contract and change shap. Ex: Elements of cytoskeleton and muscle: myosin, actin

Question 6: Psi (?)

Answer:

is the angle of rotation for the bond between the alpha carbon and the carbonyl carbon.Question 7: Which of the following is NOT correct concerning 2,3-bisphosphoglycerate (BPG)?

Answer:

It increases the affinity of hemoglobin for oxygen Question 8: Which of the following sequences of events in enzymes working by the induced-fit model? (*denotes the transition state)

Answer:

E + S ? ES ? E*S* ? EP ? E + P

Question 9: The experimental procedure used to determine the precise arrangement of atoms

within a large protein includes:

Answer:

• X-ray diffraction

• crystallogrpahy

• 3-D modelling tools

• working with Ramachandran plots

Question 10: We know that an enzyme works at initial velocity (Vo) equal to the Vmax when-

Answer:

[S] >>> Km

Question 11: Proteases are useful in sequencing because-

Answer:

Protease digestion allows reducing the size of a polypeptide so it is manageable for Edman degradation.Question 12: Below is a plot of Vo vs. [S] for a specific allosteric enzyme under different conditions. Which of the following best describes the graph?

Answer:

Curve 3 represents the effect of a negative modulator added to #2 Question 13: When a reaction achieves a steady state:

Answer:

The [ES] remains constant over time Question 14: The peptide alanylglutamylglycylalanylleucine has:

Answer:

four peptide bonds Question 15: The interactions of ligands with proteins:

Answer:

are usually short-lived Question 16: In affinity chromatography, the bound proteins are typicallty eluted by a solution

containing:

Answer:

Ligand

Question 17: A protein's native 3D structure represents-

Answer:

The lowest energy state of all possible conformations Question 18: The peptide alanylglutamylglycylalanylleucine has:

Answer:

four peptide bonds.

Question 19: Which of the following interactions is NOT a basis for an affinity chromatography procedure?

Answer:

Negative charge- positive charge

Question 20: X-ray crystallography is used to determine

Answer:

the Phi and Psi.

Question 21: In the experiment described below, which of the following is TRUE?

Answer:

Since we do not know what was the substrate concentration used, we cannot tell whether the enzyme was at Vmax

Question 22: Most proteins will denature at temperatures above

Answer:

42o C.

Question 23: Motif

Answer:

• segments of tertiary protein structure or amino acid sequence that are found in many proteins
• A super-secondary structure- simple arrangements of secondary structures that frequently occur in

protein structure Question 24: Using the Lineaweaver plot, the lines of the competitively-inhibited and the

non-inhibited reaction:

Answer:

Intersect on the Y-axis

Question 25: The reagent used in the Edman degradation is-

Answer:

PITC