An enzyme called hexokinase is exposed to a temperature of 85^{\circ}C , which is significantly higher than its optimal operating temperature. Which statement best predicts the effect of this change on the enzyme's function and provides the correct biochemical justification?

The enzyme will lose its catalytic activity because the high thermal energy disrupts the hydrogen bonds and hydrophobic interactions that maintain the specific shape of the active site.

The enzyme's primary structure will be altered as the sequence of amino acids is rearranged, leading to the creation of a different enzyme with a new function.

The enzyme will function more efficiently because the heat provides the necessary energy to break the peptide bonds, making the protein more flexible for substrate binding.

The enzyme's rate of reaction will increase indefinitely because the increased kinetic energy allows more substrate molecules to reach the activation energy.

An enzyme is specialized to function in the highly acidic environment of the human stomach (pH \approx 2.0). If this enzyme is moved to the small intestine, where the pH is approximately 8.0, what is the most likely effect on the enzyme's function?

The enzyme will fail to catalyze reactions because the change in H^{+} concentration alters the charge of R-groups, disrupting the ionic interactions that stabilize the active site.

The enzyme will retain its original shape and function because the primary structure, determined by covalent peptide bonds, is not affected by pH changes.

The enzyme's tertiary structure will be strengthened as more hydrogen bonds form between the excess amino and carboxyl groups in the more basic environment.

The enzyme will increase its activity because the more basic environment provides more hydroxide ions to accelerate the cleavage of substrate bonds.

An enzyme found in a thermophilic bacterium living in a hydrothermal vent at 95^{\circ}C is isolated and placed into a solution at room temperature ( 25^{\circ}C ). The enzyme's catalytic activity drops to near zero. Which of the following best predicts the physical state of the enzyme and the reason for its loss of function?

The enzyme is likely intact but inactive because the lower thermal energy is insufficient to overcome the activation energy barrier for the reaction and the protein lacks the molecular flexibility required for induced fit.

The enzyme has denatured because legal temperatures below the optimum cause the primary sequence of amino acids to dissociate into individual monomers.

The enzyme's active site has been permanently reshaped because cold temperatures cause the hydrophobic R-groups to become hydrophilic and move to the protein's exterior.

The enzyme has permanently lost its tertiary structure because the reduction in kinetic energy causes the hydrogen bonds to vibrate so violently that they break.

Predict effects of denaturation on protein function

Predict effects of denaturation on protein function | Quizalize

Q 1/10
Score 0
30
Q 2/10
Score 0
The protein albumin is found in egg whites and remains soluble in water due to the folding of its hydrophilic R-groups on the surface. If the pH of the environment is significantly lowered from 7.4 to 2.0, which of the following best predicts the result?
30
The protein will maintain its original function because pH changes only affect the secondary structure's alpha-helices, leaving the tertiary active sites intact.
The protein will denature as the high concentration of $H^{+}$ ions disrupts the ionic bonds and hydrogen bonds, causing the protein to unfold and lose solubility.
The protein will become more stable because the increase in protons strengthens the peptide bonds between the amino acid residues in the primary sequence.
The protein will undergo a hydrolysis reaction, breaking the covalent bonds between individual amino acids and releasing free monomers into the solution.

10 questions

30 sec

The protein albumin is found in egg whites and remains soluble in water due to the folding of its hydrophilic R-groups on the surface. If the pH of the environment is significantly lowered from 7.4 to 2.0, which of the following best predicts the result?

30 sec

The folding of a globular protein is largely driven by the burial of hydrophobic R-groups within the interior of the protein. If this protein is transferred from an aqueous environment to a nonpolar solvent like hexane, which prediction regarding its function is most accurate?

30 sec

A mutation occurs in a chaperone protein that normally assists in the folding of a cell surface receptor. If this results in the receptor protein being partially denatured or misfolded before it reaches the cell membrane, what is the most likely consequence for the cell?

30 sec

A scientist subjects a sample of the enzyme salivary amylase to a solution containing a high concentration of heavy metal ions, which are known to interfere with disulfide bridges. Which of the following best predicts the impact on the enzyme's ability to catalyze the hydrolysis of starch?

30 sec

A researcher is studying a specific enzyme that contains a high proportion of basic amino acids in its active site to facilitate binding with an acidic substrate. If the enzyme is placed in an environment where the pH is significantly increased beyond its optimal range, which prediction regarding the enzyme's function is most likely?

30 sec

The protein keratin is found in hair and is stabilized by numerous disulfide bridges between cysteine residues. When hair is chemically treated to 'perm' it, a reducing agent is applied to break these disulfide bonds, the hair is reshaped, and then an oxidizing agent is applied to reform the bonds in new positions. Which of the following best explains why the initial application of the reducing agent results in a loss of the hair's natural structural shape?

30 sec

An investigator isolates a cytosolic enzyme from a human liver cell and places it into a solution containing a high concentration of urea, a chemical known to disrupt hydrogen bonds throughout the polypeptide. Which of the following best predicts the immediate effect of urea on the enzyme's catalytic function?

30 sec

Related quizzes

Related quizzes