L8 Enzymes Part 1 of 3

A  They can increase the rate for a given reaction by a thousand fold or more.

B  They are generally equally active on D and L isomers of a given substrate.

C  Their catalytic activity is independent of pH.

D  To be effective, they must be present at the same concentration as their substrate.

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  Enzymes use covalent and non covalent interactions to accelerate reaction

B  Enzymes lower the activation energy of a reaction

C  Enzymes can increase the rate of a reaction by a factor of 10 to the 15th power

D  Enzyme change the relative energy of the initial and final states of a reaction

A  I only

B  III only

C  II and III

D  I and III

A  FALSE

B  TRUE

A  metal

B  organic

C  All of these answers are correct.

D  inorganic

A  Hydrolases catalyze the formation of a compound from two molecules using the addition of water.

B  Transferases catalyze the movement of a functional group within molecule.

C  Lyases catalyze the formation of a single molecule from two products (without hydrolysis)

D  Ligases catalyze synthesis reactions often using energy derived from the  breakdown of ATP

A  The free energy change (ΔG) of the catalyzed reaction is the same as for the uncatalyzed reaction.

B  The reaction will proceed until the enzyme concentration decreases.

C  A component of the enzyme is transferred from A to B.

D  The reaction will be most favorable at 0°C.

A  Type of reaction they catalyze

B  Size of the enzyme

C  Size of the substrate

D  Rate of reaction

A  FALSE

B  TRUE

A  A reaction may not occur at a detectable rate even though it has a favorable equilibrium.

B  After a reaction, the enzyme involved becomes available to catalyze the reaction again.

C  For S → P, a catalyst shifts the reaction equilibrium to the right.

D  Substrate binds to an enzyme’s active site.

E  Lowering the temperature of a reaction will lower the reaction rate.

A  are consumed in the reactions they catalyze

B  drive reactions to completion while other catalysts drive reactions to equilibrium

C  lower the activation energy for the reactions they catalyze

D  increase the equilibrium constants for the reactions they catalyze

E  are very specific and can prevent the conversion of products back to substrates

A  oxidoreductase

B  decarboxylase

C  dehydrogenase

D  hydrolase

A  Keq

B  Rate

A  a low temperature

B  an extreme pH

C  a high temperature

D  heavy metal ions

A  FALSE

B  TRUE

A  The absence of metallic ions in an enzyme.

B  The high molecular mass of enzymes.

C  The surface configuration of enzymes.

D  The insoluble nature of enzymes.

A  phosphorylases

B  dehydrogenases

C  isomerases

D  hydrolases

A  FALSE

B  TRUE

A  The structural adaptation that occurs between protein and inhibitor is called induced fit.

B  When an enzyme binds to a substrate it stresses and destabilizes the bonds in the substrate.

C  Enzymes have a rigid shape

D  The shape of the active site cannot be modified by the binding of substrate.

E  The active site of enzymes has a rigid shape

A  Enzymes usually double the rate of a reaction.

B  During a chemical reaction, reactants must absorb some energy and go through a more stable intermediate state before they become products.

C  A certain amount of energy must always be added to the system or no reaction will take place.

D  In chemical reaction, products cannot be formed after the activation energy has been overcome

A  it changes the optimum pH of the enzyme

B  it allows chemicals to react that otherwise wouldn’t

C  it allows reactions to proceed more quickly

D  it allows reactions to proceed at an acceptable temperature

A  An enzyme allows the reaction to go through a less stable transition state than would normally be the case.

B  An enzyme provides a reaction surface and a suitable environment for the reaction to take place.

C  An enzyme binds reactants such that they are positioned correctly and can attain their transition-state alignment.

A  substrate proteins

B  fibrous proteins

C  secondary structure proteins

D  globular proteins

E  insoluble proteins

A  produces more product per second

B  requires more energy

C  uses less substrate

D  requires a higher temperature

E  produces different products

A  reactions take place faster at lower temperatures

B  heating removes the water and oxygen from the liver

C  heating damages the enzyme in liver that breaks down hydrogen peroxide

D  heating kills the germs that cause the bubbling

A  cofactor

B  modulator

C  prosthetic group

D  co-enzyme

A  active residues

B  catalytic residues

C  amino acid residue

D  enzymatic residues

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  lowers the energy of the products

B  lowers the energy of the substrate

C  changes the concentration of the substrate

D  lowers the activation energy for the reaction

E  changes the possible product formed

A  stays the same shape while causing a change in the shape of the substrate

B  adjusts shape to adapt to the shape of the substrate

C  uses an inhibitor to adjust its shape for the substrate

D  stays the same shape during substrate binding

E  uses a cofactor to change the shape of a substrate

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  FALSE

B  TRUE