L8 Enzymes Part 1 of 3

A  Their catalytic activity is independent of pH.

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

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

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

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  Enzymes lower the activation energy of a reaction

B  Enzymes use covalent and non covalent interactions to accelerate reaction

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

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

A  III only

B  II and III

C  I only

D  I and III

A  FALSE

B  TRUE

A  inorganic

B  All of these answers are correct.

C  organic

D  metal

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

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

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

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

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

B  The reaction will proceed until the enzyme concentration decreases.

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

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

A  Size of the enzyme

B  Size of the substrate

C  Type of reaction they catalyze

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

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

D  Substrate binds to an enzyme’s active site.

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

A  lower the activation energy for the reactions they catalyze

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

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

D  increase the equilibrium constants for the reactions they catalyze

E  are consumed in the reactions they catalyze

A  decarboxylase

B  dehydrogenase

C  hydrolase

D  oxidoreductase

A  Keq

B  Rate

A  heavy metal ions

B  an extreme pH

C  a low temperature

D  a high temperature

A  FALSE

B  TRUE

A  The insoluble nature of enzymes.

B  The absence of metallic ions in an enzyme.

C  The surface configuration of enzymes.

D  The high molecular mass of enzymes.

A  isomerases

B  dehydrogenases

C  phosphorylases

D  hydrolases

A  FALSE

B  TRUE

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

B  Enzymes have a rigid shape

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

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

E  The active site of enzymes has a rigid shape

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

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

C  Enzymes usually double the rate of a reaction.

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

A  it allows reactions to proceed at an acceptable temperature

B  it changes the optimum pH of the enzyme

C  it allows chemicals to react that otherwise wouldn’t

D  it allows reactions to proceed more quickly

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  globular proteins

C  fibrous proteins

D  insoluble proteins

E  secondary structure proteins

A  requires more energy

B  requires a higher temperature

C  uses less substrate

D  produces different products

E  produces more product per second

A  reactions take place faster at lower temperatures

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

C  heating kills the germs that cause the bubbling

D  heating removes the water and oxygen from the liver

A  modulator

B  prosthetic group

C  cofactor

D  co-enzyme

A  amino acid residue

B  active residues

C  catalytic residues

D  enzymatic residues

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  changes the concentration of the substrate

B  lowers the energy of the substrate

C  lowers the energy of the products

D  changes the possible product formed

E  lowers the activation energy for the reaction

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

B  uses a cofactor to change the shape of a substrate

C  adjusts shape to adapt to the shape of the substrate

D  stays the same shape during substrate binding

E  uses an inhibitor to adjust its shape for the substrate

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  FALSE

B  TRUE