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

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

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

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

B  Enzymes use covalent and non covalent interactions to accelerate reaction

C  Enzymes lower the activation energy of a reaction

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

A  I and III

B  II and III

C  III only

D  I only

A  FALSE

B  TRUE

A  organic

B  All of these answers are correct.

C  metal

D  inorganic

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

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

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

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

A  The reaction will proceed until the enzyme concentration decreases.

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

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

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

A  Size of the substrate

B  Size of the enzyme

C  Type of reaction they catalyze

D  Rate of reaction

A  FALSE

B  TRUE

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

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

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

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

E  Substrate binds to an enzyme’s active site.

A  are consumed in the reactions they catalyze

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

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

D  increase the equilibrium constants for the reactions they catalyze

E  lower the activation energy for the reactions they catalyze

A  dehydrogenase

B  decarboxylase

C  hydrolase

D  oxidoreductase

A  Rate

B  Keq

A  a low temperature

B  heavy metal ions

C  an extreme pH

D  a high temperature

A  TRUE

B  FALSE

A  The high molecular mass of enzymes.

B  The insoluble nature of enzymes.

C  The absence of metallic ions in an enzyme.

D  The surface configuration of enzymes.

A  isomerases

B  phosphorylases

C  dehydrogenases

D  hydrolases

A  TRUE

B  FALSE

A  Enzymes have a rigid shape

B  The active site of enzymes has a rigid shape

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

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

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

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

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

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

D  Enzymes usually double the rate of a reaction.

A  it allows reactions to proceed more quickly

B  it allows reactions to proceed at an acceptable temperature

C  it changes the optimum pH of the enzyme

D  it allows chemicals to react that otherwise wouldn’t

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

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

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

A  fibrous proteins

B  insoluble proteins

C  secondary structure proteins

D  substrate proteins

E  globular proteins

A  requires more energy

B  uses less substrate

C  requires a higher temperature

D  produces more product per second

E  produces different products

A  heating removes the water and oxygen from the liver

B  reactions take place faster at lower temperatures

C  heating kills the germs that cause the bubbling

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

A  prosthetic group

B  cofactor

C  modulator

D  co-enzyme

A  enzymatic residues

B  amino acid residue

C  active residues

D  catalytic residues

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  changes the concentration of the substrate

B  lowers the activation energy for the reaction

C  lowers the energy of the substrate

D  lowers the energy of the products

E  changes the possible product formed

A  adjusts shape to adapt to the shape of the substrate

B  uses an inhibitor to adjust its shape for the substrate

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

D  uses a cofactor to change the shape of a substrate

E  stays the same shape during substrate binding

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  TRUE

B  FALSE