L8 Enzymes Part 1 of 3

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

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

C  Their catalytic activity is independent of pH.

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

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

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

C  Enzymes lower the activation energy of a reaction

D  Enzymes use covalent and non covalent interactions to accelerate reaction

A  II and III

B  I only

C  I and III

D  III only

A  TRUE

B  FALSE

A  metal

B  All of these answers are correct.

C  organic

D  inorganic

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

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

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

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

C  The reaction will proceed until the enzyme concentration decreases.

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

A  Rate of reaction

B  Size of the enzyme

C  Type of reaction they catalyze

D  Size of the substrate

A  TRUE

B  FALSE

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

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

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

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  are consumed in the reactions they catalyze

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

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  decarboxylase

B  oxidoreductase

C  hydrolase

D  dehydrogenase

A  Rate

B  Keq

A  a high temperature

B  heavy metal ions

C  a low temperature

D  an extreme pH

A  TRUE

B  FALSE

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  hydrolases

D  isomerases

A  TRUE

B  FALSE

A  Enzymes have a rigid shape

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

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

D  The active site of enzymes has a rigid shape

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

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

B  Enzymes usually double the rate of a reaction.

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

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 at an acceptable temperature

D  it allows reactions to proceed more quickly

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

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

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

A  secondary structure proteins

B  insoluble proteins

C  globular proteins

D  fibrous proteins

E  substrate proteins

A  produces different products

B  requires more energy

C  produces more product per second

D  requires a higher temperature

E  uses less substrate

A  heating kills the germs that cause the bubbling

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

C  heating removes the water and oxygen from the liver

D  reactions take place faster at lower temperatures

A  cofactor

B  prosthetic group

C  co-enzyme

D  modulator

A  catalytic residues

B  active residues

C  enzymatic residues

D  amino acid residue

A  TRUE

B  FALSE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  changes the possible product formed

B  lowers the energy of the products

C  lowers the energy of the substrate

D  changes the concentration of the substrate

E  lowers the activation energy for the reaction

A  stays the same shape during substrate binding

B  uses an inhibitor to adjust its shape for the substrate

C  adjusts shape to adapt to the shape of the substrate

D  uses a cofactor to change the shape of a substrate

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

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  FALSE

B  TRUE