POB Ch.6 Quiz Questions

Which of the following statements is true about enzymes? -They can associate with a wide variety of substrates. -They are unaffected by changes in pH. -Their 3D shape can vary and still be active. -They catalyze only one specific type of reaction. -Boiling temperatures do not affect their activity.

-They catalyze only one specific type of reaction.

In which of the following ways is the enzyme inhibitor warfarin used?

-anticoagulant medicine -rat poison

In this diagram, the molecule on the left -has more potential energy. -has a less stable configuration. -has less potential energy. -is more organized. -has a more stable configuration. -is less organized.

-has more potential energy. -has a less stable configuration. -is more organized.

Which statement most accurately describes the second law of thermodynamics?

Energy cannot be changed from one form to another without a loss of usable energy.

If an enzymatic reaction was controlled by feedback inhibition, we would expect it to stop

as soon as a critical level of end product builds up.

The main reason that ATP is considered the energy currency in cells is because it

contains accessible energy in phosphate bonds.

If you wished to increase enzyme activity, you would do all of the following except -increase the concentration of substrate. -increase the temperature moderately. -change to optimum pH for the reaction. -decrease the temperature.

decrease temp

In feedback inhibition of a metabolic pathway, where does the inhibitor bind?

enzyme of the first reaction

Enzymes are specific. This means that they

have a particular substrate.

Each enzyme has a particular substrate because enzymes

have active sites complementary in shape to their substrates.

The function of an enzyme is to

increase the rate of a metabolic reaction.

If A -> B -> C -> D -> E represents a metabolic pathway, then letter E would be

product

Occasionally someone claims to have built a machine that can run forever, producing as much energy as it consumes. This has always been disproved because it violates

the second law of thermodynamics.

Which is true about energy of activation? -Energy of activation is the difference between the energy of the reactant and the energy of the product. -The energy of activation is always lower than the energy of the reactant -Adding the correct enzyme can lower the energy of activation

Adding the correct enzyme can lower the energy of activation

Which of the following statements is not true concerning enzymatic activity? -Each enzyme has a preferred pH at which the enzyme reaction rate is highest. -Enzyme activity increases as substrate concentration increases until the maximum rate is achieved. -As the temperature increases, most enzymatic reactions will still proceed at the same rate. -Above a certain temperature, an enzyme will become denatured.

As the temperature increases, most enzymatic reactions will still proceed at the same rate.

Which of the following statements most accurately describes the first law of thermodynamics?

Energy can be neither created nor destroyed but it can be changed from one form to another.

During an enzymatic reaction, what happens to the enzyme?

The enzyme and the substrate form a temporary complex.

The location in which the enzyme and substrate complexes is called the

active site

Which of the following can act a an enzyme cofactor? iron vitamines NAD+

all of the above

ATP contains

an adenine base, a ribose sugar, and three phosphate groups

This image demonstrates the second law of thermodynamics in that (add picture)

the animal loses some energy to heat when chemical energy is converted to mechanical energy.

The high energy bond in ATP that is used by cells is found in or between

the phosphate groups.

This image demonstrates the first law of thermodynamics in that

the plants convert light energy from the sun to chemical energy.