Bio

Consider the biochemical pathway below, where A, B, and C are substrates and products and E1 and E2 are the enzymes that catalyze the reactions. If Enzyme 1 (E1) is inactive, which compounds will accumulate? -A only -C only -A and B -B only -B and C

A only

Consider the biochemical pathway below, where A, B, and C are substrates and products and E1 and E2 are the enzymes that catalyze the reactions. If Enzyme 1 (E1) is inactive, which of the following compounds will become deficient? -B and C -A and B -A only -B only -C only

B and C

Consider the biochemical pathways illustrated below. Product D will act as an allosteric inhibitor of what enzyme to regulate its own production? E1 E2 E3 E4 E3 and E4

E2

Your friend is studying a specific exergonic reaction. Your friend hypothesizes that the addition of enzyme X will reduce the delta-G of this reaction, thus allowing it to proceed spontaneously. What do you think of your friend's hypothesis? -This is a good hypothesis that fits with what is known about this reaction. -Exergonic reactions never proceed spontaneously, so this hypothesis does not fit with what is known about this reaction. -Enzymes do not change delta-G, so this hypothesis does not fit with what is known about this reaction. -Exergonic reactions cannot benefit from the use of an enzyme, so this hypothesis does not fit with what is known about this reaction.

Enzymes do not change delta-G, so this hypothesis does not fit with what is known about this reaction.

Consider the biochemical pathways illustrated below. If product D is abundant, why is it preferable to inhibit E2 rather than E1? -Inhibition of E2 will prevent the production of D, but still allow synthesis of E -Inhibition of E2 will prevent the production of D, but still allow synthesis of B -E1 can only be regulated by B or E -It is not possible for D to regulate E1, because it is too far upstream in the biochemical pathway

Inhibition of E2 will prevent the production of D, but still allow synthesis of E

What happens when the coenzyme NAD+ gains an H atom? -It also gains an electron causing it to be reduced. -It loses energy. -It also gains an electron causing it to be oxidized. -It also gains a proton causing it to be reduced. -It also gains a proton causing it to be oxidized.

It also gains an electron causing it to be reduced.

Based on the reaction in the animation, what can you say about the change in free energy of the cleavage of sucrose into glucose and fructose? -It is negative and the reaction is endergonic. -It is positive and the reaction is exergonic. -It is negative and the reaction is exergonic. -It is positive and the reaction is endergonic.

It is negative and the reaction is exergonic.

Without knowing the exact chemical reaction, what is the best indicator that a redox reaction has occurred? -ATP was produced by substrate level phosphorylation. -NADH was produced. -Carbon dioxide was produced. -A cofactor was required. -Multiple enzymes were required to act in a biochemical pathway.

NADH was produced

L-arabinose is a naturally occurring, non-caloric sweetener that acts as a non-competitive inhibitor of the enzyme sucrase. If L-arabinose is consumed, what will happen to the hydrolysis of sucrose? -Sucrose will continue to be hydrolyzed in small amounts. It will compete with L-arabinose for access to the sucrase active site. -Sucrose hydrolysis will be greatly reduced, since L-arabinose binding to sucrase will inactivate the enzyme. -Sucrose hydrolysis will be greatly reduced, since all sucrase active sites will be occupied by L-arabinose. Sucrose hydrolysis will increase, since -L-arabinose increases the efficiency of sucrase. -L-arabinose consumption will have little effect on the hydrolysis of sucrose.

Sucrose hydrolysis will be greatly reduced, since L-arabinose binding to sucrase will inactivate the enzyme.

Consider the biochemical pathway below, where A, B, and C are substrates and products and E1 and E2 are the enzymes that catalyze the reactions. If B is also the substrate of another reaction that is catalyzed by enzyme 3 (E3) to form product D, how does the cell regulate the production of C and D? -Specific molecules of B can only be converted to C, while other molecules of B can only be converted to D. -The cell uses activators and inhibitors to regulate the activity of enzymes 2 and 3 (E2 and E3). -None of these are true. It is only possible for any given molecule can to become one specific product. -Activators and inhibitors bind to substrate B to regulate what product(s) it can form. -Additional enzymes are required to regulate the production of C and D.

The cell uses activators and inhibitors to regulate the activity of enzymes 2 and 3 (E2 and E3).

Based on the animation, which observation is true? -An enzyme could create different products depending on which substrate it started with. -Each enzyme only performed its reaction once. -Multiple final products were formed depending on which enzyme catalyzed the last reaction. -Each enzyme was catalyzing the same reaction. -The product from one reaction served as the substrate for the next reaction.

The product from one reaction served as the substrate for the next reaction.

Consider the biochemical pathway used to synthesize the amino acid proline. A large increase in the level of proline will most likely lead to -a decrease in proline production. -a further increase in proline production. -no change in the rate of proline production. -proline being converted to praline. -increased breakdown of proline.

a decrease in proline production.

A hydrogen atom consists of -protons only. -a proton and an electron. -electrons only. -a proton and several electrons. -a variable number of protons and electrons.

a proton and an electron

In the example above, the final product of the pathway inhibits the pathway by binding to -the product of the first reaction. -the active site of the first enzyme in the pathway. -the substrate of the first reaction. -the active site of the last enzyme in the pathway. -an allosteric site of the first enzyme in the pathway.

an allosteric site of the first enzyme in the pathway.

The enzyme in the animation is most likely catalyzing -a hydrolysis reaction. -an anabolic reaction. -a catabolic reaction. -feedback inhibition. -an endothermic reaction.

an anabolic reaction

Molecules are synthesized in ___________ reactions.

anabolic

Molecules are broken down in ________ reactions.

catabolic

Anabolic reactions __________ NADH and ATP.

consume

NAD+ is a coenzyme for many enzymes involved in redox reactions. This means that -NAD+ has an active site. -all enzymes involved in redox reactions bind NAD+. -enzymes that use NAD+ as a coenzyme will not function properly if NAD+ is not available. -NAD+ is an inhibitor of many enzymes involved in redox chemistry.

enzymes that use NAD+ as a coenzyme will not function properly if NAD+ is not available

Hydrolysis of the last phosphate from ATP is endergonic t/f.

false

When it binds to sucrose, sucrase -becomes denatured. -is cleaved in half. -releases energy to the sucrose. -goes through a conformational change.

goes through a conformational change

Flames have ___________ energy.

kinetic

Hiking is __________ energy.

kinetic

Moving water has __________ energy.

kinetic

How often can a sucrase molecule be used to hydrolyze sucrose? -once -twice -many times -never

many times

Is Fe+2 => Fe+3 a reduction reaction?

no

NO2- => NO3- a reduction reaction?

no

Consider the biochemical pathway below, where A, B, and C are substrates and products and E1 and E2 are the enzymes that catalyze the reactions. Enzyme 1 (E1) can use -only B as substrate. -both A and B as substrates. -neither A nor B as substrate. -only A as substrate. -either A or B as substrate, but not both.

only A as substrate.

Cells obtain energy by ________ food molecules such as glucose. -oxidizing -phosphorylating -reducing -anabolizing -redoxing

oxidizing

Beans have ______________ energy.

potential

Firewood has ___________ energy.

potential

Catabolic reactions _________ NADH and ATP.

produce

What type of biological molecule are enzymes? -steroids -lipids -proteins -carbohydrates -nucleic acids

proteins

A mutation occurred in the gene that encodes the enzyme sucrase, resulting in a single amino acid substitution in the active site of the enzyme whereby a polar amino acid changed to a nonpolar amino acid. The most likely result of this mutation is -a single amino acid substitution will probably not affect the enzyme. -sucrase will not be able to bind sucrose in the active site. -sucrase will bind sucrose, but will not catalyze the hydrolysis reaction. -sucrase will no longer be specific to sucrose. It will now hydrolyze a variety of disaccharides.

sucrase will not be able to bind sucrose in the active site

In feedback inhibition, the inhibitor of the biochemical pathway is often -a product of another biochemical pathway. -the product of the enzyme inhibited. -a substance that is produced towards the middle of the biochemical pathway. -the final product of the biochemical pathway. -the substrate of the enzyme inhibited.

the final product of the biochemical pathway.

An enzyme may catalyze a reaction by stressing or destabilizing the bonds of the substrates. This point in the enzymatic reaction is known as the -activation energy. -change in free energy. -energy state. -transition state. -enzyme-substrate complex.

transition state

Once phosphates are released from ATP they can be added back to the ADP by coupling this endergonic reaction to an exergonic reaction. t/f

true

The creatine-Phosphate to creatine reaction has a ΔG of -11kcal/mole and thus can be used to generate ATP from ADP. t/f

true

The hydrolysis of ATP can be coupled to an endergonic reaction allowing the endergonic reaction to proceed in the cell. t/f

true

Sucrase uses _______ to cleave sucrose into two monosaccharides. -Oxygen -Fructose -Water -Glucose -Carbon dioxide

water

Is NAD+ + e- + H=> NADH a reduction reaction?

yes

Pyruvate +2e- => lactate a reduction reaction?

yes