Bio Chapter 6

Indicate the examples below that illustrate the first law of thermodynamics. - A plant uses sunlight to form a H+ gradient. - A H+ gradient is used to produce ATP. - 10% of the energy in one trophic level can be passed to the next trophic level. - An animal uses ATP to move its muscles. - An animal produces heat in the process of metabolism.

- A plant uses sunlight to form a H+ gradient. - A H+ gradient is used to produce ATP. - An animal uses ATP to move its muscles.

A bowl of sugar water is very stable. However, cells can rapidly break down sugar into carbon dioxide and water. What is the best explanation for this observation? - Enzymes in the cell catalyze the breakdown of glucose. - The water is activated by the presence of living cells. - Cells use energy to break down glucose. - Living cells make the water warmer, speeding up the reaction. - Breakdown of glucose has a negative delta G outside of cells, but a positive delta G inside cells. - Glucose becomes more chemically reactive inside a cell.

- Enzymes in the cell catalyze the breakdown of glucose.

What happens to sucrase when it binds to sucrose? - Sucrase becomes denatured. - Sucrase goes through a conformational (shape) change. - Sucrase is cleaved in half. - Sucrase releases energy to the sucrose.

- Sucrase goes through a conformational (shape) change.

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; a polar amino acid changed to a nonpolar amino acid. What is probably the result of this mutation. - A single amino acid substitution will probably not affect the enzyme. - Sucrase will no longer be specific to sucrose. It will now hydrolyze a variety of disaccharides. - Sucrase will bind sucrose, but will not catalyze the hydrolysis reaction. - Sucrase will not be able to bind sucrose in the active site.

- Sucrase will not be able to bind sucrose in the active site.

The process of breaking glycogen down to glucose is an example of - dehydration. - metabolism. - anabolism. - catabolism. - catalysis.

- catabolism.

You measure the amount of enzyme activity in the presence of compound X and note that as you add more substrate the amount of enzyme activity increases. This indicates that the compound X is an - enzyme. - competitive inhibitor. - non-competitive inhibitor. - allosteric inhibitor. - activator.

- competitive inhibitor.

An autotroph captures energy from other sources and does not actually produce energy because - energy cannot be created or destroyed. - kinetic energy is based on location. - the transfer of energy increases entropy. - the transfer of energy increases the disorder of a system. - once energy is created it can be destroyed.

- energy cannot be created or destroyed.

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

- many times

Altering the three-dimensional structure of an enzyme might - prevent the enzyme from adding energy to a reaction. - prevent the substrate from binding the enzyme's active site. - change the amount of energy needed for a reaction. - change the type of product produced in the reaction. - change the type of substrate that binds the enzyme's active site.

- prevent the substrate from binding the enzyme's active site.

In ALL exergonic reactions, - the reactions are nonspontaneous. - the products have more total energy than the reactants. - some reactants will be converted to products. - a net input of energy from the surroundings is required for the reactions to proceed. - the reaction proceeds with a net release of free energy.

- the reaction proceeds with a net release of free energy.

All of the following are a form of potential energy that can be used by a cell EXCEPT A. An electrical/Ion gradient B. ATP C. NADH D. Nitrogen E. Concentration Gradient

D. Nitrogen

True or False: Noncompetitive inhibitors bind the active site of an enzyme, reducing its activity and the subsequent formation of product.

False

True or False: The release of the last phosphate from ATP is endergonic.

False

True or False: When ATP is hydrolyzed to form ADP, the energy is released into the cytoplasm where enzymes use it to run endergonic reactions.

False

What would your predict about the following reaction? Pi + ADP → ATP It can be used to drive endergonic reactions. It yields energy. It has a change in free energy that is greater than 0. It has a change in free energy that is less than 0. It has a change in free energy that is greater than 0, and hence can be used to drive endergonic reactions.

It has a change in free energy that is greater than 0.

When a biological molecule is oxidized, the electrons are often captured by NAD, which is reduced to NADH. With that knowledge, identify if the substrate other than NADH or NAD in each reaction is being oxidized or reduced. - Pyruvate + NADH → Lactate + NAD⁺ - Isocitrate + NAD⁺ → alpha-ketoglutarate + CO₂ + NADH - Malate + NAD⁺ → Oxaloacetate + NADH - Diphosphoglycerate + NADH → Glyceraldehyde phosphate + NADH⁺ - Ethanol + 2NAD → Acetic Acid + 2NADH

Reduced - Pyruvate + NADH → Lactate + NAD⁺ - Diphosphoglycerate + NADH → Glyceraldehyde phosphate + NADH⁺ Oxidized - Isocitrate + NAD⁺ → alpha-ketoglutarate + CO₂ + NADH - Malate + NAD⁺ → Oxaloacetate + NADH - Ethanol + 2NAD → Acetic Acid + 2NADH

What would you predict about a reaction that has a ΔG < 0? The reaction will require energy and is spontaneous. The reaction will yield energy. The reaction will require energy. The reaction will yield energy and is spontaneous. The reaction is spontaneous.

The reaction will yield energy and is spontaneous.

True or False A reaction with a ΔG > 0 is endergonic and requires a net input of energy to proceed.

True

True or False Temperature, pH, and ionic concentrations each play an important role in the proper functioning of enzymes.

True

True or False: Creatine-P to creatine has a ΔG of -11kcal/mole and thus can be used to generate ATP from ADP.

True

True or False: Once phosphates are released from ATP they can be added back in an endergonic reaction.

True

True or False: When ATP is used in a reaction, the last phosphate is transferred to the substrate.

True

Fill in the Blank: Energetic molecules such as NADH and ATP are often reactants of __________ reactions. - Anabolic - oxidized - catabolic - reduced

anabolic

In photosynthesis, carbon dioxide gas is reduced and combined to form glucose. This is an example of - hydrolysis. - catabolism. - metabolism. - exergonic. - anabolism.

anabolism

Fill in the Blank: Energetic molecules such as NADH and ATP are often products of ____________ reactions. - Anabolic - oxidized - catabolic - reduced

catabolic

In the reaction A− +B →A + B−, A. molecule A is oxidized and molecule B is unchanged. B. molecule A is oxidized and molecule B is reduced. C. molecules A and B are both reduced. D. molecule A is reduced and molecule B is oxidized. E. molecules A and B are both oxidized.

molecule A is oxidized and molecule B is reduced

The primary function of an enzyme or any biological catalyst is to change the direction of a reaction. reduce the energy of activation and increase the rate of a reaction. reduce the energy of activation of a reaction. increase the rate of a reaction. increase the rate of a reaction and change the direction of a reaction.

reduce the energy of activation and increase the rate of a reaction.

Fill in the Blank: In the reaction Pyruvate + NADH -> Lactate + NAD+, pyruvate is being ____________ , while NADH is being ____________ . - Anabolic - oxidized - catabolic - reduced

reduced; oxidized