Chapter 6 Energy and Metabolism Flashcards by Victor Reyes

What is the term for the ability to do work?

Multiple choice question.

Kinetic energy

ATP

Potential energy

Energy

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In broad terms, energy can exist in two states:
__ energy and ___ energy.

kinetic and potential

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Which of the following describes the major difference between kinetic and potential energy?

Multiple choice question.

Kinetic energy is the energy of motion while potential energy is stored energy.

Potential energy is the energy of motion while kinetic energy is stored energy.

Kinetic energy is stored in chemical bonds while potential energy is stored in large objects

Kinetic energy is the energy of motion while potential energy is stored energy.

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One
____ is equal to the heat required to raise the temperature of one gram of water by one degree Celsius. In order to receive credit, you must spell the word (no abbreviations).

calorie

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What is the second law of thermodynamics?

Multiple choice question.

The transformation of energy from one form to another increases entropy.

Energy is conserved.

Energy cannot be created or destroyed.

The transformation of energy from one form to another increases entropy.

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As living organisms consume other living organisms, Blank______.

Multiple choice question.

sunlight can boost the energy levels of the molecules that are consumed

all of the energy of the first organism is lost

energy is created when new molecules are formed

potential energy is transferred from one organism to another

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The energy available to do work in a system is called
____ energy.

free

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Which statement accurately describes the fate of chemical potential energy in living things?

Multiple choice question.

It can be used in two ways only, more specifically, it can be shifted and stored into different molecules, or released as heat.

It can used in one way only, more specifically, it can be shifted and stored into different molecules.

It can be shifted and stored into different molecules, or it can be converted into other forms, such as kinetic energy, electricity, or light.

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According to the equation for Gibbs free energy, the free energy (G) equals the
___ minus the product of the temperature and the ____ of the system

enthalpy and entropy

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Heat is a measure of the random
___ of molecules.

motion

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According to the second law of thermodynamics,
___ increases when energy is transferred from one form to another and some energy is lost as heat in the process.

entropy

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When a physical system becomes more disordered, the entropy
____

increases

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What is the term used to describe the energy of a system that is available to do work?

Multiple choice question.

Kinetic energy

Free energy

Entropy

Enthalpy

Free energy

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Which of the following equations represents the correct relationship between free energy (G), entropy (S), temperature (T), and enthalpy (H)?

Multiple choice question.

TS = H + G

G = H + TS

H = G - TS

G = H - TS

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Select the true statements about endergonic reactions.

Multiple select question.

Endergonic reactions have a positive change in free energy.

incorrect

The products have a higher free energy than the reactants.

Endergonic reactions are not spontaneous.

Endergonic reactions have a negative change in the free energy.

Endergonic reactions have a positive change in free energy.

incorrect

The products have a higher free energy than the reactants.

Endergonic reactions are not spontaneous.

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Chemical reactions are
____ meaning they can go in either direction

reversible

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_____ energy is the energy required to destabilize existing chemical bonds and initiate a chemical reaction.

activation

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A reaction is said to be
____ when it releases excess free energy and tends to proceed spontaneously.

exergonic

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The rate of an exergonic reaction can be increased by lowering the
_____ energy required to destabilize chemical bonds in the reactants.

activation

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Select two ways to increase the rate of reactions.

Multiple select question.

Remove catalysts

Remove heat from the system

Lower the activation energy

Increase energy of reactants

Lower the activation energy

Increase energy of reactants

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Which of the following statements about chemical reactions are true?

Multiple select question.

A reaction that is exergonic in the forward direction will also be exergonic in the reverse

Chemical reactions are reversible.

Exergonic reactions are reversible, while endergonic reactions are not.

A reaction that is exergonic in the forward direction will be endergonic in the reverse direction.

Chemical reactions are reversible.

A reaction that is exergonic in the forward direction will be endergonic in the reverse direction.

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In order to be initiated, all chemical reactions, even exergonic ones, need Blank______.

Multiple choice question.

inducers

activation energy

protein catalysts

Reason: Reactions can proceed without catalysts, just more slowly.

ATP

activation energy

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The process of influencing chemical bonds to lower the activation energy of a reaction is called Blank______.

Multiple choice question.

catalysis

free energy change

feedback

the equilibrium constant

catalysis

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The
_____ ___________ for an exergonic reaction is lower in the presence of a catalyst for the reaction.

activation energy

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Select the ways in which catalysts affect chemical reactions. Multiple select question. Catalysts accelerate both the forward and reverse reactions by the same amount. Catalyzed reactions are slower than uncatalyzed reactions. Catalysts change an endergonic reaction to an exergonic reaction. Catalysts reduce activation energy.

Catalysts accelerate both the forward and reverse reactions by the same amount. Catalysts reduce activation energy.

What causes the rate of some chemical reactions to be very slow? Multiple choice question. Large release of free energy Enzymes Large activation energy Low activation energy

Large activation energy

All cells use a molecule called ____ to carry and release energy cyclically

ATP

The activation energy is a barrier to the formation of products. How can this be overcome? Multiple choice question. Activation energy cannot be changed, and reactions will proceed at a rate determined by the change in free energy. Reason: Enzymes can lower the activation energy. Adding heating can increase the activation energy. Reason: Addition of heat can lower the activation energy. Cooling the products will lower the activation energy. Catalysts can be used to lower the activation energy.

Catalysts can be used to lower the activation energy.

Which nitrogenous base is a component of ATP? Multiple choice question. Guanine Thymine Adenine Cytosine

Adenine

Answer Mode Multiple Choice QuestionYour Answer correct Hydrolysis of which covalent bonds in ATP releases a considerable amount of energy? Multiple choice question. Nitrogen-carbon double bonds Carbon-hydrogen bonds Hydrogen bonds Phosphate-phosphate bond

Phosphate-phosphate bond

Any agent that speeds up the rate of a chemical reaction without being permanently changed or consumed by it is known as a(n) ____

catalyst

How much energy is released when the outermost phosphate bond of ATP is hydrolyzed under standard conditions? Multiple choice question. 7.3 kcal/mol 73 kcal/mol 37 kcal/mol 3.7 kcal/mol

7.3 kcal/mol

When two reactions are coupled in a cell, what determines if they will both proceed spontaneously? Multiple choice question. At least one of the reactions should have a negative ΔG. The sum of ΔG of the two coupled reactions (the overall ΔG) should be negative. The sum of ΔG of the two coupled reactions (the overall ΔG) should be positive. Each of the coupled reactions should have a negative ΔG.

The sum of ΔG of the two coupled reactions (the overall ΔG) should be negative.

From the list below, select the three components of ATP. Multiple select question. Adenine Ribose Thymine A chain of three phosphates Deoxyribose Reason: ATP contains ribose, similar to nucleotides in RNA

Adenine, 3 phosphates m, ribose

The hydrolysis of ATP has Blank______. Multiple choice question. a positive ΔG a ΔG of zero a negative ΔG

a negative ΔG

Which of the ATP's phosphate bonds is hydrolyzed in most cellular reactions? Multiple choice question. The outermost The bond between the 1st and 2nd phosphates The innermost

The outermost

During the ATP cycle, energy is consumed as well as released. ATP synthesis is a(n) Blank______ step, while ATP hydrolysis is a(n) Blank______ step. Multiple choice question. energy-neutral; exergonic exergonic; endergonic Reason: ATP synthesis requires an input of energy. energy-releasing; endergonic Reason: ATP hydrolysis releases energy. endergonic; exergonic

endergonic; exergonic

Which of the following statements about the size and turnover rate of the ATP pool in a typical cell are true? Multiple select question. Most cells have a few seconds' supply of ATP. Most cells have a stockpile of ATP. Most cells maintain enough ATP to last for hours, or longer. Most cells have to produce more ATP constantly.

Most cells have a few seconds' supply of ATP. Most cells have to produce more ATP constantly.

___ are proteins or RNA molecules that act as catalysts to speed up reactions in living organisms.

enzymes

Is any energy released during ATP hydrolysis and if so, how much? Multiple choice question. Yes, a very small amount of energy is released. No, in fact, energy is required for ATP hydrolysis. Yes, a considerable amount of energy is released.

Yes, a considerable amount of energy is released.

___ , or reactants, are molecules that bind to an enzyme and are converted to products in chemical reactions.

substrates

Multiple Choice Question What is a substrate? Multiple choice question. The catalyst of a chemical reaction A reactant molecule that forms a temporary association with an enzyme before being converted to a product The products of a chemical reaction that has been catalyzed by an enzyme The location on the enzyme where chemical reactions take place

A reactant molecule that forms a temporary association with an enzyme before being converted to a product

Question Mode Fill in the Blank Question Fill in the blank question. When a reactant binds to the active site of an enzyme, a(n) - complex forms.

enzyme substrate

Question Mode Fill in the Blank Question Fill in the blank question. The binding of a substrate usually produces a slight change in the enzyme's shape resulting in a better enzyme-substrate fit; this is called ___ fit.

induced

Select the true statement about enzymes. Multiple choice question. They raise the activation energy of a reaction by binding to the substrates. They are consumed in the chemical reaction and can only be used once. They are altered by the chemical reaction and can only be used once. They lower the activation energy of a reaction by binding to the substrates.

They lower the activation energy of a reaction by binding to the substrates.

Where does a substrate bind on an enzyme in order for a chemical reaction to take place? Multiple choice question. Enzyme-substrate complex Active site Carbon molecules Catalytic site

Active site

The bacterial enzyme pyruvate dehydrogenase contains multiple copies of each of three enzymes for a total of 60 protein subunits. This is an example of Blank______. Multiple choice question. coupled enzymes a multi-stage enzyme a multienzyme complex

a multienzyme complex

A more efficient way to catalyze a sequence of related biochemical reactions is to combine several proteins into a ____; complex in this way, the product of each reaction can be delivered to the next enzyme, without being released to diffuse away.

multienzyme

Increasing the temperature outside the optimal range for an enzyme can lead to ____of the enzyme, altering the enzyme's structure and function.

denaturation

Most enzymes in the human body work best at neutral pH. Select the reasons why changing the pH of the fluid in which a human enzyme is dissolved (for example to a pH of 3) will affect the enzyme's ability to function. Multiple select question. Enzymes cannot maintain their three-dimensional shape at extreme pHs, such as a pH of 3. correct The enzyme loses its side chains at an extreme pH, such as a pH of 3. The balance between positively and negatively charged amino acids in the enzyme is shifted. The enzyme is dissolved into amino acids.

Enzymes cannot maintain their three-dimensional shape at extreme pHs, such as a pH of 3. The balance between positively and negatively charged amino acids in the enzyme is shifted.

Most enzymes only function in a narrow range of temperatures and have an optimum temperature at which they work best. Why? Multiple choice question. Lower temperatures prevent the formation of the substrate-enzyme complex while higher temperatures can denature the enzyme. At lower temperatures substrates diffuse very slowly, so they cannot reach the enzyme easily, while at higher temperatures, substrates diffuse away from the enzyme too quickly. At very low and very high temperatures, the ΔG of the reaction catalyzed by an enzyme changes.

Lower temperatures prevent the formation of the substrate-enzyme complex while higher temperatures can denature the enzyme.

Select the events that must occur before bonds in the substrate are broken during an enzyme catalyzed reaction. Multiple select question. A substrate-enzyme complex must form. The substrate must bind the enzyme. Amino acids in the enzyme must interact with the substrate. An enzyme-product complex must be formed. The substrate-enzyme complex must be broken.

A substrate-enzyme complex must form. The substrate must bind the enzyme. Amino acids in the enzyme must interact with the substrate.

Changes in pH affect an enzyme because the interaction of charged amino acid residues in the enzyme are affected by Blank______. Multiple choice question. covalent bonding hydrogen ion concentrations cofactor ions allosteric inhibitors

hydrogen ion concentrations

Select the true statements about the effect of temperature on an uncatalzyed chemical reaction. Multiple select question. Increased temperature increases the rate of the reaction. Increased temperature increases random molecular movements which increases stress on bonds. Increased temperature raises the activation energy of the reaction Reason: Higher temperature does not raise the activation energy of a reaction (that would make the reaction slower). When higher temperatures affect the activation energy of a reaction (for example, by adding stress to molecular bonds as molecules move faster) it typically lowers the activation energy. Increased temperature decreases the rate of the reaction.

Increased temperature increases the rate of the reaction. Increased temperature increases random molecular movements which increases stress on bonds.

What are competitive inhibitors? Multiple choice question. Competitive inhibitors bind to the substrate and prevent it from interacting with the enzyme. Competitive inhibitors bind to the allosteric site on an enzyme and inhibit the enzyme's functioning. Reason: This is the definition of a noncompetitive inhibitor. Competitive inhibitors bind to the active site of an enzyme and prevent substrates from binding.

Competitive inhibitors bind to the active site of an enzyme and prevent substrates from binding.

Enzyme inhibitors Blank______. Multiple choice question. bind to the substrate and prevent it from binding the enzyme break down certain substrates effectively preventing a reaction from proceeding bind to an enzyme and decrease its activity

bind to an enzyme and decrease its activity

A(n) ____ inhibitor binds to an area outside of the active site of an enzyme and impairs proper functioning of the enzyme.

allosteric

What happens if a chemical substance binds to an enzyme and alters its shape? Multiple choice question. The enzyme's activity will always remain the same but its specificity will change. The enzyme's activity can only be decreased. The enzyme's activity can be increased or decreased. The enzyme's activity can only be increased.

The enzyme's activity can be increased or decreased.

A substance that binds to an enzyme and decreases its activity is an

inhibitor

Select the true statements about allosteric sites on enzymes. Multiple select question. This is where a substrate would bind. The binding of a substance to the allosteric site can switch an enzyme between its active and inactive configurations. This is where a competitive inhibitor would bind. .

The binding of a substance to the allosteric site can switch an enzyme between its active and inactive configurations. This is where a non-competitive inhibitor would bind.

____enzymes are enzymes that can exist in either an active or inactive conformation.

allosteric

What term refers to small chemicals, usually inorganic ions, that temporarily attach to the surface of an enzyme and promote a chemical reaction? Multiple choice question. Cofactors Coenzymes Substrates Ribozymes

Cofactors

A molecule that binds to a site on the enzyme other than the active site and inhibits the enzyme's activity is a(n) ___ inhibitor.

allosteric

Which of the following are included in metabolism? Multiple choice question. Neither the synthesis nor the breakdown of organic molecules Only the synthesis of organic molecules Only the breakdown of organic molecules Both the synthesis and breakdown of organic molecules

Both the synthesis and breakdown of organic molecules

The ____ site is a specific region of an enzyme to which non-competitive inhibitors bind in order to regulate enzyme activity.

allosteric

An allosteric ____ binds to a site in the enzyme other than the active site and by doing so it keeps the enzyme in its active configuration.

activator

What is the general role of anabolic reactions in the metabolism of a cell? Multiple choice question. Anabolic reactions remove toxic chemicals from the cell. Anabolic reactions are involved in the synthesis of larger molecules from smaller precursor molecules. Anabolic pathways are involved in the breakdown of larger molecules into smaller ones.

Anabolic reactions are involved in the synthesis of larger molecules from smaller precursor molecules.

Answer Mode Fill in the Blank QuestionYour Answer correct Fill in the blank question. ___ are small organic molecules that temporarily attach to an enzyme and promote the chemical reaction catalyzed by the enzyme.

coenzymes

What statement describes metabolism? Multiple choice question. Metabolism refers to the sum of all chemical reactions that occur within an organism. Metabolism refers to the effects of pH, temperature, and allosteric substances on enzymes. Metabolism refers only to reactions that harvest energy by breaking down molecules. Reason: Metabolism is all chemical reactions, both the breakdown and synthesis of organic molecules. Metabolism refers only to reactions that expend energy to build molecules. Reason: Metabolism is all chemical reactions, both the breakdown and synthesis of organic molecules.

Metabolism refers to the sum of all chemical reactions that occur within an organism.

(catabolic or anabolic?) Cells harvest energy during -____ and expend energy during ____

catabolic and anabolic

In a cell's metabolism, what is the general role of catabolic reactions? Multiple choice question. Catabolic pathways are involved in the breakdown of larger molecules into smaller ones. Catabolic reactions are involved in the synthesis of larger molecules from smaller precursor molecules. Catabolic reactions produce permanent energy storage molecules, such as carbohydrates, and fats.

Catabolic pathways are involved in the breakdown of larger molecules into smaller ones.

Which of the following acts as an inhibitor of the first enzyme reaction in a metabolic pathway during feedback inhibition? Multiple choice question. The first product Reason: In negative feedback, when the final product accumulates it inhibits the first enzyme in the pathway. The first substrate The final substrate The final product

The final product

Select reasons why metabolic pathways are regulated. Multiple select question. By regulating metabolic pathways, cells can produce compounds in excess. Regulation allows cells to operate efficiently. By regulating metabolic pathways, cells conserve raw materials. correct By regulating metabolic pathways, cells waste less energy.

Regulation allows cells to operate efficiently. By regulating metabolic pathways, cells conserve raw materials. By regulating metabolic pathways, cells waste less energy.

In ____ inhibition, the end product of a pathway affects the first enzyme in the series to shut down the pathway.

feedback

Chapter 6 Energy and Metabolism Flashcards

Chapter 6 (75 cards)