Learn Smart PKA- Chapter Six: An Introduction to Energy, Enzymes, and Metabolism

_________ reactions break down larger molecules into smaller ones, and ___________ reactions involve the synthesis of larger molecules and macromolecules.

catabolic anabolic or biosynthetic

In general, both catabolic and anabolic reactions are endergonic. catabolic reactions are exergonic, while anabolic reactions are endergonic. both catabolic and anabolic reactions are exergonic. catabolic reactions are endergonic, while anabolic reactions are exergonic.

catabolic reactions are exergonic, while anabolic reactions are endergonic.

What is the main factor that can affect the rate of a reaction? increased entropy increased activation energy thermodynamics catalysis

catalysis

Name the type of energy that is a form of potential energy stored in chemical bonds. heat chemical mechanical electrical

chemical

What do organic molecules provide? chemical bonds to store energy cellular processes building blocks chemical reactions

chemical bonds to store energy building blocks

In a chemical reaction, an enzyme's ________ must change before it can catalyze the conversion of reactants to products.

conformation

The first law of thermodynamics is also known as the law of _____________ of energy.

conservation

Chemical ______ occurs when the rate of formation of products equals the rate of formation of reactants.

equilibrium

Organisms couple ________ and ______ reactions because many vital cellular processes would not proceed without energy input.

exergonic endergonic

The rates of enzyme-catalyzed reactions are typically millions of times than _____________ corresponding uncatalyzed reactions.

faster

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

second

Almost all enzymes bind their substrates with a high degree of .

specificity

What type of reaction results in products that contain less free energy than the reactants do? exothermic endergonic anabolic chemical spontaneous exergonic catabolic spontaneous reaction passive exergonic reaction

spontaneous exergonic spontaneous reaction exergonic reaction

Consider the reversible reaction: A + B ↔ C + D. Whether C + D are favored over A + B will depend upon: the rate of the forward reaction the rate of the reverse reaction the energy input required the concentrations of reactants and products

the energy input required the concentrations of reactants and products

Which of the following describes the hydrolysis of ATP? A molecule of ATP is formed when a water molecule adds a phosphate group to ADP. A water molecule is removed from ATP resulting in the release of ADP and inorganic phosphate. A water molecule is added to ATP resulting in its breakdown to ADP and inorganic phosphate.

A water molecule is added to ATP resulting in its breakdown to ADP and inorganic phosphate.

How can the functioning of an enzyme be affected by the external environment? Increasing the temperature is the only means to denature an enzyme and make it non-functional. Altering the pH can be harmful to an enzyme when the pH is outside the normal or optimal range for that enzyme. Factors such as temperature, pH, and ionic conditions do not usually affect the functioning of enzymes. Increasing the temperature can greatly affect the functioning of some enzymes by causing denaturation.

Altering the pH can be harmful to an enzyme when the pH is outside the normal or optimal range for that enzyme. Increasing the temperature can greatly affect the functioning of some enzymes by causing denaturation.

How is KM, a measure of the concentration of substrate needed for catalysis, related to reaction velocity? An enzyme with a lower KM requires a higher concentration of substrate to reach a particular reaction velocity. An enzyme with a higher KM requires a higher concentration of substrate to reach a particular reaction velocity.

An enzyme with a higher KM requires a higher concentration of substrate to reach a particular reaction velocity.

Which of these is a synonym for anabolic reactions? Catabolic reactions Allosteric reactions Biosynthetic reactions Redox synthesis

Biosynthetic reactions

The forward direction of the equation A+B → C+D shows that ______ are the products. C+D A+B

C+D

What factors determine the direction and rate of a chemical reaction? Catalysts influence the rate of a chemical reaction. Thermodynamics governs the direction of a reaction but not the rate of a reaction. The change in free energy will determine the direction of the reaction. Catalysts determine the direction and rate of a chemical reaction.

Catalysts influence the rate of a chemical reaction. Thermodynamics governs the direction of a reaction but not the rate of a reaction. The change in free energy will determine the direction of the reaction.

Select all of the cellular processes that require a net input of energy. ATP synthesis Endergonic reactions Cellular movements Exergonic reactions Spontaneous reactions

Endergonic reactions ATP synthesis Cellular movements

Match each type of metabolic pathway regulation with the proper description: CELLULAR

Environmental cues activate signaling pathways inside cells, and organelles compartmentalize the cell and isolate reactions.

The enzyme hexokinase recognizes and binds to glucose but does not bind to other similar sugars such as fructose. This is an example of what property? Ability of an enzyme to be reused Enzyme activation Enzyme conformational changes Enzyme specificity

Enzyme specificity

Select the reasons why changes in the pH of the fluid in which an enzyme is dissolved affect the enzyme's ability to function. The enzyme becomes inflexible, and induced fit is not possible. The enzyme's bonds become too weak to hold the enzyme together due to increased random movement of atoms in the enzyme. Enzymes have particular pH values at which they function best.

Enzymes have particular pH values at which they function best.

Match each example of the regulation of metabolic pathways with the proper mechanism: CELLULAR

Epinephrine binds to the surface of a cell and stimulates a signaling pathway leading to the phosphorylation of certain enzymes.

Why is Vmax reached during chemical reactions as the amount of substrate is increased? Vmax is reached because eventually all the substrate is converted to product and the reaction ends. Eventually Vmax is reached because all enzymes are saturated with substrate. so the rate can increase no more. Vmax is reached because at high substrate concentrations, the function of the enzyme is inhibited.

Eventually Vmax is reached because all enzymes are saturated with substrate. so the rate can increase no more.

How does the change in free energy differ between exergonic and endergonic reactions? Endergonic reactions have a negative change in free energy whereas exergonic reactions have a positive change in free energy. Exergonic reactions have a negative change in free energy whereas endergonic reactions have a positive change in free energy.

Exergonic reactions have a negative change in free energy whereas endergonic reactions have a positive change in free energy.

Match each type of metabolic pathway regulation with the proper description: GENETIC

Genes are turned on and off in response to environmental cues.

Which of the following describes the major difference between kinetic and potential energy? Kinetic energy is the energy of motion and potential energy is associated with the position of an object. Potential energy is the energy of motion and kinetic energy is associated with the position of an object. Kinetic energy is stored in chemical bonds and potential energy is associated with the position of an object.

Kinetic energy is the energy of motion and potential energy is associated with the position of an object.

Select all of the following that can take place during a chemical reaction. Molecules are broken apart. Rearrangements of atoms within molecules occur. Molecules attach to each other to form larger molecules. The amount of matter increases. Electrons are transferred between atoms.

Molecules are broken apart. Rearrangements of atoms within molecules occur. Molecules attach to each other to form larger molecules. Electrons are transferred between atoms.

Select all of the following that can take place during a chemical reaction. Molecules attach to each other to form larger molecules. The amount of matter increases. Molecules are broken apart. Electrons are transferred between atoms. Rearrangements of atoms within molecules occur.

Molecules attach to each other to form larger molecules. Molecules are broken apart. Electrons are transferred between atoms. Rearrangements of atoms within molecules occur.

Match each type of metabolic pathway regulation with the proper description: BIOCHEMICAL

Molecules such as competitive and noncompetitive inhibitors affect the activity of enzymes.

What are some examples of cellular processes that require energy? Muscle contraction, cellular movements, chemical reactions Spontaneous or exergonic reactions that occur in living organisms

Muscle contraction, cellular movements, chemical reactions

What are some examples of cellular processes that require energy? Spontaneous or exergonic reactions that occur in living organisms Muscle contraction, cellular movements, chemical reactions

Muscle contraction, cellular movements, chemical reactions

Name environmental factors that affect proper enzyme function. Temperature and ionic conditions Temperature and pH Temperature, pH and ionic conditions pH and ionic conditions

Temperature, pH and ionic conditions

What is the first law of thermodynamics? The first law states that transfer of energy increases entropy. The first law states that energy cannot be created or destroyed. The first law states that some energy becomes unusable when transferred from one form to another.

The first law states that energy cannot be created or destroyed.

Select the statements that describe the free energy (G) change of a spontaneous reaction. The free energy of the products is greater than the reactants. There is no change in free energy. The free energy of the products is less than the reactants. There is a positive free energy change. Free energy is released during product formation. There is a negative free energy change.

The free energy of the products is less than the reactants. Free energy is released during product formation. There is a negative free energy change.

Match each example of the regulation of metabolic pathways with the proper mechanism: BIOCHEMICAL

The product of a metabolic pathway inhibits one of the early steps in the pathway.

What is the second law of thermodynamics? The second law states that energy cannot be created or destroyed. The second law states that transfer of energy from one form to another increases entropy. The second law states that energy is conserved.

The second law states that transfer of energy from one form to another increases entropy.

When is Vmax reached as the amount of substrate is increased during a chemical reaction? Vmax is reached when all the substrate is converted to product. Vmax is reached when all enzymes are saturated with substrate.

Vmax is reached when all enzymes are saturated with substrate.

Match each example of the regulation of metabolic pathways with the proper mechanism: GENETIC

When a particular sugar is available, a bacterial cell turns on the genes that encode enzymes needed to break down the sugar.

What occurs during a redox reaction? When an atom or molecule is oxidized, the electron that is removed is transferred to another atom or molecule, which is thereby reduced. When an atom or molecule is reduced, the electron that is removed is transferred to another atom or molecule, that is thereby oxidized.

When an atom or molecule is oxidized, the electron that is removed is transferred to another atom or molecule, which is thereby reduced.

Why do organisms couple exergonic and endergonic reactions? Coupling of endergonic and exergonic reactions results in less loss of usable energy in the form of heat. When exergonic and endergonic reactions are coupled, the endergonic reaction will proceed if the net free energy change is negative. Endergonic reactions cannot proceed unless they are coupled to an exergonic reaction.

When exergonic and endergonic reactions are coupled, the endergonic reaction will proceed if the net free energy change is negative.

Why do organisms couple exergonic and endergonic reactions? When exergonic and endergonic reactions are coupled, the endergonic reaction will proceed if the net free energy change is negative. Coupling of endergonic and exergonic reactions results in less loss of usable energy in the form of heat. Endergonic reactions cannot proceed unless they are coupled to an exergonic reaction.

When exergonic and endergonic reactions are coupled, the endergonic reaction will proceed if the net free energy change is negative.

During which step during an enzyme-catalyzed reaction does the initial conformational change occur? When substrate binds to the active site, causing an induced fit Whenever an enzyme is present When products are released from the enzyme During the conversion of substrate to product

When substrate binds to the active site, causing an induced fit

When does chemical equilibrium occur? When a chemical reaction has gone to completion and the rate is zero When no more reactants are available for the reaction When the rate of formation of products equals the rate of formation of reactants When there is no enzyme available to catalyze a reaction

When the rate of formation of products equals the rate of formation of reactants

Catalyzed reactions occur at ______ rate compared to uncatalyzed reactions. the same a faster a slower

a faster

Anabolic reactions are also called _________ reactions.

biosynthetic, synthetic, or synthesis

Which line indicates an enzyme which is lowering the activation energy of the reaction may be present? Blue line Red line

blue line

Which line on the graph indicates the activation energy in the presence of an enzyme for the reaction? Blue line Red line

blue line

Which line on the graph indicates the activation energy in the presence of an enzyme for the reaction? Red line Blue line

blue line

Metabolic pathways can be categorized according to whether the sequence of coordinated chemical reactions leads to the ________ or _______ of substances.

breakdown synthesis

An enzyme with a _____________ KM requires a greater concentration of substrate to achieve a particular reaction velocity compared to an enzyme with a ____________ KM.

higher lower

When a water molecule is used to remove a phosphate group from ATP, this is called the _______ of ATP.

hydrolysis

Altering the pH outside the optimal range for a protein can cause denaturation and can ______ the function of an enzyme. not affect enhance impair

impair

When conformational changes cause enzyme and substrate to bind more tightly, this is called _______________ _________________.

induced fit

__________ energy is associated with movement, while _____________ energy is stored energy.

kinetic potential

When the free energy change that occurs as a result of a chemical reaction is _________ than zero, the reaction is spontaneous.

less

The general term for all types of coordinated sequences of chemical reactions that occur in cells is __________ pathways.

metabolic

Exergonic reactions have a(n) __________ change in free energy, and endergonic reactions have a(n) __________ change in free energy.

negative positive

________ molecules provide the building blocks for cell structures.

organic

Chemical energy is a form of ______ energy stored in chemical bonds. electrical kinetic heat mechanical potential

potential

Enzymes are typically composed of which type of macromolecule? Carbohydrate Nucleic acid Protein Lipid

protein

Enzymes are typically composed of which type of macromolecule? Lipid Protein Nucleic acid Carbohydrate

protein

In general, enzymes are composed of ______.

proteins

During ________ reactions, one or more substances are changed or converted into other substances.

redox

The term "redox reaction" is short for a(n) ___________ - ___________ reaction.

reduction oxidation

True or false: Only after conformational changes cause an induced fit, can substrates be converted to products during an enzyme catalyzed reaction. True False

true