Energy Concepts and Cellular Processes
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Questions and Answers

What is exhibited by a space station orbiting Earth?

kinetic energy

'Conservation of energy' refers to the fact that _____.

energy cannot be created or destroyed but can be converted from one form to another.

Chemical energy is a form of _____ energy.

potential

What process converts the chemical energy found in glucose into the chemical energy found in ATP?

<p>cellular respiration</p> Signup and view all the answers

Which are the by-products of cellular respiration?

<p>heat, carbon dioxide, and water</p> Signup and view all the answers

In general, enzymes are what kinds of molecules?

<p>proteins</p> Signup and view all the answers

Enzymes work by _____.

<p>reducing EA (activation energy)</p> Signup and view all the answers

An enzyme _____.

<p>is an organic catalyst</p> Signup and view all the answers

What name is given to the reactants in an enzymatically catalyzed reaction?

<p>substrate</p> Signup and view all the answers

As a result of its involvement in a reaction, an enzyme _____.

<p>is unchanged</p> Signup and view all the answers

What is the correct label for 'A'?

<p>energy of activation</p> Signup and view all the answers

What would happen to the rate of the forward reaction if the temperature were lowered to 100?

<p>The reaction rate would decrease.</p> Signup and view all the answers

What would happen to the rate of the forward reaction if the concentration of nitrogen were decreased?

<p>The reaction rate would decrease.</p> Signup and view all the answers

Which of the following would increase the rate of the reverse reaction?

<p>increasing the concentration of ammonia</p> Signup and view all the answers

What will happen to the rates of the forward and reverse reactions when a catalyst is added?

<p>Both forward and reverse rates increase.</p> Signup and view all the answers

An enzyme is ___ when it loses its native conformation and its biological activity.

<p>denatured</p> Signup and view all the answers

An enzyme is considered a ___ because it speeds up chemical reactions without being used up.

<p>catalyst</p> Signup and view all the answers

An enzyme is considered ___ because of its ability to recognize the shape of a particular molecule.

<p>specific</p> Signup and view all the answers

A ___, such as a vitamin, binds to an enzyme and plays a role in catalysis.

<p>cofactor</p> Signup and view all the answers

When properly aligned, the enzyme and the substrate form an enzyme-substrate (ES) ___.

<p>complex</p> Signup and view all the answers

A substrate binds to an enzyme at the ___, where the reaction occurs.

<p>active site</p> Signup and view all the answers

In a catalyzed reaction, a reactant is often called the ___.

<p>substrate</p> Signup and view all the answers

Select the highest energy form of adenosine from the following images.

<p>ATP adenosine triphosphate, contains most phosphate groups</p> Signup and view all the answers

Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions?

<p>lambda-phosphate (the terminal phosphate)</p> Signup and view all the answers

In this reaction _____.

<p>the products have less potential energy than the reactants and heat has been released to the environment</p> Signup and view all the answers

The reaction A --> B + C + heat is released in a(n) _____ reaction.

<p>exergonic</p> Signup and view all the answers

A(n) _____ reaction occurs spontaneously.

<p>exergonic</p> Signup and view all the answers

Which of these reactions requires a net input of energy from its surroundings?

<p>endergonic</p> Signup and view all the answers

In cells, what is usually the immediate source of energy for an endergonic reaction?

<p>ATP</p> Signup and view all the answers

The reaction ADP + P --> ATP is a(n) _____ reaction.

<p>endergonic</p> Signup and view all the answers

The energy for an endergonic reaction comes from a(n) _____ reaction.

<p>exergonic</p> Signup and view all the answers

What is the fate of the phosphate group that is removed when ATP is converted to ADP?

<p>It is acquired by a reactant in an endergonic reaction.</p> Signup and view all the answers

This graph illustrates a(n) _____ reaction.

<p>endergonic</p> Signup and view all the answers

What is the definition of motion in terms of energy?

<p>kinetic energy</p> Signup and view all the answers

In biological context, what is the definition of a protein?

<p>enzyme</p> Signup and view all the answers

What term describes a reaction that is nonspontaneous?

<p>endergonic</p> Signup and view all the answers

What term describes a spontaneous reaction?

<p>exergonic</p> Signup and view all the answers

What is positional energy known as?

<p>potential energy</p> Signup and view all the answers

What is the use of energy released from an exergonic reaction to drive an endergonic reaction?

<p>energy coupling</p> Signup and view all the answers

In which region does the reaction rate remain constant?

<p>region C</p> Signup and view all the answers

In which region is the enzyme saturated with substrate?

<p>region C</p> Signup and view all the answers

What is the best option for increasing the rate of a reaction if the enzyme is operating at optimum temperature and pH, and has been saturated with substrate?

<p>Increase the enzyme concentration.</p> Signup and view all the answers

What is the statement about feedback-regulated enzymatic pathway where P4 binds E1?

<p>P4 binds E1 and deactivates it.</p> Signup and view all the answers

All ___ reactions proceed with a net release of free energy.

<p>exergonic</p> Signup and view all the answers

A chemical reaction that has a positive is correctly described as?

<p>endergonic</p> Signup and view all the answers

When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?

<p>It is lost to the environment.</p> Signup and view all the answers

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's?

<p>activation energy</p> Signup and view all the answers

A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because?

<p>the activation energy barrier for this reaction cannot be surmounted.</p> Signup and view all the answers

During a laboratory experiment, if an enzyme-catalyzed reaction has an energy of -20 kcal/mol, what will be the same for the new reaction after doubling the enzyme?

<p>-20 kcal/mol</p> Signup and view all the answers

___ increase the rate of chemical reactions by lowering activation energy barriers.

<p>Enzymes</p> Signup and view all the answers

What is the purpose of using malonic acid in the inhibition of succinate dehydrogenase?

<p>It is a competitive inhibitor.</p> Signup and view all the answers

Which of the following terms best describes the reaction?

<p>exergonic</p> Signup and view all the answers

Which of the following represents the activation energy required for the enzyme-catalyzed reaction?

<p>b</p> Signup and view all the answers

What must occur for the final attachment to tRNA to happen using an aminoacyl-tRNA synthetase?

<p>The binding of the first two molecules must cause a 3-dimensional change that opens another active site on the enzyme.</p> Signup and view all the answers

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?

<p>by changing the shape of an enzyme</p> Signup and view all the answers

What is the function of a substance that binds to an enzyme at a position remote from its active site?

<p>an allosteric inhibitor</p> Signup and view all the answers

How does growing organisms relate to the second law of thermodynamics?

<p>As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth.</p> Signup and view all the answers

How is the ATPase acting when pumping calcium ions across membranes?

<p>ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient.</p> Signup and view all the answers

Study Notes

Energy Concepts

  • A space station orbiting Earth demonstrates kinetic energy.
  • "Conservation of energy" means that energy cannot be created or destroyed but can be transformed between forms.
  • Chemical energy is classified as potential energy.

Cellular Processes

  • Cellular respiration converts the chemical energy in glucose to ATP.
  • By-products of cellular respiration include heat, carbon dioxide, and water.

Enzymes and Catalysts

  • Enzymes are primarily proteins and function as organic catalysts by reducing activation energy (EA).
  • The reactants in an enzymatically catalyzed reaction are known as substrates.
  • Enzymes remain unchanged after participating in reactions, distinguishing them as catalysts.

Reaction Dynamics

  • The energy of activation is the minimum energy needed for a reaction to occur.
  • Changes in temperature affect reaction rates, with lower temperatures leading to decreased rates.
  • Decreasing reactant concentrations also declines reaction rates, while increasing product concentration favors the reverse reaction.

Reaction Characteristics

  • Forward and reverse reaction rates increase with the addition of a catalyst.
  • Exergonic reactions release energy, while endergonic reactions require energy input.
  • The hydrolysis of ATP releases the terminal phosphate, providing immediate energy for biological processes.

Energy Transfer and Coupling

  • Energy coupling uses the energy from exergonic reactions to drive endergonic reactions.
  • ATP is the main energy source for endergonic reactions in cells.
  • The product of ATP hydrolysis ultimately transfers its phosphate group to a reactant in endergonic processes.

Enzyme Function and Inhibition

  • An enzyme's effectiveness is often monitored through substrate-enzyme complex formation at the active site.
  • Enzymes like succinate dehydrogenase can be inhibited by competitive inhibitors, which resemble substrates.
  • Noncompetitive inhibitors alter enzyme shape, reducing activity regardless of substrate concentration.

Thermodynamics and Biological Order

  • Organisms exhibit increased complexity and decreased entropy internally, generating more environmental disorder in accordance with the second law of thermodynamics.
  • ATPases pump ions across membranes, like calcium ions in muscle cells, often against concentration gradients.

Reaction Energy and Control

  • Exergonic reactions yield free energy, while endergonic reactions have a positive free energy change, indicating non-spontaneity.
  • Feedback regulation can occur where end products inhibit the enzymes involved in their synthesis, exemplified by P4 binding E1 to deactivate it.

Graphical Representation

  • Reaction graphs indicate zones where the enzyme is either saturated with substrate or where reaction rates are constant. Increasing enzyme concentration can enhance reaction rates in optimal conditions.

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Description

This quiz covers key concepts of energy, cellular respiration, and enzymatic activity. Understand how kinetic and potential energy relate, as well as the role enzymes play as catalysts in biochemical reactions. Test your knowledge on how these principles govern cellular activities.

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