Textbook Question
Match the term to the statement (some statements may be used more than once; others may not be used at all).
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Ch. 8 - Microbial Metabolism
Norman-McKay2nd EditionMicrobiology: Basic and Clinical PrinciplesISBN: 9780137661619
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Table of contents
- Ch. 1 - Introduction to Microbiology22
- Ch. 2 - Biochemistry Basics19
- Ch. 3 - Introduction to Prokaryotic Cells17
- Ch. 4 - Introduction to Eukaryotic Cells16
- Ch. 5 - Genetics25
- Ch. 6 - Viruses and Prions12
- Ch. 7 - Fundamentals of Microbial Growth20
- Ch. 8 - Microbial Metabolism16
- Ch. 9 - Principles of Infectious Disease and Epidemiology11
- Ch. 10 - Host Microbe Interactions and Pathogenesis19
- Ch. 11 - Innate Immunity24
- Ch. 12 - Adaptive Immunity22
- Ch. 13 - Immune System Disorders15
- Ch. 14 - Biomedical Applications: Vaccines, Diagnostics, Therapeutics, and Molecular Method14
- Ch. 15 - Antimicrobial Drugs18
- Ch. 16 - Respiratory System Infections16
- Ch. 17 - Skin and Eye Infections19
- Ch. 18 - Nervous System Infections12
- Ch. 19 - Digestive System Infections20
- Ch. 20 - Urinary and Reproductive System Infections10
- Ch. 21 - Cardiovascular and Lymphatic Infections15
Norman-McKay2nd EditionMicrobiology: Basic and Clinical PrinciplesISBN: 9780137661619Not the one you use?Change textbook
Chapter 8, Problem 3
The graph shows an enzyme-catalyzed reaction.
a. Draw a line that would correspond to a noncatalyzed reaction.
b. Is this an endergonic or exergonic reaction? How can you tell?
c. Label the point on your graph that corresponds with the activation energy.
Verified step by step guidance1
Step 1: Understand the difference between catalyzed and noncatalyzed reactions. In an enzyme-catalyzed reaction, the enzyme lowers the activation energy, so the graph shows a lower peak compared to a noncatalyzed reaction. To draw the line for a noncatalyzed reaction, sketch a curve with a higher peak (activation energy) but the same starting and ending energy levels as the catalyzed reaction.
Step 2: Determine if the reaction is endergonic or exergonic by comparing the free energy of reactants and products. If the products have lower free energy than the reactants, the reaction releases energy and is exergonic. If the products have higher free energy, it requires energy input and is endergonic.
Step 3: Identify the activation energy on the graph. Activation energy is the energy difference between the reactants and the highest point (peak) on the curve. Label this vertical distance on the graph as the activation energy.
Step 4: Note that the enzyme lowers the activation energy by stabilizing the transition state, which is why the catalyzed reaction curve has a lower peak compared to the noncatalyzed reaction.
Step 5: Remember that the overall change in free energy (ΔG) between reactants and products remains the same whether the reaction is catalyzed or not; the enzyme only affects the activation energy, not the thermodynamics of the reaction.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Enzyme Catalysis and Activation Energy
Enzymes speed up chemical reactions by lowering the activation energy, which is the energy barrier that must be overcome for reactants to convert into products. This results in a faster reaction rate without altering the overall energy change of the reaction.
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Enzyme Activation Energy
Endergonic vs. Exergonic Reactions
Exergonic reactions release energy and have a negative Gibbs free energy change (ΔG), while endergonic reactions require energy input and have a positive ΔG. The direction of energy flow can be inferred from the relative energy levels of reactants and products on the graph.
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Interpreting Reaction Energy Graphs
Reaction energy graphs plot the energy of reactants and products over the course of a reaction. Key features include the activation energy peak and the difference in energy between reactants and products, which helps identify the reaction type and the effect of catalysts.
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Related Practice
Textbook Question
Label each reactant and product in the reactions as reduced or oxidized (X is a theoretical molecule or atom).
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Textbook Question
Indicate which statements about fermentation are true, and then correct the false statements.
a. Fermentation is an anaerobic process that can be used by prokaryotic or eukaryotic cells.
b. Sugars are the only nutrients that can be fermented.
c. Fermentation is a low ATP yielding process.
d. There are only five types of fermentation: homolactic, heterolactic, alcohol, mixed acid, and butanediol fermentation.
e. Fermentation is the same as anaerobic respiration.
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Textbook Question
Complete the table.
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Textbook Question
Indicate the true statements about ATP, and then reword the false statements so that they are true.
a. ATP is made using anabolic reactions.
b. Substrate-level phosphorylation converts ATP to ADP.
c. ATP is commonly used by cells to store energy.
d. ATP is used to jump-start cellular respiration.
e. Catabolic reactions are used to make ATP.
f. In cellular respiration, the most ATP is made by glycolysis.
g. ATP can be made by phosphorylating ADP.
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