Ch.8 - Energy and MetabolismSee all chapters
All Chapters
Ch.1 - Introduction to Biology
Ch.2 - Chemistry
Ch.3 - Water
Ch.4 - Carbon
Ch.5 - Biological Molecules
Ch.6 - Cells
Ch.7 - The Membrane
Ch.8 - Energy and Metabolism
Ch.9 - Respiration
Ch.10 - Photosynthesis
Ch.11 - Cell Signaling
Ch.12 - Cell Division
Ch.13 - Meiosis
Ch.14 - Mendelian Genetics
Ch.15 - Chromosomal Theory of Inheritance
Ch.16 - DNA Synthesis
Ch.17 - Gene Expression
Ch.18 - Regulation of Expression
Ch.19 - Viruses
Ch.20 - Biotechnology
Ch.21 - Genomics
Ch.22 - Development
Ch.23 - Evolution by Natural Selection
Ch.24 - Evolution of Populations
Ch.25 - Speciation
Ch.26 - History of Life on Earth
Ch.27 - Phylogeny
Ch.28 - Prokaryotes
Ch.29 - Protists
Ch.30 - Plants
Ch.31 - Fungi
Ch.32 - Overview of Animals
Ch.33 - Invertebrates
Ch.34 - Vertebrates
Ch.35 - Plant Anatomy
Ch.36 - Vascular Plant Transport
Ch.37 - Soil
Ch.38 - Plant Reproduction
Ch.39 - Plant Sensation and Response
Ch.40 - Animal Form and Function
Ch.41 - Digestive System
Ch.42 - Circulatory System
Ch.43 - Immune System
Ch.44 - Osmoregulation and Excretion
Ch.45 - Endocrine System
Ch.46 - Animal Reproduction
Ch.47 - Nervous System
Ch.48 - Sensory Systems
Ch.49 - Muscle Systems
Ch.50 - Ecology
Ch.51 - Animal Behavior
Ch.52 - Population Ecology
Ch.53 - Community Ecology
Ch.54 - Ecosystems
Ch.55 - Conservation Biology
Sections
Thermochemistry
ATP
Enzymes
Metabolism

Concept #2: Enzyme Catalysis and Cofactors

Concept #3: Enzyme Inhibition

Concept #4: Kinases and Cooperativity

Concept #5: Feedback Inhibition

Practice: By increasing the substrate concentration, one can overcome the effects of a competitive inhibitor. Why doesn’t this work for noncompetitive inhibitor?

Practice: What is the difference between a cofactor and a prosthetic group?

Practice: Enzymes catalyze reactions by lowering the amount of ______ needed for a reaction to proceed.

Practice: ________ is when the product of a biochemical pathway serves to inhibit the activity of that product's production.

Practice: All of the following affect the ability of an enzyme to catalyze a reaction EXCEPT:

Additional Problems
The specificity of an enzyme is due to its active site. The active site is shaped so that only a certain a. substrate molecule can fit into it b. product molecule can fit into it c. reactant molecule can fit into it d. cofactor molecule can fit into it e. histone molecule can fit into it
The organic non-protein components that aid in enzyme functioning are called a. reactants b. cofactors c. coenzymes d. substrates e. products
The inorganic non-protein components that participate in enzyme catalysis are known as a. coenzymes b. cofactors c. end-products d. substrates e. reactants
Chemical reactions can be influenced by a. temperature only b. concentration of reactants and products c. catalysts d. only a and b e. a, b, and c
Protein catalysts that speed up the various metabolic biological reactions in an organism are called a. substrates b. cofactors c. reactants d. products e. enzymes
Enzymes have specific ________ with which they interact.a. productsb. substratesc. reactantsd. atomse. end-products
An enzyme is a lipid that catalyzes chemical reactions. a. Trueb. False
An enzyme is a protein that catalyzes chemical reactions. a. Trueb. False
Which of the following is true of enzymes?a. Enzyme function is independent of physical and chemical environmental factors such as pH and temperatureb. Nonprotein cofactors alter the substrate specificity of enzymesc. Enzymes increase the rate of chemical reaction by lowering activation energy barriersd. Enzyme function is often increased if the 3-D structure or conformation of an enzyme is alterede. Enzymes increase the rate of chemical reaction by providing activation energy to the substrateYou have an enzymatic reaction proceeding at the optimum pH and optimum temperature. You add a competitive inhibitor to the reaction and notice that the reaction slows down. What can you do to speed the reaction up again?a. Increase the pH.b. Add more substrate it will outcompete the inhibitor and increase the reaction rate.c. Increase the temperatured. Add more inhibitor to speed up the reaction.
The active site of an enzyme is the region that _________.a. binds allosteric regulators of the enzymeb. is involved in the catalytic reaction of the enzymec. binds noncompetitive inhibitors of the enzymed. is inhibited by the presence of a coenzyme or a cofactor
 Enzymes typicallya. raise the activation energy.b. bind non-specifically to the substrate.c. provide a microenvironment that inhibits the reaction.d. catalyze both the forward and the reverse reaction.
The enzyme phosphokinase 1,4 alpha- aminohydratase catalyses the reaction protoporphyrin → hemoglobin → 1,3 diphosphoglycerate. The region of the enzyme where phosphokinase 1,4 alpha- amminohydratase attaches to the substrate is:a. competitive siteb. active sitec. non-competitive sited. feed back site
What is an enzyme's chemical nature and role in biochemical reactions?
Why does increasing the amount of enzyme increase the amount of products that can be produced per unit time?
What is an enzyme? What is activation energy? How are those terms related? Define enzymatic activity
Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increaseing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid.Which of the following is most consistent with the information above?A. Succinate dehydrogenase is an enzyme, fumarate is a substrate, and malonic acid is an inhibitor.B. Suucinate dehydrogenase is a substrate, fumarate is a product, and malonic acid is a catalyst.C. Succinate dehydrogenase is a catalyst, succinate is a substrate, and fumarate is a product.D. Succinate dehydrogenase is an enzyme, succinate is a product, and malonic acid is a substrate.
Which of the following is/are true of enzymes?A. They are involved in almost all facets of a cell's metabolism.B. They function by lowering activation energy of reactions.C. are composed primarily of polypeptides, which are polymers of amino acids.D. A and B are trueE. All of the above are true.
An enzyme _______.A. becomes part of the final productsB. is nonspecific for substratesC. is affected by heat and pHD. is consumed by the reaction
A hypothetical free energy curve for an enzymeatic reaction is shown. Curve A corresponds to uncatalyzed reaction and curve Bc orresponds to the catalyzed reaction. What can you say about this enzymatic process?A. This enzyme does not alter the rate of chemical reaction.B. This enzyme reduces the rate of the chemical reaction.C. This enzyme binds the substrate strongly.D. both (A) and (C)E. both (B) and (C)
Which of the following is NOT a characteristic of enzymes?A. Speed up reactionsB. Altered by the reactions they catalyzeC. Very specificD. Recycled to do the same reaction over and over againE. Activity is regulated
Why does pH affect enzyme activity?
Which of he following refers to the whole enzyme?A. apoenzymeB. holoenzymeC. cofactorD. coenzyme
The _____ is defined as the protein portion of an enzyme exclusive of any organic or inorganiccofactors or prosthetic groups that might be required for catalytic activity.A. coenzymeB. apoenzymeC. holoenzymeD. porphyrin
Enzymes only work at certain temperatures, ionic strengths and pH ranges. Why? 
All of the following would have an effect on an enzyme speed except _____.A. oxygen concentrationB. temperatureC. pHD. substrate concentrationE. cofactors and vitamins
Enzymes are divided into six major classes, based on the type of reaction they catalyze. Based on this, in which enzyme do the β-lactamases belong?A. hydrolaseB. oxidoreductaseC. isomerasesD. ligasesE. lyasesF. transferases
Name 5 environmental factors that influence enzyme activity.
People often put on weight after a period of fasting (dieting) because fasting increases the activity of two major enzymes that are essential for fatty acid biosynthesis. (i) Name these two enzymes (ii) Choose one of these enzymes and describe the biochemical reaction/s that it catalyses