CH8-Microbial Metabolism
How many bonds must be broken in ADP to form AMP?
1
Please order the following choices to reflect the sequence of electron carriers in the respiratory chain of most aerobic organisms.
1. NADH dehydrogenase 2. Flavin mononucleotide 3. Coenzyme Q 4. Cytochrome b 5. Cytochrome c1 and c 6. Cytochrome a and a3
Order the following molecules from where electrons are first donated from NADH to their terminal acceptor oxygen.
1. NADH dehydrogenase 2. ubiquinone 3. cytochrome bc reductase 4.cytochrome c 5. cytochrome c oxidase
Some bacteria use anaerobic respiration to generate ATP.Instead of oxygen, these microbes can use molecules like nitrate as an electron acceptor.Indeed, during the process of denitrification, nitrate can be completely reduced to nitrogen gas.Denitrification is an important means to enable nitrogen cycling in the biosphere.Order the following nitrogen-containing compounds from least to most reduced.
1. Nitrate 2. Nitrite 3. Nitric Oxide 4. Nitrous Oxide 5. Dinitrogen
Please match the sources of energy with the statements that most accurately describe them, to test your understanding of diverse sources of energy.
1. Thermal energy Molecular motion Correct 2. Radiant energy Visible light or other rays Correct 3. Electrical energy Flow of electrons Correct 4. Mechanical energy Physical change in position Correct 5. Atomic energy Reactions in the nucleus of an atom Correct 6. Chemical energy Present in the bonds of molecules Correct
Please match the following enzyme classes with the statements that most accurately describe them to test your understanding of enzyme names and functions.
1. Transferases Transfer functional groups from one substrate to another Correct 2. Hydrolases Cleave bonds on molecules with the addition of water Correct 3. Isomerases Change substrates to another form with same molecular formula Correct 4. Ligases Catalyze the formation of bonds with the input of ATP and the removal of water Correct
For each molecule of glucose that enters glycolysis, the last five reactions (of glycolysis) occur___ times
2
How many net ATP are generated during fermentation?
2
The Kreb's cycle must turn________times for each glucose that entered glycolysis.
2
Typically, __________ATP are netted by fermentation.
2
For each glucose that enters glycolysis, the NET output is:
2 ATP 2 NADH 2 Pyruvic acid
For each glucose that enters glycolysis, acetyl CoA formation results in the production of ______.
2 NADH 2 CO2
During acetyl CoA formation _____ CO2 and _____ NADH are produced per initial glucose that enters glycolysis.
2, 2
The NET output of glycolysis is __________ATP, ------------NADH, and _________pyruvic acid molecules per glucose.
2, 2, 2
How many phosphate groups does ATP contain?
3
At best, cells can generate _________ ATP from the complete oxidation of one glucose molecule during aerobic cellular respiration.
38
In bacterial cells and eukaryotic microbes, when glucose is completely oxidized by all the pathways of aerobic cellular respiration, what is the maximum number of ATP generated?
38
What is the maximum yield of ATP from aerobic respiration in prokaryotes?
38
During the Kreb's cycle _____ CO2, _____FADH2, _____NADH, and _____ATP are produced per initial glucose that enters glycolysis.
4, 2, 6, 2
Please select all of the structural components of ATP.
5-carbon ribose sugar chain of three phosphate groups adenine
Eventually, _________carbon dioxide molecules will be produced from one molecule of glucose by the end of respiration.
6
How many molecules of carbon dioxide are generated by the Krebs cycle for every glucose entering glycolysis?
6
How many oxygen molecules are consumed during electron transport for each glucose during aerobic respiration?
6
If one glucose (C6H12O6) is completely oxidized during cellular respiration, then how many oxygen molecules are needed to act as terminal hydrogen acceptors at the end of the electron transport system?
6
The Kreb's cycle has ____ steps
8
Glycolysis consists of how many steps?
9
Glycolysis has __________ enzymatic steps for glucose to be converted to two pyruvates. (number)
9
In the cell, energy released by electrons is often used to phosphorylate
ADP
Which is NOT a common cellular coenzyme that carries electrons?
ADP
Which is an energy-rich product of aerobic respiration?
ATP
Which of the following couples (links) anabolic reactions with catabolic reactions?
ATP
_________(acronym) is the useful final product of aerobic respiration.
ATP
___________is the energy currency of the cells, coupling energy releasing reactions with energy requiring reactions.
ATP
What occurs in the last 3 steps of glycolysis?
ATP forms by substrate-level phosphorylation
Protons can only cross the mitochondrial inner membrane through
ATP, synthase
Most condensation reactions require an input of ______________ and result in a loss of ______________
ATP, water
Which is typically reduced to form ethanol during fermentation?
Acetaldehyde
The minimum amount of energy required for a reaction to proceed is termed the energy of
Activation
What term is used to describe the minimum amount of energy required for a reaction to proceed?
Activation energy
Which feature of an enzyme is the "most" unique?
Active site
Which nitrogenous base is found in ATP?
Adenine
Which of the following is correct regarding aerobic and anaerobic respiration pathways?
Aerobic pathways use oxygen.
Which is the primary pathway used by heterotrophic microorganisms to obtain energy?
Aerobic respiration
Identify two different fermentation pathways.
Alcoholic fermentation Acidic fermentation
Which Krebs cycle substrates undergo decarboxylation reactions?
Alpha-ketoglutarate Isocitrate
_________________is the cellular process of taking monomers of compounds and producing polymers (e.g., amino acids are combined to make proteins).
Anabolism or Biosynthesis
What term refers to a biological catalyst that lacks an essential cofactor?
Apoenzyme
Which of the following is NOT a characteristic commonly associated with enzymes?
Are much smaller than their substrates Increase activation energy Are used up by the reaction
Consider the biochemical pathway: A - E1 -> B - E2 -> CIf Enzyme 2 is inactive, which of the following compounds will accumulate?
B only
Which term is used to describe the study of the mechanisms of cellular energy release, including catabolic and anabolic pathways?
Bioenergetics
__________ is a study of the mechanisms of cellular energy release, including catabolic and anabolic pathways.
Bioenergetics
Competitive inhibition decreases the activity of an enzyme by
Blocking the active site of the enzyme Preventing the enzyme-substrate interaction
Which of the following is an energy-poor product of aerobic respiration?
Both CO2 and water
Krebs Cycle
Both NADH and FADH2 are produced in the reactions. Two ATPs are made through substrate-level phosphorylation. The Initial reactant of the pathway is regenerated through the reaction.
The term "metabolism" includes which type(s) of cellular reactions?
Both anabolic and catabolic
Identify any of the following which serve as energy-poor products of aerobic respiration.
CO2 Water
______________ are used as cellular energy sources because they are superior electron donors.
Carbohydrates
Select the oxidized compounds that can be used as a final electron acceptors in anaerobic respiration.
Carbonate Sulfate Nitrate
Which of the following is the decomposition of complex compounds during cellular metabolism?
Catabolism
__________refers to the decomposition of complex compounds during cellular metabolism, usually with the release of energy.
Catabolism
Which of the following can result in the denaturation of enzymes?
Chemicals Changes in pH High temperatures
________is the generation of a proton motive force by the pumping of hydrogen ions to the outer side of the membrane during electron transport and the movement of those hydrogen ions down their electrochemical gradient through the ATP synthase enzyme.
Chemiosmosis
Which of the following represent cofactors?
Coenzymes Small organic molecules Metal ions
Which of the following is needed for an apoenzyme to be fully functional?
Cofactor
___________________enzyme inhibition is a mechanism of regulation where the active site is blocked by a molecule that resembles the true substrate.
Competitive
Which component of the electron transport chain accepts electrons from NADH?
Complex I
Which group of iron-sulfur proteins in the electron transport chain accepts electrons from FADH2?
Complex II
What name is used to describe enzymes that are generally found at constant amounts in the cell independent of substrate concentrations?
Constitutive enzymes
After glycolysis, which is the initial step in alcoholic fermentation?
Conversion of pyruvic acid to acetaldehyde
What happens to glucose-6-phosphate in glycolysis?
Converted into fructose-6-phosphate
Which statement is FALSE regarding enzymes?
Create reactions
Which compound blocks cytochrome oxidase, causing a termination of aerobic respiration and death?
Cyanide
When the starting molecule of a biochemical pathway is regenerated through the series of connected reactions, it is referred to as a(n) ___________pathway.
Cyclic
What compound is composed of a heme (iron containing) component which can shuttle electrons through the ETS during respiration?
Cytochrome
Which component of the electron transport system catalyzes the terminal step of aerobic respiration?
Cytochromes a and a3
Which is NOT a method of overcoming activation energy in any reaction?
Decreasing the substrate concentration
What term is used to describe proteins losing their three dimensional structure as a consequence of changes in the environmental conditions such as excessive heat or salt?
Denaturation
Which enzymes neutralize toxic products of respiration in aerobic organisms?
Dismutase Catalase Peroxidase
Which of the following would produce the most ATP?
E. coli growing in a well-aerated glucose broth for 48 hours
Regulated enzymes are repressed according to the concentration of which of the following?
End product
What term is used to describe enzymes which work within the cell that produces them?
Endoenzymes
Regulated enzyme
Enzyme is induced or reduced with changing substrate levels.
_________act as catalysts in virtually all metabolic pathways.
Enzymes
Reactions that release energy as they proceed are called __________, while reactions that require energy to complete are called __________.
Exergonic and Endergonic
Each of the following are electron carriers except
FADP
Which best describes the function of enzymes?
Facilitate metabolic pathways
ATP is composed of deoxyribose, adenine, and 3 phosphate groups.
False
If the end product of a biochemical pathway becomes available in the environment, the cell must continue making the product.
False
The Krebs cycle provides a significant means to synthesize a small amount of ATP in the absence of oxygen and also to generate pyruvic acid, an essential intermediary metabolite.
False
Which term describes the incomplete breakdown of glucose due the absence of an electron acceptor for the electron transport system?
Fermentation
Which aspect of an enzyme's structure gives rise to the specificity for its substrate?
Folding to produce a 3-D structure
Glycolysis
Four ATPs are made through substrate-level phosphorylation, but two ATPs are used in the reactions. A six-carbon compound is catabolized into two three-carbon compounds. Two NADHs are produced.
Why do the last five reactions of glycolysis occur twice for each glucose substrate?
Glucose is split into 2 intermediates at step 4
Which of the following identifies best the reason for the Krebs cycle must occur twice per glucose molecule?
Glucose will yield two pyruvates
Which of the following metabolic pathways begins with glucose and yields two pyruvates?
Glycolysis
___________________is the multi-step energy-yielding conversion of glucose to pyruvic acid.
Glycolysis
The primary catabolism of molecules by most organisms would include which three of the following pathways?
Glycolysis Respiratory chain Kreb's cycle
Which type of acidic fermentation produces mixed acid products?
Heterolactic
Identify any of the following which could INCREASE the rate of an enzymatic reaction which is currently not at optimal conditions.
Increase temperature slightly Increase substrate(s) concentration Decrease temperature slightly Increase enzyme concentration
What adaptation explains how some fermentative bacteria can grow as fast as they would in the presence of oxygen?
Increased rate of glycolysis
In most living systems, which of the following mechanisms is usually NOT a possibility for increasing the rate of a chemical reaction?
Increasing thermal energy Increasing the concentration of reactants
Carbon dioxide released during the Krebs cycle comes from which substrates?
Isocitrate and Alpha-ketoglutarate
What is the typical "next step" for pyruvate at the end of glycolysis following normal aerobic or anaerobic respiration?
Kreb cycle
In strict aerobes and some anaerobes, pyruvic acid enters the ___________ , or citric acid, cycle.
Krebs
Which two of the following macromolecules have the most accessible energy stored within their structures?
Lipids Carbohydrates
Which model is sometimes used to describe enzyme-substrate interactions?
Lock-and-key
If the membranes of the mitochondrion were permeable to protons then what would happen?
Loss of proton motive force
Select the ways that cells manage the energy needed for metabolic reactions.
Making and breaking chemical bonds Transferring electrons
Which Krebs cycle substrate is converted to oxaloacetate so that the cycle can begin again?
Malate
The ETS is found embedded in the inner membrane of the __________ of eukaryotes while the ETS is found embedded in the ___________ membrane of prokaryotes.
Mitochondria ,cytoplasma
Which type of fermentation best describes degradation of pyruvic acid that results in the production of some combination of lactic, acetic, succinic, and formic acids?
Mixed acid
During the conversion of pyruvic acid to acetyl CoA, electrons reduce _________________
NAD
In step five of glycolysis, glyceraldehyde-3-phosphate donates electrons that reduce the coenzyme .
NAD
Using an abbreviated acronym, name any common coenzymes acting as electron carriers in your cells: (Do not add the hydrogen to the end)
NAD
Which is the most common redox (electron) carrier in cells?
NAD
____________is the most common redox (electron) carrier in cells.
NADH
Which occurs during fermentation?
NADH NAD
During fermentation, ____________(NAD or NADH) is oxidized to form ____________(NAD or NADH).
NADH, NAD
In ____________ enzyme inhibition, a regulatory molecule binds to a site other than the active site.
Noncompetitive
In aerobic respiration __________ is the final electron acceptor, whereas in anaerobic respiration another oxidized ion such as __________ is the final electron acceptor.
O2, NO3-
Which of the following could not be a cofactor?
Organic acids
Which serves as a terminal electron acceptor in fermentation?
Organic compounds
A redox reaction involves the coupling of which two types of reactions?
Oxidation and reduction
Series of reactions involving electron transport and ATP Synthase
Oxidative phosphorylation
What term is used to describe the process of ATP production from the ETS?
Oxidative phosphorylation
Which of the following is best associated with the electron transport system?
Oxidative phosphorylation
Electron Transport Chain
Oxidative phosphorylation. Involves proteins in the cell membrane of prokyaryotes or the inner mitochondrial membrane of eukaryotes. Oxygen is required as the final electron acceptor. Generates a theoretic yield of approximately 30 ATPs.
For aerobic respiration, which is the final electron acceptor?
Oxygen
What is the most common target when cells regulate metabolic pathways?
Pacemaker enzyme
Which term is used to describe the addition of a phosphate group?
Phosphorylation
What is the first step in glycolysis?
Phosphorylation of glucose
ATP is formed by means of a light-driven electron transport mechanism
Photophosphorylation
uses light-driven electron transport to generate ATP
Photophosphorylation
Which is NOT an advantage of fermentation to microbial survival and growth?
Promotes growth in oxygen-rich areas of the host
Besides proteins, which type of molecule has been shown to have catalytic activity?
RNA
Which best defines an active site?
Region of an enzyme where the substrate binds
What is the ecological benefit of denitrification?
Replenishes nitrogen in the atmosphere
Which of the following sugars is part of the structure of ATP?
Ribose
Which of the following is true regarding alcohol fermentation within cells?
Several different alcohols can be produced
What is the result of fermentation processes by homolactic bacteria?
Souring of milk
What name is given to the compound upon which an enzyme will act?
Substrate
Which is NOT a physical condition needed for optimal function of an enzyme?
Substrate concentration
Excluding use of the electron transport chain, what method is used to generate ATP in all cells?
Substrate level phosphorylation
A process where ATP is formed by transfer of a phosphate group from a high-energy compound directly to ADP
Substrate-level phosphorylation
Which of the following compounds make the "best" electron donors in aerobic respiration?
Sugars
Which is NOT a toxic product generated by side reactions during aerobic respiration?
Superoxide dismutase
Which is NOT a function of metallic cofactors?
Supplying energy for the reaction
Most enzymes are named to reflect which of the following?
The action of the enzyme
Which of the following are correct descriptions of biological oxidation-reduction reactions?
The compound that loses electrons is oxidized. The compound that gains electrons is reduced.
Where do you find the high energy bonds in a molecule of ATP?
The last phosphate groups
Photosynthetic eukaryotic microbes utilize mitochondria in cellular metabolism.
True
The Krebs cycle allows the acetyl groups from the breakdown of certain fats to enter the pathway and be used as an energy source.
True
Enzymes are named and classified according to their
Type of action Substrate Site of action
Another name for Coenzyme Q is
Ubiquinone
_____________are principle components of coenzymes and this is why they are important components of our diet.
Vitamins
When would human cells use fermentation as opposed to respiration to produce ATP?
When oxygen is low
apoenzyme
a polypeptide of protein component of an enzyme that needs a cofactor in order to function
After the generation of pyruvate, pyruvate is converted into __________ which is typically reduced to form ethanol during alcohol fermentation.
acetaldehyde
___________-CoA feeds directly into the Krebs cycle.
acetyl
In aerobic respiration the first release of carbon dioxide occurs during the formation of ______________ ______________
acetyl, coA
Enzymes typically lower the ___________ energy needed for a reaction to proceed.
activation
The amount of energy required to initiate every metabolic reaction is called
activation energy.
An enzyme's ________ site is unique for each substrate.
active
The_________ site is the region on an enzyme that binds substrate.
active
The nitrogenous base ____________ is a component of ATP.
adenine
Most heterotrophic organisms use respiration to obtain energy.
aerobic
in _____________ respiration, electrons are transferred from fuel molecules to oxygen which acts as the terminal electron acceptor.
aerobic
The two general categories of fermentation pathways are __________and ___________fermentation.
alcohol, acid
The regulatory site of an enzyme can also be referred to as the_________ site
allosteric
ATP synthase is principally composed of ______.
amino acids
The specific process of ______ incorporates nutrients into larger, complex structures through biosynthesis.
anabolism
Which oxidized compound can be used as a final electron acceptor in anaerobic respiration?
any of these
A non-functional enzyme which needs a cofactor is called a(n)
apoenzyme
A(n) _____________enzyme consists of protein alone, while a(n) __________enzyme (or holoenzyme) consists of protein and nonprotein components.
apoenzyme, conjugated
For an apoenzyme to become a functional holoenzyme, it must ______.
bind to a cofactor
The study of the mechanisms of cellular energy release, including catabolic and anabolic pathways, is called
bioenergetics
Energy management in a cell most often involves the making or breaking of chemical __________ and the transfer of __________ from one molecule to another.
bonds, electrons
FAD, NADP, and NAD are all carriers of
both hydrogen and electrons.
Enzymes serve as catalysts for
both types of reactions
Enzymes are indispensable for life because they
can speed up the rate of an uncatalyzed reaction by up to 100 trillion fold.
Energy-rich _______________(i.e. glucose) and________________(i.e. fatty acids) can both enter respiration pathways.
carbohydrates, lipids
An enzyme acts as a biological ___________that alters the rate of a reaction without being changed by the reaction.
catalyst
If internal cellular enzymes are denatured, it can lead to:
cell death
In bacterial cells, the electron transport system and ATP synthase are located in the
cell membrane.
In prokaryotes, the protons are pumped actively across the ______ membrane by the electron transport carriers.
cellular
Labile means which of the following?
chemically unstable
Production of ATP occurs by the process of ______, where hydrogen ions travel down their concentration gradient through channels in ATP synthase complexes.
chemiosmosis
The concept of __________ describes the active transport of protons across a membrane to set up a concentration gradient called the proton motive force to set the stage for ATP synthesis.
chemiosmosis
The first step of the Krebs cycle results in the formation of ________.
citric acid
The first step of the Krebs cycle is the formation of ________acid from ________acid and the acetyl group of acetyl CoA.
citric, oxaloacetic
A complex organic molecule, often derived from vitamins, that acts in conjunction with an enzyme is known as a(n)
coenzyme
Often derived from vitamins, a ______ is a type of cofactor that will act in conjunction with an enzyme to carry out activity.
coenzyme
When combined with its apoenzyme, a(n) ____________ is an organic compound that functions to move (carry) functional groups from one substrate to another.
coenzyme
Which of the following acts as a carrier to move a chemical group from one substrate molecule to another?
coenzyme
organic cofactors work with an apoenzyme to catalyze a chemical reaction
coenzyme
A(n) _____________ is an organic molecule or inorganic element that may be required for an enzyme to become functional.
cofactor
________________ can be (are) metals that activate enzymes and help bring the active site and substrate together.
cofactors
In ________ inhibition, a molecule occupies the active site which prohibits the substrate from binding and therefore, inhibits the enzyme's activity on the substrate.
competitive
Inhibitors that share binding affinity with the substrate is termed a ______ inhibitor.
competitive
__________ inhibition occurs when the inhibitor molecule is contending with the substrate for the binding site.
competitive
An enzyme with another molecule, such as a metal or vitamin cofactor, bound covalently to it is termed a(n) _______.
conjugated enzyme
A(n) _____________ enzyme describes an enzyme present in constant amounts regardless of the presence of substrate.
constitutive
Enzymes that are always present, regardless of the amount of substrate are
constitutive enzymes.
Choose all the true statements about the enzyme pyruvate dehydrogenase.
couples oxidation of pyruvate with reduction of NAD+ contains four vitamin cofactors catalyzes release of CO2 from pyruvate
Metabolic pathways in which the starting molecule is regenerated through the series of reactions are called ______ pathways.
cyclic
A(n) ___________ is an iron containing (heme) protein electron carrier in the last phases of aerobic respiration.
cytochrome
Cytochrome aa3, also known as , ___________ ___________catalyzes the terminal step of aerobic respiration.
cytochrome, oxidase
Enzymes that catalyze the removal of carbon dioxide from a substrate are called
decarboxylases.
Negative feedback is a process that ______ enzyme activity when a certain concentration of ______ is produced.
decreases; product
Given a sucrose molecule and glucose molecule that will become bonded, what type of reaction takes place?
dehydration
The loss of the normal or native shape of a protein due to chemical or physical disruption of tertiary structure is called protein________
denaturation
The reduction of nitrite to nitrous oxide or nitrogen gas by some species of bacteria is called ________.
denitrification
The return of nitrogenous compounds to the atmosphere at the end of the nitrogen cycle is called
denitrification
____________ is an important process that is involved in the recycling the nitrogen contained in organisms back into the biosphere.
denitrification
A chemical reaction that requires energy to proceed is referred to as a(n) ______ reaction.
endergonic
Chemical reactions that are driven forward with the addition of energy are called __________ reactions.
endergonic
A(n) ____________describes any enzyme that works within a cell in which it was produced.
endoenzyme
enzymes that are retained and function intracellularly
endoenzyme
All cells need a constant input and expenditure of ________ in a usable form.
energy
All living cells require a constant input and expenditure of usable __________
energy
A(n)____________ is a biological catalyst.
enzyme
Each reaction in a metabolic pathway is catalyzed by a separate _________
enzyme
Composed principally of amino acids, ______ act as biological catalysts, facilitating metabolic activities of the cell.
enzymes
In alcohol fermentation, pyruvate is converted to acetaldehyde which is then converted to .
ethanol
Alcoholic fermentation in bacteria could result in the production of:
ethanol butanol isopropanol carbon dioxide
A chemical reaction that releases energy as it proceeds is referred to as a(n) ______ reaction.
exergonic
A(n) ________________________ describes any enzyme that works outside a cell in which it was produced.
exoenzyme
enzymes that are exported extracellularly where they perform their function
exoenzyme
The best way to control a metabolic pathway is to control the fastest enzyme in the series.
false
In the process of making swiss cheese there was no CO2 produced. What was the cause of this gas not being released?
fermentation
In very rare instances of intoxication, yeast in the small intestine can convert dietary carbohydrates to alcohol, a situation called gut_____________syndrome.
fermentation
The incomplete breakdown of glucose in the absence of oxygen that yields only a small amount of ATP and produces a variety of byproducts is a process called
fermentation
The incomplete oxidation of glucose or other carbohydrates without the use of oxygen is a process referred to as __________.
fermentation
Glucose-6-phosphate is converted into _________-6-phosphate in the second reaction of glycolysis.
fructose
Which of the following represents the path of electrons during aerobic respiration?
glucose - NADH - electron transport chain - oxygen
In glycolysis, ________ donates the electrons that reduce NAD to NADH.
glyceraldehyde-3-phosphate
Some fermentative bacteria can grow as fast under anaerobic conditions as they do in aerobic conditions due to the increase in ____________(ATP generating metabolic process) that fermentation provides.
glycolysis
Which of the following are the three main catabolic pathways of aerobic respiration?
glycolysis electron transport chain Krebs cycle
The three coupled pathways that many organisms utilize during the catabolism of fuel molecules are , the cycle, and the chain.
glycolysis, krebs, respiratory
Aerobic respiration and fermentation are similar in that they both begin with the process of __________ and they both produce ATP and __________.
glycolysis; CO2
A high level of blood alcohol caused by reactions in the small intestine that use carbohydrates to produce alcohol causes ______ syndrome.
gut fermentation
One evolutionary strategy to deal with an "enzymatic-block" to a particularly necessary metabolic product is to
have alternative enzymatic methods to synthesize the product
The production of mixed acids, one being lactic acid, during fermentation is a good definition of fermentation.
heterolactic
An enzyme with its apoenzyme and cofactors is referred to as a(n) , _____________or a conjugated enzyme.
holoenzyme
Please choose the term that refers to a conjugated enzyme.
holoenzyme
a conjugated enzymes composed of both protein and nonprotein molecules
holoenzyme
The souring of milk is primarily due to the activity of certain bacteria producing mainly lactic acid so it is called ______ fermentation.
homolactic
Certain species of Lactobacillus ferment glucose into mainly lactic acid in a process termed __________, while other species of Lactobacillus ferment a mixture including lactic acid, acetic acid and carbon dioxide in a process termed __________.
homolactic, heterolactic fermentation
The atom is added to NAD to reduce it.
hydrogen
As the electron transport carriers shuttle electrons, they actively pump _____ into the outer membrane compartment setting up a concentration gradient called the proton motive force.
hydrogen ions
Reactions that involve the breaking of bonds and an input of water are called ______ reactions.
hydrolysis
The digestion of larger substrates into smaller molecules, involving the use of water, is usually the result of ____________ reactions.
hydrolysis
Slight changes occur in the shape of the enzyme in order to guide the substrate into the active site. This is referred to as a(n) .
induced fit
When a substrate binds to an enzyme's active site, often an _____ occurs which brings the substrate tightly within the active site pocket.
induced fit
The electron transport chain is located in the ______ membrane of eukaryotic cells and the ______ membrane of bacteria.
inner mitochondrial; plasma
A regulated enzyme
is produced in response to changes in substrate or product concentration.
Compounds are called _____________ when they can be easily denatured, distorted and/or degraded by mild changes to the environment.
labile
In animals, the common end product of fermentation of pyruvate is ______.
lactic acid
The end product of fermentation by human muscle cells is
lactic acid
During fermentation, different organisms reduce pyruvate to a variety of chemical compounds including:
lactic acid, ethanol, acetic acid, propionic acid
Enzymes are typically ____ than substrates.
larger
Fermentation results in the production of ______ ATPs than aerobic and anaerobic respiration.
less
Enzyme-substrate interactions are sometimes referred to as a(n) " ___________and key" interaction.
lock
Compounds that are oxidized will
lose electrons
Each of the following are denaturing agents except
low temperature
Typically, the presence of enzymes ____ the activation energy for a reaction to proceed.
lowers
In the last step of the Krebs cycle, ______is dehydrogenated to produce ________which is then available to react with acetyl-CoA to start the cycle again.
malate, oxaloacetate
The combination of all reactions (catabolic + anabolic) within a cell is termed
metabolism
Which term refers to all of the chemical reactions within the cell?
metabolism
The location of the Krebs cycle enzymes in eukaryotes is in the ______________ matrix, while in prokaryotes the enzymes are found in the __________________
mitochondria, cytoplasm
In eukaryotic cellular respiration, the charge gradient that exists between the inner and outer ___________membranes during chemiosmosis is called proton motive force.
mitochondrial
A mechanism that can slow down enzymatic activity once a certain concentration of product is produced is called ____________ feedback.
negative
An inhibitor which binds to a site other than the active site and controls enzyme activity is called a ____ inhibitor.
noncompetitive
The terminology "enzyme repression" implies that the enzyme is
not longer being synthesized
In eukaryotes, ATP synthase enzymes are found
on the inner membrane of the mitochondria
Typically, each reaction (step) in a metabolic pathway will require
one enzyme
To form ADP, a total of _____________ phosphate bond(s) must be broken from ATP.
one, single
Important components of coenzymes include the presence of
organic molecules.
Cyanide causes rapid death in humans and other eukaryotes because it terminates aerobic respiration by blocking cytochrome .
oxidase
During aerobic respiration, glucose and oxygen are converted to carbon dioxide and water.In this reaction glucose undergoes __________, while oxygen undergoes __________.
oxidation, reduction
ATP is synthesized via ______ phosphorylation during the electron transport phase of respiration.
oxidative
An electron transport system and chemiosmosis are used to produce ATP in non photosynthetic microorganisms via _______________-phosphorylation.
oxidative
In a redox reaction, one compound is __________ and another compound is ______________
oxidized, reduced
Enzymes that catalyze removing electrons from one substrate and adding electrons to another substrate are called
oxidoreductases
Aerobic respiration requires ________, whereas fermentation and anaerobic respiration occur without this molecule.
oxygen
Consider the simplified aerobic respiration formula: Sugar + O2 --> ATP + CO2 + Heat (__________ is simply NOT part of the fermentation pathway)
oxygen
In anaerobic respiration, __________ is NOT used as a final electron acceptor.
oxygen
The final step of the ETS in aerobic respiration occurs when electrons are passed to ________.
oxygen
The term "aerobic respiration" implies that ____ is required for the metabolic pathway to be completed.
oxygen
Which is NOT associated with fermentation?
oxygen
______________ is the terminal electron acceptor in aerobic respiration.
oxygen
Fermentation allows survival and growth in the absence of ___________and allows colonization of ______________ environments.
oxygen, anaerobic
When _____________ supplies have been depleted in human muscle cells, ATP can be produced by ___________acid fermentation for short periods of time.
oxygen, lactic
In the last step of the ETS, the electrons are passed to _________along with hydrogen which results in the formation of _________
oxygen, water
Often, regulation of metabolic pathways occurs with activation or repression of the ____________ -maker enzyme.
pace
In bacteria, protons are moved from the cytoplasm to the _________space during chemiosmosis.
periplasmic
The high energy of ATP is located in the bonds of the groups.
phosphate
The addition of a phosphate group is referred to as __________________
phosphorylation
The first step in glycolysis is the of ______ glucose to produce glucose-6-phosphate.
phosphorylation
Photosynthetic microorganisms produce ATP via ___________ using an electron transport system powered by light and water.
photophosphorylation
Photosynthetic organisms use a sunlight-driven electron transport chain to generate ATP via ________.
photophosphorylation
Costitutive enzyme
present in constant amounts even with changing substrate concentration
Repression of the activity of a regulated enzyme is completely dependent on end ____________concentration.
product
Negative feedback inhibition is best described as
product binding to enzyme in noncompetitive site.
Most competitive inhibitors found in cells are
products of metabolic pathways
Most enzymes are a functional type of __________(a type of macromolecule).
protein
Which of the following macromolecules can commonly act as a catalyst?
proteins
As hydrogen ions accumulate between the inner and outer membranes of the mitochondrion, a(n) _____ is generated which powers ATP production.
proton motive force
The active pumping of hydrogen ions across the cristae membrane sets up a concentration gradient of hydrogen ions called the
proton motive force
The charged gradient which is formed in the ETS results in the
proton motive force
The impermeability of the inner cristae membrane to __________ is crucial for the maintenance of the chemiosmotic gradient.
protons
Which of the following is not produced during an anabolic process?
pyruvic acid.
By the end of glycolysis, glucose is converted into two 3-carbon
pyruvic acids molecules
Typically, once an enzyme performs a "job", it is
ready to "work" again
Collective reactions which transfer hydrogens/electrons from one compound to another are termed ___________ reactions.
redox
Paired reactions where an electron donor transfers electrons to an electron acceptor are called ______ reactions.
redox
Oxidation reactions are coupled with ________________ reactions.
reduction
A(n)___________ enzyme describes an enzyme that is not always present in the cell since its production responds to changes in concentration of substrate or product.
regulated
The activity of an enzyme can be controlled through the binding of molecules to a site other than the active site that is called a(n) ______.
regulatory site
The term enzyme ___________ refers to an inhibition of the genetic apparatus responsible for replacing the enzyme which results in a decrease in the number of enzyme molecules.
repression
Fermentation
requires an organic electron acceptor.
ATP contains an adenine linked to , a 5-carbon sugar.
ribose
A catalyst composed of RNA is called a(n)
ribozyme
Substrates are generally than the enzymes to which they bind.
smaller
The capacity of photosynthesis to convert __________ energy into __________ energy provides both a nutritional and an energy basis for all heterotrophic living things.
solar, chemical
Protein folding determines the 3-D shape in enzymes needed for their for a particular substrate.
specificity
Induction of the activity of a regulated enzyme is completely dependent on ___________ concentration.
substrate
Regulated enzymes are induced according to the concentration of which of the following?
substrate
The _________________is the term for a specific molecule on which an enzyme acts.
substrate
In _______________-__________- phosphorylation, phosphate groups are transferred from one molecule to AMP or ADP to form ATP.
substrate level
During glycolysis, ATP is made directly by __________-_____________- phosphorylation.
substrate level
During the last steps of glycolysis, ATP is generated by ______________ _________________phosphorylation
substrate level
The ATP generated in the Krebs cycle is produced by _________ phosphorylation.
substrate level
The Krebs cycle generates ATP by __________ _____________phosphorylation
substrate level
Glycolysis provides a net gain of two ATP molecules through ______ phosphorylation.
substrate-level
An enzyme promotes a chemical reaction by serving as a physical site upon which __________ can be positioned for various interactions.
substrates
An enzyme promotes a reaction by serving as a physical site upon which the reactant molecules, called __________, can be positioned for various interactions.
substrates
In metabolic pathways, the products of one enzymatic reaction may act as the ________ for the next step in the pathway.
substrates
In mixed acid fermentation, pyruvic acid is converted into some combination of
succinic acid formic acid lactic acid acetic acid
ATP _______ is an enzyme in the mitochondrial cristae that harnesses the flux of hydrogen ions across the membrane during oxidative phosphorylation.
synthase
The majority of NAD reduction occurs in
the Krebs cycle
ATP has phosphate groups. (number)
three
substrate-level phosphorylation
transfer of phosphate from high-energy compound to ADP to directly generate ATP
All of the anaerobic pathways produce less ATP than aerobic respiration.
true
Changes in environmental conditions can cause the denaturation of cellular enzymes, resulting in blocks to metabolic reactions and ultimately in cell death.
true
Fermentation uses an organic compound for the electron acceptor.
true
True or false: Metabolic pathways are interconnected.
true
Vitamin deficiencies can prevent the complete holoenzyme from forming, because some of the most common components of coenzymes are vitamins.
true
At the end of glycolysis, the carbons from glucose are now located in
two pyruvic acids.
oxidative phosphorylation
uses electron transport and an enzyme to generate ATP
Which of the following is not true of anaerobic respiration?
uses the same final electron acceptors as aerobic respiration
The major difference between aerobic and anaerobic respiration is ______.
using or not using oxygen
Which of the following is the most common component of coenzymes?
vitamins
Most condensation reactions involve the loss of:
water
The bonds that form enzyme-substrate complexes are __________and easily reversible.
weak
Enzymes bond _____ with their substrate.
weakly
