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