BIOL 101 quiz 3 solutions complete answers

BIOL 101 quiz 3 solutions complete answers 

 

An ATP molecule carries potential energy in the easily broken bond

New molecules of glucose are produced

Accessory pigments and chlorophylls work together within the thylakoid membrane in clusters called __________ . They harvest light energy and use it to transfer electrons to _______________.

Systems that convert energy from one form to another are

The structure of DNA was unraveled using

One glucose molecule plus six oxygen molecules plus 36 ADPs generate six molecules of carbon dioxide, 6 molecules of water and 36 molecules of ATP in a process known as

_________ is a reactant in the process of aerobic respiration and _______ is a product of the same process.

The value of the three stages of aerobic respiration is their ability to break down glucose, a single molecule, with the resultant production of about

A producer organism is called a “producer” because it produces

The immediate source of electrons for electron transfer phosphorylation is

An excess amount of product accumulates at the end of a metabolic pathway. The product then binds to the allosteric site of the first enzyme along the pathway shutting down the pathway. We call this process

The cell’s pumping of substances against diffusion forces that would carry those substances the other way is termed

In nature, as energy freely changes from one form to another

The immediate product of photosynthesis, three-carbon PGALs

________ and ________ are products of aerobic respiration.

In a crowded, unventilated room, the temperature rises because

A single regulatory molecule can shut down multiple metabolic pathways if it is able to

In photosynthesis, ______ and ______ are used to build_______ and release______.

The final stage of aerobic respiration involves

Which of the following substances would most likely enable a flagellum to drive a bacterium forward through the medium in which it is swimming?

Existing chemical bonds between atoms are broken and new ones are formed between different atoms. This process

Biological information must exist because

Energy supplied to break bonds in reactant molecules is known as

Which of the following features of glycolysis is a value to the cell?

One of the laws governing the behavior of energy in living things describes energy conversion as inefficient, with much energy being lost in the form of

 

Question 1

In the process of glycolysis one molecule of _______ is converted to two molecules of __________.

Question 2

Which of the following is a stage of aerobic respiration?

Question 3

All of the six carbon atoms in each glucose molecule leave respiration in the form of carbon dioxide. Most of them leave during which part of aerobic respiration?

Question 4

The activation energy of a reaction can be lowered if the reaction is catalyzed by

Question 5

Biological information must exist because

Question 6

A producer organism is called a “producer” because it produces

Question 7

__________ is a process that uses chlorophyll molecules to produce high-energy carbohydrates.

Question 8

An excess amount of product accumulates at the end of a metabolic pathway. The product then binds to the allosteric site of the first enzyme along the pathway shutting down the pathway. We call this process

Question 9

Light dependent reactions are carried out both on and in between photosystems. This process is like the last stage of aerobic respiration in that both

Question 10

The process of __________ can be defined as about 30 individual, sequential chemical reactions that form three metabolic pathways: one in the cytoplasm and two within the mitochondrion.

Question 11

In a(n)________ the product of one reaction becomes the reactant of the next reaction and so on.

Question 12

Existing chemical bonds between atoms are broken and new ones are formed between different atoms. This process

Question 13

The immediate source of electrons for electron transfer phosphorylation is

Question 14

Enzymes lower activation energies by

Question 15

Griffith exposed weak living bacteria to just the fluids from dead virulent bacteria. Some of these weak bacteria became virulent and could now kill mice. What control experiment did he do to argue that his weak bacteria changed to virulence in these studies?

Question 16

When light of the correct wavelength hits a photosynthetic pigment molecule

Question 17

The Krebs cycle’s NADH products are of value because

Question 18

Which of the following is not a major sort/category of energy change within the cell?

Question 19

Which of the following features of glycolysis is a value to the cell?

Question 20

Three phosphate groups linked to a ribose sugar which, in turn, is linked to a pyrimidine base known as adenine: this phrase describes the structure of

Question 21

One of the laws governing the behavior of energy in living things describes energy conversion as inefficient, with much energy being lost in the form of

Question 22

Physicists define energy as

Question 23

To derive energy from an ATP molecule

Question 24

Light dependent reactions of photosynthesis produce

Question 25

DNA was discovered by Friederick Miescher; he isolated it from

 

Question 1

Glucose + _________ + 36 ADP yields _________ + 6H2O + 36 _________.

Question 2

Enzymes lower activation energies by

Question 3

Which of the following phrases best describes the role of NADPH in photosynthesis?

Question 4

The immediate source of electrons for electron transfer phosphorylation is

Question 5

Light dependent reactions of photosynthesis produce

Question 6

DNA was discovered by Friederick Miescher; he isolated it from

Question 7

Three phosphate groups linked to a ribose sugar which, in turn, is linked to a pyrimidine base known as adenine: this phrase describes the structure of

Question 8

The physicist’s definition of energy is _______________ for use in defining energy changes within a living cell.

Question 9

The three metabolic pathways that make up aerobic respiration are really all parts of one larger pathway because

Question 10

Physicists define energy as

Question 11

Biological information must exist because

Question 12

The activation energy of a reaction can be lowered if the reaction is catalyzed by

Question 13

The Krebs cycle’s NADH products are of value because

Question 14

Autotrophic organisms are supportive of man. They

Question 15

Accessory pigments enable the chloroplast to

Question 16

______ is freely convertible from one form to another but _______ can never be created or destroyed.

Question 17 The process of __________ can be defined as about 30 individual, sequential chemical reactions that form three metabolic pathways: one in the cytoplasm and two within the mitochondrion.

Question 18

The most valuable product, energetically, of electron transfer phosphorylation is

Question 19

Producer organisms convert _______ energy to chemical energy—the energy of C―H and C―O―H bonds.

Question 20

Which of the following substances would most likely enable a flagellum to drive a bacterium forward through the medium in which it is swimming?

Question 21

All of the six carbon atoms in each glucose molecule leave respiration in the form of carbon dioxide. Most of them leave during which part of aerobic respiration?

Question 22

Systems that convert energy from one form to another are

Question 23

In a crowded, unventilated room, the temperature rises because

Question 24

Which of the following is not a product of the Krebs cycle?

Question 25 

In living organisms, the activation energy of desired reactions is lowered by the use of 

 

Question 1 Accessory pigments and chlorophylls work together within the thylakoid membrane in clusters called __________ . They harvest light energy and use it to transfer electrons to _______________.

Question 2 Systems that convert energy from one form to another are

Question 3 Enzymes are important because they

Question 4 NADPH is formed when

Question 5 During the electron transfer reactions, protons (H+ ions) are pumped (moved) to one side of the inner membrane of the mitochondrion. The value of this pumping is that the proton gradient is then used

Question 6 A producer organism is called a “producer” because it produces

Question 7 In respiration, chemical energy is transferred from glucose to ATP. The energy transfer however, is not 100% efficient. In the transfer, some of the energy is lost as

Question 8 The Krebs cycle’s NADH products are of value because

Question 9 In photosynthesis, ______ and ______ are used to build_______ and release______.

Question 10 An excess amount of product accumulates at the end of a metabolic pathway. The product then binds to the allosteric site of the first enzyme along the pathway shutting down the pathway. We call this process

Question 11 The value of the three stages of aerobic respiration is their ability to break down glucose, a single molecule, with the resultant production of about

Question 12 Each wavelength of light has its own

Question 13 Which of the following is not a major sort/category of energy change within the cell?

Question 14 The final stage of aerobic respiration involves

Question 15 For most chemical reactions in the non­living world, the energy required to break bonds in the reactant molecules

Question 16 A useful way for a cell biologist to define energy is

Question 17 A lit match cannot continue to burn when the wood of the match stick is consumed. This statement illustrates the more general principle that

Question 18 If the final product of a metabolic pathway begins to build up in excess, the pathway can often be slowed down by a process called

Question 19 In living organisms, the activation energy of desired reactions is lowered by the use of

Question 20 When your car engine burns the octane in gasoline, at least 50% of the energy of the octane

Question 21 The three metabolic pathways that make up aerobic respiration are really all parts of one larger pathway because

Question 22 When activation energy is not available for a given chemical reaction

Question 23 Which of the following is neither a reactant nor a product of glycolysis?

Question 24 In photosynthesis the H atoms used to make high­energy carbohydrates like glucose come from

Question 25 To derive energy from an ATP molecule

 

Question 1

During the electron transfer reactions, protons (H+ ions) are pumped (moved) to one side of the inner membrane of the mitochondrion. The value of this pumping is that the proton gradient is then used

Question 2

Which of the following features of glycolysis is a value to the cell?

Question 3

DNA is stored within the ____________ of a cell in a __________ fiber called chromatin.

Question 4

Accessory pigments and chlorophylls work together within the thylakoid membrane in clusters called __________ . They harvest light energy and use it to transfer electrons to _______________.

Question 5

DNA contains two chains of nucleotides in which ______ and ______ alternate in supporting each chain structurally.

Question 6

The overall process that uptakes energypoor molecules (CO2 and H2O) from their reservoirs in nature and converts them into energyrich molecules is

Question 7

Enzymes are important because they

Question 8

Light dependent reactions of photosynthesis produce

Question 9

If the final end product of a metabolic pathway is continually removed and used elsewhere then

Question 10

Autotrophic organisms are supportive of man. They

Question 11

The wavelengths of light used in photosynthesis are found in the _________ portion of the electromagnetic spectrum.

Question 12

Which of the following phrases best describes the role of NADPH in photosynthesis?

Question 13

The immediate source of electrons for electron transfer phosphorylation is

Question 14

The value of the three stages of aerobic respiration is their ability to break down glucose, a single molecule, with the resultant production of about

Question 15

Biological information must exist because

Question 16

Which of the following is neither a reactant nor a product of glycolysis?

Question 17

Energyreleasing reactions drive biosynthetic ones forward by contributing to a pool of

Question 18

The physicist’s definition of energy is _______________ for use in defining energy changes within a living cell.

Question 19

The activation energy of a reaction can be lowered if the reaction is catalyzed by

Question 20

Photosynthesis and respiration are complementing processes within a global cycle known as the

Question 21

The (gene)tic information in a single strand of DNA is found in

Question 22

The process of __________ can be defined as about 30 individual, sequential chemical reactions that form three metabolic pathways: one in the cytoplasm and two within the mitochondrion.

Question 23

Plants are considered autotrophic because their cells contain

Question 24

Energy supplied to break bonds in reactant molecules is known as

Question 25

_________ is a reactant in the process of aerobic respiration and _______ is a product of the same process.

 

Question 1 __________ is a process that uses chlorophyll molecules to produce high­energy carbohydrates.

Question 2 One of the laws governing the behavior of energy in living things describes energy conversion as inefficient, with much energy being lost in the form of

Question 3 During the electron transfer reactions, protons (H+ ions) are pumped (moved) to one side of the inner membrane of the mitochondrion. The value of this pumping is that the proton gradient is then used

Question 4 If the final end product of a metabolic pathway is continually removed and used elsewhere then

Question 5 The immediate product of photosynthesis, three­carbon PGALs

Question 6 In nature, as energy freely changes from one form to another .

Question 7 On a cold day, your cells depend on ________ to maintain an operating temperature of 37 degrees Celsius.

Question 8 An ATP molecule carries potential energy in the easily broken bond

Question 9 The physicist’s definition of energy is _______________ for use in defining energy changes within a living cell.

Question 10 In a crowded, unventilated room, the temperature rises because

Question 11 DNA was discovered by Friederick Miescher; he isolated it from

Question 12 In photosynthesis the H atoms used to make high­energy carbohydrates like glucose come from

Question 13 A lit match cannot continue to burn when the wood of the match stick is consumed. This statement illustrates the more general principle that

Question 14 A producer organism is called a “producer” because it produces

Question 15 The overall process that uptakes energy­poor molecules (CO2 and H2O) from their reservoirs in nature and converts them into energy­rich molecules is

Question 16 Autotrophic organisms are supportive of man. They

Question 17 New molecules of glucose are produced

Question 18 In respiration, chemical energy is transferred from glucose to ATP. The energy transfer however, is not 100% efficient. In the transfer, some of the energy is lost as

Question 19 ______ is freely convertible from one form to another but _______ can never be created or destroyed.

Question 20 The Krebs cycle’s NADH products are of value because

Question 21 When light of the correct wavelength hits a photosynthetic pigment molecule

Question 22 Accessory pigments and chlorophylls work together within the thylakoid membrane in clusters called __________ . They harvest light energy and use it to transfer electrons to _______________.

Question 23 Metabolic pathways

Question 24 Which of the following is not a product of the Krebs cycle?

Question 25 Which of the following is not a major sort/category of energy change within the cell?

 

Question 1 In the process of ____________, three interrelated, exergonic pathways and oxygen are used to igenerate large amounts of ATP from glucose molecules.

Question 2 Accessory pigments enable the chloroplast to

Question 3 For most chemical reactions in the non­living world, the energy required to break bonds in the reactant molecules

Question 4 Which of the following is a stage of aerobic respiration?

Question 5 If the final end product of a metabolic pathway is continually removed and used elsewhere then

Question 6 The Krebs cycle’s NADH products are of value because

Question 7 The final stage of aerobic respiration involves

Question 8 Griffith exposed weak living bacteria to just the fluids from dead virulent bacteria. Some of these weak bacteria became virulent and could now kill mice. What control experiment did he do to argue that his weak bacteria changed to virulence in these studies?

Question 9 Light dependent reactions are carried out both on and in between photosystems. This process is like the last stage of aerobic respiration in that both

Question 10 Three phosphate groups linked to a ribose sugar which, in turn, is linked to a pyrimidine base known as adenine: this phrase describes the structure of

Question 11 Accessory pigments and chlorophylls work together within the thylakoid membrane in clusters called __________ . They harvest light energy and use it to transfer electrons to _______________.

Question 12 DNA was discovered by Friederick Miescher; he isolated it from

Question 13 Photosynthesis and respiration are complementing processes within a global cycle known as the

Question 14 When activation energy is not available for a given chemical reaction

Question 15 Biological information must exist because

Question 16 A single regulatory molecule can shut down multiple metabolic pathways if it is able to

Question 17 A lit match cannot continue to burn when the wood of the match stick is consumed. This statement illustrates the more general principle that

Question 18 ______ is freely convertible from one form to another but _______ can never be created or destroyed.

Question 19 Light dependent reactions of photosynthesis produce

Question 20 The three metabolic pathways that make up aerobic respiration are really all parts of one larger pathway because

Question 21 The immediate source of electrons for electron transfer phosphorylation is

Question 22 To derive energy from an ATP molecule

Question 23 The process of aerobic respiration begins with

Question 24 New molecules of glucose are produced

Question 25 DNA is stored within the ____________ of a cell in a __________ fiber called chromatin.

 

Question 1 New molecules of glucose are produced

Question 2 Glucose + _________ + 36 ADP yields _________ + 6H2O + 36 _________.

Question 3 The energy storage molecule that connects endergonic and exergonic reactions, driving endergonic reactions forward, is

Question 4 If the final product of a metabolic pathway begins to build up in excess, the pathway can often be slowed down by a process called

Question 5 If the final end product of a metabolic pathway is continually removed and used elsewhere then

Question 6 Reactants like hydrogen and oxygen molecules and are converted into a product like water molecules in the course of

Question 7 The structure of DNA was unraveled using

Question 8 The most energetic and useful product of the Krebs cycle is

Question 9 An endergonic reaction always

Question 10 In photosynthesis the H atoms used to make high­energy carbohydrates like glucose come from

Question 11 DNA is stored within the ____________ of a cell in a __________ fiber called chromatin.

Question 12 ________ organisms build their own energy­rich molecules using solar energy.

Question 13 The cell’s pumping of substances against diffusion forces that would carry those substances the other way is termed

Question 14 Autotrophic organisms are supportive of man. They

Question 15 In photosynthesis, ______ and ______ are used to build_______ and release______.

Question 16 The (gene)tic information in a single strand of DNA is found in

Question 17 Systems that convert energy from one form to another are

Question 18 The immediate product of photosynthesis, three­carbon PGALs

Question 19 Photosynthesis and respiration are complementing processes within a global cycle known as the

Question 20 An excess amount of product accumulates at the end of a metabolic pathway. The product then binds to the allosteric site of the first enzyme along the pathway shutting down the pathway. We call this process

Question 21 The activation energy of a reaction can be lowered if the reaction is catalyzed by

Question 22 Which of the following features of glycolysis is a value to the cell?

Question 23 NADPH is formed when

Question 24 Energy supplied to break bonds in reactant molecules is known as

Question 25 Existing chemical bonds between atoms are broken and new ones are formed between different atoms. This process

 

Question 1 Light dependent reactions are carried out both on and in between photosystems. This process is like the last stage of aerobic respiration in that both

Question 2 In the chloroplast, light dependent reactions take place in the __________________ while light independent reactions take place in the __________________.

Question 3 When your car engine burns the octane in gasoline, at least 50% of the energy of the octane

Question 4 The value of the three stages of aerobic respiration is their ability to break down glucose, a single molecule, with the resultant production of about

Question 5 Enzymes are important because they

Question 6 Accessory pigments and chlorophylls work together within the thylakoid membrane in clusters called __________ . They harvest light energy and use it to transfer electrons to _______________.

Question 7 Energy­releasing reactions drive biosynthetic ones forward by contributing to a pool of

Question 8 The energy storage molecule that connects endergonic and exergonic reactions, driving endergonic reactions forward, is

Question 9 ________ and ________ are products of aerobic respiration.

Question 10 The physicist’s definition of energy is _______________ for use in defining energy changes within a living cell.

Question 11 The final stage of aerobic respiration involves

Question 12 The cell’s pumping of substances against diffusion forces that would carry those substances the other way is termed

Question 13 An allosteric enzyme

Question 14 Each wavelength of light has its own

Question 15 The three metabolic pathways that make up aerobic respiration are really all parts of one larger pathway because

Question 16 Which of the following is not a product of the Krebs cycle?

Question 17 Which of the following phrases best describes the role of NADPH in photosynthesis?

Question 18 The process of __________ can be defined as about 30 individual, sequential chemical reactions that form three metabolic pathways: one in the cytoplasm and two within the mitochondrion.

Question 19 Griffith exposed weak living bacteria to just the fluids from dead virulent bacteria. Some of these weak bacteria became virulent and could now kill mice. What control experiment did he do to argue that his weak bacteria changed to virulence in these studies?

Question 20 Glucose + _________ + 36 ADP yields _________ + 6H2O + 36 _________.

Question 21 DNA is stored within the ____________ of a cell in a __________ fiber called chromatin.

Question 22 For most chemical reactions in the non­living world, the energy required to break bonds in the reactant molecules

Question 23 _________ is a reactant in the process of aerobic respiration and _______ is a product of the same process.

Question 24 NADPH is formed when

Question 25 Existing chemical bonds between atoms are broken and new ones are formed between different atoms. This process

 

Question 1 For most chemical reactions in the non-living world, the energy required to break bonds in the reactant molecules 

Question 2 In biosynthesis of a protein, energy for bonding amino acids together comes from 

Question 3 A producer organism is called a “producer” because it produces 

Question 4 Physicists define energy as 

Question 5 Reactants like hydrogen and oxygen molecules and are converted into a product like water molecules in the course of 

Question 6 Systems that convert energy from one form to another are 

Question 7 In a long metabolic pathway, the multiple changes made to an initial reactant molecule are entirely controlled by 

Question 8 Energy-releasing reactions drive biosynthetic ones forward by contributing to a pool of 

Question 9 If bacteria can get their energy for life from a single kind of chemical reaction, then that reaction 

Question 10 An endergonic reaction always 

Question 11 An allosteric enzyme 

Question 12 A useful way for a cell biologist to define energy is 

Question 13 In nature, as energy freely changes from one form to another 

Question 14 On a cold day, your cells depend on ________ to maintain an operating temperature of 37 degrees Celsius. 

Question 15 Whenever chemical bonds are broken, energy is __________. Whenever chemical bonds form, energy is __________. 

Question 16 Producer organisms convert _______ energy to chemical energy—the energy of C―H and C―O―H bonds. 

Question 17 Three phosphate groups linked to a ribose sugar which, in turn, is linked to a pyrimidine base known as adenine: this phrase describes the structure of 

Question 18 An excess amount of product accumulates at the end of a metabolic pathway. The product then binds to the allosteric site of the first enzyme along the pathway shutting down the pathway. We call this process 

Question 19 The energy storage molecule that connects endergonic and exergonic reactions, driving endergonic reactions forward, is 

Question 20 Existing chemical bonds between atoms are broken and new ones are formed between different atoms. This process 

Question 21 The activation energy of a reaction can be lowered if the reaction is catalyzed by 

Question 22 A single regulatory molecule can shut down multiple metabolic pathways if it is able to 

Question 23 In respiration, chemical energy is transferred from glucose to ATP. The energy transfer however, is not 100% efficient. In the transfer, some of the energy is lost as 

Question 24 Moving ions across a membrane requires energy when 

Question 25 Which of the following substances would most likely enable a flagellum to drive a bacterium forward through the medium in which it is swimming? 

 

Question 1 Light dependent reactions of photosynthesis produce 

Question 2 The wavelengths of light used in photosynthesis are found in the _________ portion of the electromagnetic spectrum. 

Question 3 When light of the correct wavelength hits a photosynthetic pigment molecule 

Question 4 All of the six carbon atoms in each glucose molecule leave respiration in the form of carbon dioxide. Most of them leave during which part of aerobic respiration? 

Question 5 Which of the following phrases best describes the role of NADPH in photosynthesis? 

Question 6 In the process of glycolysis one molecule of _______ is converted to two molecules of __________. 

Question 7 The overall process that uptakes energy-poor molecules (CO2 and H2O) from their reservoirs in nature and converts them into energy-rich molecules is 

Question 8 The process of aerobic respiration begins with 

Question 9 Photosynthesis and respiration are complementing processes within a global cycle known as the 

Question 10 Photosynthesis and respiration are complementary processes within 

Question 11 The value of the three stages of aerobic respiration is their ability to break down glucose, a single molecule, with the resultant production of about 

Question 12 The Krebs cycle’s NADH products are of value because 

Question 13 In photosynthesis, ______ and ______ are used to build_______ and release______. 

Question 14 When electrons flow between photosystems, they ________ which can be used to generate new ____________ molecules. 

Question 15 New molecules of glucose are produced 

Question 16 Accessory pigments enable the chloroplast to 

Question 17 In photosynthesis the H atoms used to make high-energy carbohydrates like glucose come from 

Question 18 In the electron transfer phosphorylation process, ______ is a reactant and _____ is a product. 

Question 19 In the chloroplast, light dependent reactions take place in the __________________ while light independent reactions take place in the __________________. 

Question 20 If fermentation reactions did not occur on earth then in places where no oxygen is available 

Question 21 Oxygen is an important molecule to both respiration and photosynthesis. If evolution created these two processes one after the other, which would probably have had to appear first on earth? 

Question 22 During the electron transfer reactions, protons (H+ ions) are pumped (moved) to one side of the inner membrane of the mitochondrion. The value of this pumping is that the proton gradient is then used 

Question 23 Fermentation of sugar causes grape juice to become wine. In fermentation, the two products given off are ____________ and _________. The latter product accumulates in the wine during the process. 

Question 24 The three metabolic pathways that make up aerobic respiration are really all parts of one larger pathway because 

Question 25 Which of the following is valuable as the most immediate source of the greatest amount of ATP energy given off during aerobic respiration? 

 

Reactants like hydrogen and oxygen molecules and are converted into a product like water molecules in the course of

The structure of DNA was unraveled using

Biological information must exist because

The most energetic and useful product of the Krebs cycle is

Producer organisms convert _______ energy to chemical energy—the energy of C―H and C―O―H bonds

The most valuable product, energetically, of electron transfer phosphorylation is

All of the six carbon atoms in each glucose molecule leave respiration in the form of carbon dioxide. Most of them leave during which part of aerobic respiration?

Existing chemical bonds between atoms are broken and new ones are formed between different atoms. This process

If the final product of a metabolic pathway begins to build up in excess, the pathway can often be slowed down by a process called

An allosteric enzyme

In nature, as energy freely changes from one form to another

Systems that convert energy from one form to another are

The final stage of aerobic respiration involves

Plants are considered autotrophic because their cells contain

Light dependent reactions of photosynthesis produce

The three metabolic pathways that make up aerobic respiration are really all parts of one larger pathway because

Three phosphate groups linked to a ribose sugar which, in turn, is linked to a pyrimidine base known as adenine: this phrase describes the structure of

The immediate source of electrons for electron transfer phosphorylation is

DNA was discovered by Friederick Miescher; he isolated it from

Metabolic pathways

An excess amount of product accumulates at the end of a metabolic pathway. The product then binds to the allosteric site of the first enzyme along the pathway shutting down the pathway. We call this process

Which of the following is a stage of aerobic respiration

________ organisms build their own energy-rich molecules using solar energy

The energy storage molecule that connects endergonic and exergonic reactions, driving endergonic reactions forward, is

When activation energy is not available for a given chemical reaction