1.7: Enzyme action

Question 1

Enzymes are what proteins?

Answer 1

Enzymes are globular proteins

Question 2

Enzymes are globular proteins that act as what?

Answer 2

Enzymes are globular proteins that act as catalysts

Question 3

Enzymes are globular proteins that act as catalysts.

Catalysts do what without doing what themselves?

Answer 3

Catalysts alter the rate of a chemical reaction without undergoing permanent changes themselves

Question 4

Enzymes are globular proteins that act as catalysts.

Catalysts alter the rate of a chemical reaction without undergoing permanent changes themselves.

Catalysts can be reused how many times?

Answer 4

Catalysts can be reused repeatedly

Question 5

Enzymes are globular proteins that act as catalysts.

Catalysts alter the rate of a chemical reaction without undergoing permanent changes themselves.

Catalysts can be reused repeatedly and are therefore what?

Answer 5

Catalysts:

1. Can be reused repeatedly
2. Are therefore effective in small amounts

Question 6

Enzymes are globular proteins that act as catalysts.

Catalysts alter the rate of a chemical reaction without undergoing permanent changes themselves.

Catalysts can be reused repeatedly and are therefore effective in small amounts.

Enzymes do not make reactions happen - they do what?

Answer 6

Enzymes do not make reactions happen - they speed up reactions that already occur

Question 7

Enzymes are globular proteins that act as catalysts.

Catalysts alter the rate of a chemical reaction without undergoing permanent changes themselves.

Catalysts can be reused repeatedly and are therefore effective in small amounts.

Enzymes do not make reactions happen - they speed up reactions that already occur, sometimes by a factor of what?

Answer 7

Enzymes do not make reactions happen - they speed up reactions that already occur, sometimes by a factor of many millions

Question 8

A typical chemical reaction:

Sucrose + what —> what + what? (substrates) —> (products)

Answer 8

Sucrose + Water —> Glucose + Fructose (substrates) —> (products)

Question 9

A typical chemical reaction:

Sucrose + Water —> Glucose + Fructose (substrates) —> (products)

For reactions like this to take place naturally, a number of conditions must be satisfied:

1. The sucrose and water molecules must collide with what?

Answer 9

The sucrose and water molecules must collide with sufficient energy to alter the arrangement of their atoms to form:

1. Glucose
2. Fructose

Question 10

A typical chemical reaction:

Sucrose + Water —> Glucose + Fructose (substrates) —> (products)

For reactions like this to take place naturally, a number of conditions must be satisfied:

1. The sucrose and water molecules must collide with sufficient energy to alter the arrangement of their atoms to form glucose and fructose.
2. The free energy of the products (glucose and fructose) must be what?

Answer 10

The free energy of the products (glucose and fructose) must be less than that of the substrates (sucrose and water)

Question 11

A typical chemical reaction:

Sucrose + Water —> Glucose + Fructose (substrates) —> (products)

For reactions like this to take place naturally, a number of conditions must be satisfied:

1. The sucrose and water molecules must collide with sufficient energy to alter the arrangement of their atoms to form glucose and fructose.
2. The free energy of the products (glucose and fructose) must be less than that of the substrates (sucrose and water).
3. Many reactions require an initial what to start?

Answer 11

Many reactions require an initial amount of energy to start

Question 12

A typical chemical reaction:

Sucrose + Water —> Glucose + Fructose (substrates) —> (products)

For reactions like this to take place naturally, a number of conditions must be satisfied:

1. The sucrose and water molecules must collide with sufficient energy to alter the arrangement of their atoms to form glucose and fructose.
2. The free energy of the products (glucose and fructose) must be less than that of the substrates (sucrose and water).
3. Many reactions require an initial amount of energy to start.

What is activation energy?

Answer 12

Activation energy is the minimum amount of energy needed to activate the reaction in this way

Question 13

There is an activation energy level, which must initially be overcome before what?

Answer 13

There is an activation energy level, which must initially be overcome before the reaction can proceed

Question 14

There is an activation energy level, which must initially be overcome before the reaction can proceed.

Enzymes work by doing what?

Answer 14

Enzymes work by lowering this activation energy level

Question 15

There is an activation energy level, which must initially be overcome before the reaction can proceed.

Enzymes work by lowering this activation energy level.

In this way, enzymes allow reactions to take place at what than normal?

Answer 15

In this way, enzymes allow reactions to take place at a lower temperature than normal

Question 16

There is an activation energy level, which must initially be overcome before the reaction can proceed.

Enzymes work by lowering this activation energy level.

In this way, enzymes allow reactions to take place at a lower temperature than normal.

This enables what at the human body temperature of how many degrees Celsius?

Answer 16

This enables some metabolic processes to occur rapidly at the human body temperature of 37 degrees Celsius

Question 17

There is an activation energy level, which must initially be overcome before the reaction can proceed.

Enzymes work by lowering this activation energy level.

In this way, enzymes allow reactions to take place at a lower temperature than normal.

This enables some metabolic processes to occur rapidly at the human body temperature of 37 degrees Celsius, which is relatively low in terms of what?

Answer 17

This enables some metabolic processes to occur rapidly at the human body temperature of 37 degrees Celsius, which is relatively low in terms of chemical reactions

Question 18

There is an activation energy level, which must initially be overcome before the reaction can proceed.

Enzymes work by lowering this activation energy level.

In this way, enzymes allow reactions to take place at a lower temperature than normal.

This enables some metabolic processes to occur rapidly at the human body temperature of 37 degrees Celsius, which is relatively low in terms of chemical reactions.

Without enzymes, these reactions would do what?

Answer 18

Without enzymes, these reactions would proceed too slowly to sustain life as we know it

Question 19

Enzymes, being globular proteins, have a specific what?

Answer 19

Enzymes, being globular proteins, have a specific 3-D shape

Question 20

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their what?

Answer 20

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure)

Question 21

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure).

A specific region of the enzyme is what?

Answer 21

A specific region of the enzyme is functional

Question 22

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure).

A specific region of the enzyme is functional.

This is known as the what?

Answer 22

This is known as the active site

Question 23

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure).

A specific region of the enzyme is functional.

This is known as the active site.

The active site is made up of a relatively small number of what?

Answer 23

The active site is made up of a relatively small number of amino acids

Question 24

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure).

A specific region of the enzyme is functional.

This is known as the active site.

The active site is made up of a relatively small number of amino acids.

The active site forms a small what within the much larger enzyme molecule?

Answer 24

The active site forms a small depression within the much larger enzyme molecule

Question 25

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure).

A specific region of the enzyme is functional. This is known as the active site.

The active site is made up of a relatively small number of amino acids.

The active site forms a small depression within the much larger enzyme molecule.

The molecule on which the enzymes does what is called the substrate?

Answer 25

The molecule on which the enzymes acts is called the substrate

Question 26

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure).

A specific region of the enzyme is functional. This is known as the active site.

The active site is made up of a relatively small number of amino acids.

The active site forms a small depression within the much larger enzyme molecule.

The molecule on which the enzymes acts is called the substrate.

This substrate fits nearly into this depression and forms what?

Answer 26

This substrate:

1. Fits nearly into this depression
2. Forms an enzyme-substrate complex

Question 27

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure).

A specific region of the enzyme is functional. This is known as the active site.

The active site is made up of a relatively small number of amino acids.

The active site forms a small depression within the much larger enzyme molecule.

The molecule on which the enzymes acts is called the substrate.

This fits nearly into this depression and forms an enzyme-substrate complex.

The substrate molecule is held within the active site by what?

Answer 27

The substrate molecule is held within the active site by bonds

Question 28

Enzymes, being globular proteins, have a specific 3-D shape that is the result of their sequence of amino acids (primary protein structure).

A specific region of the enzyme is functional.

This is known as the active site.

The active site is made up of a relatively small number of amino acids.

The active site forms a small depression within the much larger enzyme molecule.

The molecule on which the enzymes acts is called the substrate.

This fits nearly into this depression and forms an enzyme-substrate complex.

The substrate molecule is held within the active site by bonds that do what?

Answer 28

The substrate molecule is held within the active site by bonds that temporarily form between:

1. Certain amino acids of the active site
2. Groups on the substrate molecule

Question 29

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a what?

Answer 29

This is known as a scientific model

Question 30

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include what?

Answer 30

Examples of scientific models include the physical models used to explain enzyme action

Question 31

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

What does the induced fit model of enzyme action propose?

Answer 31

The induced fit model of enzyme action proposes that the active site forms as the:

1. Enzyme
2. Substrate

interact

Question 32

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in what) leads to what?

Answer 32

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme

Question 33

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms what?

Answer 33

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site

Question 34

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is what?

Answer 34

In other words, the enzyme is flexible

Question 35

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around what in the way that a glove moulds itself to the shape of the hand?

Answer 35

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand

Question 36

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand.

The enzyme has a certain what shape?

Answer 36

The enzyme has a certain general shape

Question 37

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand.

The enzyme has a certain general shape, just as a glove has, but this alters in the presence of the what?

Answer 37

The enzyme has a certain general shape, just as a glove has, but this alters in the presence of the substrate

Question 38

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand.

The enzyme has a certain general shape, just as a glove has, but this alters in the presence of the substrate.

As it changes its shape, the enzyme does what to the substrate molecule?

Answer 38

As it changes its shape, the enzyme puts a strain on the substrate molecule

Question 39

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand.

The enzyme has a certain general shape, just as a glove has, but this alters in the presence of the substrate.

As it changes its shape, the enzyme puts a strain on the substrate molecule.

This strain does what?

Answer 39

This strain distorts:

1. A particular bond

Or,

2. Bonds

in the substrate

Question 40

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand.

The enzyme has a certain general shape, just as a glove has, but this alters in the presence of the substrate.

As it changes its shape, the enzyme puts a strain on the substrate molecule.

This strain distorts a particular bond or bonds in the substrate and consequently does what?

Answer 40

This strain:

1. Distorts a particular bond or bonds in the substrate
2. Consequently lowers the activation energy needed to break the bond

Question 41

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand.

The enzyme has a certain general shape, just as a glove has, but this alters in the presence of the substrate.

As it changes its shape, the enzyme puts a strain on the substrate molecule.

This strain distorts a particular bond or bonds in the substrate and consequently lowers the activation energy needed to break the bond.

Any change in an enzyme’s environment is likely to do what?

Answer 41

Any change in an enzyme’s environment is likely to change its shape

Question 42

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand.

The enzyme has a certain general shape, just as a glove has, but this alters in the presence of the substrate.

As it changes its shape, the enzyme puts a strain on the substrate molecule.

This strain distorts a particular bond or bonds in the substrate and consequently lowers the activation energy needed to break the bond.

Any change in an enzyme’s environment is likely to change its shape.

The very act of doing what is a change in its environment?

Answer 42

The very act of colliding with its substrate is a change in its environment

Question 43

Scientists often try to explain their observations by producing a representation of how something works.

This is known as a scientific model.

Examples of scientific models include the physical models used to explain enzyme action.

The induced fit model of enzyme action proposes that the active site forms as the enzyme and substrate interact.

The proximity of the substrate (a change in the environment of the enzyme) leads to a change in the enzyme that forms the functional active site.

In other words, the enzyme is flexible and can mould itself around the substrate in the way that a glove moulds itself to the shape of the hand.

The enzyme has a certain general shape, just as a glove has, but this alters in the presence of the substrate.

As it changes its shape, the enzyme puts a strain on the substrate molecule.

This strain distorts a particular bond or bonds in the substrate and consequently lowers the activation energy needed to break the bond.

Any change in an enzyme’s environment is likely to change its shape.

The very act of colliding with its substrate is a change in its environment and so what?

Answer 43

The very act of colliding with its substrate is a change in its environment and so its shape changes - induced fit

Question 44

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as what?

Answer 44

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock

Question 45

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific what?

Answer 45

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape

Question 46

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that does what?

Answer 46

The lock and key model of enzyme action: One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that:

1. Fits
2. Operates

only a single lock

Question 47

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit what?

Answer 47

In a similar way, a substrate will only fit the active site of one particular enzyme

Question 48

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are what?

Answer 48

This model was supported by the observation that enzymes are specific in the reactions that they catalyse

Question 49

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are specific in the reactions that they catalyse.

The shape of the substrate (key) exactly fits what?

Answer 49

The shape of the substrate (key) exactly fits the active site of the enzyme (lock)

Question 50

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are specific in the reactions that they catalyse.

The shape of the substrate (key) exactly fits the active site of the enzyme (lock).

This is known as the lock and key model.

One limitation of this model is that the enzyme, like a lock, is considered to be what?

Answer 50

One limitation of this model is that the enzyme, like a lock, is considered to be a rigid structure

Question 51

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are specific in the reactions that they catalyse.

The shape of the substrate (key) exactly fits the active site of the enzyme (lock).

This is known as the lock and key model.

One limitation of this model is that the enzyme, like a lock, is considered to be a rigid structure.

However, scientists had observed that other molecules could do what?

Answer 51

Scientists had observed that other molecules could bind to enzymes at sites other than the active site

Question 52

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are specific in the reactions that they catalyse.

The shape of the substrate (key) exactly fits the active site of the enzyme (lock).

This is known as the lock and key model.

One limitation of this model is that the enzyme, like a lock, is considered to be a rigid structure.

However, scientists had observed that other molecules could bind to enzymes at sites other than the active site.

In doing so, they altered what?

Answer 52

In doing so, they altered the activity of the enzyme

Question 53

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are specific in the reactions that they catalyse.

The shape of the substrate (key) exactly fits the active site of the enzyme (lock).

This is known as the lock and key model.

One limitation of this model is that the enzyme, like a lock, is considered to be a rigid structure.

However, scientists had observed that other molecules could bind to enzymes at sites other than the active site.

In doing so, they altered the activity of the enzyme.

This suggested that the enzyme’s shape was being altered by what?

Answer 53

This suggested that the enzyme’s shape was being altered by the binding molecule

Question 54

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are specific in the reactions that they catalyse.

The shape of the substrate (key) exactly fits the active site of the enzyme (lock).

This is known as the lock and key model.

One limitation of this model is that the enzyme, like a lock, is considered to be a rigid structure.

However, scientists had observed that other molecules could bind to enzymes at sites other than the active site.

In doing so, they altered the activity of the enzyme.

This suggested that the enzyme’s shape was being altered by the binding molecule.

In other words, its structure was not rigid, but what?

Answer 54

In other words, its structure was not rigid, but flexible

Question 55

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are specific in the reactions that they catalyse.

The shape of the substrate (key) exactly fits the active site of the enzyme (lock).

This is known as the lock and key model.

One limitation of this model is that the enzyme, like a lock, is considered to be a rigid structure.

However, scientists had observed that other molecules could bind to enzymes at sites other than the active site.

In doing so, they altered the activity of the enzyme.

This suggested that the enzyme’s shape was being altered by the binding molecule.

In other words, its structure was not rigid, but flexible.

In true scientific fashion, this led to an alternative model being proposed, one that better fitted what?

Answer 55

In true scientific fashion, this led to an alternative model being proposed, one that better fitted the current observations

Question 56

The lock and key model of enzyme action:

One earlier model of enzyme action proposed that enzymes work in the same as a key operates a lock - Each key has a specific shape that fits and operates only a single lock.

In a similar way, a substrate will only fit the active site of one particular enzyme.

This model was supported by the observation that enzymes are specific in the reactions that they catalyse.

The shape of the substrate (key) exactly fits the active site of the enzyme (lock).

This is known as the lock and key model

One limitation of this model is that the enzyme, like a lock, is considered to be a rigid structure.

However, scientists had observed that other molecules could bind to enzymes at sites other than the active site.

In doing so, they altered the activity of the enzyme.

This suggested that the enzyme’s shape was being altered by the binding molecule.

In other words, its structure was not rigid, but flexible.

In true scientific fashion, this led to an alternative model being proposed, one that better fitted the current observations.

This was the induced fit model.

The induced fit model is therefore a what version of the lock and key model?

Answer 56

The induced fit model is therefore a modified version of the lock and key model

Question 57

Free energy

Answer 57

Free energy is the energy of a system that is available to perform work

Question 58

To help you understand the importance of enzymes, it is necessary to appreciate that they catalyse a wide range of reactions both where?

Answer 58

To help you understand the importance of enzymes, it is necessary to appreciate that they catalyse a wide range of reactions both:

1. Inside the cell
2. Outside the cell

Question 59

To help you understand the importance of enzymes, it is necessary to appreciate that they catalyse a wide range of reactions both inside the cell and outside the cell.

Inside the cell is what?

Answer 59

Inside the cell is intracellular

Question 60

To help you understand the importance of enzymes, it is necessary to appreciate that they catalyse a wide range of reactions both inside the cell and outside the cell.

Outside the cell is what?

Answer 60

Outside the cell is extracellular

Question 61

To help you understand the importance of enzymes, it is necessary to appreciate that they catalyse a wide range of reactions both inside the cell (intracellular) and outside the cell (extracellular).

In doing so, enzymes determine what?

Answer 61

In doing so, enzymes determine the:

1. Structures
2. Functions

of all parts of living matter

Question 62

To help you understand the importance of enzymes, it is necessary to appreciate that they catalyse a wide range of reactions both inside the cell (intracellular) and outside the cell (extracellular).

In doing so, enzymes determine the structures and functions of all parts of living matter from what to what?

Answer 62

In doing so, enzymes determine the structures and functions of all parts of living matter from:

1. Cells

to

2. Complete organisms

Question 63

An initial input of energy (activation energy) starts a reaction that then does what?

Answer 63

An initial input of energy (activation energy) starts a reaction that then continues of its own accord

Question 64

The substrate does not have the ‘same shape’ as the active site.

The substrate has a what shape to the active site?

Answer 64

The substrate has a complementary shape to the active site

Question 65

Enzymes have an active site, but not all proteins are enzymes.

Many proteins have what that are not active sites?

Answer 65

Many proteins have:

1. Binding sites

Or,

2. Receptor sites

that are not active sites

Question 66

Enzymes have an active site, but not all proteins are enzymes.

Many proteins have binding sites or receptor sites that are not active sites.

Some hormones are proteins and these have receptor sites, but they are not what?

Answer 66

Some hormones are proteins and these have receptor sites, but they are not active sites

Question 67

Enzymes catalyse both what reactions?

Answer 67

Enzymes catalyse both:

1. Anabolic
2. Catabolic

reactions

Question 68

Anabolic reactions

Answer 68

Anabolic reactions are reactions that build up molecules

Question 69

Catabolic reactions

Answer 69

Catabolic reactions are reactions that break down molecules

Question 70

Metabolism

Answer 70

Metabolism is all the chemical processes that take place in living organisms

Question 71

Catalyst

Answer 71

A catalyst is a substance that speeds up reactions without changing the produced substances

Question 72

Metabolic pathway

Answer 72

Metabolic pathway is the sequence of enzyme-controlled reactions

Question 73

Specifity is when enzymes are what?

Answer 73

Specifity is when enzymes are only able to catalyse specific reactions

Question 74

Substrate

Answer 74

A substrate is the molecule(s) the enzyme acts on

Question 75

Each enzyme has a specific what?

Answer 75

Each enzyme has a specific role

Question 76

Cells require hundreds of what to survive and function?

Answer 76

Cells require hundreds of biochemical reactions to:

1. Survive
2. Function

Question 77

What is point A?

Answer 77

Point A is the initial energy state of the substrates

Question 78

Point A is the initial energy state of the substrates.

What is point B?

Answer 78

Point B is the activation energy of the uncatalysed reaction

Question 79

Point A is the initial energy state of the substrates.

Point B is the activation energy of the uncatalysed reaction.

What is point C?

Answer 79

Point C is the activation energy of the enzyme-catalysed reaction

Question 80

Point A is the initial energy state of the substrates.

Point B is the activation energy of the uncatalysed reaction.

Point C is the activation energy of the enzyme-catalysed reaction.

What is point D?

Answer 80

Point D is the final energy state of the products

Question 81

Enzymes lower activation energy by forming what?

Answer 81

Enzymes lower activation energy by forming enzyme/substrate complexes

Question 82

Catabolic reactions are reactions that break down molecules.

In catabolic reactions, what happens?

Answer 82

In catabolic reactions, the enzyme active site affects the bonds in substrates, so that they are easier to break

Question 83

Anabolic reactions are reactions that build up molecules.

In anabolic reactions, what happens?

Answer 83

In anabolic reactions, enzymes bring the substrate molecules together

Question 84

Enzymes are globular proteins.

The active site has a what?

Answer 84

The active site has a specific shape

Question 85

Enzymes are globular proteins.

The active site has a specific shape, due to what?

Answer 85

The active site has a specific shape, due to the tertiary structure the protein

Question 86

Enzymes are globular proteins.

The active site has a specific shape, due to the teritary structure of the protein.

A change in what affects what?

Answer 86

A change in the shape of the protein affects the:

1. Shape of the active site
2. So the function of the enzyme

Question 87

The lock and key hypothesis, the old model, assumes what?

Answer 87

The lock and key hypothesis, the old model, assumes that the active site of an enzyme is rigid in its shape

Question 88

The lock and key hypothesis, the old model, assumes that the active site of an enzyme is rigid in its shape.

However, what indicate that proteins are what?

Answer 88

Crystallographic studies indicate that proteins are flexible

Question 89

The lock and key hypothesis, the old model, assumes that the active site of an enzyme is rigid in its shape.

However, crystallographic studies indicate that proteins are flexible.

What is the new and more accepted model?

Answer 89

The:

1. New
2. More accepted

model is the induced-fit model

Question 90

The lock and key hypothesis, the old model, assumes that the active site of an enzyme is rigid in its shape.

However, crystallographic studies indicate that proteins are flexible.

The new and more accepted model is the induced-fit model.

What does the induced-fit hypothesis suggest?

Answer 90

The induced-fit hypothesis suggests that the active site:

1. Is flexible
2. Only assumes its catalytic conformation after the substrate molecules bind to the site

Question 91

The lock and key hypothesis, the old model, assumes that the active site of an enzyme is rigid in its shape.

However, crystallographic studies indicate that proteins are flexible.

The new and more accepted model is the induced-fit model.

The induced-fit hypothesis suggests that the active site is flexible and only assumes its catalytic conformation after the substrate molecules bind to the site.

When the product leaves the enzyme, what happens?

Answer 91

When the product leaves the enzyme, the active site reverts to its inactive state