1.7: Enzyme action Flashcards Preview

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Flashcards in 1.7: Enzyme action Deck (91):
1

Enzymes are what proteins?

Enzymes are globular proteins

2

Enzymes are globular proteins that act as what?

Enzymes are globular proteins that act as catalysts

3

Enzymes are globular proteins that act as catalysts.

Catalysts do what without doing what themselves?

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

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?

Catalysts can be reused repeatedly

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?

Catalysts:

1. Can be reused repeatedly

2. Are therefore effective in small amounts

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?

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

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?

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

8

A typical chemical reaction:

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

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

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?

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

1. Glucose

2. Fructose

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?

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

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?

Many reactions require an initial amount of energy to start

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?

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

13

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

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

14

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

Enzymes work by doing what?

Enzymes work by lowering this activation energy level

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?

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

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?

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

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?

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

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?

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

19

Enzymes, being globular proteins, have a specific what?

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

20

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

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

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?

A specific region of the enzyme is functional

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?

This is known as the active site

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?

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

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?

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

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?

The molecule on which the enzymes acts is called the substrate

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?

This substrate:

1. Fits nearly into this depression

2. Forms an enzyme-substrate complex

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?

The substrate molecule is held within the active site by bonds

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?

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

29

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

This is known as a what?

This is known as a scientific model

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?

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

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?

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

1. Enzyme

2. Substrate

interact

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?

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

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?

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

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?

In other words, the enzyme is flexible

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?

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

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?

The enzyme has a certain general shape

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?

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

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?

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

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?

This strain distorts:

1. A particular bond

Or,

2. Bonds

in the substrate

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?

This strain:

1. Distorts a particular bond or bonds in the substrate

2. Consequently lowers the activation energy needed to break the bond

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?

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

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?

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

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?

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

44

The lock and key model of enzyme action:

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

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

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?

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

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?

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

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?

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

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?

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

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?

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

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?

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

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?

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

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?

In doing so, they altered the activity of the enzyme

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?

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

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?

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

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?

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

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?

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

57

Free energy

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

58

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

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

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?

Inside the cell is intracellular

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?

Outside the cell is extracellular

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?

In doing so, enzymes determine the:

1. Structures

2. Functions

of all parts of living matter

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?

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

1. Cells

to

2. Complete organisms

63

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

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

64

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

The substrate has a what shape to the active site?

The substrate has a complementary shape to the active site

65

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

Many proteins have what that are not active sites?

Many proteins have:

1. Binding sites

Or,

2. Receptor sites

that are not active sites

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?

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

67

Enzymes catalyse both what reactions?

Enzymes catalyse both:

1. Anabolic

2. Catabolic

reactions

68

Anabolic reactions

Anabolic reactions are reactions that build up molecules

69

Catabolic reactions

Catabolic reactions are reactions that break down molecules

70

Metabolism

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

71

Catalyst

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

72

Metabolic pathway

Metabolic pathway is the sequence of enzyme-controlled reactions

73

Specifity is when enzymes are what?

Specifity is when enzymes are only able to catalyse specific reactions

74

Substrate

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

75

Each enzyme has a specific what?

Each enzyme has a specific role

76

Cells require hundreds of what to survive and function?

Cells require hundreds of biochemical reactions to:

1. Survive

2. Function

77

What is point A?

Point A is the initial energy state of the substrates

78

Point A is the initial energy state of the substrates.

What is point B?

Point B is the activation energy of the uncatalysed reaction

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?

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

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?

Point D is the final energy state of the products

81

Enzymes lower activation energy by forming what?

Enzymes lower activation energy by forming enzyme/substrate complexes

 

82

Catabolic reactions are reactions that break down molecules.

In catabolic reactions, what happens?

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

83

Anabolic reactions are reactions that build up molecules.

In anabolic reactions, what happens?

In anabolic reactions, enzymes bring the substrate molecules together

84

Enzymes are globular proteins.

The active site has a what?

The active site has a specific shape

85

Enzymes are globular proteins.

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

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

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?

A change in the shape of the protein affects the:

1. Shape of the active site

2. So the function of the enzyme

87

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

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

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?

Crystallographic studies indicate that proteins are flexible

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?

The:

1. New

2. More accepted

model is the induced-fit model

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?

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

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?

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