2.5 Enzymes Flashcards

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1
Q

What is an enzyme?

A

A globular protein that acts as biological catalyst by speeding up the rate of a chemical reaction

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2
Q

What happens to enzymes when they catalyse a reaction?

A

They are not changed or consumed by the reaction

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3
Q

Can enzymes be reused?

A

Yes

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4
Q

What are enzymes typically named after?

A

The molecules they react with

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5
Q

What is the active site?

A

The region on the surface of the enzyme which binds to the substrate molecule

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6
Q

What are the two ways the active site and substrate complement each other?

A

Shape and chemical properties

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7
Q

What is capable of binding to a particular enzymes active site?

A

A specific substrate

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8
Q

Where do enzyme reactions typically take place?

A

In aqueous solution

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9
Q

What does the fact that enzyme reactions take place in aqueous solutions show about its position?

A

The substrate and the enzyme are randomly moving within the solution

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10
Q

What does an enzyme being in a fixed position do?

A

Serves to localise reactions to particular sites

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11
Q

What does enzyme catalysis need?

A

The substrate to be in close proximity with the active site

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12
Q

When is an enzyme-substrate complex formed?

A

When a substrate binds to the enzymes active site

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13
Q

How is an enzyme product complex created?

A

When the enzyme catalyses the conversion of the substrate into product

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14
Q

What happens after the enzyme product complex is created?

A

The enzyme and product dissociate

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15
Q

How can you increase the rate of enzyme catalysis?

A

By increasing the frequency of collisions

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16
Q

How can you increase the rate of collisions?

A

Increasing the molecular motion of the particles
Increasing the concentration of the particles

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17
Q

What are the shape and chemical properties of an active site dependent on?

A

The tertiary structure of the enzyme

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18
Q

What can cause an enzyme structure to be modified?

A

External factors like temperature and pH

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19
Q

How does temperature and pH affect enzymes?

A

They disrupt the chemical bonds which maintains the structure of the enzyme causing denaturation

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20
Q

What will a change to the structure of the active site do?

A

Negatively affect the enzymes capacity to bind to the substrate

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21
Q

What affects the rate of activity of an enzyme?

A

Temperature
pH
Substrate concentration

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22
Q

What does low temperature during a reaction result in?

A

Insufficient thermal energy for the enzyme catalysed reaction to happen

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23
Q

What does increasing the temperature do during a reaction?

A

Increases the speed and motion of both enzyme and substrate

24
Q

Why does an increase in temperature result in higher enzyme activity?

A

Because a higher kinetic energy results in more collisions between the enzyme and the substrate

25
Q

What happens at an optimal temperature?

A

The rate of enzyme activity will be at its peak

26
Q

In terms of temperature what causes an enzyme stability to decrease and why?

A

Higher temperatures as the thermal energy disrupts the enzymes hydrogen bonds

27
Q

What does changing the pH do to the enzyme?

A

Alter the charge of the enzyme and thus its solubility an overall shape

28
Q

What does changing the shape or the charge of the active site do?

A

Stop its ability to bind to the substrate

29
Q

What does moving out of an enzymes optimal pH do?

A

Stop its enzyme activity

30
Q

What does increasing the substrate concentration do?

A

Increase the activity of a corresponding enzyme

31
Q

What does having more substrates mean?

A

There is an increased chance of enzyme and substrate colliding and reacting in a given period

32
Q

When talking about substrate concentration, what happens after a certain point?

A

The rate of activity will stop regardless of substrate levels because all enzymes will be bound and reacting

33
Q

What is the shape of rate of reaction against temperature graph?

A

Slow gradient and steep decrease

34
Q

What is the shape of rate of reaction against pH graph?

A

Equal rise to peak as downhill from peak

35
Q

What is the shape of rate of reaction against substrate concentration graph?

A

Sharp increase then it plateaus

36
Q

When designing an experiment to test the effect of factors affecting enzyme activity, what are the three key decisions?

A

Which factor to investigate?
Which enzyme/substrate reaction to use?
How to measure the enzyme activity?

37
Q

When designing an experiment to test the effect of factors affecting enzyme activity, what are your choice of independent variables?

A

Temperature
pH
substrate concentration
Presence of inhibitor

38
Q

When designing an experiment to test the effect of factors affecting enzyme activity, what are the two ways reactions are measured in accordance to?

A

The amount/rate of substrate decomposition or product formation

39
Q

What are immobilised enzymes used for?

A

To be fixed to a static surface in order to improve the efficiency of the catalysed reaction

40
Q

Why is separation of the product more easily achieved?

A

The enzyme remains attached to the static surface

41
Q

How are enzymes used in biofuels?

A

To breakdown carbohydrates to produce ethanol-based fuels

42
Q

How are enzymes used in medicine?

A

To identify a range of conditions like pregnancy or certain diseases

43
Q

How are enzymes used in biotechnology?

A

In multiple processes like gene splicing

44
Q

How are enzymes used in food production?

A

In the production and refinement of beers and dairy products

45
Q

How are enzymes used in textiles?

A

In the processing of fibres

46
Q

How are enzymes used in paper?

A

Assisting the pulping of wood for paper production

47
Q

What is lactose?

A

A disaccharide of glucose and galactose

48
Q

What can break down lactose?

A

Lactase

49
Q

Where is lactose intolerance particularly high?

A

In asian, african and aboriginal populations

50
Q

Why is lactose intolerance lower in europeans?

A

A mutation that maintains lactase production into adulthood

51
Q

When do mammals show a decrease in lactase production?

A

After weaning

52
Q

How can lactose free milk be produced?

A

By treating the milk with lactase

53
Q

What is the process of using lactase for lactose free milk?

A

The lactase is purified by yeast or bacteria and then bound to an inert substance. the milk is then passed through this repeatedly

54
Q

How are scientists trying to create a cow that produces lactose free milk?

A

By splicing the lactase gene in the cows genome so lactose is broken down before milking

55
Q

What are the four advantages of lactose free milk?

A

It is a source of dairy for lactose free individuals
Ir is a means of increasing sweetness without artificial sweetners
A way of reducing crystillisation of ice cream
Reduces production time for cheeses and yogurts