B2.3 - Enzymes Flashcards Preview

GCSE Biology > B2.3 - Enzymes > Flashcards

Flashcards in B2.3 - Enzymes Deck (47):
0

What do proteins do?

They act as:
- structural components of tissues
- hormones
- antibodies
-catalysts

1

What is a protein?

A long chain of amino acids.

2

What are enzymes?

Large protein molecules that act as a biological catalyst.

3

How do enzymes work?

-The substrate fits into the active site of the enzyme.
-The enzyme and substrate bind together.
-The reaction takes place rapidly and the products are released from the surface of the enzyme.
-The enzyme is then ready to use again.

4

What do enzymes do?

- Building large molecules from smaller ones.
- Changing one molecule into another.
- Breaking down large molecules into smaller ones.

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5

Why does milk go off?

Enzymes in bacteria break down the protein structure.

6

What are the two main factors that affect enzymes?

-Temperature
-pH level

7

What is the temperature at which most enzymes denature?

40C

8

What is the relationship between temperature and the rate of reactions controlled by enzymes?

As the temperature increases, the rate of reaction increases up to a point.

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9

What is denaturing?

When the temperature is too high, the amino acids unravel therefore changing the shape of the active site rendering the enzyme useless.

10

What is the optimum temperature for human enzymes?

36.5C

11

Where is pepsin found?

The stomach

12

Where is amylase found?

The pancreas

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13

Why does the pH level denature enzymes?

Forces hold the folded chains of amino acids together and a change in pH affects the forces changing the shape of the active site.

14

Why can't enzymes be killed?

They are non-living.

15

What do digestive enzymes do?

They break down large insoluble molecules.

16

What does the stomach do?

It squeezes and breaks up food into smaller pieces with a large surface area. It mixes food with the digestive juices to enable contact with enzymes.

17

Where are enzymes made?

Specialist glands:
- salivary glands
- Pancreas
- Lining of the gut

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18

Which enzymes break down carbohydrates?

Carbohydrases

19

Where is amylase produced?

In the salivary glands and pancreas.

20

Which enzyme breaks down starch?

Amylase

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21

Which enzymes break down proteins?

Proteases

22

Where are proteases produced?

Stomach, pancreas and small intestine.

23

What are proteins broken down into?

Amino acids

24

Which enzymes break down lipids?

Lipases

25

What are lipids broken down into?

Fatty acids and glycerol

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26

Where are lipases produced?

Pancreas and small intestine

27

Why does the stomach contain hydrochloric acid?

The enzymes in the stomach work best at low pH levels.
Bacteria is killed by the acid.

28

What conditions do proteases need?

Alkaline

29

What does bile do?

Neutralises stomach acid and emulsifiers fats.

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30

What is the mucus layer in the stomach for?

It prevents the stomach being digested by the acid and enzymes.

31

Why is bile important in digestion?

-The semi-digested food is acidic and the enzymes from the pancreas and small intestine need alkaline conditions.
-Bile breaks up large drops of fat giving a larger surface area for lipase enzymes to work.

32

How are enzymes used in baby foods?

They predigest some protein in the food making it easier for the baby's to get the amino acids from the food.

33

How do biological detergents work?

They contain proteases and lipases that break down proteins and fats in stains.

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34

How are enzymes used to produce food?

Carbohydrases convert starch into sugar syrup which makes food taste sweet.

35

What is isomerase?

An enzyme that changes glucose syrup into fructose syrup.

36

Give two advantages of using enzymes industrially.

-Reactions can be run at relatively low temperatures and pressures.
-They are cheaper to run.

37

How is isomerase used in food production?

Converting glucose into fructose means less is needed to make food taste sweet, therefore reducing energy intake. Food tastes sweet but has fewer calories.

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38

Give three disadvantages of using enzymes industrially.

-Temperature has to be controlled.
-pH level has to be controlled.
-Enzymes are expensive to produce.

39

Give a disadvantage of using biological washing powders.

-They aren't as good at killing pathogens.

40

Give four advantages of using biological detergents.

-Clothes can be cleaned at lower temperatures.
-They break down biological stains.
-They are cheaper to use.
-They are better for the environment.

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41

How are enzymes used to diagnose liver damage?

If the liver is damaged, some enzymes may leak into the bloodstream meaning a blood test can reveal liver damage.

42

Give five ways in which enzymes are used in medicine.

-Detecting liver disease.
-Diagnosing diabetes.
-Extra enzymes to help digest food.
-Dissolving clots.
-Treating cancer.

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43

How are enzymes used to diagnose diabetes?

The strip used to test urine for glucose contains enzymes. The enzymes catalyse the breakdown of glucose making the strip change colour.

44

How are enzymes used after a heart attack?

Streptokinase dissolves clots in arteries reducing the damage done to the heart muscle.

45

How are enzymes used for a damaged pancreas?

A damaged pancreas cannot make enzymes. Taking extra enzymes ensures food is digested.

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47

How are enzymes used to treat cancer?

Blood cancer cells cannot make a particular amino acid so takes it from body fluids. Enzymes speeds up the breakdown of the amino acid, killing the cancer cell. Normal cells can make the amino acid themselves.

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