Enzymes , Enzymes and Digestion

Question 1

Why to reactions need to be controlled carefully?

Answer 1

To ensure there are the right amount of substances

Question 2

What is one usual way of making a reaction happen faster?

What are the problems with this? (2)

Answer 2

Raise the temperature
It would also speed up the unwanted reactions.
There’s a limit to how far the temperature can be raised inside of a living creature without its cells being damaged.

Question 3

Why do living things produce enzymes?

Answer 3

To act as biological catalysts.

Question 4

Enzymes reduce the need for…., and we only have enzymes to speed up the …. reactions in our bodies.

Answer 4

Enzymes reduce the need for high temperatures and we only have enzymes to speed up the useful chemical reactions in our bodies.

Question 5

What is a catalyst?

Answer 5

A substance which increases the speed of a reaction without being changed or used up in the reaction.

Question 6

What are enzymes made of?
What are these made up of?
How do enzymes do their jobs using the above?

Answer 6

They are made of proteins
These are made of chains of amino acids
They fold into unique shapes to do their particular job.

Question 7

What do proteins do in the body? (used for? 4)

Answer 7

Catalysts
Act as structural components of tissues (muscles)
Hormones
Antibodies

Question 8

Why do enzymes have special shapes?

Answer 8

To catalyse reactions

Question 9

When do things split apart or join together?

Answer 9

In chemical reactions

Question 10

What does every enzyme have?

Answer 10

A unique shape that fits onto another substance in the reaction

Question 11

How many reactions can enzymes typically catalyse?

Answer 11

One

Question 12

Why do enzymes typically catalyse one reaction?

Answer 12

For the enzyme to work they must fit with the substance. If the substance doesn’t fit the enzyme’s special shape, the reaction won’t be catalysed. E.g a key in a lock, they have to fit together to work.

Question 13

Enzymes need just the right conditions to work properly…

They aren’t….

Answer 13

They aren’t versatile

Question 14

Enzymes need two things…

Answer 14

The right temperature

The right PH

Question 15

Changing the … and … changes the rate of an enzyme-catalysed reaction.

Answer 15

The temperature

The PH

Question 16

What effect does the temperature have on the enzyme...
As temperature increases...
Gets too hot...
Effect on the enzyme...
What is the optimum temperature?

Answer 16

The rate of reaction increases.
The enzyme’s bonds begin to break, destroying the enzyme’s special shape so it no longer works. This is denatured.
The optimum temp where enzymes work the best is 37 in a human , the enzyme is most active, any over it will denature.

Question 17

What effect does the temperature have on the enzyme…
Effect on the enzyme…
What is the optimum PH?

Answer 17

As the levels get to high or too low they interfere with the bonds of the enzyme.
Changes its shape and denatures it.
All have an optimum, sometimes 7, but pepsin used to breakdown proteins in the stomach works best in the acidic pH of the stomach, 2.

Question 18

Where do enzymes work?

Answer 18

Inside and outside cells

Question 19

What do digestive enzymes do to big molecules?

Answer 19

They break them down into smaller ones

Question 20

Give three examples of big molecules, to big to pass through the walls of the digestive system…
How are they made to fit?

Answer 20

Starch
Proteins
Fats
Digestive enzymes break them down into smaller molecules.

Question 21

Give four examples of small molecules, that can pass easily through the walls of the digestive system…

Answer 21

Sugars
Amino acids
Glycerol
Fatty Acids

Question 22

Where are amylase enzymes made? 3

What does they do?

Answer 22

Salivary glands
Pancreas
Small intestine
Converts starch into sugars e.g maltose

Question 23

Where are protease enzymes made? 3

What does they do?

Answer 23

Stomach (called pepsin here)
Pancreas
Small intestine
Converts proteins into amino acids

Question 24

Where are lipase enzymes made? 2

What do they do?

Answer 24

Pancreas
Small intestine
Convert lipids (fats and oils) into glycerol and fatty acids

Question 25

What does bile do?

Where is it produced?

Answer 25

Neutralises the stomach acid in the small intestine and emulsifies fats
In the liver

Question 26

Where is bile stored then released into?

Answer 26

Stored in the gall bladder before it’s released into the small intestine.

Question 27

Why is bile needed in the small intestine (acidity)?

Answer 27

The hydrochloric acid from the stomach is too acidic for the enzymes in the small intestine, so the ALKALINE bile is released.
This neutralises the acid and turns the conditions alkaline where the enzymes work best.

Question 28

Why is bile needed? (lipase)

Answer 28

It emulsifies fat!
It breaks it down into tiny droplets and this gives the fat a larger surface area for the enzyme lipase to work on making digestion faster.

Question 29

What catalyses the break down of food?

Answer 29

Enzymes

Question 30

Where are the enzymes produced for the digestive system and what by?

Answer 30

They are produced by specialised cells in glands and the gut lining.

Question 31

Salivary glands produce…

Answer 31

Amylase enzyme in the saliva

Question 32

What does the stomach do? (digestion 3)

Answer 32

Pummels the food with muscular walls
Produces the protease enzyme, pepsin
Produces hydrochloric acid for two reasons…
1. to kill bacteria
2. to give the right pH for the protease enzyme to work - pH2

Question 33

Large intestine does what?

Answer 33

Absorbs excess water.

Question 34

Rectum does what?

Answer 34

stores the mostly undigested food.

Question 35

Small intestine does two things….

Answer 35

Produces lipase and amylase and protease enzymes for digestion.
Absorbs digested food into the blood stream.

Question 36

The pancreas …. does what?

Answer 36

Produces lipase amylase and protease to release into the small intestine.