Digestive System + Enzymes

Question 1

What does the Benedict test for?

Answer 1

Sugars

Question 2

What does the buiret test for?

Answer 2

Proteins

Question 3

What does the iodine test for?

Answer 3

Starch

Question 4

What does the Sudan III test for?

Answer 4

Lipids

Question 5

If no reducing sugars are in the Benedict solution, what colour will it be?

Answer 5

Stays blue

Question 6

If there are reducing sugars in the Benedict test, what colour will the solution be?

Answer 6

Green/yellow/brick red depending on concentration.

Question 7

If the sample does have starch, the solution

Answer 7

Will change from brown-orange to blue-black

Question 8

If there is protein in the sample, the solution will

Answer 8

Turn from blue to pink or purple.

Question 9

If there is a lipid present, the solution

Answer 9

Should get stained, bright red layer at the top

Question 10

Carbohydrate is broken down by

Answer 10

Amylase into smaller sugars eg maltose

Question 11

Amylase in made in 3 places which are

Answer 11

Salivary glands, pancreas, small intestine

Question 12

Proteins are broken down by

Answer 12

Protease, into amino acids

Question 13

Which 3 places are proteases made

Answer 13

Stomach (pepsin), pancreas, small intestine

Question 14

Fats (lipids) are broken down by

Answer 14

Lipases, into glycerol and fatty acids

Question 15

Lipase is produced in the

Answer 15

Pancreas and small intestine

Question 16

Energy is needed so

Answer 16

We can move about and keep our metabolism going

Question 17

The role of digestion is

Answer 17

To break food down into small pieces so we can absorb it into our body cells

Question 18

Once you have food in your mouth you

Answer 18

Break it down physically by chewing, but you also release saliva, also amylase is produced.

Question 19

After the food has been swallowed in the mouth, the food

Answer 19

• Passes through the osophagus to the stomach.

Question 20

What happens in the stomach?

Answer 20

• The stomach contracts its muscular foods to push the food around and mix it.
• It produces pepsin to break down protein.
• It produces hydrochloric acid which kills bacteria and provides the right environment for the pepsin enzyme to work.

Question 21

After the stomach,

Answer 21

• The digested food goes to the small intestine which is where the digested food is absorbed into the bloodstream. This is also where most of the digestion will take place. It produces enzymes itself to aid digestion. The pancreas makes most of the digestive enzymes and pushes them into the small intestine in the form of pancreatic juices.

Question 22

In the gall bladder,

Answer 22

It releases bile which
- Is alkaline to neutralise acid from the stomach
- Emulsifies the fats
- The bile is made in the liver, just stored in the gall bladder.

Question 23

After the small intestine,

Answer 23

• The digested food can be absorbed across the lining of the intestine into the bloodstream.

Question 24

The small intestine is adapted for exchanging surfaces by

Answer 24

• Villi, which increases the surface area, it can be absorbed into the bloodstream much more quickly
• It only has one single layer of villi so they only have to diffuse a very short distance
• They have a good blood supply which maintains the concentration gradient

Question 25

The large intestine

Answer 25

Absorbs excess water, leaves faeces which is stored in the rectum until it’s removed.

Question 26

Enzymes are important as they

Answer 26

Are biological catalysts so they help speed up chemical reactions which are normally quite slow.

Question 27

Enzymes are large proteins, so are made out of

Answer 27

Chains of amino acids

Question 28

What is the active site?

Answer 28

Part of the enzyme with a unique shape that is complementary to the substrate.

Question 29

What is the lock and key model?

Answer 29

Scientists thought that the substrate had to fit **perfectly** into the active site

Question 30

As the temperature increases, the rate of reaction

Answer 30

Increases

Question 31

optimum temperature definition

Answer 31

Where the rate of reaction is the highest

Question 32

Why do high temperatures denature enzymes?

Answer 32

The active site changes shape, the enzyme can’t bind to the substrate.

Question 33

If the pH gets too low or high, the rate of reaction

Answer 33

Decreases

Question 34

The optimal pH is

Answer 34

- Where the enzymes works best - Depends on where the enzyme normally works