Enzymes, Food Tests And Digestion

Question 1

What are enzymes ?

Answer 1

• Enzymes are catalysts in chemical reactions (E.g digestion of food)

Question 2

Give an example of when the use of enzymes are key.

Answer 2

• Digestion of food
• The control of one’s metabolism

Question 3

Key structural parts of an enzyme.

Answer 3

• Active sites (which have a unique shape)
  
  • Each enzyme has a unique active site. The substance involved in the chemical reaction will have to fit into the active site for the enzyme to work
  • Enzymes are really specific so will usually catalyse (speed up) one specific reaction

Question 4

What two things are key for an enzyme to be successful?

Answer 4

• Ph level
• Temperature

Question 5

What does temperature effect ?

Answer 5

• Temperature effects the Rate of reaction
• An increased temperature increases the rate of reaction
• A decreased temperature decreases the reaction rate

Question 6

What happens if the temperature is too high ?

Answer 6

• The enzyme DENATURES
• Binds will start ti breach which holds the enzyme together which will make the enzyme less effective

Question 7

What is different between all enzymes ?

Answer 7

• All enzymes have different optimum temperatures (The best/most efficient template which the enzyme works at)

Question 8

What does Ph effect in an enzyme ?

Answer 8

• Ph also effects the rate of reaction of an enzyme

Question 9

Why do you need to consider the Ph while using enzymes ?

Answer 9

• If the Ph is too high or low it affects the bonds in which hold the enzyme together. If the bonds become denatured the active site shape changes which leads to the enzyme not being able to be used.

Question 10

What does the enzyme of amylase promote ?

Answer 10

• The breakdown of strath to sugar

Question 11

How can you detect if starch is present ?

Answer 11

• The use of iodine solution
• If starch is present the iodine solution will change from browny-orange to a blue-black colour

Question 12

How do you calculate rate of reaction ?

Answer 12

Rate of reaction = 1000/Time(S)

Question 13

What is the Benedict’s test used for ?

Answer 13

• To test for the presence of reducing sugars (e.g Glucose)
• If sugars is detected the solution will change colour from blue to either green, yellow or brick-red. (This depends on how much sugar is in the food)

Question 14

What is the Iodine test used for ?

Answer 14

• To test for the presence of starch
• if starch is present the solution will change colour from browny orange to either black or blue-black

Question 15

What is the test for Lipids ?

Answer 15

• Sudan III (3)
• If the food contains lipids the mixture will separate into two layers.
• The top layer will be bright red

Question 16

Why do we need digestive enzymes ?

Answer 16

• To break down larger molecules such as starch, protons and fats to be able to pass through the walls of the digestive system.
• So digestive enzymes breaks down larger molecules into smaller ones

Question 17

What are the benefits of having smaller molecules over larger molecules ?

Answer 17

• So the food can pass through the digestive system easily
• So the smaller, soluble molecules can be absorbed into the bloodstream.

Question 18

What is starch (a charbohydrate) broken down by ?

Answer 18

• Amylase
• Amylase is a carbohydrase
• Amylase is mad in the salivary glands pancreas and small intestine.
• Amylase works in the mouth and small intestine to break down food

Question 19

What is starch broken down into ?

Answer 19

• Sugars
• (E.g Glucose)

Question 20

What are proteins broken down by ?

Answer 20

• Protease
• Proteases are made in the stomach, pancreas and small intestine
• They work in the stomach and small intestine

Question 21

What are protons broken down into ?

Answer 21

• Amino acids

Question 22

What are broken down into Glycerol and fatty acids ?

Answer 22

• Lipids

Question 23

What is lipases used for ?

Answer 23

• The break down of lipids
• Lipases are found in the pancreas and small intestine
• They work in the small intestine

Question 24

What is the use of Bile ?

Answer 24

• Neutralises the stomach acid
• Emulsifies fats

Question 25

Is bile acidic or alkaline ?

Answer 25

• Alkaline

Question 26

Where is bile produced and stored ?

Answer 26

• Produced in the liver
• Stored in the gall blader

Question 27

Where is bile released into ?

Answer 27

• The small intestine

Question 28

Where is bile released into ?

Answer 28

• The small intestine

Question 29

What is the process of emulsification of fats ?

Answer 29

• The break down of fats into smaller droplets.
• This gives a bigger surface area of fat for lipase to work on.
• This makes digestion a faster process

Question 30

Why is bile released into the small intestine ?

Answer 30

• Because the enzymes in the small intestine work best in alkaline conditions