UNIT 1 - Enzymes And The Digestive System

Question 0

What does the Oesophagus do in the digestive system?

Answer 0

Carries food from the mouth to the stomach.

Question 1

What are the major parts of the digestive system?

Answer 1

Oesophagus, stomach, small intestine, large intestine, rectum, salivary glands and the pancreas

Question 2

What is the stomachs role in digestion?

Answer 2

To store and digest food especially proteins which are digested by secreted enzymes. It also secretes mucus to prevent the stomach being digested

Question 3

What is the role of the small intestine in the digestive system?

Answer 3

Food is further digested by enzymes produced by it’s walls. The villi and microvilli means the intestine is adapted to absorb products into the bloodstream due to it’s large surface area

Question 4

What is the role of the large intestine in digestion?

Answer 4

Absorbs water - the remaining product is faeces

Question 5

What is the role of the rectum in digestion?

Answer 5

The faeces are stored here before being removed via the anus in a process called egestion

Question 6

What is the role of the salivary glands in digestion?

Answer 6

Secrete the enzyme amylase which breaks starch into maltose

Question 7

What is the role of the pancreas in the digestive system?

Answer 7

It produces pancreatic juice which contains proteases that digest proteins, lipase to digest lipids and amylase to digest starch

Question 8

What is chemical digestion?

Answer 8

The breaking down of large, insoluble molecules into smaller, soluble ones.

Question 9

What are the three types of digestive enzyme within chemical digestion?

Answer 9

Carbohydrase, Lipases and Proteases

Question 10

What are the two names used when discussing the making of large molecules?

Answer 10

Monomer and Polymer

Question 11

What is a single monomer called in the case of a carbohydrate?

Answer 11

Monosaccharide

Question 12

What is the name given to two monosaccharides joined together?

Answer 12

Disaccharide

Question 13

What are many monosaccharides joined together called?

Answer 13

Polysaccharide

Question 14

What is an example of a monosaccharide?

Answer 14

Glucose

Question 15

What is the test for reducing sugars?

Answer 15

Benedicts test

Question 16

What is the Benedicts test for reducing sugars?

Answer 16

Add a fixed amount of the food sample to the test tube - must be liquidised.
Add an equal amount of Benedicts reagent to test tube
Heat the mixture in a gently boiling water bath for 5 minutes

Question 17

In testing for a reducing sugar, how would you know if you have one?

Answer 17

If the solution turns red then it’s present

Question 18

What will Glucose linked to another Glucose form?

Answer 18

Maltose

Question 19

What will glucose linked to fructose form?

Answer 19

Sucrose

Question 20

What will Glucose linked to galactose form?

Answer 20

Lactose

Question 21

How do monosaccharides join together?

Answer 21

Forms by removing a molecule of water which is called a condensation reaction

Question 22

What is the bond between two monosaccharides called?

Answer 22

A glycosidic bond

Question 23

How are disaccharides separated?

Answer 23

When water is added in suitable conditions the monosaccharides desperate - this is called hydrolysis.

Question 24

How do you test for non-reducing sugars?

Answer 24

In order to detect a non-reducing sugar it must be first broken down into monosaccharide components by hydrolysis
Do Benedicts test
If solution remains blue then the reducing sugar is not present
Add an equal amount of hydrochloric acid to an equal food sample, place in water bath for 5 minutes.
Slowly add sodium hydrogen carbonate solution to the test tube in order to neutralise the hydrochloric acid
Re-test in Benedicts reagent
The solution will turn orange-brown due to a non-reducing sugar being present

Question 25

What are polysaccharides?

Answer 25

They’re polymers formed by combining many monosaccharides together.

Question 26

How are monosaccharides joined together to form polysaccharides?

Answer 26

Joined by glycosidic bonds formed by condensation reactions

Question 27

What is an example of a polysaccharide?

Answer 27

Cellulose

Question 28

Why are polysaccharides good for storage?

Answer 28

They are very large molecules and so are insoluble

Question 29

What is the test for starch?

Answer 29

• Place 2cm of sample into test tube

* add 2 drops of iodine and stir

Question 30

How would you know if starch is present within a solution?

Answer 30

Indicated by blue-black colouration