Digestion And Absorption

Question 1

Large molecules are ——- into smaller molecules

Answer 1

Hydrolysed

Question 2

What does the hydrolysing of large molecules to small mean?

Answer 2

It means the molecules can easily be absorbed and transported

Question 3

Most polymers are large ———- that are hydrolysed into ——- (smaller molecules)

Answer 3

• Biological molecules
• Monomers

Question 4

What are carbohydrates broken down into?

Answer 4

Carbohydrates } Disaccharides } Monosaccharides

Question 5

What can lipids be broken down into?

Answer 5

Fatty acids and monoglycerides

Question 6

What are used to hydrolyse Biological molecules in food?

Answer 6

Digestive enzymes

Question 7

Where and how are digestive enzymes made? And where are they released?

Answer 7

• they are produced by specialist cells in the digestive system of mammals
• they are then released into the gut to mix with food

Question 8

What are carbohydrates broken down by?

Answer 8

They are broken down by amylase and membrane bound disaccharidases

Question 9

Describe the role of amylase

Answer 9

• catalyses the conversion of starch into maltose

Question 10

Where is amylase produced and secreted?

Answer 10

1. produced by the salivary gland and released in the mouth
   And:
2. It can be produced by the pancreas and released into the small intestine

Question 11

Define membrane bound disaccharidases

Answer 11

They are enzymes that attach to the cell membranes of epithelial cells, lining the ileum

Question 12

What is the role of membrane bound disaccharidases

Answer 12

To help break down disaccharides into monosaccharides

Question 13

List the disaccharides and the disaccharidases that hydrolyse them

Answer 13

Maltose } maltase
Sucrose } sucrase
Lactose } lactase

Question 14

what monosaccharides does maltose produce?

Answer 14

Glucose + glucose

Question 15

what monosaccharide product does sucrose make?

Answer 15

Glucose + fructose

Question 16

What monosaccharide product does lactose produce?

Answer 16

glucose + galactose

Question 17

what can monosaccharides be transported across?

Answer 17

The cell membranes of the ileum epithelial cells via specific transporter proteins

Question 18

what are lipids broken down by?

Answer 18

By the enzyme Lipase and Bile Salts

Question 19

What is the role of lipase when hydrolysing lipids?

Answer 19

lipase catalyses the hydrolysis of lipids into monoglycerides and fatty acids, through the hydrolysis of ester bonds

Question 20

Where are lipases made and released?

Answer 20

They are made in the pancreas and secreted in the small intestine

Question 21

Where are bile salts made?

Answer 21

In the liver

Question 22

What is the role of bile salts?

Answer 22

To emulsify lipids, causing them to form small droplets

Question 23

Why is emulsification of lipids important?

Answer 23

As it increases their surface area and means that there’s an increased area for the lipase to work on

Question 24

What are micelles?

Answer 24

Tiny structures that form as the monoglycerides and fatty acids stick to the bile salt

Question 25

What are proteins broken down by?

Answer 25

Proteases or peptidases

Question 26

what bonds need hydrolysing for proteins?

Answer 26

Peptide bonds

Question 27

Name the two kind of peptidases

Answer 27

Endopeptidase and Exopeptidase

Question 28

What is the role of endopeptidases?

Answer 28

To hydrolyse peptide bonds WITHIN a protein molecule

Question 29

Name an example of an endopeptidase and where it’s released

Answer 29

Pepsin
- it’s released into the stomach by cells in the stomach lining

Question 30

What role do exopeptidases have?

Answer 30

To hydrolyse peptide bonds at the END of protein molecules

Question 31

Name an example of exopeptidases

Answer 31

Dipeptidases (work on dipeptides, two amino acids)

Question 32

Where are dipeptidases normally located?

Answer 32

In the cell surface membrane of epithelial cells in the small intestine

Question 33

The products of digestion are absorbed across the ———- into the bloodstream

Answer 33

Ileum epithelium

Question 34

How are the monosaccharides absorbed?

Answer 34

Glucose + galactose: absorbed via active transport with sodium ions via a co-transporter
Fructose: is absorbed via facilitated diffusion through a different transporter protein

Question 35

How are monoglycerides and fatty acids absorbed?

Answer 35

• while the reforming, the micelles “release” monoglycerides and fatty acids
• monoglycerides and fatty acids are lipid-soluble, meaning they can diffuse directly across the epithelial cell membrane

Question 36

How are amino acids absorbed?

Answer 36

they are absorbed via co-transport
1. Sodium ions are actively transported out of the ileum cells into the blood
2. This creates a sodium concentration gradient
3. Sodium ions can then diffuse from the lumen of the ileum into epithelial cells through sodium dependent transporter proteins
4. The sodium ions carry amino acids with them