Digestion and Absorption

Question 1

What is digestion?

Answer 1

The hydrolysis of large insoluble food molecules into small soluble food molecules that can be absorbed into the blood

Question 2

What do the teeth do?

Answer 2

Physically break down food into smaller pieces

Question 3

What do the salivary glands do?

Answer 3

Release salivary amylase enzymes

Question 4

What does the oesophagus do?

Answer 4

Carries food to the stomach

Question 5

What does the stomach do?

Answer 5

Produces hydrochloric acid and protease enzymes. Physically churns food.

Question 6

What does the pancreas do?

Answer 6

Produces pancreatic amylase, protease and lipase

Question 7

What does the liver do?

Answer 7

Produces bile

Question 8

What does the gall bladder do?

Answer 8

Stores/releases bile into ileum

Question 9

What is the ileum?

Answer 9

Small intestine

Question 10

What does the (ileum) small intestine do?

Answer 10

Absorbs products of food digestion into the blood

Question 11

What does the large intestine do?

Answer 11

Absorbs water

Question 12

What do the rectum and anus do?

Answer 12

Rectum stores faeces. Faeces exits via anus.

Question 13

What are the carbohydrate substrates?

Answer 13

Starch
Maltose
Sucrose
Lactose

Question 14

Which enzyme is starch hydrolysed by?

Answer 14

Pancreatic/ salivary amylase

Question 15

What product is formed from the hydrolysis of starch?

Answer 15

maltose

Question 16

Where is pancreatic/ salivary amylase made?

Answer 16

Salivary glands, pancreas

Question 17

Where does starch act?

Answer 17

Mouth and ileum

Question 18

Which bonds are broken when starch breaks down?

Answer 18

alpha 1,4 and alpha 1,6 glycosidic bonds

Question 19

How is glucose absorbed?

Answer 19

Co-transport with sodium

Question 20

What enzyme is maltose hydrolysed by and what product is formed through this?

Answer 20

maltase (membrane bound)

2 x alpha glucose

Question 21

Where is maltase made?

Answer 21

Ileum lining

Question 22

Where does maltase act?

Answer 22

Ileum

Question 23

Which bonds are broken when maltose breaks down?

Answer 23

alpha 1,4 glycosidic bonds

Question 24

Which enzyme is sucrose hydrolysed by?

Answer 24

Sucrase (membrane bound)

Question 25

What product is formed when sucrose is hydrolysed?

Answer 25

alpha glucose and fructose

Question 26

Where is sucrase made and where does it act?

Answer 26

made- ileum lining acts- ileum

Question 27

Which enzyme is lactose hydrolysed by?

Answer 27

lactase (membrane bound)

Question 28

What product is formed when lactose is hydrolysed?

Answer 28

alpha glucose and galactose

Question 29

Where is lactase made and where does it act?

Answer 29

made- ileum lining acts- ileum

Question 30

What are the protease substrates?

Answer 30

Protein Dipeptides

Question 31

What are the two types of enzymes protein is hydrolysed by?

Answer 31

Endopeptidase and Exopeptidase

Question 32

What product is formed when protein is hydrolysed (endopeptidase)?

Answer 32

smaller peptides

Question 33

Where is endopeptidase made and where does it act?

Answer 33

made- pancreas, stomach acts- stomach, ileum

Question 34

What bonds are broken during the hydrolysis of protein (endopeptidase)?

Answer 34

peptide bonds

Question 35

What product is formed when protein is hydrolysed (exopeptidase)?

Answer 35

amino acids, dipeptides

Question 36

Where is exopeptidase made and where does it act?

Answer 36

made- stomach, pancreas acts- ileum

Question 37

What bonds are broken during the hydrolysis of protein (exopeptidase)?

Answer 37

peptide bonds

Question 38

What enzymes are dipeptides hydrolysed by?

Answer 38

dipeptidases (membrane bound)

Question 39

What products are formed when dipeptides are hydrolysed?

Answer 39

amino acids

Question 40

Where are dipeptidases made and where do they act?

Answer 40

made- ileum lining acts- ileum

Question 41

Which bonds are broken during the hydrolysis of dipeptides?

Answer 41

peptide bonds

Question 42

Which enzyme are lipids hydrolysed by?

Answer 42

lipase

Question 43

What product is formed during the hydrolysis of lipids?

Answer 43

2 x fatty acids, monoglyceride

Question 44

Where is lipase made and where does it act?

Answer 44

made- ileum lining, pancreas acts- ileum

Question 45

Which bonds are broken during the hydrolysis of lipids?

Answer 45

ester

Question 46

What are micelles?

Answer 46

Tiny droplets of monoglycerides and fatty acids that release monoglycerides close to the surface of the cell

Question 47

Where do micelles diffuse?

Answer 47

Epithelium of ileum (small intestine)

Question 48

How do micelles work?

Answer 48

1. Droplets increase surface area (for lipase/ enzyme action) 2. So faster hydrolysis/ digestion (of triglycerides/lipids) 3. Micelles carry fatty acids and glycerol/ monoglycerides 4. Through membrane to (intestinal epithelial) cell

Question 49

How are amino acids absorbed?

Answer 49

-In the ileum by active transport through epithelial cells -Sodium ions transported out of these cells into the blood, creating a concentration gradient -They then diffuse back into the epithelial cells from the gut lumen through a co-transport protein, bringing amino acids with them. - AA move into bloodstream by facilitated diffusion

Question 50

Describe the structure of the small intestine:

Answer 50

-Walls are folded into villi -Walls are 1 cell thick -Many capillaries

Question 51

Explain how walls being folded into villi helps aid the function of the ileum:

Answer 51

Increases surface area for faster absorption

Question 52

Explain how walls being one cell thick helps aid the function of the ileum:

Answer 52

Shorter diffusion distance for faster absorption

Question 53

Explain how many capillaries helps aid the function of the ileum:

Answer 53

Rich blood supply maintains diffusion gradient

Question 54

How is Golgi apparatus involved in the absorption of lipids?

Answer 54

1. Modifies or processes triglycerides 2. Combines Triglycerides with proteins 3. Packages for release or exocytosis