L09: Digestion And Absorption Of Fat

Question 1

In fasted state what is the source of energy we use

Answer 1

Fat

Question 2

How do we get the energy from fat when fasting

Answer 2

Beta oxidation

Question 3

Describe the process of beta oxidation

Answer 3

1) free fatty acid is converted to fatty acetyl coA
2) fatty acetyl coA enters beta oxidation
3) oxidation of fatty acetyl coA occurs which gives FADH2
4) hydration
5) oxidation to give NADH
6) cleavage to give Acetyl coA which enters the kerbs cycle for more energy

Question 4

Why is fat important for the vitamin absorption

Answer 4

Vitamins are fat soluble so we need fat to absorb them

Question 5

What are the fat soluble vitamins found in the body

Answer 5

Vitamin A, D, E, K

Question 6

Why is vitamin A important

Answer 6

Vision

Question 7

What is the importance of vitamin D

Answer 7

In your diet you get D3 which is converted to the active form of 1,25D3 by the liver and kidney

Question 8

What does Vitamin D deficiency lead to

Answer 8

Rickets
Osteoporosis
Forms of cancer

Question 9

What is the importance of vitamin E

Answer 9

Antitoxidant Protection against cardiovascular disease and cancer

Question 10

What does Vitamin E deficiency lead to

Answer 10

Poor nerve conduction

Question 11

What is the importance of Vitamin K

Answer 11

Blood clotting

Calcium binding

Question 12

Where is vitamin K made

Answer 12

Intestinal bacteria and food

Question 13

What are the 3 fatty acids in the body

Answer 13

1) linoleic acid
2) linolenic acid
3) arachidonic acid

Question 14

What is the importance of fatty acids

Answer 14

Brain 
Nervous system 
Cell membrane function 
Blood pressure 
Inflammatory responce

Question 15

What can fatty acid deficiency give

Answer 15

High blood pressure 
Impaired vision 
Haemorrhaging dermatitis 
Dry skin 
Immune deficiency

Question 16

What is the 3 types of fat we have in the body

Answer 16

Triglycerides
Phospholipids
Cholesterol

Question 17

Describe the structure of a triglyceride

Answer 17

Glycerol

3 fatty acid

Question 18

Describe the structure of a phospholipid

Answer 18

Polar group
Phosphate
Glycerol
2 fatty acid

Question 19

What is the endogenous source of fat in the body

Answer 19

Bile

Question 20

What does bile contain

Answer 20

Phospholipids
Unesterified chlosterol
Membrane lipids
Lipids from dead colonic bacteria

Question 21

Which enzyme emulsifies fat

Answer 21

Lipase

Question 22

Name 4 processes that carry out emulsification

Answer 22

Food prep
Chewing and gastric churning
Gastric contents into the duodenum
Intestinal peristalsis

Question 23

What does coalescing mean

Answer 23

To come together and form one big mass

Question 24

Where does lipid digestion start

Answer 24

In the mouth

Question 25

What Enzyme digests lipids

Answer 25

Lingual lipase in mouth | Lingual lipase and gastric lipase in stomach

Question 26

What product does lipid digestion give

Answer 26

Single fatty acid and diglyceride

Question 27

What type of fatty acids does gastric lipase not absorb at the stomach

Answer 27

Long fatty acid

Question 28

What happens when fatty acid reaches the duodenum

Answer 28

1) I cells detect fatty acid and release CCK 2) CCK stimulates the flow of bile into the duodenum 3) CCK stimulate the secretion of pancreatic enzymes

Question 29

What is the role of pancreatic enzymes

Answer 29

Pancreatic lipase digest fat

Question 30

How is pancreatic lipase activated

Answer 30

Zymogen is activated by trypsin

Question 31

What are the other pancreatic enzymes that can hydrolyse fat

Answer 31

Carboxyl ester hydrolase | Phospholipase A2

Question 32

How does fatty acid enter enterocytes by leaving the mixed micelle

Answer 32

Non ionic diffusion Collision and in operation of fatty acid into cell membrane Active carrier

Question 33

Where are bile salts recycled

Answer 33

Terminal ileum

Question 34

Which type of fatty acid has no problem entering the enterocyte and blood

Answer 34

Short and medium fatty acid

Question 35

What happens when long fatty acids enter enterocyte

Answer 35

Bind to fatty acid binding protein to stop leaking back Fatty acid binding protein directs fatty acid to SER SER converts fatty acid back to triglycerides Apoproteins made in the RER are taken to SER Apoprotein bind to fat droplet to form chylomicrons Chylomicron are released out of the enterocytes into the lymph

Question 36

What are the 2 pathways of re-esterification in the enterocyte

Answer 36

1) monoglyceride pathway | 2) phosphatidic acid pathway

Question 37

What is the monoglyceride pathway

Answer 37

When 2 monoglyceride enter the enterocyte

Question 38

When does phosphatidic acid pathway occur

Answer 38

When you have long chain fatty acid

Question 39

What happens to chylomicrons

Answer 39

They find their way to endothelial surface where lipoprotein lipase hydrolysed triglycerides in the chylomicron

Question 40

What are the different types of chylomicrons

Answer 40

LDLs HDLs VLDLs

Question 41

What is the treatment for obesity

Answer 41

Orlistat

Question 42

What does orlistat do

Answer 42

Inhibit lipase