Lipids and Bile Salts

Question 1

Lipids examples

Answer 1

Fats/oils
Fatty acids - saturated/unsaturated
Phospholipids
Cholesterol & Cholesterol esters

Question 2

Lipid solubility

Answer 2

Insoluble or poorly soluble in water

causes problems for digestion and absorption

Question 3

Lipid digestion in stomach

Answer 3

Mechanical movements in stomach mix food with gastric lipase which begins digestion and forms an ‘emulsion’.
The emulsified fats are ejected from stomach and into the duodenum

Question 4

Lipid digestion in duodenum

Answer 4

Emulsified fats in the duodenum are attacked by pancreatic lipase and bile salts

Question 5

Bile salts

Answer 5

Synthesised in liver
Stored in GB
Released from GB in presence of CCK
Coat lipid droplets and help to digest lipids

Question 6

Failure to secrete bile salts

Answer 6

Steatorrhoea (fatty poo, floating, pale)

Secondary vitamin deficiency

Question 7

Bile salts and pancreatic lipase

Answer 7

Pancreatic lipase is inactive in the presence of bile salts

Question 8

Co-lipase

Answer 8

Forms a complex with lipase and bile salt and allows the lipase to be active in the presence of the bile salt.
Lipase can only work if co-lipase is also present.

Question 9

Micelles

Answer 9

Final digestion products are stored in and released from mixed micelles.
Micelle - lipid particle which contains many different lipid molecules
Hydrophilic head, hydrophobic core