Theme 1 - Part V

Question 1

primary energy stores in adipose tissues during fastin

Answer 1

TAG

Question 2

Influx of TAG into adipose tissue

• mediated
• unregulated

Answer 2

mediated by tissue lipoprotein lipase

Upregulated by insulin

Question 3

Fat digestion lipase

Answer 3

Lingual lipase secreted by serous glands

Gastric lipase secreted by gastric glands in the fundic mucosa

Acid enzyme not requiring bile or colipase (pancreas)

50% of lipid hydrolysis in children, 30% in adults

Question 4

SI [3]

Answer 4

Bile acids from liver - cholic and chenodeoxycholic acid

Pancreatic lipase along pro-colipase

Triglycerides hydrolysed to monoglycerol, fatty acids and glycerol

Question 5

Carbohydrate absorption

Answer 5

Limited to monosaccharides (fructose absorption limited)

Question 6

Carbohydrate digestion

Answer 6

Starch is digested by a-amylases in saliva and pancreatic excretions to form maltose, maltotriose and a-dextrins

Further digestion by brush border enzymes - gluco-amylase, a-dextrinase, sucrase and maltase to form glucose and fructose

Question 7

Non-starch polysaccharides and other CHO

Answer 7

Not digested and absorbed by the small intestine

Soluble fibres (pectin / gum) are fermented by bacteria in the colon

Insoluble fibres make up the cellulose roughage in the diet

Question 8

Microbial fermentation leads to production of:

Answer 8

Gas - CO2, H2, CH4

Short chain fatty acids:

Acetate (enters peripheral circulation)

Propionate (taken up by liver)

Butyrate (used by colonic cells)

Question 9

Pepsin digestion

Answer 9

Pepsinogen released by chief cells in stomach

HCl released by parietal cells, forming pepsin

Only protease which can break down collagen

Question 10

Pancreatic proteases

Answer 10

Trypsin and chymotrypsin

Synthesized and packaged in vesicles as pro enzymes

Activated by enterokinase

Vesicles contain trypsin inhibitor