Macronutrients

Question 1

Starch components

Answer 1

30% amylose, 70% amylopectin

Question 2

Fluid absorption in small intestine

Answer 2

9 litres of fluid enter GI tract, 8 litres absorbed through small intestine

Question 3

Disaccharide digestion

Answer 3

Disaccharides - further digestion occurs by action of brush border enzymes - glucoamylase, alpha dextrine, sucrase, maltase
Forms monosaccharides - glucose, fructose and galactose

Question 4

Fat absorption in small intestine

Answer 4

Micelles pass through unstirred water overlying the microvillus
Monoglycerol and fatty acids cross apical membrane of microvillus through passive diffusion and lupus protein transporter mechanisms

Question 5

Protein absorption

Answer 5

Pepsin in stomach
Trypsin - pancreatic proteases
Peptidases - brush border enzymes
PEPT1 - human peptide transporter 1
NHE3 - sodium hydrogen exchanger 3

Question 6

Non-starch polysaccharides (NSP)

Answer 6

= fibre
Not digested and absorbed
Soluble fibres (pectin/gum) are fermented by bacteria in colon
Insoluble fibres make up cellulose roughage of diet
Microbial fermentation leads to production of gas (CO2 , H2, CH4), short chain fatty acids (acetate, propionate and butyrate)
This enhances microbial growth

Question 7

Functions of carbs

Answer 7

Energy substrate
Builds macromolecule
Glycogenesis
Spares protein and fat
NSP - fermentation in colon, excretion of dead cells
Fibre - faecal bulk

Question 8

What is the influx of TAG in adipose tissue mediated by

Answer 8

LPL - lipoprotein lipase

Question 9

What is lingual lipase secreted by

Answer 9

Serous glands