digestion Flashcards
Enzyme
- protein molecule
- biological catalyst
- speeds up chemical reactions without itself undergoing any chemical change
Protease only acts in an
acidic medium
amylase acts in an
alkali medium
lipase acts in an
alkali medium
Where are the enzymes secreted?
small intestine and pancreas
explain the function of bile (4)
- Bile is produced in the liver and stored in the gallbladder
- alkali-neutralises stomach acid
- emulsifies fats into droplets- large SA:VR.
ingestion
intake of food
digestion
breakdown of large food molecules into small food molecules, Mechanically and chemically (enzyme) for absorption.
What happens in the mouth?
mastication
Absorption
Food particles diffusing into the villi/microvilli of the small intestine into the bloodstream.
Assimilation
The build up of new molecules in the body from smaller food molecules eg: new cells, tissues
1, ingestion 2, Peristalsis 3, digestion 4,absorption 5, assimilation 6, egeStion
EgeStion
A process during which Solid faeces is removed.
Ball of food
Bolus
Peristalsis
The wave-like movement of a bolus of food because of muscular contractions.
SM^2ART
- large SA:VR to maximise the rate of diffusion
- surfaces need to be moist for easy absorption
- mitochondria- cellular respiration to release energy for active transport
- rich blood supply in the villi and microvilli: creates a high concentration gradient
- 1 cell Thick: shorter diffusion path
coeliac disease
- The microvilli are damaged and this reduces the SA for absorption of food molecules
- Fewer amino acids and glucose molecules are absorbed
- less glucose means less respiration meaning less energy
- Fewer amino acids –> less proteins –> smaller growth
Food tests-starch
-To the test sample, add a few drops of iodine
Original colour-brown. If it turns blue black starch is present.
Food tests-protein
To the test sample add a few drops of biuret. Goes from blue to purple.
Food tests-glucose
Heat the test sample to about 50/60/70 degrees. Add a few drops of Benedict’s solution. Blue –> green/red (depends on concentration)
Food tests-lipids
emulsion using suDan 111. Swirl the contents. If there is a reD ring, it confirms lipiDs.
