Mammalian Nutrition Two basic types of nutrition exist: HETEROTROPHIC Organisms eat food containing Organic molecules. AUTOTROPHIC Organisms manufacture food containing organic molecules.

Oesophagus Salivary glands Stomach Pancreas Palate Teeth Tongue Epiglottis Liver Gall bladder Duodenum Transverse colon Ascending colon Small intestine Appendix Descending colon Rectum AnusSigmoid colon

Water,inorganic ions, vits & minerals are small enough to be absorbed into the walls of the alimentary canal LUMEN Wall of A.Canal Macromolecules (starch/protein) are too large to pass through into The wall of the ACanal, they need to undergo some form of digestion. ENZYME E.G. Polymers broken down into monomers

There are two types of digestion PHYSICAL DIGESTION Here large pieces of food are broken up into small pieces of food CHEMICAL DIGESTION Here large molecules are broken up into small molecules. The mouth & stomach do this Enzymes do this

INGESTION – food enters the Alimentary canal EGESTION – faeces leaves the Alimentary canal DIGESTION Ingestion to egestion.

CHEMICAL DIGESTION Recap When we a building large polymers in biology, you take MONOMERS and you create bonds, by removing water. a.k.a CONDENSATION REACTIONS So to break these bonds (digestion) you need to add water a.k.a HYDROLYSIS REACTIONS

SUBSTRATE e.g. Macromolecule e.g. Starch ENZYME e.g. Amylase or Maltase ENZYME SUBSTRATE COMPLEX ENZYME (unchanged) e.g. Amylase or Maltase PRODUCT e.g. monomers e.g. Glucose ENZYME + SUBSTRATE → ENZYME SUBSTRATE COMPLEX → PRODUCTS

CLASSIFYING DIGESTIVE ENZYMES HYDROLASES –all work via hydrolysis Proteases or Peptidases 1.ENDOpeptidases Trypsin & Chymotrypsin 2.EXOpeptidases Carboxypeptidase Carbohydrases AMYLASE MALTASE SUCRASE LACTASE Lipases

Peptidases – hydrolyse proteins to amino acids ENDOPEPTIDASES These hydrolyse peptide bonds within the protein molecule ENDOPEPTIDASES PEPSIN – TRYPSIN – CHYMOTRYPSIN are examples of endopeptidases

Peptidases – hydrolyse proteins to amino acids EXOPEPTIDASES These hydrolyse peptide bonds at the edge of short protein chains CARBOXYPEPTIDASE is an examples of exopeptidases AMINO ACIDS Monomers

Carbohydrases – hydrolyse polysaccharides to monosaccharides 2 monosaccharides connected by a glycosidic link (disaccharide!) Digestion of starch begins in mouth; amylase hydrolyses starch to maltose. 3 Maltose, maltase hydrolyses maltose to glucose. A A M 6 glucose molecules.

SUCROSEFRUCTOSEGLUCOSE + LACTOSEGALACTOSEGLUCOSE + SUCRASE LACTASE

Lipase – hydrolyse triglycerides to fatty acids & glycerol Ester bond Fatty acids Glycerol Lipase TRIGLYCERIDES 3 FATTY ACIDS GLYCEROL +

What happens where? STARCH to MALTOSESALIVARY AMYLASE REACTANT/PRODUCTENZYME PROTEINS to PEPTIDES LIPASE Chymo/trypsin LIPIDS to FAs & GLYCEROL PROTEINS to PEPTIDES PROTEINS to A.ACIDS PEPSIN Carboxypeptidase LIPIDS to FAs & GLYCEROL LIPASE

MALTOSE to GLUCOSE SUCROSE to GLUCOSE + FRUCTOSE LACTOSE to GLUCOSE + GALACTOSE PEPTIDES to AMINO ACIDS MALTASE SUCRASE LACTASE PEPTIDASE