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level: 6.9 Enzymes and digestion

Questions and Answers List

level questions: 6.9 Enzymes and digestion

QuestionAnswer
Major parts of the digestive system- Salivary glands - Oesophagus - Stomach - Pancreas - Ileum - Large intestine - Rectum
Oesophagus- Carries food from the mouth to the stomach
Stomach- Muscular sack - Inner layer has glands, produces enzymes - Stores + digests food, especially proteins
Ileum- Long muscular tube - Food digested by enzymes - Has villi
Large intestine- Absorbs water
Rectum- Final section of intestines - Where faeces are stored - Removed via anus, called egestion
Salivary glands- Near mouth - Secretes amylase, hydrolyses starch into amylose
Pancreas- Large gland below stomach - Produces pancreatic juice - Contains protease, lipase and amylase
What is digestionTwo stages - Physical breakdown - Chemical breakdown
Physical breakdown- Teeth breaks down large molecules into smaller ones - So food can be ingested - LSA for chemical digestion - Food churned by muscles in stomach
Chemical breakdown- Hydrolysis of large insoluble molecules into smaller soluble ones - Enzymes hydrolyse molecules, adding water
Types of enzymes- Carbohydrase/amylase - Lipase - Protease
Carbohydrase- Hydrolyses carbohydrates into monosaccharides - Made by pancreas, small intestine, salivary glands
Lipase- Hydrolyses lipids into glycerol + fatty acids - Made by pancreas, small intestine
Protease- Hydrolyses proteins into amino acids - Made by pancreas, small intestine, stomach
Membrane-bound disaccharidases- Enzymes attached to cell membranes of epithelial cells lining the ileum - Helps break down disaccharides into monosa.
Carbohydrate digestion (1)- Salivary amylase in the mouth hydrolyses starch (macromolecule) into maltose - Breaking 1-4 glycosidic bonds
Carbohydrate digestion (2)- Salivary amylase is denatured in the stomach
Carbohydrate digestion (3)- After the stomach food then enters the small intestine where it mixes with pancreatic juice
Carbohydrate digestion (4)- Pancreatic amylase hydrolyses starch
Carbohydrate digestion (5)- There are maltase enzymes on epithelial cells of ileum
Carbohydrate digestion (6)- These hydrolyse maltose to alpha glucose - Glucose can be absorbed into the blood
Bile salts- Produced by the liver - Emulsifies lipids into small droplets
Importance of bile salts- Small lipid droplets increases SA for lipase to work on
Peptidases- Group of proteases - Proteins are large, complex
The different peptidases- Endopeptidases - Exopeptidases - Dipeptidases
Endopeptidases- Breaks down specific amino acids in the middle of a polypeptide
Exopeptidases- Break down specific amino acids at the end of a polypeptide
Dipeptidases- Hydrolyses dipeptides into amino acids