Digestion ( 3 ) Flashcards
Besides maltose, what other disaccharides are hydrolysed?
- Sucrose
* Lactose
What hydrolyses sucrose?
Sucrase
What hydrolyses lactose?
Lactase
What does sucrase do?
- Hydrolyses glycosidic bond in sucrose molecules.
* Produces two monosaccharides: • Glucose • Fructose
What does lactase do?
- Hydrolyses the single glycosidic bond in the lactose molecule
- Hydrolysis produces two monosaccharides glucose and galactose
What are lipids hydrolysed by?
lipases
What are lipases?
• Enzymes produced in the pancreas that hydrolyse the ester bond found in triglycerides to form fatty acids and monoglycerides
What are monoglycerides?
Glycerol molecule with a single fatty acid molecule attached
What splits up lipids?
• Bile salts
What is the process of emulsification?
- Lipids are split up into droplets called micelles
* This is done by bile slats
Where are bile salts produced?
Liver
What is the purpose of emulsification?
- Increases surface area of lipids
* This will speed up action of lipases
What group of enzymes hydrolyse proteins?
Peptidases
What are the different peptidases?
- Endopeptidases
- Exopeptidases
- Dipeptidases
What do endopeptidases do?
• Hydrolyse the peptide bonds between amino acids in the central region of a protein molecule forming a series of peptide molecules
What is the purpose of exopeptidases?
- Hydrolyse the peptide bonds on the terminal amino acids of the peptide molecules formed by endopeptidases
- This way, they progressively release dipeptides and single amino acids
What is the purpose of dipeptidases?
- Hydrolyse bond between two amino acids or a dipeptide
* Dipeptidases are membrane bound, being part of the cell surface membrane of the epithelial cells lining the ileum
What are membrane bound disaccharides?
Enzymes that are attached to the cell membranes of epithelial cells lining the ileum ( final part of the small intestine )
What is the purpose of membrane bound disaccharides?
- Help break down disaccharides into monosaccharides
* Hydrolysis of glycosidic bonds
How are monosaccharides transported across the cell membrane of the ileum?
Via specific transporter proteins
What bonds does lipase hydrolyse?
Ester bonds in lipids
Where are lipases produced?
Pancreas
Why are the conditions of the stomach acidic?
- Released into the stomach by cells in the stomach lining
* Pepsin only works in acidic condition, these are provided by hydrochloric acid in the stomach
