Digestion And Absorption Flashcards
1
Q
Describe the process of starch digestion.
A
- salivary amylase converts to maltose
- maltase converts maltose to glucose
- glycosidic bonds hydrolysed
2
Q
Describe lipid digestion into lymph vessels.
A
- lipid droplets emulsified by bile salts
- increases surface area as smaller droplets
- triglycerides hydrolysed into glycerol, fatty acids and monoglycerides
- bile salts, fatty acids and glycerol form micelles
- micelles make fatty acids water soluble
- fatty acids enter epithelial by simple diffusion
- at S.E.R triglycerides reformed
- at GOLGI, triglycerides have protein added = chylomicrons
- chylomicrons transported into lymph by exocytosis
3
Q
Describe role of micelle role in the absorption of fats.
A
- micelles include bile salts and fatty acids
- makes fatty acids more soluble in water
- bring fatty acids to, lining of ileum
- maintain fatty acid conc gradient to lining
- fatty acids absorbed by diffusion
4
Q
Role of enzymes in digestion of proteins in a mammal.
A
- peptide bonds hydrolysed
- endopeptidase act in middle of polypeptides
- exopeptidase act on ends of polypeptides
- dipeptidase act between two amino acids
5
Q
Features found in a cell specialised for absorption.
A
- microvilli so large surface area
- large number of co-transport proteins so after absorption rate
- large number of mitochondria so more ATP by respiration
- membrane-bound enzymes so maintains conc gradient for faster absorption
6
Q
Describe the co-transport of glucose.
A
- sodium ions actively transported from ileum cell to blood
- maintains sodium diffusion gradient (sodium-potassium pump)
- gluclose moves against its conc gradient
- gluclose enters by facilitated diffusion
7
Q
Describe the mechanism for absorption of amino acids into ileum.
A
- facilitated diffusion of amino acid into cell
- co-transport
- sodium ions actively transported from cell to blood
- sodium conc gradient created
- facilitated diffusion of amino acid into blood
