3.2 Mass transport Flashcards
what products are formed from the hydrolysis of carbohydrates?
disaccharides then monosaccharides
what products are formed from the hydrolysis of fats?
fatty acids and monoglycerides
what products are formed from the hydrolysis of proteins?
amino acids
where are digestive enzymes produced?
specialised cells in mammal digestive systems
which enzyme catalyses the digestion of starch?
amylase
which enzyme catalyses the digestion of lipids?
lipase
which enzyme catalyses the digestion of proteins?
peptidases - endo and exo
where is amylase produced and released?
produced by salivary glands and released in mouth. produced by pancreas and released in small intestine
how does amylase work?
hydrolyses glycosidic bonds in starch
what are membrane-bound disaccharidases?
enzymes attached to the cell membranes of epithelial cells lining the ileum
what is the function of membrane-bound disaccharides?
break down disaccharides into monosaccharides through hydrolysis of glycosidic bonds
which disaccharidase hydrolyses sucrose?
sucrase
which disaccharidase hydrolyses maltose?
maltase
which disaccharidase hydrolyses lactose?
lactase
where is lipase produced and released?
produced by pancreas and released in small intestine
how does lipase work?
hydrolyse ester bonds in lipids
where are bile salts produced, stored and released?
produced in the liver, stored in the gall bladder, released in the small intestine
what is the function of bile salts?
emulsify lipids into smaller droplets to increase surface area
how are micelles formed?
monoglycerides and fatty acids attach to bile salts
explain the process of lipid digestion [5]
- bile salts emulsify lipids to form smaller droplets
- surface area available for lipase to work on is increased
- lipase hydrolyses ester bonds in lipid droplets
- monoglycerides and fatty acids are produced
- these stay attached to bile salts to form micelles
what is the role of the oesophagus in the digestive system?
to carry food from the mouth to the stomach
what is the role of the stomach in the digestive system?
stores and digests food using enzymes produced by glands in the inner layer
what is the role of the ileum in the digestive system?
to digest food and absorb nutrients
explain how the epithelial cells lining the small intestine are adapted for the absorption of glucose [6]
- microvilli provide a large surface area
- many mitochondria to produce ATP for active transport
- carrier proteins for active transport
- channel/carrier proteins for facilitated diffusion
- co-transport of sodium ions and glucose
- membrane-bound enzymes digest disaccharides and produce glucose
what is the role of the large intestine in the digestive system?
to absorb water into the bloodstream
what is the role of the salivary glands in the digestive system?
To secrete the enzyme amylase into the mouth, which hydrolyses starch into maltose
what is the role of the pancreas in the digestive system?
To secrete pancreatic juice, which contains proteases to hydrolyse proteins, lipase to hydrolyse lipids, and amylase to hydrolyse starch
Describe the processes involved in the absorption and transport of digested lipid molecules from the ileum into lymph vessels [5]
- micelles contain bile salts, fatty acids and monoglycerides
- carry fatty acids and monoglycerides to ileum lining
- fatty acids and monoglycerides are absorbed by diffusion
- triglycerides reform
- chylomicron released via exocytosis
