2 - Energy and carbohydrates Flashcards
Monosaccharides contain __ molecule
e.g. _____________________
– Disaccharides contain __ molecules
e.g. _____________________
– Oligosaccharides contain ___ monosaccharides
– Most polysaccharides consist of hundreds to thousands of glucose molecules- Divide into:
» _______
» _______
Monosaccharides contain one molecule
» Glucose, fructose, ribose and galactose
– Disaccharides contain two molecules
» Lactose, maltose, and sucrose
• Complex carbohydrates
– Oligosaccharides contain 3 to 10 monosaccharides
– Most polysaccharides consist of hundreds to thousands
of glucose molecules- Divide into:
» Starch: -glucans
» Nonstarch polysaccharides (non -glucans)
What is the definition of dietary fibre?
Carbohydrates polymers with ten or monomeric units, which are not hydrolysed by the endogenous
enzymes in the small intestine of humans
What is soluble fibre? + Examples
What is insoluble fibre? + Examples
Soluble = dissolves in water and fermentable. E.g. PEctin, gum, mucilage
Insoluble = Does not dissolve in water and cannot be fermented. Promote regular bowel movements E.g. Lignins, cellulose, hemicelluloses.
What are the main organs that play a role in carbohydrate digestion?
Mouth - Chewing and salivary amylase
Stomach
Pancrease - Pancreatic amylase secreted to small intestine
Small intestine - Enzymes break down disaccharides, monosaccharides are absorbed
Large intestine - Bacteria fermentation
Liver - Monosaccharides converted to glucose and glycogen.
How are glucose and galactose absorbed from the lumen to the blood?
Secondary active transport across apical membrane
Facilitated diffusion across basolateral membrane
How is fructose absorbed from the lumen to the blood?
Facilitated diffusion across apical and basolateral membrane.
What are the 3 short fatty acids generated during carbohydrate fermentation and their functions?
Acetate - readily absorbed, stimulating sodium absorption. Basses to the liver and then blood (energy source)
Propionate - absorbed and passes to the liver. Metabolised aerobiclly.
Butyrate - Major energy source for the colonic epithelial cell. Promotes cell differentiation and inhibits cell division.
What are some hormones that control blood glucose levels?
Insulin, Glucagon, Epinephrine, Norepinephrine, Cortisol, Growth hormone.
Where is insulin secreted?
Islets of Langerhans in the pancreas
What is Glucuronic acid and what is it required for?
Synthesised from glucose and required for the conjugation of sterols and foreign compounds to aid their solubility and thus excretion in bile and kidney.
How does fibre effect bile digestion and thus blood cholesterol?
Biles is secreted into the intestine to aid in fat digestion. Fibre binds to bile and both are excreted in the feces. Less cholesterol is therefore reabsorbed from the bile and blood levels are reduced.
What is the difference between reactive and fasting hypoglycemia.
Fasting = eg in the morning after a long period of no carbs
Reactive - After a meal which spiked your blood sugars.
