78 - Nutritional Value of Carbohydrates Flashcards
Product of glucose that is converted to fat
Pyruvate
Anomer of glucose that is in starch and glycogen
Alpha-D-glucopyranose
Antique name for glucose
Dextrose
GLUT in liver
GLUT2
GLUT that is insulin-sensitive
GLUT4 in skeletal muscle
Only organs with the ability to release free glucose from glycogen
Liver and kidney (have glucose-6-phosphatase)
Pathways stimulated by insulin in a cell
Growth pathway (cell proliferation, counters apoptosis) Metabolic pathway (glycogen synthesis, protein synthesis, NOS formation, antilipolysis)
Size of glycogen molecules
Can have up to 55,000 glucose units in a glycogen molecule
Osmotic action of glycogen
A single glycogen molecule is osmotically equivalent to a single glucose (so doesn’t make the liver swell).
Pompe’s disease
Lysosomes engorge with glycogen due to a lack of a-1,4-glucosidase.
Respiratory failure causes death, usually before age 2.
Example of a glycogen storage disease
Pompe’s disease
Stimuli that lead to breakdown of glycogen
Stress (EG adrenaline) or fasting (EG glucagon)
Universal cellular stress signal
cAMP
How is cellulose digested?
By bacteria in gut. Humans don’t make enzymes to break down cellulose.
Part of cereals that provide most energy
Endosperm contains starch and proteins
When does a person exhale large amounts of hydrogen gas?
When gut bacteria metabolise dietary sugars due to pancreatic insufficiency, lactose intolerance or coeliac disease
How does sugar result in tooth cavities?
Sugar is metabolised to acetic, propionic and butyric acids by bacteria in dental plaques. Teeth (calcium phosphate) dissolve at pH of ~5.5.
Two diseases of low dietary fibre
Haemorrhoids
Diverticulosis
Effect of fibre on gut microflora
Promotes growth of protective microbes
Glycaemic index
% response of blood glucose elevation relative to 50grams of glucose (EG: 100% means that food elevates blood glucose as much as pure glucose)
