53 - Nutrient metabolism. Carbohydrate metabolism. Level and regulation of Glucose. Protein metabolism and its regulation. Lipid metabolism and its regulation.

section

types of metabolism

carbohydrate metabolism

level and regulation of glucose

steps of protein metabolism

protein regulation

lipid metabolism

types of metabolism

• anabolic reactions - build-up of larger molecules from smaller ones

• catabolic reactions - breaking down of larger molecules into smaller ones.

• All energy foods involve carbohydrates, lipids are protein can be oxidised in cells.

carbohydrate metabolism

• carbohydrate → glucose, fructose and galactose.

• Glucose needed to produce energy, in body, brain needs-120g a day

• Glycolysis is the breakdown of glucose → ATP

• Glucose is stored as glycogen in the liver

• Level and regulation of Glucose

  • Regulated by insulin- lowers glucose levels after feeding

  • Glucagon- stimulates gluconeogenesis to increase glucose

steps of protein metabolism (catabolism)

1. breakdown of proteins → amino acids which are then absorbed into the bloodstream. – used for protein building and repair

2. removal of amino group- deamination. to form ammonia

   • Ammonia →urea →filtered through the kidney to form urine.

   • The carbon skeleton can be used for protein synthesis, ATP

protein regulation

1. Pituitary glands produce growth hormone that activates thyroid and adrenal glands all helping to stimulate growth

2. Parasympathetic-growth hormones, insulin, thyroid hormones and glucocorticoids all have an anabolic effect

3. Sympathetic influences via glucocorticoids have a catabolic effect

lipid metabolism

• Lipids:--TAG→FFA and glycerol

• Lipids are an Energy source

• Anabolism- lipogenesis activated by insulin

• Lipolyisis activated by glucagon and – glucocorticoids, cortisol, sympathetic nervous system, GH,