Metabolism

metabolism

• refers to all the chemical reactions in the body

• Utilizing Macromolecules called proteins, fats, carbs and nucleic acid

catabolism

includes all chemical reactions that break down complex organic molecules (carbs, proteins, nucleic acids and lipids)

anabolism

refers to chemical reactions that combine simple molecules to form complex molecules (amino acids, monosaccharides, fatty acids)

carbohydrate metabolism

• During digestion, polysaccharides and disaccharides are converted to monosaccharides (primarily glucose)

• primarily concerned with glucose metabolism

lipid metabolism

• Lipid is broken down and synthesizes through the process of beta-oxidation

protein metabolism

• Amino acids go through the process of transamination, transferring the amine group from the amino acid to another molecule

• Deamination: glutamate is converted to alpha-ketoglutrate releasing ammonia

• urea cycle: ammonia is converted to urea through the urea cycle and excreted out via urine

lipids

made up of fats such as triglycerides, unsaturated/saturated fats

proteins

made up of amino acids which are important for a lot of bodily functions (contractile proteins: actin and myosin, antibodies, heme (RBC), hormones (Insulin), and enzymes

glycogenesis

glucose storage as glycogen

Glycogenolysis

glucose release by conversion of glycogen into glucose

Lipogenesis

Fatty acid synthesis from carbohydrates during the consumption of excess carbohydrates

absorptive state

• period immediately after a meal is eaten when nutrients are being absorbed through the intestinal wall into the circulatory system

• starts approx. 4 hours after eating

postabsorptive state

• late morning, late in afternoon, during the night concluded maintain blood glucose level

• 12 hours, during late morning, late afternoon, and most of the evening

Fat-soluble vitamins

• emulsified into micelles and absorbed along with ingested dietary fats by the small intestine

• stored in cells (particularly liver cells) and include vitamins A, D, E, and K.

Water-soluble vitamins

• absorbed along with water in the GI tract and dissolve in the body fluids

• include vitamins B and C

hypothalamus

contains two centers related to regulation of food intake: the feeding (hunger) center and satiety center

leptin

• the satiety hormone

• acts on the hypothalamus to inhibit ciruits that stimulate hunger & eating and to activate circuits that increase energy expenditure

minerals

• help regulate enzymatic reactions

• regulate osmosis of water

• generation of nerve impulses

• calcium, iron, magnesium

calcium and phosphorus

form part of the matrix of bone

magnesium

catalyst for conversion of ADP to ATP