Metabolism

Chapter 25

Essential Nutrients

45 – 50 molecules must be ingested.

This includes representatives from the 4 major organic molecule groups, plus a number of inorganic substances such as including water, vitamins and minerals (Na, Fe, etc.)

The USDA Food Pyramid

Nutrient –A substance in food used by the body for growth,

maintenance, energy and repair.

• Carbohydrates: 55 – 60 % of daily calories. 125 – 175 g.

• Lipid: < 30% of daily calories. 80 – 100 g.

• Protein: 0.8g/kg body weight.

• Nucleic acids: not established

• Water: 1500 ml (average) per day.

Uses of nutrients

• Carbohydrate: Primary energy molecule. Also found on cell membranes and as part of structure of connective tissue matrix molecules

• Lipid: Energy storage, plasma membrane structure, cushioning, steroid hormones.

• Proteins: Enzymes, receptors, hormones, structures of all kinds. Must be “complete” or “complimentary” in order to supply essential amino acids.

Essential amino acids

Energy Metabolism

• Metabolism = catabolism + anabolism

• Cellular respiration is a series of catabolic reactions that provide energy for the production of

• This energy is used to generate ATP from phosphorylation of ADP.

• It is a series of Redox reactions.

ATP

Summary of steps of energy

metabolism

Generation of ATP by “substrate-level phosphorylation”

Oxidative phosphorylation

Overview of cellular respiration

Carbohydrate Metabolism

C6H12O6 + 6 O2 6 CO2 + 6 H2O + 36 ATP + Heat

Oxidation of Glucose

Glycolysis: an Anaerobic process.It is the first stage in cellular respiration

Krebs cycle

The Electron Transport Chain

The ETC energy gradient

Summary of ATP synthesisGains & losses

Glycogenesis/Glycogenolysis

Summary of lipid

metabolism:oxidation

Metabolism of Triglycerides

Protein metabolism in the Liver

Carbohydrate/fat & amino acid pools

Interconversion of carbohydrate, lipid and protein

Pathways of the Absorptive state

The effects of insulin on

metabolism

Major Events of the Postabsorptive state

Influences of

Glucagon on blood glucose levels

Pathways of the Postabsorptive state

Composition of

Lipoproteins

Hypothetical feeding control mechanism

Heat Balance

Temperature regulation mechanisms

Maynard or Hans?