Cellular Metabolism

Metabolism
       Anabolic - build up
       Catabolic - break down

Anabolic Metabolism
       Smaller molucules used to build larger molecules
       Process used is "dehydration synthesis"
               H+ and OH- are removed (H2O)
       Monosaccharides (glucose) syntehsize complex carbohydrates
       Glycerol and Fatty Acids syntensize lipids
       Amino Acids synthesize proteins
               peptide bonds occur (between C and N atoms)

Catabolic Metabolism
       Larger molecules are broken down to smaller molecules
       Process used is "hydrolysis"
               H2O is added (as H+ and OH-)
       Opposite reactions occur as far as:
               complex carbohydrates
               lipids
               proteins

Enzymes

       Usually proteins, these speed up/assist reactions
       May contain inactive part used for binding
               called a cofactor
               if Organic, is a CoEnzyme
                      CoEnzymes are frequently vitamin molecules
       Read about in text

Energy for Metabolic Reations
       Energy is stored in the bonds between atoms
       When molecules are broken down, energy is given off
               when glucose is burned, is oxidataion
       Some energy is captured chemically (ATP)
               ATP has high energy bonds
       Some energy escapes (warms the body)

Production of Energy (two phases):           
       Anaerobic Metabolism
       Aerobic Metabolism

Anaerobic
       Glucose is broken down to Pyruvic Acid (pyruvate)
               6 Carbon Glucose => 2 3 Carbon Pyruvates
               This is called glycolysis
               This gives off energy for 2 ATP molecules
                      Occurs very fast
                      Rapid form of energy
               Pyruvate is unstable, quickly converted to Lactic Acid (lactate)
               Lactate is later removed by Oxygen

Aerobic Metabolism
       Pyruvate breaks down to a 2 Carbon Acetyl Group
               2 pyruvates => 3 acetyl's
       Acetyl group combines with CoEnzyme A (Acetyl CoA)
       Acetyl CoA acted on by Oxygen
               goes through a series of steps (Citric Acid Cycle - Kreb Cycle)
               gives off 36 ATP molecules
               by products are CO2 and H20
       Requires Oxygen
       Produces ATP slowly

Metabolic Pathways
       series of reactions to convert substance to ATP

Carbohydrate Pathway
       Described above

Lipid Pathway
       Fats must first undergo hydrolysis (addition of water)
               Are then converted to Acetyl-CoA (through beta-oxidation)
       Others are converted first to ketone bodies, then to Acetyl-CoA
       is the efficient way of burning fuel
       body always performs the most efficient method

Protein Pathways
       Proteins are converted to Amino Acids
       Amino Acids have Amino's removed (deamination)
       Various pathways occur, depending upon the Amino Acid
               some paths lead to Acetyl-CoA
               others lead to various steps in the Kreb Cycle

       by product is Urea (high in nitrogen)
       is hard on the liver to deaminate proteins