Chapter 6: “Cellular Respiration” Other Metabolic Pathways “Glucose Is Not the Only Food Molecule” Pgs Objective: I can describe how other types of food besides carbohydrates are metabolically processed to provide energy for my cells.

The Path of Glucose (a review) Glucose (C 6 H 12 O 6 ) enters cell (cytoplasm) Undergoes glycolysis 1 st Turns to pyruvate in the end Enters mitochondria (where?) Transition Step Oxidizes into Acetyl Co-A Enters matrix of mitochondria Krebs Cycle (Electron Carriers go to ETC on inner membr.) “Remains” of glucose: CO 2 + H 2 O (intermembrane space)

Do you only eat glucose? Typical American Food: Hamburger Bun (bread) made of… Starch (“chemical”) Type of polysaccharide Type of carbohydrate Polysaccharide broken down into glucose  How? Hydrolysis (add water/splits) Exergonic Releases energy (but VERY little)

Do you only eat carbs? Cheese is basically Fat (Lipids) - Triglyceride Breaks down into Glycerol & Fatty Acids (hydrolysis) Fats have more nrg bcoz Has more C-H bonds… Fatty Acids (  ) oxidized Turn into Acetyl-CoA (2-carbons) 1 fatty acid  9 Acetyl-CoA 1 glucose  2 Acetyl-CoA ATP

What else do you eat? Meat is Protein (polypeptide) Broken down into Amino Acids (hyd) Veggies + fruits have Nucleic Acids (DNA) Broken down into Nucleotides (hyd) Both can release NH 3 “Carbon remains” enter Krebs Cycle (rarely)

URINE Nucleic Acids??

Food can be used for Biosynthesis This is endergonic  requires energy This is endergonic  requires energy Use same processes that break down to build up Use same processes that break down to build up Anabolic Anabolic Catabolic Catabolic Regulate via feedback inhibition Regulate via feedback inhibition

Review: When there is Oxygen… Oxygen is used in ETC Accepts electrons from NADH & FADH 2 Allows them to turn back to NAD+ & FADH Then, NAD+ and FADH can return to previous steps to oxidize and bring in more electrons to make more ATP e-e- Aerobic Respiration NAD+ FADH

Review: When there is no Oxygen… ETC shuts down (nothing to accept e-) Build up of NADH and FADH2 Krebs Cycle shuts down (no NAD+ or FADH) Transition step shuts down, too Glycolysis will shut down, too UNLESS can oxidize NADH… (recycle NAD+)

Review: Fermentation (a side path) NADH can reduce pyruvate directly Lactic Acid Fermentation NADH can reduce acetaldehyde (from pyruvate) Alcoholic F. Only glycolysis can make ATP = Fermentation does NOT make ATP directly Pyruvate NAD+e-e-  Lactic Acid  Acetaldehyde CO 2 NAD+e-e-  Ethanol (alcohol) - it merely oxidizes NADH so it can return to glycolysis to oxidize again 2 Anaerobic Respiration (much less efficient) “Regular Lingo”  “Fermentation” = entire Glycolysis-Fermentation process