Key Terms
Metabolism
The sum of ALL chemical reactions in the body — both breakdown and buildup. Two sides to it:
ATP (adenosine triphosphate) structure
Adenine + ribose + 3 phosphate groups The high-energy bond is between the 2nd and 3rd phosphate groups.
When that bond breaks
ATP becomes ADP + Pi (inorganic phosphate) + energy.
Oxidation
Loss of an electron Reduction: gain of an electron These always happen in pairs — one molecule gets oxidized, another ge
Net result
1 glucose molecule = 36 ATP (aerobic conditions)
Location
Primarily the liver Triggers: fasting, starvation, low- carbohydrate diets
Output per cycle
1 ATP (via GTP), 3 NADH, 1 FADH2, 2 CO2
Before the cycle starts
Pyruvate is converted to acetyl CoA by pyruvate dehydrogenase; CO2 is released and NAD+ becomes NADH.
Definition
Synthesis of fats from acetyl CoA Trigger: excess glucose/carbohydrate intake Location: cytoplasm of adipocytes and hepa
Starting materials
Pyruvate, lactate, glycerol, alanine, glutamine
After digestion
Fatty acids and monoglycerides cross the intestinal wall, get reassembled into triglycerides, and packaged into chylomic
Lipolysis
Triglycerides broken down into glycerol + 3 fatty acids
Beta-oxidation
Fatty acids converted to acetyl CoA, which enters the Krebs cycle
Trigger
Excess acetyl CoA overloads the Krebs cycle (during prolonged fasting or uncontrolled diabetes) Location: liver mitochon
Problem
Acetyl CoA is made in the mitochondria but lipogenesis happens in the cytoplasm. Solution: pyruvate converts to citrate,