00:00Good morning students. Today we explore mitochondria — the powerhouse of the cell. Before we begin, open your notebook to page 142 in your FSc Part I textbook.
04:30The mitochondrion has two membranes. The outer membrane is smooth and permeable. The inner membrane is folded into cristae. This folding dramatically increases surface area for ATP synthesis.
22:10Now notice the inner membrane folded into finger-like projections — these are cristae. This is critical for MDCAT. The matrix inside the inner membrane contains enzymes for the Krebs cycle. Remember: cristae increase surface area.
31:00The electron transport chain consists of four protein complexes embedded in the inner mitochondrial membrane. NADH and FADH2 donate electrons which pass through these complexes, releasing energy.
35:40This is chemiosmosis. The proton gradient drives ATP synthase — think of it like water turning a turbine. H+ ions flow from the intermembrane space back into the matrix through ATP synthase, generating ATP.
44:15So the total ATP yield per glucose molecule is approximately 36 to 38 ATP in eukaryotes. Compare this with anaerobic respiration which yields only 2 ATP. This is why aerobic respiration is so much more efficient.
52:00For your MDCAT, remember these key numbers: 10 NADH, 2 FADH2, and 2 ATP from the Krebs cycle per glucose. Now let's do some MCQ practice for the remaining 6 minutes.
