Electron Transport Chain Lecture 3

Glycolysis Review Questions What is needed to start the reactions of glycolysis? Where does Glycolysis occur in the cell? What Kingdoms perform Glycolysis? How many total ATP are produced during glycolysis? How many net ATP? What electron carrying molecule is produced during glycolysis? Is glucose oxidized or reduced during glycolysis? What is glucose converted into at the end of glycolysis?

Kreb’s Cycle Review Questions Where does the Kreb’s cycle occur in eukaryotes? Why is the Kreb’s cycle cyclic? What electron carrying molecules are produced during the Kreb’s cycle? What is the acetyl CoA converted into during the Kreb’s cycle? What type of ATP production is occurring during the Kreb’s cycle: oxidative or substrate level phosphorylation?

Electron Transport Chain Final step of cellular respiration Requires oxygen (aerobic) Located in the inner mitochondrial membrane (cristae)

Electron transport chain Electrons lost from NADH and FADH2 move through a series of enzymes (ubiquinone and cytochromes) Energy used to move H+ from NADH and FADH2 (protons to the inner membrane space) Oxygen accepts electrons at last enzyme and creates water

More on Making ATP 3 places in the chain make ATP NADH FADH2 Electrons from NADH start “higher” in the waterfall, so they generate more ATP than FADH2 electrons, which start “lower” (less PE) and miss 1 ATP-generating step.

CHEMIOSMOSIS = makes ATP from a proton gradient. It occurs in all living things Protons move through ATP synthase from high (inner membrane space) to low concentration (matrix) spinning turbine that produces ATP in matrix Prokaryotes create gradient across cell membrane to make ATP to pump nutrients & waste and move flagella http://student.ccbcmd.edu/~gkaiser/biotutorials/energy/atpsynthase_il.html

OXIDATIVE PHOSPHORYLATION = using proton gradient created by electron transport chain in cristae membrane to make ATP MITOCHONDRION

Cellular respiration Kreb’s Cycle: mitochondrial matrix; pyruvate → CO2 NADH made Electron Transport Chain: cristae; NADH & FADH2 donate electrons → oxygen Glycolysis: cytosol; glucose → pyruvate

Cellular Respiration Grand Total Glycolysis: →2 ATP (substrate-level phosphorylation) Kreb’s Cycle:→ 2 ATP (substrate-level phosphorylation) Electron transport & oxidative phosphorylation: 2 NADH (glycolysis) → 5 ATP 2 NADH (acetyl CoA) →5 ATP 6 NADH (Kreb’s) → 15 ATP 2 FADH2 (Kreb’s) → 3 ATP 32 TOTAL ATP from 1 molecule of glucose (-2 ATP to transport 2 pyruvate into mitochondria) NET of 30 ATP Eukaryotes (32 Prokaryotes)