16. Energy Generation in Mitochondria and Chloroplast

• Photosynthesis • Oxidative Catabolism

6CO2 + 6O2 ——> C6H12O6 + 6O2 • Uses energy from sunlight to reduce carbon from atmospheric CO2 to sugar • O2 produced as a by-product

C6H12O6 + 6O2 ——> 6CO2 + 6H2O • Oxidizes carbon from sugar to release energy to power metabolism • CO2 produced as a by-product.

main source of energy for many reactions in cells in eucaryotes ATP produced. • during glycolysis ( small amount) • in mitochondria ( most of ATP production) • in chloroplast ( plants and green algae

chemiosmotic coupling - in mitochondria and chloroplast, in cell membrane of many bacteria

Digestion

Enzymatic hydrolysis of macromolecules digestive tract/organelles.

• partial oxidation of glucose to pyruvate in the cytosol • does not require oxygen • basis of anaerobic metabolism

In the matrix of mitochondria -requires oxygen

• driven by electron transport across the inner mitochondrial membrane • generates ATP • requires oxygen

Partial oxidation of glucose (6 carbon) to pyruvate ( 3 Carbon) • does not require oxygen • occurs in steps- allow energy to be efficiently captured • Production of ATP and NADH

2 molecules of pyruvate 2 molecules of ATP 2 molecules of NADH

Pyruvate —> acetyl CoA + CO2 Sources of pyruvate: Yglycolysis Yamino acids

pyruvate dehydrogenase complex

1 NADH

Oxidation of acetl CoA to CO2 Fatty acids also oxidized to acetyl CoA

Net results : 3 NADH 1GTP 1 FADH2

• Sugars • amino acids • nucleotides • Lipids • produced during glycolysis and citric acid cycle are used as the precursors for synthesis of many macromolecules.

Double membrane organelle of varable size and shape that provides a site for: • Oxidation of pyruvate–> acetyl CoA + NADH • Oxidation of fatty acids—-> acetyl CoA + NADH + FADH2 • Citric acid cycle —–> NADH + FADH2 +GTP • Oxidative phosporylation

Main site of energy production in eucaryotic cells. vry efficient: • glycolysis harvest less than 10% of the total free energy potentially avaiable from the glucose (2 ATP molecules produced per gllucose molecule) • in mitochondria- ~ 30 ATP molecules produced for each glucose molecule.

• thier own DNA and RNA • Complete transcription and translation machinery ( ribosomes) • present in large numbrs (~2000 in hepatocytes) • can be extremely motile or stationary • stay in close location to a site high ATP consumption ( close to the contractile apparatus in muscle cells, wrapped tightly around the base of the motile flagellum) • defects in mitochondrial function - serious effects on the body function (especially affected are tissues with high energy need e.g. muscles and nervous tissue; MERRF - myoclonic epilepsy and ragged red fiber disease - mutation in one of mitochondrial tRNA genes —> decrease in synthesis of electron transport proteins)