Photosynthesis and Cellular Respiration

ATP (Adenosine Triphosphate) * 1st Law of Thermodynamics- Energy not created or destroyed 1. The sum of energy in universe- constant * 2nd Law of Thermodynamics- energy transfer results in increase entropy (less organization!!) * Adenosine is bonded to 3 phosphates 2. When cell needs energy… it splits off that 3rd P 3. Energy is released, ADP + P is formed, cell uses that energy for whatever it needs 4. Destination of the broken Phosphate??- Used as part of an endergonic reaction in another cell? * Exergonic- catabolism 1. Cellular Respiration, Digestion * Endergonic- anabolism 2. Protein Synthesis (Polymerization), making cell parts
Cellular Respiration * Aerobic Respiration 1. Glycolysis 2. Formation of acetyl CoA 3. Krebs Cycle 4. Oxidative Phosphorylation
Glycolysis
* Glucose goes into the cycle… * 6 Carbon to 2, 3 Carbon molecules, called Pyruvic acid * Occurs in cytoplasm (cytosol) * Net ATP of 2 (because you used 2 in the beginning), 2 pyruvic acids, 2 NADH * GLYCOLYSIS CAN BE DONE WITH OR WITHOUT OXYGEN * At this point, the cell can either continue anaerobically or switch to TRUE aerobic respiration
Formation of Acetyl CoA * When oxygen is present, pyruvic acid enters the mitochondrion 1. Each pyruvic acid (2) converted to Acetyl CoA (2) 2. Co2 (2) is released 3. 2 NADH made (still in cytoplasm)
Krebs Cycle * aka CITRIC ACID CYCLE, takes place in Mitochondrial Matrix * Acetyl CoA enters the cycle one at a time, and all carbons will eventually be converted to CO2 * Oxaloacetate- a 4-Carbon molecule (the Acetyl CoA binds with in this stage…) * this forms a 6-Carbon molecule- Citric Acid * Since there’s 2 Acetyl CoA to begin with, cycle must turn 2x: 1. 2 ATP 2. 6 NADH 3. 2 FADH2
***** WE MADE 4 ATP SO FAR; 2 GLYCOLYSIS, 2 KREBS*****

Oxidative Phosphorylation * From our notes: uses proton gradient created by ETC to make ATP * Occurs in Inner Mitochondrial Membrane * these electron carriers NAD, FAD can also be called hydrogen carriers (in class we refer to NADH, FADH2 as electron carriers) b/c most electron carriers also carry hydrogen atoms * BY THE TIME WE GET TO ETC… 1. 2 NADH molecules from Glycolysis 2. 2 NADH from prod. Of Acetyl CoA 3. 6 NADH from Krebs 4. 2 FADH2 from Krebs * Electron carriers (NADH, FADH) shuttle electrons to the ETC 1. (ETC made of up of proteins embedded in the cristae) 1. Hydrogen atoms are split 2. You get hydrogen ions and electrons from it 3. Electrons travel down the ETC with the help of the carriers 4. They go until reach the final electron acceptor—oxygen 5. Oxygen combines with electrons (and some H) to from WATER * Chemiosmosis 1. SO, another process is happening at the same time as electrons are going down the ETC 2. The hydrogen ions (aka, protons) that split from the ORIGINAL HYDROGEN ATOM …. 3. They’re pumped across the inner mitochondrial. Membrane into the intermembrane space (by the way, the energy released from the ETC fuels this pumping) 4. The pumping of hydrogen ions into the intermembrane space creates a pH gradient or proton gradient, this gradient responsible for producing ATP 5. ATP Synthase- channels that hydrogen ions pass through (which they have to cross if they want to diffuse across the inner membrane) 6. AT THE END OF EVERYTHING (THE OXIDATIVE PHOSPORYLATION), ABOUT 32 ATP IS PRODUCED 7. Every NADH = 3 ATP (except from GLYCOLYSIS, only produce 2)
Every FADH2 = 2 ATP

***** ABOUT 36-38 ATP IS PRODUCED IN TOTAL*****

Anaerobic Respiration * From Glycolysis to Fermentation (No OXYGEN is present) * Alcohol Fermentation 1. 2 pyruvic acid undergoes fermentation and makes 2 ethanol, CO2, 2 NAD+ 2. yeast cells or some bacteria * Lactic Acid Fermentation 3. 2 pyruvic acid (if it doesn’t undergo alcohol fermentation) makes 2 Lactic Acid, 2 NAD+ 4. Muscles cells in human undergo this kind of fermentation due to low oxygen during exercise 5. Some bacteria as well