2. Energy! Forms of energy include chemical, radiant (heat and light), mechanical and electrical Chemical energy is contained in the chemical bonds of molecules Radiant energy travels in waves (ex: visible light) Energy can be transferred from one form to another Law of Thermodynamics Energy cannot be created or destroyed - can be converted from one form to another Usable energy is lost during transformations
3. ATP!! Composed of adenine base, ribose sugar, and 3 phosphate groups (PO4) Phosphorylation – the addition of a phosphate group Substrate-level phosphorylation– enzymes help break and down and convert those high energy PO4 bonds When the bond is broken it releases energy, a phosphate group and ADP
4. Enzymes in Metabolic Pathways! I ♥ NADH! Biological catalysts Speeds up chemical reactions Weakens existing bonds in substrates which lowers the amount of activation energy needed NADH – a second energy carrying molecule in mitochondria and produces 3 ATP FADH2– a third energy carrying molecule in the mitochondria and produces 2 ATP
5. Mitochondria! Has a smooth, outer membrane and a folded inner membrane Cristae – folds of inner membrane – electron transport chain occurs here Matrix – space inside cristae and contains DNA and ribosomes – Krebs cycle takes place here Site of aerobic respiration
6. Cellular Respiration Overview! C6H12O6 + 6O2 6CO2 + 6H2O (heat and ATP) Controlled release of energy from organic molecules Glucose is oxidized (loses e-) and oxygen is reduced (gains e-) Carbon atoms of glucose is released as CO2 One glucose molecule generates 36 ATP 3 steps Glycolysis Kreb’s Cycle Electron Transport Chain (ETC) Glucose rhymes with lumos!
7. Glycolysis! Occurs in cytoplasm Summary of steps 2 ATP added to glucose (6C) to energize it Glucose splits into two PGAL (3C) H+ and e- is removed from each PGAL and given to make 2 NADH NADH – energy and electron carrier Each PGAL is rearranged into pyruvate (3C) with energy and transferred to make 4 ATP Creates 4 ATP but glycolysis requires 2 ATP so the net product is 2 ATP If oxygen is available then the pyruvate will move to the mitochondria and being aerobic respiration
8. Glycolysis (cont.) If no oxygen is available (anaerobic) the pyruvate will be fermented by the addition of 2 H from the NADH, which changes it to NAD+ and keeps glycolysis going Net yield of Glycolysis 4 NADH2 2 CO2 2 ATP
9. Kreb’s Cycle! AKA Citric Acid cycle Requires 2 cycles to metabolize glucose Acetyl Co-A (2C) enters the Kreb’s cycle and combines with oxaloacetic acid (4C) to make citric acid (6C) Citric acid is oxidized releasing CO2, free H+, and e- forming ketoglutaric acid (5C) Free e- reduce NAD+ to NADH2 and FAD+ to FADH2 Ketoglutaric acid is also oxidized releasing more CO2, free H+, and e-
10. Kreb’s Cycle (cont.) The cycle continues oxidizing the carbon compounds producing more CO2, NADH2, FADH2, and ATP H2O is added to supply more H+ CO2 is a waste product and leaves the cell Oxaloacetic acid is regenerated to start the cycle again NADH2 and FADH2 migrate to the ETC Net yield from Kreb’s Cycle (2 turns) 6 NADH2 2 FADH2 4 CO2 2 ATP
11. Electron Transport Chain! Found in the cristae Contains 4 protein-based complexes that works in sequence moving H+ from the matrix across the inner membrane (proton pumps) A concentration gradient of H+ between the inner and outer membrane occurs H+ concentration gradient causes the synthesis of ATP by chemiosmosis Energized e- and H+ from 10 NADH2 and 2 FADH2 are transferred to O2 to produce H2O
