1 26 15 Lecture 6 Cellular Metabolic Pathways 1 Glycolysis o Break down of glucose a carbohydrate This is Catabolism Anabolism means to build something from smaller units o Makes ATP via substrate level phosphorylation o Always starts with a carbohydrate Glycolysis can only break down glucose o NOT a single step process Series of 10 enzymatic reactions An enzyme is a protein that is able to speed up chemical reactions without being consumed It is reusable Think of the Phys phabs and TA s as enzymes for learning physiology ase is the suffix for enzymes o Location cytosol Glycolysis does not happen in any special organelle All cells are able to do glycolysis o Net production 2 ATP per glucose Byproducts H Pyruvate under aerobic conditions when O is present Or Lactate under anaerobic conditions without O Glycolysis does not require O o Regulation of glycolysis ATP regulates the process When ATP is high glycolysis is down regulated inhibited But when ADP are high glycolysis is upregulated Krebs Cycle o Makes ATP via substrate label Phosphorylation o Aka citric acid cycle and TCA cycle tricarboxylic acid cycle o Starting point Mainly uses pyruvate from glycolysis BUT it can also start from other molecules We eat sugars fats and proteins Krebs cycle can use catabolism to break down all 3 o Series of 8 enzymatic reactions o Location the mitochondria Area responsible for making energy Only cells with mitochondria can do krebs cycle Red blood cells don t have mitochondria Red blood cells create ATP only via glycolysis 1 26 15 o Net production 2ATP Via substrate level phosphorylation Byproducts H CO O is indirectly required o Regulation coenzymes Because there are coenzymes in this process that require When ATP is high krebs is down regulated inhibited But when ADP are high krebs is upregulated 3 Electron Transport chain o In THIS class is it synonymous with oxidative phosphorylation o Starting materials H and coenzymes Uses components from prior two metabolic pathways krebs and glycolysis o Location Mitochondria o Net production 34 ATP Byproducts H O This process recycles coenzymes Directly requires O Last step in the chain involves oxygen as an electron receptor o Note instead of producing H O we can produce free radicals O and OH to help fight pathogens when our body needs to Figure 3 46 Equation 2 is essentially o Glycolysis krebs cycle oxidative phosphorylation Membrane Transport Table 4 1 cells o We see higher concentrations of ATP and proteins on the inside of our o Higher concentration of glucose outside of our cells Selective permeability o Polarity is important Polar substances cannot cross the membrane easily Nonpolar molecules cross easily o Size is important Small molecule can pass not large molecules How do polar molecules cross membrane o Regulated by proteins o channels gates transporters 1 26 15 Diffusion o Figure 4 2 o Moves from high concentration to low concentration o Dependent on Permeability The bigger the permeability the quicker diffusion occurs o Direct relation mathematically As one increases so does the other Surface area of interface Direct relationship with diffusion o The more surface area there is on the membrane the faster diffusion occurs Concentration gradient Direct relationship diffusion occurs Distance Inverse relationship o The higher the concentration gradient the faster o As one goes up the other one goes down o If the distance increases then the rate of diffusion decreases o Diffusion through lipid bilayer Small and nonpolar things can move simply by diffusion with their gradient O and CO High to low No energy cost What problem does this cause for us o See next lecture
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