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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure 1. phospholipids POLAR END (react with water) NON-POLAR END (hyrophobic)
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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure 2. proteins and carbohydrates
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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure B. Membrane Function 1. semi-permeable barrier Aqueous Solution (outside cell) dissolved ions dissolved polar molecules suspended non-polar (lipid soluble) Aqueous Solution (inside cell) dissolved ions dissolved polar molecules suspended non-polar (lipid soluble)
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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure B. Membrane Function 1. semi-permeable barrier 2. transport Net diffusion Net diffusion equilibrium
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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure B. Membrane Function 1. semi-permeable barrier 2. transport – facilitated diffusion
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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure B. Membrane Function 1. semi-permeable barrier 2. transport - osmosis
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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure B. Membrane Function 1. semi-permeable barrier 2. transport – active transport
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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure B. Membrane Function 1. semi-permeable barrier 2. transport 3. metabolism (enzymes nested in membrane) 4. signal transduction
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Cell Biology Overview II. Membranes – How Things Get in and Out of Cells A. Membrane Structure B. Membrane Function 1. semi-permeable barrier 2. transport 3. metabolism (enzymes nested in membrane) 4. signal transduction 5. cell-cell binding 6. cell recognition 7. cytoskeleton attachment
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Cellular Respiration
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III. Cellular Respiration Overview:
Some trapped in bonds between ADP + P ATP NAD + H+ NADH Some E lost (heat) Organic Molecules: C—C—C—C Break C—C bonds release E Proteins, Carbohydrates, Fats, Nucleic Acids C C C C (These are CO2 molecules)
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III. Cellular Respiration Overview:
Some trapped in bonds between ADP + P ATP NAD + H+ NADH Some E lost (heat) Organic Molecules: C—C—C—C Break C—C bonds release E Proteins, Carbohydrates, Fats, Nucleic Acids C C C C (These are CO2 molecules) Break NADH ADP + P Make ATP NAD, H+
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III. Cellular Respiration
Overview: Focus on core process… Glucose metabolism GLYCOLYSIS
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Glucose 2 pyruvate C6H12O6 2 C3 III. Cellular Respiration Overview:
1. Glycolysis: - All cells do this! (very primitive pathway) - Occurs in the cytoplasm of all cells - Occurs in presence OR absence of oxygen gas. Glucose C6H12O6 2 pyruvate 2 C3
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Glucose 2 pyruvate C6H12O6 2 C3 III. Cellular Respiration Overview:
1. Glycolysis: - Energy in 2 ATP is used to ‘activate’/start reaction 2 ATP 2 ADP + P Glucose C6H12O6 2 pyruvate 2 C3
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Glucose 2 pyruvate C6H12O6 2 C3 III. Cellular Respiration Overview:
1. Glycolysis: - Energy in 2 ATP is used to ‘activate’/start reaction - breaking the C-C bond in glucose releases e- /Energy - electrons accepted by NAD NAD- +H NADH NAD NADH 2 ATP 2 ADP + P Glucose C6H12O6 2 pyruvate 2 C3 4 ADP + P ATP
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Anaerobic Respiration
III. Cellular Respiration Overview: GLYCOLYSIS PYRUVATE METABOLISM Oxygen Absent? Oxygen Present? Anaerobic Respiration Or Fermentation Aerobic Respiration SOME ATP MORE ATP
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C3 C2-CoA + CO2 III. Cellular Respiration Overview: Glycolysis
Anaerobic Respiration C C2-CoA + CO2 Pyruvate Acetyl-CoA NAD NADH
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Incomplete Citric Acid Cycle C5 + CO2
III. Cellular Respiration Overview: Glycolysis Anaerobic Respiration C C2-CoA + CO2 CoA NAD NADH NAD NADH C6 C4 Incomplete Citric Acid Cycle C5 + CO2
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2. Anaerobic Respiration
Electron Transport Chain across a membrane to convert energy harvested in NADH into bonds in ATP. OUTER Intermembrane (periplasmic) space INNER e- NADH NAD + H+ STEP 1: NADH gives up electron to an electron acceptor protein in the membrane, splitting into NAD and H+ ions. NAD is RECYCLED at this step, so GLYCOLYSIS can continue!
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2. Anaerobic Respiration
Electron Transport Chain across a membrane to convert energy harvested in NADH into bonds in ATP. OUTER Intermembrane (periplasmic) space H+ H+ e- INNER e- NADH NAD + H+ H+ Step 2: The electron is passed from protein to protein, across the inner membrane. This movement of negative charge draws H+ ions across through protein channels… H+ build up in the intermembrane space, creating a CHARGE DIFFERENTIAL.
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2. Anaerobic Respiration
Electron Transport Chain across a membrane to convert energy harvested in NADH into bonds in ATP. OUTER Intermembrane (periplasmic) space H+ H+ H+ e- INNER e- ATP synthase NADH NAD ADP + P ATP Step 3: The charge differential is electric potential energy. Eventually, the differential is so great that H+ ions flow back through the membrane. The energy in this ‘current’ of charged particles is used to add P + ADP ATP.
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2. Anaerobic Respiration
Electron Transport Chain across a membrane to convert energy harvested in NADH into bonds in ATP. OUTER Intermembrane (periplasmic) space e- INNER ADP + P ATP e- NADH NAD S- H2S S H+ H+ Step 4: The electron(s) are accepted by a ‘final electron acceptor’. In anaerobic respiration, this is CO2, NO3, Fe, or S. And the anion formed reacts with H+ ions. THUS, ENERGY IN NADH IS USED TO MAKE BONDS IN ATP.
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III. Cellular Respiration Overview: Glycolysis Anaerobic Respiration
Ethanol Fermentation: Some bacteria, plants, yeasts Lactate Fermentation: Some bacteria, animals
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Anaerobic Respiration
III. Cellular Respiration Overview: GLYCOLYSIS PYRUVATE METABOLISM Oxygen Absent? Oxygen Present? Anaerobic Respiration Or Fermentation Aerobic Respiration SOME ATP MORE ATP
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III. Cellular Respiration Overview: Glycolysis Anaerobic Respiration
Occurs in: Aerobic bacteria Aerobic Archaea All Eukaryotes (in the mitochondria descended from aerobic bacteria!) GLYCOLYSIS OCCURS IN THE CYTOPLASM. THAT’S WHERE THE PYRUVATES ARE PRODUCED.
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C3 C2-CoA + CO2 III. Cellular Respiration Overview: Glycolysis
Anaerobic Respiration C C2-CoA + CO2 Pyruvate Acetyl-CoA NAD NADH “Gateway Step” In Eukaryotes
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CoA – C2 C6 C4 C5 + CO2 + CO2 CoA REVIEW – ANAEROBIC RESPIRATION
Incomplete Citric Acid Cycle CoA – C2 C4 C6 C5 + CO2 NAD NADH + CO2 FAD FADH2 ADP + P ATP CoA (oxaloacetate) NAD NADH
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CoA – C2 C6 C4 C5 + CO2 + CO2 CoA Aerobic Respiration
Citric Acid (“Krebs”) Cycle CoA – C2 C4 C6 C5 + CO2 NAD NADH + CO2 FAD FADH2 ADP + P ATP CoA (oxaloacetate) NAD NADH The C5 molecule is recycled into oxaloacetate (C4), with the release of even MORE ENERGY trapped in ATP, NADH, and FADH
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2. Aerobic Respiration Electron Transport Chain across a membrane to convert energy harvested in NADH into bonds in ATP. OUTER Intermembrane (periplasmic) space H+ H+ H+ H+ H+ H+ e- INNER e- e- ADP + P ATP NADH NAD + H+ O2 2 O-- 2 H2O FADH FAD + H+ 2H+ 2H+ SAME THING: Electrons transferred, H+ ions pulled across membrane, and flood back across creating ATP. But O2 is the final electron acceptor, making WATER!! MORE electrons transferred, stronger ‘pull’ exerted by oxygen, more ATP made.
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Alcohol fermentation CO2 2 NADH 2 NAD+ 2 Acetaldehyde 2 ATP 2 ADP + 2
LE 9-17a CO2 2 NADH 2 NAD+ 2 Acetaldehyde 2 ATP 2 ADP + 2 i 2 Pyruvate 2 Ethanol Glucose Glycolysis P 2 + 2 H+ Alcohol fermentation
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Lactic acid fermentation
LE 9-17b + 2 H+ 2 NADH 2 NAD+ 2 ATP 2 ADP + 2 P 2 Pyruvate Glucose Glycolysis i Lactate 2 Lactate Lactic acid fermentation
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