CELLULAR RESPIRATION Chapter 7
7.1 GLYCOLYSIS AND FERMENTATION If I have a $10.00 bill and a $10.00 check, which is better? ATP is like cash in the cell Glucose, NADH, FADH2 are like checks in a cell. They have to be converted in order to use for energy. What happens when you breathe on a window? What two things are released? Water and Carbon Dioxide These are byproducts of Cellular Respiration Write down the equation for photosynthesis and cellular respiration. Compare 6CO2 + 6H20 +energy--- C6H1206 +6O2 C6H1206 +6O2-6CO2 + 6H20 + ATP
CELLULAR RESPIRATION Cellular Respiration and Photosynthesis are not the reverse of each other. The products of photosynthesis are the starting point of cellular respiration. 1 st Law of Thermodynamics: energy is neither created nor destroyed Photosynthesis= 686 Kcal of energy in one mole of glucose Cell. Respiration releases 686 Kcal from one mole of glucose Cellular Respiration is the process by which cells make ATP by breaking down organic compounds There are TWO stages: Glycolysis and Aerobic Respiration
Stop, Day 1
GLYCOLYSIS 1 molecule of glucose is converted into 2-3carbon molecules of Pyruvic Acid and a small amount of ATP and NADH If Oxygen is present, Pyruvic Acid is broken down and NADH makes a large amount of ATP. This is Aerobic Respiration. If no oxygen is present, Pyruvic acid can go through anaerobic pathways called Fermentation.
FERMENTATION Many cultures depend on fermentation for their diets. Examples? If oxygen is not present, Pyruvic Acid goes along another pathway. It does not produce ATP, but other organic molecules that regenerates NAD+ to keep the cycle going. In Lactic Acid Fermentation, it converts to lactic acid. In Alcoholic Fermentation, it converts to ethyl alcohol and carbon dioxide.
ELECTRON TRANSPORT CHAIN The electron transport chain allows the release of the large amount of chemical energy stored in reduced NAD+ (NADH) and reduced FAD (FADH2). The energy released is captured in the form of ATP (3 ATP per NADH and 2 ATP per FADH2).
PHOTOSYNTHESIS AND CELLULAR RESPIRATION Photosynthesis Cellular Respiration Organelle for process Chloroplast Mitochondria Reactants CO2 and H₂O Sugars (C₆H₁₂O₆) and O₂ Electron transport chain Cycle of chemical reactions Products Proteins with thylakoid membrane Calvin Cycle in chloroplasts builds sugar molecules Sugars (C₆H₁₂O₆) and O₂ Proteins with inner mitochondrial membrane Krebs cycle in matrix of mitochondria breaks down carbon-based molecules CO2 and H₂O
CELLULAR RESPIRATION OCCURS IN 1. Chloroplast 2. Ribosome 3. Golgi apparatus 4. Mitochondria 10 0% 0% 0% 0% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4
FORMS OF ENERGY MUST BE CONVERTED TO THIS TO BE USED BY THE CELL 1. NADH 2. Glucose 3. ATP 4. FADH2 10 0% 0% 0% 0% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4
CELLULAR RESPIRATION Plants and animals must break down molecules from food to produce ATP. They break this down through the process of Cellular Respiration. This is the process that cells make ATP by breaking down the organic molecules. C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O
ATP (ADENOSINE TRIPHOSPHATE) Most of the energy from cell respiration is converted into ATP ATP is a substance that powers most cell activities.
CELLULAR RESPIRATION Mitochondria cannot make ATP from food. It must break it down into smaller molecules like glucose. Then glucose is broken down.
CELLULAR RESPIRATION Divided into 2 categories: Glycolysis- this is anaerobic because it does not require oxygen Aerobic Respiration- Oxygen is present in the cells environment
AN ANAEROBIC PROCESS 1. Requires the presence of oxygen 2. Does NOT require the presence of oxygen 10 0% 0% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2
GLYCOLYSIS Splits glucose into two three-carbon molecules of pyruvic acid and makes two molecules of ATP and NADH Pyruvic acid- made from glucose and supplies energy to cells
GLYCOLYSIS 1. Two phosphate groups are attached to one molecule of glucose. 2. 6-carbon compound is split into two threecarbon molecules of G3P (glyceraldehyde 3- phosphate)
3. Two G3P molecules are oxidized, each receives a phosphate group. 4. Phosphate groups are removed and 2 molecules of pyruvic acid are produced. Net yield of 2 ATP molecules for every glucose molecule converted into pyruvic acid.
WHAT IS NEXT? If oxygen is present, cellular respiration enters the pathways or aerobic respiration. If oxygen is NOT present, anaerobic, some cells can convert pyruvic acid into other compounds. Fermentation- combination of glycolysis and the additional pathways to regenerate NAD+.
WHAT IS THE NET YIELD OF ATP FROM GLYCOLYSIS? 1. 4 ATP 2. 2 ATP 3. 6 ATP 4. 8 ATP 10 0% 0% 0% 0% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4
WHAT HAPPENS TO THE PYRUVIC ACID
FERMENTATION These additional pathways do not produce ATP. This process recycles NAD+ from NADH. If this didn t occur, glycolysis would stop. The fermentation pathways allow for the production of ATP to continue.
LACTIC ACID FERMENTATION Oxygen is absent An enzyme converts pyruvic acid (made from glycolysis) into lactic acid. NADH is oxidized to NAD+ This NAD+ is regenerated used in glycolysis.
LACTIC ACID FERMENTATION Occurs in muscles during strenuous exercise Muscle cells use oxygen faster than the receive oxygen Oxygen becomes depleted, muscle cells switch to lactic acid fermentation. Lactic acid builds up, leading to cramps.
WHICH OF THE FOLLOWING OCCURS IN LACTIC ACID FERMENTATION? 1. Oxygen is consumed 2. Lactic acid is converted into pyruvic acid. 3. NAD+ is regenerated for use in glycolysis 4. Electrons pass through the electron transport chain 0% 0% 0% 0% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4 10
ALCOHOLIC FERMENTATION Plants and unicellular organisms, like yeast use this Process of converting pyruvic acid into ethyl alcohol Co2 makes the bread rise
ALCOHOLIC FERMENTATION After glycolysis, requires 2 steps: CO2 is removed from pyruvic, leaving a 2-carbon compound 2 hydrogen are added to the 2-carbon to form ethyl alcohol Regenerates NAD+ for glycolysis.
EFFICIENCY OF GLYCOLYSIS Not very efficient on transferring energy from glucose to ATP Efficiency is 2% Ends 7.1 Notes
WHAT HAPPENS TO THE PYRUVIC ACID
CELLULAR RESPIRATION Aerobic Respiration- Oxygen is present 2 major stages: Krebs Cycle Oxidation of glucose, that began in glycolysis is completed Electron Transport Chain NADH is used to make ATP
KREBS CYCLE AND ELECTRON TRANSPORT CHAIN In prokaryotes, take place in the cytosol of the cell. In eukaryotes, take place in the mitochondria. Pyruvic acid from glycolysis diffuses into the mitochondrial matrix.
KREBS CYCLE Occurs in the mitochondrion matrix. Pyruvic acid enters the matrix, it reacts with coenzyme A, loses CO2 to form acetyl CoA. NAD+ is reduced to NADH. Glycolysis yields 2 molecules of pyruvic acid and each react with coenzyme A to form acetyl CoA. Krebs Cycle- breaks down the acetyl CoA to produce CO2, hydrogen, and ATP.
KREBS CYCLE Produces : 4 CO2 2 ATP molecules Hydrogen molecules that are used to make 6 NADH and 2 FADH2 (electron acceptor) Glycolysis produces 2 pyruvic acid molecules. It takes 2 turns of the Krebs cycle to break down one glucose molecule.
HOW MANY TURNS OF THE KREBS CYCLE DOES IT TAKE TO BREAK DOWN ONE GLUCOSE MOLECULE? 1. 1 2. 2 3. 3 4. 4 85% 15% 0% 0% 1 2 3 4
KREB CYCLE PRODUCTION Glycolysis produces two NADH molecules The conversion of pyruvic acid to acetyl CoA produces two more NADH. Plus the six from Krebs Cycle gives us 10 NADH molecules for every one glucose molecule oxidized. The 10 NADH and the 2 FADH2 drive the next stage.
WHICH OF THE FOLLOWING IS NOT A PRODUCT OF THE KREBS CYCLE? 1. CO2 2. ATP 3. FADH2 4. Ethyl alcohol 96% 0% 4% 0% 1 2 3 4
ELECTRON TRANSPORT CHAIN AND CHEMIOSMOSIS Electron transport chain- series of molecules in a membrane that transfer electrons from one molecule to another ATP is produced NADH and FADH2 release hydrogen atoms, which regenerates NAD+ and FAD.
ELECTRON TRANSPORT Proteins make up the chain They use energy from the electrons supplied from NADH and FADH2 to pump hydrogen ions against the gradient and across the membrane. Protons flow back across the membrane later to produce ATP, through chemiosmosis Oxygen picks up hydrogen and electrons to form water.
ATP IS SYNTHESIZED IN CHEMIOSMOSIS WHEN THIS MOVES ACROSS THE MITOCHONDRIAL MEMBRANE 1. NADH 2. Oxygen 3. Protons 4. Citric acid 88% 13% 0% 0% 1 2 3 4
ELECTRON TRANSPORT
ATP YIELD Total yield of 38 ATP Varies from cell to cell
EFFICIENCY OF CELLULAR RESPIRATION 39% Almost 20 times more efficient than glycolysis Provides ATP that cells need to support the activities of life.