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Transcript
Name: ___________________________ Cellular Respiration Notes Use your textbook or cell phones to find the following information: Define the following terms: Glycolysis Mitochondrion Mitochondrial Matrix Krebs Cycle Oxidative ATP Synthesis Alcohol Fermentation Lactic Acid Fermentation Maximum O2 Consumption Lactic Acid Threshold A process for harnessing energy in which a glucose molecule is broken into two pyruvate molecules in the cytoplasm of a cell A eukaryotic cell organelle in which aerobic cellular respiration occurs The fluid that fills the interior space of the mitochondrion A cyclic series of reactions that transfers energy from organic molecules to ATP, NADH, and FADH2, and removes carbon atoms as CO2 The production of ATP from a series of oxidation reactions A form of fermentation occurring in yeast in which NADH passes its hydrogen atoms to acetaldehyde, generating carbon dioxide, ethanol and NAD+ A form of fermentation occurring in animal cells in which NADH transfers its hydrogen atoms to pyruvate, regenerating NAD+ and lactic acid The maximum volume of oxygen, in mL, that the cells of the body can remove from the bloodstream in one min/kg of body mass while the body experiences maximal exhertion The value of exercise intensity at which lactic acid production increases Glycolysis: Stage One of Cellular Respiration (pages 210-212) Fill in the blank: Both aerobic and anaerobic respiration begins with the process of glycolysis. Glycolysis is Greek for sugar-splitting and this accurately describes what is happening during this stage of cellular respiration. The carbon backbone of glucose is essentially split in half. Glucose is a 6 carbon sugar and at the end of glycolysis, it has been converted to a 3 carbon sugar called pyruvate. Label Glycolysis does not require oxygen to work. It takes place in the cytoplasm of the cell. There are 10 reactions in glycolysis that is each catalyzed by a specific enzymes in the cytoplasm. During these reactions 2 ATP molecules are used and 4 ATP molecules are produces. Therefore, glycolysis produces a net total of 2 ATP. It also produces 2 NADH+ ions. Label Explain the key events shown above: (page 211) - 2 ATP molecules are used in the first stages NAD+ ions remove H+ atoms from the pathway creating NADH and release 2 H+ ions into the cytoplasm 4 ADP molecules join with 4 P molecules to form 4 ATP When finished, the cell has taken a single glucose molecule and made 2 ATP, 2 NADH, and 2 pyruvate ATP is now available for other cell functions Fill in the table below: (page 211) Reactants Glucose 2 NAD+ 2 ATP 4 ADP Products 2 pyruvate 2 NADH 2 ADP 4 ATP Write the net equation of glycolysis below: 1 glucose + 2 ADP + 2 P + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 2 H+ Glycolysis only transfers about 2.2% of the free energy available in glucose to ATP. Some of the energy is released as thermal energy but the vast majority is still trapped in the 2 pyruvate and 2 NADH molecules. Mitochondria Draw and label a mitochondrion below: Why is this organelle so important for cellular respiration? It is important because it is where 3 of the stages occur and it is the power-house of the cell creating large quantities of ATP Stage 2: Pyruvate Oxidation After glycolysis, the cell had formed: - 2 ATP - 2 NADH -2 Pyruvate Pyruvate oxidation connects stage one (glycolysis) and stage two (Krebs cycle). There are three changes that occur in this stage, explain them below: 1. A CO2 is removed from each pyruvate and released as waste 2. The remaining 2 carbon portions are oxidized by NAD+ and H atoms from pyruvate reduce NAD+ molecules. The remaining 2 carbon molecule becomes an acetyl group. 3. CoA attaches to acetyl groups formed above to create a 2 carbon molecule called acetyl-CoA The products of pyruvate oxidation are: 1. CO2 2. NADH 3. acetyl CoA Stage Three: The Krebs Cycle Fill in the blank: In 1937 Sir Hans Kreb discovered the series of metabolic reactions that became known as the Krebs cycle. The Krebs cycle is an 8 step process that is each catalyzed by a specific enzyme. Explain the key features of the cycle below: - the Krebs cycle occurs twice for each molecule of glucose processed - as acetyl-CoA enters the cycle the CoA is released - during one complete cycle, a total of 3 NAD+ and 2 FAD are reduced to form 3 NADHs and 1 FADH2 - during one complete cycle, 1 ATP is formed - during one complete cycle, 2 CO2 molecules are produced and released as waste MEMORIZE ME! Label By the end of the Krebs cycle, all 6 carbon molecules that were found in glucose have now been oxidized into CO2 and released as waste from the cell. All that is left of the original glucose is free energy in the form of ATP, NADH, and FADH2. Stage 4: Electron Transport and Chemiosmosis (pages 216-218) Fill in the blank: NADH and FADH2 eventually transfer the hydrogen atom electrons they carry to a series of compounds, mainly proteins, in the inner mitochondrial membrane called the electron transport chain (ETC). The NADH gives up 2 high energy electrons at the beginning of the ETC. At the same time, it releases 1 H+ ion into the matrix. The electrons move down the ETC using carrier molecules and they are releasing energy as they move. This energy is used to force a number of H+ ions from within the mitochondrial matrix across the inner membrane. By the time the two electrons reach the last component of the ETC, they are in a low energy state. Oxygen strips the two electrons from the final carrier in the chain and together with two H+ ions, from the matrix form water. Oxygen acts as the final electron acceptor in this electron transport process. This final step is the reason many organisms require oxygen. The electron transport chain has a similar process for FADH2 molecules that come over to it. The ETC converts chemical energy of electrons into electrochemical potential energy of an H+ gradient. This energy being formed by H+ ions is what is used in chemiosmosis and ATP synthesis. Chemiosmosis and ATP Synthesis Remember back to photosynthesis: - Chemiosmosis uses H+ ions travelling through a protein (ATP synthase) to create energy (ATP) Read and Highlight: H+ ions from the ETC pass through ATP synthase in the mitochondrial membrane and this passage of ions releases energy that allows ADP to bind with a P ion to form ATP. This specific formation of ATP is called oxidative ATP synthesis because it results from a series of oxidation reactions. After ATP is formed, it is transported through both mitochondrial membranes into the cytoplasm where it is used to drive processes that require energy like movement, active transport, and other reactions in the cell. Quick Summary