Cellular Respiration & Fermentation 4.4, 4.6
4.4 – Overview of Cellular Respiration Key Concept: The overall process of cellular respiration converts sugar into ATP using oxygen. Cellular respiration is an aerobic process with two main stages.
Purpose of Cellular Respiration To make ATP from the energy stored in glucose Glucose comes from an organism doing photosynthesis themselves or from eating foods containing glucose Remember: the purpose of photosynthesis was just to get glucose
Cellular Respiration has 2 parts Anaerobic (does not require oxygen) Glycolysis Aerobic (requires oxygen) Krebs Cycle (Citric acid Cycle) Electron Transport Chain (ETC)
STOP & REVIEW 1. What is the main reason that an organism needs to go through cellular respiration (to make what)? 2. What word means does not require oxygen? 3. What word means requires oxygen? 4. What step of cellular respiration happens first and is anaerobic? 5. What 2 steps happen next in cellular respiration and are aerobic?
STOP & REVIEW 1. What is the main reason that an organism needs to go through cellular respiration (to make what)? 1. ATP 2. What word means does not require oxygen? 2. Anaerobic 3. What word means requires oxygen? 3. Aerobic 4. What step of cellular respiration happens first and is anaerobic? 4. Glycolysis 5. What 2 steps happen next in cellular respiration and are aerobic? 5. Krebs Cycle & ETC
2nd stage (aerobic stage) 4. 6CO2 6. ETC: energy from glycolysis and 6O2 enter 1. mitochondrion matrix (area enclosed by inner membrane) inner membrane ATP 5. Energy transferred to 2nd stage (aerobic stage) 1 2 4 and Glycolysis: Anaerobic process in cytoplasm that splits glucose into two 3C molecules (pyruvate) 3. Kreb’s Cycle Takes place in: matrix of mitochondria; produces 2 ATP 2. 2 pyruvate 7. 6 H2O produced and a large amount of ATP (32) 1
Glycolysis Takes place in cytoplasm (eukaryotes and prokaryotes do this step since all cells have cytoplasm) Splits one glucose molecule into two pyruvate (pyruvic acid) molecules Costs the cell 2 ATP molecules to do this 4 ATP molecules are produced (only gain 2 ATP)
STOP & REVIEW 1. Glycolysis (the first step in C.R.) takes place where? 2. One glucose is split into 2? 3. How many ATP does the cell actually gain from this part? 4.Can prokaryotes and eukaryotes go through glycolysis? Why or why not?
STOP & REVIEW 1. Glycolysis (the first step in C.R.) takes place where? 1. Cytoplasm 2. One glucose is split into 2? 2. Pyruvates 3. How many ATP does the cell actually gain from this part? 3. 2 ATP 4.Can prokaryotes and eukaryotes go through glycolysis? Why or why not? 4.Yes, they both have cytoplasm, so both types of cells can go through glycolysis.
Krebs Cycle (Citric Acid Cycle) Takes place in matrix of mitochondria (only in eukaryotes) 2 pyruvate (made during glycolysis) enter the mitochondrion Each pyruvate is broken down to create 1 ATP Total products of Krebs cycle (because of 2 pyruvates): 2 ATP 6CO2
STOP & REVIEW 1. The Krebs Cycle (second step) takes place where? 2. The 2 pyruvates from glycolysis are broken down here to make how many total ATP’s? 3. So, with the last step (glycolysis) and this step (Kreb’s) how many total ATP have been made so far?
STOP & REVIEW 1. The Krebs Cycle (second step) takes place where? 1.Matrix of mitochondria 2. The 2 pyruvates from glycolysis are broken down here to make how many total ATP’s? 2.2 ATP 3. So, with the last step (glycolysis) and this step (Kreb’s) how many total ATP have been made so far? 3. 4ATP
Electron Transport Chain (ETC) Takes place in inner membrane of mitochondria (cristae) Folded to create more surface area for reactions to produce more ATP in a small space Oxygen and hydrogen ions combine to form water (released as a waste product) 32 ATP are made
STOP & REVIEW 1. The third step (ETC) takes place where? 2. Why is the inner membrane folded? 3. What combines here and gets released as waste? 4. How many ATP are made by just this step? 5. How many total ATP have been made by all three steps together?
STOP & REVIEW 1. The third step (ETC) takes place where? 1. Inner membrane of mitochondria 2. Why is the inner membrane folded? 2. To create more surface area to make more ATP. 3. What combines here and gets released as waste? 3. H and O combine to make/release water. 4. How many ATP are made by just this step? 4. 32 ATP 5. How many total ATP have been made by all three steps together? 5. 36 ATP
ATP from Cellular Respiration 4 from Glycolysis (uses up 2, so really only gain 2 ATP) 2 ATP from Kreb’s cycle 32 ATP from ETC GAIN 36 ATP from one glucose molecule
Equation for Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O + 36ATP Like the reverse of photosynthesis Energy transformations: CPECPE https://www.youtube.com/watch?v=00jbG_cfGuQ (4 mins)
What happens when there’s no/not enough oxygen or there are no mitochondria? Answer: Fermentation Two Kinds: Lactic Acid Fermentation Alcoholic Fermentation
Allows glycolysis to continue making ATP without oxygen
Lactic Acid Fermentation Anaerobic Occurs in muscle cells Produces burning feeling in muscles Occurs when body is worked to the point that more oxygen is being used than what is being taken in This is why you breathe harder when you’re exercising is to get more oxygen to keep making ATP Produces Lactic Acid and 2 (net) ATP
Alcoholic Fermentation Anaerobic Occurs in some bacteria and yeast Produces CO2, ethyl alcohol, and 2 (net) ATP Used in food production (bake bread and make wine)
STOP & REVIEW 1. Why does fermentation occur? 2.Out of all 3 steps of cellular respiration, which one does fermentation only use? Why? 3. Which form of fermentation occurs in animals when not enough oxygen is consumed? 4. How many ATP are made by this form of fermentation? 5. Which form of fermentation do bacteria and yeast use? 6.What are the byproducts of this form of fermentation (produced)?
STOP & REVIEW 1. Why does fermentation occur? 1. Because too little or no oxygen is available. 2.Out of all 3 steps of cellular respiration, which one does fermentation only use? Why? 2. Glycolysis (only one that is anaerobic) 3. Which form of fermentation occurs in animals when not enough oxygen is consumed? 3. Lactic Acid Fermentation (produces lactic acid) 4. How many ATP are made by this form of fermentation? 4. 2ATP (glycolysis only makes 2) 5. Which form of fermentation do bacteria and yeast use? 5. Alcoholic Fermentation 6.What are the byproducts of this form of fermentation (produced)? 6. Alcohol, 2 ATP, CO2
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