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Photosynthesis & Cellular Respiration Cellular Energy Or Bioenergetics How does energy from the sun become energy for life? Organisms called producers convert light energy to chemical energy using a process called photosynthesis. PhotosynthesisAmoeba Sisters The chemical energy produced in photosynthesis is in the form of sugar. This allows producers to store the energy for later use. Photosynthesis Method of converting sun energy into chemical energy usable by cells Autotrophs utilize this process – Photoautotrophs- light – Chemoautotrophs- chemicals Equation 6CO2 + 6H2O + light → C6H12O6 + 6O2 Fill It In … The goal of photosynthesis is … Photosynthesis takes place within the cell In eukaryotic cells, organelles called chloroplasts are the site of photosynthesis Photosynthesis takes place within the cell Chloroplasts are filled with a pigment called chlorophyll. This pigment allows the cell to “gather” energy from light waves. Photosynthesis takes place within the cell Some prokaryotic cells can photosynthesize, but they do NOT have chloroplasts. They do, however, contain chlorophyll. Photosynthesis is a metabolic pathway. This means it is a series of chemical reactions. All of these reactions can be simplified into one chemical equation: CO2 + H2O + sunlight (radiant energy) -> C6H12O6 + O2 (reactants) (products) http://www.youtube.c om/watch?v=wj8TGh cCnxs CO2 + H2O + sunlight (radiant energy) -> C6H12O6 + O2 The reactants (things that are used) for photosynthesis are obtained from the environment. The carbon dioxide enters the leaves from the air and the water enters the roots from the soil. CO2 + H2O + sunlight (radiant energy) -> C6H12O6 + O2 The products (things that are made) of photosynthesis include sugar and oxygen. Sugar is stored in the cell and used as food. Oxygen is released into the air. Electron Carriers Carrier molecule- a compound that can accept a pair of high-energy electrons and transfer them along with most of their energy to another molecule – Process: electron transport – Molecule: electron transport chain NADP+: NADP+ accepts and holds 2 high-energy electrons along with H+ When this occurs it becomes NADPH NADPH can then carry high-energy electrons to chemical reactions elsewhere Light-Dependent Reactions Require light Produce oxygen gas Convert ADP and NADP into ATP and NADPH Light-Dependent Reactions Pigments in photosystem II absorb light Energy is absorbed by electrons which are passed on to electron transport chain 1. 2. - Electrons come from breaking bonds between water molecules - Create 2 electrons, H+ ions, and oxygen Light-Dependent Reactions 3. Electrons move through electron transport chain – – from photosystem II to photosystem I Energy is used to transport H+ ions from stroma to inner thylakoid 4. Pigments in photosystem I use energy from light to reenergize the electrons – – NADP+ picks up high energy electrons and H+ ions Becomes NADPH Light-Independent Reaction Calvin Cycle Uses ATP and NADPH to produce high-energy sugars Does not require light Calvin Cycle 1. 6 CO2 molecules enter cycle – – Combine with 6 5-carbon molecules Result = 12 3-carbon molecules 2. 3-carbon molecules are converted into higher-energy forms (energy from ATP and NADPH) 3. 2 3-carbon molecules are removed from cycle – Used to produce sugars, lipids, amino acids, etc.. For metabolism and growth of plant Calvin Cycle 4. Remaining 10 3-carbon molecules are converted back to 6 5-carbon molecules – Combine with 6 new carbon dioxide molecules to begin the next cycle Factors affecting Photosynthesis Water – Lack of water can slow or even stop photosynthesis – Desert plants have waxy coating to reduce water loss Temperature – Enzymes function at particular temp ranges Intensity of Light – Increasing light increases rate of photosynthesis – There is a maximum rate of photosynthesis Fill It In … Reactants for photosynthesis: 1. 2. 3. Products of photosynthesis: 1. 2. Photosynthesis provides no DIRECT source of energy for the cell. The cell must convert the sugar produced to another form of energy: ATP What is ATP, and why should I care? ATP stands for adenosine triphosphate This basically means that it is a chemical with three phosphate groups attached. What is ATP, and why should I care? The cell uses ATP for energy. ATP is much smaller and faster to use than a larger molecule such as sugar. The energy in ATP is in the bonds connecting the four parts together. Energy and ATP ATP – Adenosine triphosphate – Adenine, 5-carbon sugar, 3 phosphate groups ADP – Adenosine diphosphate – Adenine, 5-carbon sugar, 2 phosphate groups Fill It In … ATP is used for … What is ATP, and why should I care? When the cell needs energy from ATP, it uses enzymes to break the third phosphate off of the molecule. The energy released is used for things in the cell such as active transport Removing the third phosphate creates ADP and a loose phosphate ENERGY What is ATP, and why should I care? ATP can be recycled. When more energy is available, a third phosphate is added to ADP to make more ATP. ADP and ATP Storing energy – When a cell has energy available, it can store small amounts by adding a phosphate group to ADP, producing ATP Releasing energy Breaking bonds between the 2nd and 3rd phosphate groups – Powers several cellular activities – Active transport, protein synthesis, muscle contraction How do cells use the sugar to Cellular Respirationmake ATP? All cells must use a process called cellular respiration to create ATP. Cellular respiration converts sugar (produced in photosynthesis) to create ATP Cellular respiration takes place in the Mitochondria Amoeba Sister Fill It In … The goal of cellular respiration is … Cellular respiration takes place within the cell In eukaryotic cells, organelles called mitochondria are the sites of cellular respiration Cellular respiration takes place within the cell Mitochondria use many enzymes to break down sugar (glucose) and store the energy in the chemical bonds of ATP Cellular respiration takes place within the cell Prokaryotes also use cellular respiration, but the do NOT have mitochondria. Instead, prokaryotes use parts of their cell membrane. Fill It In … Types of organisms that use cellular respiration: Cellular respiration is also a metabolic pathway. The simplified equation for cellular respiration is: C6H12O6 + O2 -> CO2 + H2O + ATP (reactants) (products) C6H12O6 + O2 -> CO2 + H2O + ATP The reactants of respiration are glucose and oxygen. The sugar (glucose) is obtained from the vacuole (in plant cells) or from ingestion (eating) of food. If oxygen is used, it is obtained from the air. C6H12O6 + O2 -> CO2 + H2O + ATP The products of respiration are ATP, water, and carbon dioxide. The water and carbon dioxide are released into the environment as waste products. ATP is kept in the cell for use as an energy molecule. Cellular Respiration Breakdown of glucose to produce energy – – 1g of sugar releases 3811 calories of heat energy Calorie- amount of energy needed to raise the temp of 1g of water 1˚ Celsius 6O2 + C6H12O6 → 6CO2 + 6H2O + energy Steps: – – – Glycolysis Krebs Cycle Electron Transport Chain Glycolysis Process in which one molecule of glucose is broken in half, producing 2 molecules of pyruvic acid (3-carbon compound) In cytoplasm 2 ATP → 4 ATP NAD+ = electron carrier – Accepts 4 high-energy electrons – Becomes NADH Glycolysis Energy yield is small but happens very fast Does not require oxygen Problem: NAD+ molecules fill up with electrons; without NAD+ ATP production stops Fill It In … Reactants of cellular respiration: 1. 2. Products of cellular respiration: 1. 2. 3. There are two types of cellular respiration: aerobic and anaerobic There are two types of cellular respiration: Aerobic respiration requires the use of oxygen and makes A LOT of ATP Krebs Cycle Pyruvic acid is broken down into carbon dioxide in a series of energyextracting reactions Aerobic- requires oxygen AKA citric acid cycle – because citric acid is the first compound produced In mitochondrion Krebs Cycle Krebs Cycle Pyruvate Oxidation: – Pyruvic acid enters mitochondrion – A carbon atom is removed to form CO2 – The other 2 carbon atoms are joined to coenzyme A to form acetyl-CoA A. Acetyl-CoA adds to a 4-carbon molecule producing a 6-carbon molecule called citric acid Krebs Cycle B. -Citric acid is broken down to produce a 5-carbon chain - CO2 is released - electrons transferred to energy carriers C.- 5-carbon chain is broken down into a 4 carbon chain - CO2 is released - ATP is produced D. – 4 carbon chain is ready to accept acetyl CoA to start cycle all over - FAD is converted to FADH2 - NAD+ is converted to NADH Electron Transport Chain Uses high-energy electrons from the Krebs cycle to convert ADP to ATP In mitochondrion Electron Transport Chain A.-NADH and FADH2 are passed along ETC and transfer their electrons down ETC Eukaryotes: membrane of mitochondrion Prokaryotes: cell membrane – H+ ions are transferred to intermembrane space B.-electrons from ETC combine with H+ ions and oxygen to produce H2O Electron Transport Chain C. Energy is used to transport of hydrogen ions by 2 high-energy electrons – H+ ions build up in the intermembrane space making it positively charged – The other side of the membrane is negatively charged Electron Transport Chain D.-Inner membranes of mitochondria contain ATP synthase - ATP spins when H+ ion crosses membrane - While rotating, the enzyme grabs a low-energy ADP and attaches a phosphate producing ATP Totals Glucose = 2 ATP Krebs + ETC = 34 ATP Total = 36 ATP Final wastes: water and carbon dioxide There are two types of cellular respiration: Anaerobic respiration (also called fermentation) takes place when no oxygen is available to the cell and produces very little ATP. However, this process is much faster than aerobic respiration. Fermentation Releases energy from food molecules by producing ATP in the absence of oxygen – Anaerobic- not in air 2 main types – Alcoholic fermentation – Lactic acid fermentation Convert NADH to NAD+ – Allows glycolysis to continue producing a steady supply of ATP Alcoholic Fermentation Pyruvic acid + NADH → alcohol + CO2 + NAD+ Causes bread dough to rise Yeast in dough runs out of oxygen, begins fermentation which produces CO2 Lactic Acid Fermentation Pyruvic acid + NADH → lactic acid + NAD+ Produced in muscles during rapid exercise when the body cannot supply enough oxygen to the tissues Some unicellular organisms produce lactic acid as a waste product – Cheese, yogurt, buttermilk, sour cream – Pickles, sauerkraut Fill It In … Differences in ATP production in aerobic vs. anaerobic respiration: Aerobic Anaerobic - Fill It In … Anaerobic respiration is also called … Types of anaerobic respiration: In most microorganisms, fungi, and plant cells, anaerobic respiration produces alcohol as a waste product (alcoholic fermentation) Alcohol fermentation also produces carbon dioxide gas Alcohol fermentation occurs in yeast – – The carbon dioxide causes dough to rise The alcohol burns off when the dough is baked Types of anaerobic respiration: In animal cells, anaerobic respiration produces lactic acid as a waste product (lactic acid fermentation) This mostly occurs in muscle cells. Build up of lactic acid causes cramps. Uses for anaerobic respiration A key idea … Photosynthesis and respiration form a cycle! A key idea … Photosynthesis and respiration form a cycle! A key idea … The products from one reaction become the reactants for the other reaction A key idea … The products from one reaction become the reactants for the other reaction A key idea … Check Yourself! 1. 2. 3. 4. 5. 6. 7. 8. 9. What pigment AND reactants are required for photosynthesis to occur? What does photosynthesis produce? Where does photosynthesis occur in eukaryotic cells? Where is the energy in ATP stored? Why does the cell use ATP instead of sugar for energy? What reactants are required for cellular respiration to occur? What does cellular respiration produce? Where does cellular respiration occur in eukaryotic cells? How is fermentation alike and different from aerobic respiration? Check Yourself! 1. What pigment AND reactants are required for photosynthesis to occur? CHLOROPHYLL CARBON DIOXIDE (CO2) WATER (H2O) SUNLIGHT (ENERGY) Check Yourself! 2. What does photosynthesis produce? GLUCOSE (C6H12O6) OR SUGAR OXYGEN (O2) Check Yourself! 3. Where does photosynthesis occur in eukaryotic cells? CHLOROPLAST Check Yourself! 4. Where is the energy in ATP stored? IN THE BONDS CONNECTING THE PHOSPHATES Check Yourself! 5. Why does the cell use ATP instead of sugar for energy? ATP IS FASTER AND SMALLER TO USE Check Yourself! 6. What reactants are required for cellular respiration to occur? GLUCOSE (C6H12O6) OR SUGAR OXYGEN (O2) Check Yourself! 7. What does cellular respiration produce? CARBON DIOXIDE (CO2) WATER (H2O) ATP (ENERGY) Check Yourself! 8. Where does cellular respiration occur in eukaryotic cells? MITOCHONDRIA Check Yourself! 9. How is fermentation alike and different from aerobic respiration? ALIKE - USES GLUCOSE AS A REACTANT PRODUCES ATP (ENERGY) DIFFERENT - AEROBIC USES OXYGEN FERMENTATION DOES NOT AEROBIC PRODUCES LOTS OF ATP FERMENTATION PRODUCES ONLY 2 ATP Comparing Photosynthesis & Respiration Photosynthesis Cellular Respiration Function Energy Storage Energy Release Location Chloroplasts Mitochondria Reactants CO2 and H2O and C6H12O6 and O2 sun C6H12O6 and O2 CO2 and H2O and energy Products Equation 6CO2 + 6H2O +sun C6H12O6 + 6O2 C6H12O6 + 6O2 6CO2 + 6H2O + energy Cell Energy Cell Energy Processes include: Photosynthesis Photosynthesis is a STERNGRR process Cellular Respiration is a STERNGRR process and Cellular Respiration The two processes work together in a cycle! Photosynthesis Involves making FOOD (sugar/glucose) for nutrition CO2 + H2O + sun C6H12O6 + O2 REACTANTS PRODUCTS Occurs in the CHLOROPLASTS of plant cells. Uses the green pigment CHLOROPHYLL to capture light energy Green light is reflected… all other wavelengths of light are absorbed by the plant. Photosynthesis What is going in and coming out of the plant? ATP The food made in photosynthesis is used to make energy for cells! Organisms (including plants) must use this food to produce energy Plants make food for all living organisms (sugar) Food is NOT energy! They are 2 different things! Adenosine Energy is stored in a chemical bond – when the bond is broken, energy is released! P Energy P P ATP is the energy molecule for cells Cellular Respiration Involves using food made in photosynthesis for respiration, to make ATP for energy. C6H12O6 + O2 REACTANTS CO2 + H2O + ATP PRODUCTS Occurs in the Mitochondria of ALL cells Cellular Respiration Cellular respiration can take place WITH Aerobic respiration occurs when oxygen is present Anaerobic respiration (fermentation) takes place when oxygen is NOT present Makes a LOT of ATP Makes a little ATP Or WITHOUT Oxygen! In plants and microorganisms: Alcoholic fermentation In animals: Lactic acid fermentation