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MODULE 4 Photosynthesis and Cellular Respiration BIO 001– Modern Biology ENGR. AL R. ROMANO Faculty, Department of Environmental and Sanitary Engineering College of Engineerin...

MODULE 4 Photosynthesis and Cellular Respiration BIO 001– Modern Biology ENGR. AL R. ROMANO Faculty, Department of Environmental and Sanitary Engineering College of Engineering and Architecture Technological institute of the Philippines-Quezon City  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Intended Learning Outcomes Explain why almost organisms depends on photosynthesis Describe the role of chlorophylls and other pigment in photosynthesis Summarize the main evens of the light reactions Explain how ATP is made during the light reactions  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Metabolic Diversity Among Organisms  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis-a chemical reaction Autotrophic Process: Plants and plant-like organisms, algae, make their energy (glucose) from sunlight. Organism that use energy form sunlight or from chemical bonds in inorganic substances to make organic compounds Stored as carbohydrate in their bodies. The tree depends on the sun for energy. Like all heterotrophs, the caterpillar and bird depend on an autotrophs (the tree) for energy  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis- a chemical reaction Photosynthesis is the process that converts solar energy into chemical energy that is used by biological systems (that means us). Photosynthesis has 3 major events: 1. Sunlight is converted into chemical energy 2. Water (H2O) is split into oxygen (O2) 3. Carbon dioxide (CO2) is fixed into sugars (C6H12O6) The photosynthesis reaction: 6 CO2 + 12 H2O + sunlight → C6H12O6 + 6 H2O + 6 O2 6 Carbon 12 Water 1 Sugar 6 Water 6 Oxygen dioxide molecules (glucose) molecules molecules molecules molecule  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology PHOTOSYNTHESIS- a chemical reaction Photosynthesis is carried out by: These organisms are known as certain bacteria plants photoautotrophs or producers meaning they make their own food and energy from the sun. Consumers such as herbivores and carnivores depend on the products of photosynthesis that producers make to live. most algae cyanobacteria phytoplankton  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis- Lights and Pigments Photons: discreet packets of kinetic energy crest When white light strikes an object, its component colors can be reflected, transmitted, or absorbed by the object. Electro magnetic Spectrum: range of all possible frequencies White light can be separated into its of radiation component colors by passing the light through a prism.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis- Lights and Pigments Chlorophyll absorbs all wavelength colors except green, which is reflected off giving plants their green appearance. When you see something, you’re actually seeing the reflection of that wavelength of light!  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis- Lights and Pigments Two types of Chlorophyll During the fall, many plants 1. Chlorophyll a lose their chlorophylls, and 2. Chlorophyll b their leaves take on rich hues of the carotenoids. Cold Weather: Fewer daylight hours Little chlorophyll is produced Leaf absorbs all colors but yellow to orange Chlorophyll a absorbs less blue light but more red light than chlorophyll b absorbs. Both reflect green light.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis – Two Stages  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis Light Reactions Dark Reactions Light reactions or “light dependent reactions” capture light energy to power photosynthesis. Light reactions occur during the day Absorption of light in light reactions begins within time. chloroplast, organelles found in the cell of plants and algae. They take place in the thylakoids.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis – Capturing Light Energy Light Reactions Chloroplasts are full of round flattened discs called Light reactions or “light dependent A stack of thylakoids. reactions” capture light energy to thylakoids is called power photosynthesis. a granum. Light reactions occur during the day time. They take place in the thylakoids. Stroma is the space inside Chloroplasts are where photosynthesis occurs. chloroplasts  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Catabolic Reaction: Converting Light to Chemical Energy Functional Components of a Photochemical System: 1. light harvesting pigments 2. a membrane electron transport system 3. an ATPase enzyme  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Catabolic Reaction: Converting Light to Chemical Energy 2 types of Photosystems: The contain similar kinds of pigment, but different roles in the light reaction. 1. Photosystem I 2. Photosystem II In each photosystem, the acquired energy is passed quickly to the other pigment molecules until it reaches a specific pair of chlorophyll-a molecules (reaction center) The event that occur next can be divided into five steps.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Catabolic Reaction: Converting Light to Chemical Energy Photo ETC Excitation Photo Excitation Chemiosmosis A MEMBRANE ELECTRON TRANSPORT SYSTEM:  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis-Making ATP Cyclic photophosphorylation (PSI) The electrons return to the chlorophyll.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis-Making ATP and NADPH Non-Cyclic photophosphorylation (PSI and PSII) Photolysis the electrons are used to reduce NADP+ , and electrons are returned to chlorophyll from H2O or H2S  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis Light Reactions Dark Reactions Dark reactions or “light independent Light reactions or “light dependent reactions” do not need light energy to reactions” capture light energy to power their reactions and can occur day power photosynthesis. or night. Discovered by three scientists, the dark Light reactions occur during the day reactions are also called the Calvin- time. Bensen-Bassham cycle or just Calvin Cycle. They take place in the thylakoids. Dark reactions occur in the stroma of chloroplasts (the space that surrounds thylakoids) and fix carbon dioxide into glucose. C B B  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Photosynthesis- The Calvin Cycle The Calvin cycle is a series of enzyme-assisted chemical reactions that produces a three-carbon sugar. In the Calvin cycle, carbon atoms from CO2, in the atmosphere are bonded, or "fixed," into organic compounds. This incorporation of CO2, into organic compounds is called carbon fixation. A total of three CO2, molecules must enter the Calvin cycle to produce each three-carbon sugar that will be used to make the organic compounds.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Carbon Photosynthesis- The Calvin Cycle Fixation Auto RuBP Replacement Activation and Reduction Activation Reduction  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Summary of Photosynthesis Plants are the producers of the biosphere creating the oxygen and glucose needed for most organisms. Chloroplasts are the site of photosynthesis in plants. Chloroplasts contain thylakoids where the light reactions take place. Light reactions convert sunlight into ATP and NADPH. The dark reactions or Calvin Cycle uses ATP and NADPH to convert CO2 into sugar. The light reactions and the dark reactions cooperate to convert light energy into chemical energy housed in glucose. Plants and animals use glucose to power metabolic processes. MODULE 4.1 Cellular Respiration BIO 001– Modern Biology  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Heterotrophic Metabolism Two basic types of heterotrophic metabolism: 1. Respiration - Requires an external electron acceptor not derived from the organic substrate. 2. Fermentation - is metabolism in which energy is derived from the partial oxidation of an organic compound using organic intermediates as electron donors and electron acceptors  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Heterotrophic Metabolism  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Cellular Respiration Two types of Heterotrophic Respiration Aerobic respiration begins with an organic molecule and combines it with oxygen in an oxidation-reduction process that ends with the formation of CO2 and H2O plus a substantial amount of ATP.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Cellular Respiration Cellular respiration is the complex process in which cells make adenosine triphosphate (ATP) by breaking down organic compounds. 2 Stages of Cellular Respiration: 1. Glycolysis : Organic compounds are converted into pyruvic acid, producing a small amount of ATP and NADH. (anaerobic process). 2. Aerobic Respiration : Pyruvic acid is broken down and NADH is used to make a large amount of ATP through the process known as aerobic respiration. Pyruvic acid can enter other pathways if there is no oxygen present in the cell's environment. The combination of glycolysis and these Both Autotrophs and heterotrophs produce anaerobic pathways is called fermentation. carbon dioxide and water to cellular respiration  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Respiratory Metabolism Aerobic respiration begins with an organic molecule and combines it with oxygen in an oxidation-reduction process that ends with the formation of 𝐶𝑂2 and 𝐻2 𝑂 plus a substantial amount of ATP. Example: Aerobic respiration of glucose 3 Phases of Respiratory Metabolism 1. Glycolysis 2. Tricarboxylic Acid Cycle 3. Electron Transport Chain  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Cellular Respiration Organisms use cellular respiration to harness energy from organic compounds in food. (a) Glycolysis, the first stage of cellular respiration, produces a small amount of ATP. Most of the ATP produced in cellular respiration results from aerobic respiration, which is the second stage of cellular respiration. (b) In some cells, glycolysis may result in fermentation if oxygen is not present  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Cellular Respiration: Glycolysis Glycolysis is a biochemical pathway in which one six-carbon molecule of glucose is oxidized to produce two three-carbon molecules of pyruvic acid. Like other biochemical pathways, glycolysis is a series of chemical reactions catalyzed by specific enzymes. What happens to the pyruvic acid depends on the type of cell and on whether oxygen is present. Notice that two ATP molecules were used in step 1, but four were produced in step 4. Therefore, glycolysis has a net yield of two ATP molecules for every molecule of glucose that is converted into pyruvic acid.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Tricarboxylic Acid (TCA) Cycle [Krebs Cycle] At the end of the TCA cycle, Glycolysis yields two molecules of pyruvic all the carbon has been acid. In aerobic respiration, each molecule of converted to CO2. pyruvic acid reacts with coenzyme A (COA) to TCA plays a central role in form a molecule of acetyl CoA. Notice that the flow of carbon through CO2, NADH, and H+ are also produced in this the cell. reaction It supplies organic precursor molecules to many biosynthetic pathways. Some of the intermediates in the TCA cycle must be resynthesized to maintain TCA cycle activity  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Electron Transport Chain Electrons are brought to the electron transport chain by NADH. The electron transport chain consists of carriers, including flavoproteins, cytochromes, and ubiquinones. Electrons are passed from one carrier to the next, the energy is used to drive proton pumps. The final electron acceptor is irreversibly reduced; it may be oxygen (aerobic) or another inorganic molecule (anaerobic)  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Aerobic Respiration The Overall Process of Respiratory Metabolism: A substrate such as glucose is completely oxidized to 𝐶𝑂2 by the combined pathways of glycolysis and the TCA cycle. Electrons removed from the glucose by NAD are fed into the Electron Transport System (ETS) in the membrane. As the electrons traverse the ETS, a Protonmotive force (pmf) becomes established across the membrane. The electrons eventually reduce an outside electron acceptor, O2 , and reduce it to H20. The pmf on the membrane is used by the ATPase enzyme to synthesize ATP by a process referred to as "oxidative phosphorylation".  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Aerobic Respiration  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Aerobic Respiration: Net ATP Generation  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Aerobic Respiration: Net ATP Generation How many ATP molecules are made in cellular respiration? Glycolysis and the Krebs cycle each produce two (2) ATP molecules Furthermore, each NADH molecule that supplies the electron transport chain can generate three ATP molecules, and each FADH, molecule can generate two ATP molecules. Thus, the 10 NADH and two FADH, molecules made through glycolysis, conversion of pyruvic acid to acetyl CoA, and the Krebs cycle can produce up to 34 ATP molecules by the electron transport chain and chemiosmosis. Adding the four ATP molecules from glycolysis and the Krebs cycle gives a maximum yield of 38 ATP molecules per molecule of glucose  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Fermentation Fermentation is any process that releases energy from sugars or other organic molecules by oxidation, does not require O2, the Krebs cycle, or an electron transport chain, and uses an organic molecule as the final electron acceptor. Fermentation can sometimes occur in the presence of O2 Fermentation produces two ATP molecules by substrate-level phosphorylation. Electrons removed from the substrate reduce NAD+ to NADH.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Lactic Acid Fermentation Lactic acid fermentation by microorganisms plays an essential role in the manufacture of many dairy products. Milk will ferment naturally if not refrigerated properly or consumed in a timely manner. Such fermentation of milk is considered "spoiling." In cheese making, fungi or bacteria are added to large vats of milk. The microorganisms carry out lactic acid fermentation, converting some of the sugar in the milk to lactic acid.  Technological Institute of the Philippines-QC 938 Aurora Blvd., Cubao, Quezon City Environmental and Sanitary Engineering Department BIO 001|Modern Biology Alcoholic Fermentation Alcoholic fermentation by yeast cells such as those in Figure 7-7 is the basis of the wine and beer industry. Yeasts are a type of fungi. These microorganisms cannot produce their own food. But supplied with food sources that contain sugar (such as fruits and grains), yeast cells will perform the reactions of fermenta- tion, releasing ethyl alcohol and carbon dioxide in the process. The ethyl alcohol is the 'alcohol' in alcoholic beverages.  THANK YOU Questions? References of photos are still to be indicated.