Presentation on theme: "Biology 20 Photosynthesis, Cellular Respiration. ATP WHAT IS ATP? Universal Energy Molecule Energy in a form the cell can use Makes energy readily available."— Presentation transcript:
Biology 20 Photosynthesis, Cellular Respiration
ATP WHAT IS ATP? Universal Energy Molecule Energy in a form the cell can use Makes energy readily available Continuously being remade Stands for Adenosine Triphosphate P P + P Adenosine
ATP WHAT IS ATP? Universal Energy Molecule Makes energy readily available Continuously being remade Stands for Adenosine Triphosphate P P + P P P P High Energy Bond Adenosine
ATP What is ATP used for? 1.Motion 2. Transport of ions and molecules. 3. Building molecules 4. Switching reactions on or off
Electron Transfer The transfer of electrons is important in ATP production. Electron carriers –strip a hydrogen proton and its electron from a number of organic compounds Respiration –NAD + (becomes NADH) Photosynthesis –NADP + (becomes NADPH)
Biology 20 Photosynthesis
Introduction Photosynthesis is… –the process by which plants and some bacteria use chlorophyll, a green pigment, to trap sunlight energy. –The energy is used to synthesize carbohydrates
Chlorophyll A green chemical which traps sunlight energy Located in the chloroplast
Chloroplast Parts Thylakoid –Disk –Granum = stack of disks –Grana = many stacks –site of light dependent reaction Stroma –gel surrounding the thylakoids –site of light independent reaction
Leaves in the fall Why do leaves change colors in the fall?
Pigments White light is composed of all colors –red, orange, yellow, green, blue, indigo, violet Chlorophyll –reflects green light –absorbs blue and red ends of the spectrum chlorophyll a -- blue green chlorophyll b -- green Other pigments absorb light energy from other parts of the spectrum.
Leaves in the fall Because of light. A decrease in light intensity and length. Causes the chlorophyll molecule to break down, exposing the other pigments
General Equation There are two steps in photosynthesis –Light Dependent Reaction –Light Independent Reaction (no light required)
General Outline Light Dependent Reaction Light Independent Reaction
Cellular Respiration -Explain how glucose is oxidized during Glycolysis and the Krebs Cycle to produce reducing power in NADH and FADH -Describe where in the cell this takes place -Explain how chemiosmosis converts the reducing power of NADH and FADH to store chemical potential energy as ATP -Describe where in the mitochondrion this takes place
Cellular Respiration Photosynthesis – stores energy Cell Respiration – releases energy = + 6 Sunlight Energy CO 2 H2OH2OGlucose O2O2 Photosynthesis
Cellular Respiration Photosynthesis – stores energy Cell Respiration – releases energy + 6 Sunlight Energy CO 2 H2OH2O Glucose O2O2 Photosynthesis Chemical Energy CO 2 H2OH2O Glucose O2O2 + 6 + Cellular Respiration! 6
Notice that the wastes from photosynthesis are used as raw materials in cellular respiration Atmospheric CO 2 and water are used in photosynthesis, while Oxygen is released. Atmospheric oxygen is used during Cellular respiration, while CO 2 and water is released.
General Information Cellular respiration the process by which cells break down glucose into carbon dioxide and water, releasing energy You can think of respiration as the combustion of gasses in a car’s engine.
Car’s Engine MAIN ENGINE = Mitochondrion – The site of the majority of ATP synthesis MAIN FUEL = Glucose – fats and proteins may also be used in some instances MAIN EXHAUST = CO 2 and H 2 O.
The 4 Steps of Cellular Respiration 1.Glycolysis 2.Pyruvate Oxidation 3. Krebs Cycle 4. Electron Transport Chain
1. Glycolysis (in cytoplasm)
Mitochondria mitochondrial matrix the fluid that fills the interior space of the mitochondrion
2. Pyruvate Oxidation After glycolysis, if there is oxygen available, the pyruvate molecules are changed so the Krebs cycle can use them. CO 2 portion is removed and released as waste product An electron is released to NAD+ NADH Pyruvate Acetyl-CoA
3. Krebs Cycle Discovered by Sir Hans Kreb in 1937 The Krebs cycle is an eight-step process Key features of the Krebs Cycle –During one complete cycle a total of three NAD+ and one FAD are reduced to form three NADH and one FADH –During one complete cycle one ATP is formed –During one complete cycle three CO 2 molecules are produced –However since glycolysis provides 2 pyruvate molecules, we double all our numbers!
4. Electron Transport Chain Electron Transport Chain –Occurs on the inner membrane of the mitochondrion –Involves a group of molecules built into the inner membrane of the mitochondrion –Electrons pulled off of food by Glycolysis and Krebs are passed between these molecules. This will ultimately result in the production of ATP –Oxygen is required for this step. –Lots of ATP is made (32)
Electron Transport Chain
For each NADH that enters the Electron Transport Chain, how many ATP are produced?
For Each NADH Entering the ETC, 3 ATP Are Produced! But What About FADH?
chemiosmosis a process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme
What’s Up With Oxygen? Oxygen is the final electron acceptor. If there is no oxygen, the electron transport chain gets “backed up” as there is no where for the electrons to go. NADHNAD + –As a result, Krebs stops due to lack of NAD + Lack of NAD + also causes [H + ] to increase –The body’s pH begins to fall inhibiting normal enzyme activity.
Review -Explain how glucose is oxidized during Glycolysis and the Krebs Cycle to produce reducing power in NADH and FADH -Describe where in the cell this takes place -Explain how chemiosmosis converts the reducing power of NADH and FADH to store chemical potential energy as ATP -Describe where in the mitochondrion this takes place
Let’s revisit Glycolysis! Glycolysis created two molecules of pyruvate Oxygen available aerobic respiration occurs (Krebs, ETC) No oxygen anaerobic respiration
Anaerobic Respiration Since pyruvic acid is poisonous, it must be converted into a safer form. –In animals (muscles!) -- LACTIC ACID causes muscle cramps process is called Lactic Acid Fermentation
Anaerobic Respiration –In bacteria and yeast -- ETHYL ALCOHOL & CO 2 process is called Alcohol Fermentation Both only Yield 2 ATP! Very inefficient!
Comparison of Photosynthesis and Respiration Photosynthesis Energy required Oxygen released CO 2 and H 2 0 required Glucose produced Respiration Energy Produced Oxygen required CO 2 and H 2 0 produced Glucose required