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Transcript
Section One: Chemical Energy and ATP ATP A molecule that transfers energy from the breakdown of food molecules to the cell processes The chemical energy used for most cell processes Energy is released when a phosphate group is removed ATP ADP ADP is a lower energy molecule that can be converted to ATP by the addition of a phosphate group Section One: Chemical Energy and ATP ATP Digestion of food breaks it down into smaller molecules that can be used to make ATP The number of ATP created depends on the type of food broken down Carbohydrate Lipid: yield the most ATP Protein: needed to build amino acids and are rarely broken down for ATP Section One: Chemical Energy and ATP Chemosynthesis The process by which some organisms use chemical energy instead of light energy to make energy storing carbon based molecules. The organism still require ATP Section Two: Overview of Photosynthesis Photosynthesis: the process that captures energy from sunlight to make sugars that store chemical energy Used by producers Occurs in chloroplasts Chlorophyll is a molecule in chloroplasts that absorbs light energy Two MainTypes: chlorophyll A & B Section Two: Overview of Photosynthesis Section Two: Overview of Photosynthesis Photosynthesis Occurs in chloroplasts Most found in leaf cells Two main parts are the grana and stroma Grana: stacks of coin shaped membrane enclosed compartments called thylakoids Thylakoid membranes contain chlorophyll Stroma: fluid that surrounds the grana Section Two: Overview of Photosynthesis Photosynthesis 2 Parts: Light-dependent reaction and lightindependent reactions Light-dependent reactions: capture energy from sunlight Take place in and across the membrane of thylakoids Uses water and sunlight Steps 1. Chlorophyll absorbs energy from the sunlight. The energy is transferred from the thylakoid membrane. Water molecules are broken down and oxygen is released. 2. Energy carried along the thylakoid membrane is transferred to molecules that carry energy, such as ATP Section Two: Overview of Photosynthesis Section Two: Overview of Photosynthesis Photosynthesis Light-independent reactions Use energy created during the light-dependent reactions to make sugars Occurs in the stroma Needs carbon dioxide molecules Steps 1. Carbon dioxide is added to a cycle of chemical reactions to build larger molecules. Energy from the light-dependent reactions is used in these reactions 2. A molecule of simple sugar is formed. The sugar, usually glucose (C6H12O6), stores some of energy that was captured from sunlight. Section Two: Overview of Photosynthesis Photosynthesis Light energy, carbon dioxide from the atmosphere, and water are used to create sugar and oxygen Only one molecule of carbon at a time is used to create a six carbon sugar Section Three: Photosynthesis in Detail Light-dependent Reactions Energy is captured and transferred in the thylakoid membranes by molecules called photosystems Photosystem I and Photosystem II Steps: Photosystem II and Electron Transport 1. Chlorophyll and other light absorbing molecules in the thylakoid membrane absorb the light energy from sunlight. The energy is transferred to electrons (e-). These high energy electrons leave the chlrophyll and enter the electron transport chain, which is a series of proteins in the membrane of the thylakoid Section Three: Photosynthesis in Detail Light-dependent Reactions 2. Enzymes break down water molecules. Oxygen, hydrogen ions (H+), and electrons are separated from each other. The oxygen is released as waste. The electrons from water replace those electrons that left chlrophyll. 3. Electrons move from protein to protein in the electron transport chain. The energy used to pump hydrogen ions from the outside of the thylakoid to the inside, which is against the concentration gradient. Hydrogen ions build up inside the thylakoid. Electrons move to photosystem I. Section Three: Photosynthesis in Detail Section Three: Photosynthesis in Detail Light-dependent Reactions Photosystem I 4. Chlorophyll and other light absorbing pigments absorb energy. Electrons are energized and leave the thylakoid molecule 5. The energized electrons are added to a molecule called NADP+. It functions like ADP. A molecule of NADPH is made. NADPH works like ATP. The NADPH molecules made will enter the light-independent reactions. Section Three: Photosynthesis in Detail Light-dependent Reactions ATP Production 6. Hydrogen ions flow through the protein channel in the thylakoid membrane. The concentration rises inside the membrane. The difference between the outside and inside concentrations is called chemiosmotic gradient. It stores potential energy. The ions flow through the membrane by diffusion. 7. The protein channel in step 6 is part of a complex enzyme called ATP synthase. As the ions flow through the channel, ATP synthase makes ATP by adding a phosphate group to ADP. Section Three: Photosynthesis in Detail Section Three: Photosynthesis in Detail Light-independent Reactions Take place in chloroplast in the stroma Light is not required Also called the Calvin Cycle 1. 2. Use carbon dioxide gas from the atmosphere and the energy carried by ATP and NADPH to make simple sugars Carbon dioxide is added to a five carbon molecule already in the carbon cycle, forming a six carbon molecule Energy from the light dependent reactions (ATP & NADPH) is used by enzymes to split the six carbon molecules into 2 three carbon molecules Section Three: Photosynthesis in Detail Light-independent Reactions 3. Most of the three carbon molecules stay in the Calvin Cycle, but one leaves. After two leave they are bonded together to form a six carbon sugar molecule like glucose. 4. Energy from the ATP is used to change the three carbon molecules back into five carbon molecules. The five carbon molecules stay in the cycle and are added to new carbon dioxide molecules that enter the cycle. Section Three: Photosynthesis in Detail Section Three: Photosynthesis in Detail Photosynthesis Functions Allows food production for plants and other organisms Provides material for plant growth and development Removes carbon dioxide from the atmosphere Creates oxygen for organisms that breathe it Section Four: Overview of Cellular Respiration Cellular Respiration Releases chemical energy from sugars and other carbon based molecules to make ATP when oxygen is present Aerobic: needs oxygen to take place Needs glycolysis: splits glucose into two 3 carbon molecules and makes two molecules of ATP Takes place in the cytoplasm Anaerobic: does not need oxygen Section Four: Overview of Cellular Respiration Cellular Respiration Occurs in the mitochondria Occurs through 2 stages: Krebs Cycle and Electron Transport Up to 38 ATP are made from one glucose molecule Section Four: Overview of Cellular Respiration Cellular Respiration Stage One: Krebs Cycle 1. 2. Krebs Cycle: produces molecules that carry energy to the second part of cellular respiration Takes place in the matrix of the mitochondria 3 carbon molecules from glycolysis are broken down. A small number of ATP are made, along with other types of energy carrying molecules. Carbon dioxide is given off as a waste product. Energy is transferred from the second stage of cellular respiration. Section Four: Overview of Cellular Respiration Cellular Respiration Stage Two: Electron transport Takes place in inner mitochondrial membrane An electron transport chain made of proteins needs energy carrying molecule from the Krebs cycle and oxygen to make ATP. 3. Energy is transferred to a chain of proteins in the inner membrane of the mitochondria 4. A large number of ATP molecules are made and oxygen enters the process and is used to make water molecules. Water and heat are given off as waste products Section Five: Cellular Respiration in Detail Glycolysis Take place in the cytoplasm before cellular respiration Anaerobic Steps: 1. 2. Two ATP are used to energize a glucose molecule. The glucose is split into 2 three carbon molecules, and then through enzymes and chemical reactions is rearranged. Energized electrons from the three carbon molecules are transferred to molecules of NAD+. Molecules of NADH are formed. A series of reactions converts the three carbon molecule to pyruvate, which enter cellular respiration, and four ATP are made. Section Five: Cellular Respiration in Detail Cellular Respiration Stage One: Krebs Cycle (Citric Acid Cycle) 1. 2. 3. Makes more ATP than glycolysis A pyruvate molecule is split into a 2 carbon molecule and a molecule of carbon dioxide (waste product). High energy electrons are transferred from the 2 carbon molecule to NAD+ producing NADH. NADH moves to the electron transport chain. A molecule called coenzyme A bond to the 2 carbon molecule and the intermediate molecule they form enter the Kreb cycle The intermediate is added to a 4 carbon molecule to form citric acid ( 6 carbon molecule). Coenzyme A will return to step 2. Section Five: Cellular Respiration in Detail Cellular Respiration Stage One: Krebs Cycle (Citric Acid Cycle) 4. The citric acid is broken down by an enzyme into a 5 carbon molecule. A molecule of NADH is formed and leaves the Krebs cycle. A molecule of carbon dioxide is given off as a waste product. 5. The 5 carbon molecule is broken down by an enzyme, forming a 4 carbon molecule, NADH, and ATP. NADH leaves and carbon dioxide is given off as a waste product. 6. Enzymes rearrange the 4 carbon molecule and high energy electrons are released. NADH and FADH2, an electron carrier, are made. They leave Krebs and the 4 carbon molecule stays. Section Five: Cellular Respiration in Detail Section Five: Cellular Respiration in Detail Breakdown of Krebs 3 molecules of carbon dioxide created as waste 1 molecule of ATP made 4 molecules of NADH sent to ETC 1 molecule of FADH2 sent to ETC Section Five: Cellular Respiration in Detail Cellular Respiration Stage Two: Electron Transport Chain (ETC) Takes place in and across inner membrane of mitochondria Made of proteins Uses the energy from NADH and FADH2 to pump hydrogen ions against their concentration gradient, and across the inner mitochondrial membrane. As hydrogen ions move out of the inner membrane back to outer membrane they produce ATP Section Five: Cellular Respiration in Detail Cellular Respiration Stage Two: ETC 1. 2. 3. 4. Protein in the inner mito. membrane take electrons from NADH and FADH2. (Uses 2 NADH and one FADH2) The electrons travel through proteins in the ETC and the proteins use the energy from the electrons to pump hydrogen ions into the inner mito. membrane. The hydrogens build up in the membrane and are pumped against the concentration gradient. Hydrogens leave the inner mito. membrane through a protein channel that is part of the ATP synthase enzyme. As they leave it allows ATP synthase to add a phosphate group to ADP creating ATP. Oxygen picks up the hydrogens and electrons finished with the process and creates water as a waste product. Section Five: Cellular Respiration in Detail Section Five: Cellular Respiration in Detail Breakdown of Cellular Respiration Carbon dioxide is created Water is created from the ETC A net gain of 38 ATP Section Six: Fermentation Fermentation Does not make ATP but allows glycolysis to continue when no oxygen is present Occurs when your body cannot get enough oxygen fast enough to perform cellular respiration Removes electrons from NADH and recycles NAD+ molecules for glycolysis Lactic acid fermentation occurs when your body is fatigued and can’t get oxygen Section Six: Fermentation Lactic Acid Fermentation Latic Acid: is what causes your muscles to feel sore or burn during exercise 1. Pyruvate and NADH from glycolysis enter fermentation. NADH provide energy to turn pyruvate into lactic acid. NADH forms NAD+ after usage. 2. The NAD+ goes to glycolysis, allowing it to continue. Section Six: Fermentation Fermentation Used to make cheese, bread, yogurt, and alcohol Bacteria in animal stomach use it to get energy