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QUIZ 1. 2. 3. 4. T/F Energy is the ability to do work. T/F One way cells use energy is to maintain homeostasis. T/F ADP is recharged into ATP by adding a phosphate group. Where do autotrophs get their energy? Cell Energy Notes Photosynthesis and Cellular Respiration Energy Energy = the ability to do work Energy is usually released when bonds are broken and needed to put bonds together All living organisms must be able to produce, store, and use energy. Our food energy must always be converted to ATP energy to be useful to our cells Energy 2 types of organisms Autotrophs- use energy from sun or inorganic compounds to make organic compounds (like sugar). They use: Photosynthesis Chemosynthesis Heterotroph- organisms that get energy from food Energy The main source of cell energy is called ATP (adenosine triphosphate) ATP is made of an adenosine molecule with three (tri =3) phosphate groups attached. The energy is stored in the bonds of the molecule as “potential energy” (energy available for potential, or future, use) Energy The energy of ATP is released when the covalent bond between the 2nd and 3rd P (phosphate group) is broken. Energy is released and the resulting molecule is ADP or adenosine diphosphate; di=2 Energy ADP and P can form ATP again when energy is added back in and the P bonds to the ADP Cells can make more when needed ATP is a short term energy storage molecule- once it is made, it is used pretty quickly (the bonds are unstable) How do cells use the Energy stored in ATP? When ATP is broken down and the energy is released, cells must have a way to capture the energy and use it efficiently or it will be wasted Cell proteins have specific sites where ATP can bind, then the phosphate bond is broken and energy is released The cell can use the energy for activities such as making a protein or transporting molecules through the plasma membrane (active transport) How do cells use the Energy stored in ATP? Nerve cells transmit signals by using ATP to power the active transport of certain ions Making enzymes that help carry out chemical reaction Build membranes and cell organelles Kidneys use energy to move molecules and ions in order to eliminate wastes while keeping needed substances in the blood stream Cells use energy to maintain homeostasis Enzymes All of the chemical reactions that occur in your body are called your metabolism. Most of these reactions require energy Enzymes lower the amount of energy needed for a reaction to occur This means more reactions can happen in a shorter amount of time because they need less energy Without enzymes, our metabolism would be too slow for us to live!! Enzymes •Key terms •Substrate = substance enzyme acts on •Active site = region where enzyme binds •“Lock and Key” Model = one specific enzyme for one reaction Enzymes Enzymes… Are proteins that act as catalysts Speed up reactions without being changed (so one enzyme can catalyze many reactions) Ex: break down toxins in liver, digest your food in your stomach Enzyme reactions happen at an average rate of 1000 reactions per second! Only work with ONE TYPE of reaction What can affect the functioning of Enzymes? Heat Higher temps increase the collisions of substrates and enzymes, which makes the reactions happen faster So, lower temps DECREASE reaction rates BUT, if temp is too high, enzymes can be denatured (change shape) and not work Our enzymes work best at 35-40OC (body temp is normally 37OC) What can affect the functioning of Enzymes? pH Large changes in pH also denature enzymes Some enzymes, like the ones in our stomachs, work best in acidic conditions Best pH for our enzymes is 6-8 So, heat and pH can denature (change the shape of) enzymes, which makes them no longer able to function Catalase Other factors: Radiation, Electricity, Chemicals Photosynthesis Photosynthesis Cell Equipment: Stomata Chloroplasts Electron carriers 2 Parts Light Reactions Calvin Cycle (also called Dark or light indepepndent Reactions) Equipment for Photosynthesis Stomata are like pores, plants use them to take in CO2 and release O2 Water is also be released when they are open Stomata Electron Carriers Used in many places throughout photosynthesisthere job is to carry electrons from one place to another Light Reactions Require light to happen Also called light dependent reactions Light is absorbed by the chloroplasts Light Reactions There are pigments in the thylakoid membrane of the chloroplasts that absorb light The color you SEE is NOT the color absorbed, all other colors are absorbed When you see a green leaf, it is because the leaf absorbs all other colors and REFLECTS green (so that green hits your eyes). Light Reactions There are several pigments found in the membrane of the thylakoids, the most prominent is chlorophyll a and b which absorb most colors except green. Chlorophyll a is directly involved in photosynthesis, and other pigments assist it in absorbing other colors of light. More colors absorbed means more energy! Light Reactions Pigments that assist chlorophyll are called accessory pigments Light Reactions So, what happens in the fall? Normally, the green color of chlorophyll masks all other colors In the fall, many plants lose their chlorophyll So you are able to see the colors of the carotenoids instead (yellow, brown, and orange) Light Reactions Turns (ATP) light energy into chemical energy Involves Takes an enzyme called ATP synthase place in the thylakoid membranes H2O molecules and light energy make ATP, an e- carrier, and O2 The oxygen leaves the cell, the ATP and e- carriers move to the Calvin Cycle Calvin Cycle Powered by ATP & e- carriers made by light reactions. Needs CO2 Happens in stroma of a chloroplast Sugars are mainly built in this cycle, but lipids, proteins, and nucleic acids can also be made Other paths When stomata are open, water is lost This is BAD for desert plants which need to conserve water C4 plants keep there stomata half closed during the hottest part of the day They are able use the small amount of CO2 that enters CAM plants keep there stomata closed during the day. They hold on to the CO2 that they get at night and use it during the day Photosynthesis- Summary Photosynthesis has 2 main parts 1. Light reactions - where light energy is absorbed and converted into ATP and e- carriers 2. Calvin Cycle – where organic compounds are formed using the chemical energy in ATP and e- carriers 6CO2 + 6H2O + light C6H12O6 + 6O2 PhotosynthesisSummary Reactants (what is Products (what needed?) is produced?) Light 1. Light 1. O2 Reactions 2. Water 2. e- carrier 3. ATP Calvin Cycle 1. CO2 2. e- carrier 3. ATP 1. Organic compounds 2. e- carrier 3. ADP + P Cellular Respiration Cellular Respiration The energy stored in the chemical bonds of organic molecules (carbs, lipids, etc) must be released and turned in to ATP to be useful to your cells The process by which this is done is called cellular respiration Cell Respiration Cell Equipment: Cytoplasm Mitochondria Electron carriers (NADP/NADPH) 3 Parts Glycolysis Krebs Cycle ETC Equipment for Cellular Respiration Equipment for Cellular Respiration Electron Carriers- Cell respiration has them too, they are just different kinds of molecules Anaerobic Respiration-Glycolysis Anaerobic means WITHOUT oxygen Takes place in the cytoplasm Uses 2 ATP & glucose, to make a total of 4 ATP (net gain of 2 ATP), 2 pyruvate, & e- carriers. Since few ATP are produced, only VERY SMALL organisms can live by glycolysis alone Anaerobic Respiration- Fermentation When oxygen is not present, fermentation occurs after glycolysis It occurs in the cytoplasm Fermentation allows glycolysis to continue So, SMALL amounts of ATP can continue to be produced without oxygen Anaerobic RespirationLactic Acid Fermentation This type of respiration is used by many kinds of bacteria and is responsible for cheese, buttermilk, sour cream, and yogurt During strenuous activity, lactic acid fermentation is used by our muscle cells. Produces lactic acid and CO2 The build up of lactic acid in our muscle cells is what causes pain, fatigue, and cramps after strenuous activities Anaerobic RespirationAlcoholic Fermentation Creates ethyl alcohol and CO2 This type of fermentation is used in plants and some microorganisms, such as yeast. This type of fermentation is used in the beer and wine industry It is also used in the bread industry, because yeast give off CO2 when they ferment (this creates fluffy bread) Aerobic Respiration Happens after glycolysis IF OXYGEN IS PRESENT 2 major stages Krebs Cycle ETC Pyruvic acid created in Glycolysis diffuses into the mitochondrial matrix Aerobic RespirationKrebs Cycle Occurs within the mitochondrial matrix Starts with pyruvate molecules from glycolysis Produces ATP, ecarriers, & some CO2 molecules (CO2 is released from the cell). ETC (Electron Transport Chain) The ETC is in the inner membrane of the mitochondrion in the folds called cristae It uses the e- carriers made by Krebs Cycle and O2 to make H2O and 32 ATP. Lots of energy! 32 ATP just from 1 glucose using these ETC reactions. Produces way more ATP than any of the other reactions. Cellular RespirationSummary C6H12O6 + 6O26CO2 + 6H2O + ATP In the anaerobic process of glycolysis, organic compounds are converted into pyruvic acid, producing a small amount of ATP and e carriers in the process In aerobic respiration pyruvic acid is broken down using oxygen into CO2 and water, which produces a large amount of ATP This process is 39% efficient (means 39% of the stored energy in your food is used) Reactants Respiartion- Summary Products Glycolysis 1. 2 ATP 1. 4 ATP 2. Glucose 2. e- carrier 3. Pyruvate Krebs Cycle ETC 1. Pyruvate 1. CO2 2. e- carrier 2. 2 ATP 3. ADP 3. e- carriers 1. e- carriers 1. Water 2. Oxygen 2. 32 ATP 3. ADP Cellular RespirationSummary But remember that 2 ATP were used in Glycolysis, so cellular respiration produces 36 NET ATP Energy Cycle sun Photosynthesis light CO2 + H2O + energy C6H12O6 + O2 plants CO2 H2O glucose animals, plants ATP C6H12O6 + O2 energy + CO2 + H2O Cellular Respiration ATP O2