Cellular Respiration Definition: Gradual release of energy by the break-down of food molecules in aerobic conditions (= O 2 present) Definition: Gradual.

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<ul><li> Slide 1 </li> <li> Cellular Respiration Definition: Gradual release of energy by the break-down of food molecules in aerobic conditions (= O 2 present) Definition: Gradual release of energy by the break-down of food molecules in aerobic conditions (= O 2 present) </li> <li> Slide 2 </li> <li> Energy in Food ________________________ Light provides the energy to make molecules from Where does the energy in food come from? </li> <li> Slide 3 </li> <li> + Water </li> <li> Slide 4 </li> <li> 6CO 2 +H 2 O C 6 H 12 O 6 +6O 2 Occurs in grasses (and other plants) growing Which are eaten by cattle </li> <li> Slide 5 </li> <li> And end up as food on our Plates (Or vegetarians fill their plates with products made from green plants) </li> <li> Slide 6 </li> <li> Question 1: Where does the energy in food come from? Originates in sunlight During photosynthesis light energy is converted into chemical energy in food molecules </li> <li> Slide 7 </li> <li> How does energy get released from food? In humans and many other vertebrates: Food particles get broken down in the digestive system. Chewing - teeth Acids - stomach Enzymes small intestine </li> <li> Slide 8 </li> <li> Role of the small intestine Tiny projections called villi line the small intestine (increases surface area), which absorb digested food into the capillaries (small blood vessels).*vessels).* </li> <li> Slide 9 </li> <li> Food, Energy and Blood Tiny food particles (glucose) is carried in the blood to each cell in the body. Glucose enters each cell by the process of _______________________ Facilitated diffusion </li> <li> Slide 10 </li> <li> Which organelle releases the energy from glucose? </li> <li> Slide 11 </li> <li> What happens next? The chemical reaction for cellular respiration: 6O 2 + C 6 H 12 O 6 6H 2 O + 6CO 2 __________ High energy bonds low energy bonds What is missing from the equation? + ENERGY </li> <li> Slide 12 </li> <li> Cellular respiration Occurs in THREE STAGES This allows the energy found in glucose to be released slowly rather than all at once. The energy in glucose is found in chemical bonds. When the bonds are broken, the energy is released and stored in molecules of ATP. </li> <li> Slide 13 </li> <li> Stage 1 - Glycolysis What happens? 1 molecule of glucose is broken into 2 molecules of pyruvic acid. Bonds are broken and energy is released C 6 H 12 O 6 2 C 3 H 4 O 3 + 4H + _____________ (glucose) (pyruvic acid) What is missing from the equation? + ENERGY </li> <li> Slide 14 </li> <li> Glycolysis (Cont) Glycolysis releases energy. The energy is stored in the chemical bonds of two molecules. ADP (low energy) is converted to ATP (high energy) and NAD + (nicotinamide adenine dinucleotide) is converted into NADH (holds high energy electrons) </li> <li> Slide 15 </li> <li> Glycolysis (cont) The amount of energy produced from glycolysis is small but the process occurs quickly. Glycolysis nets 2 ATP molecules </li> <li> Slide 16 </li> <li> Stage 2 Krebs Cycle or Citric Acid Cycle Hans Krebs (19001980) Discovered the citric acid cycle, (aka) Krebs Cycle, in 1937. Awarded the Nobel Prize for his discovery in 1953. </li> <li> Slide 17 </li> <li> Krebs Cycle Under aerobic conditions (O 2 present), pyruvic acid, passes to the second stage of cellular respiration What happens? Pyruvic acid is broken down into CO 2 (this is the CO 2 we breathe out). A small amount of energy is stored in ATP </li> <li> Slide 18 </li> <li> Krebs Cycle (cont) Occurs in the mitochondrion of Eukaryotes Occurs in the cytoplasm of Prokaryotes </li> <li> Slide 19 </li> <li> Stage 3 Electron Transport Chain Electron transport chain series of reactions What happens? High energy NADH converts low energy ADP into ATP. About 34 ATP molecules are formed from the Krebs cycle and electron transport chain combined. Occurs in the mitochondrion of Eukaryotes Occurs in the cytoplasm of Prokaryotes </li> <li> Slide 20 </li> <li> Question! Why are mitochondria called the POWERHOUSE OF THE CELL? </li> <li> Slide 21 </li> <li> Cell Respiration Together ____________, the _______________and the _________________________________________ make up cell respiration. Glycolysis Electron Transport Chain Krebs Cycle In most cells, 1 molecule of glucose produces 36 molecules of ATP. This amounts to 38% of the total energy stored in glucose. The rest of the energy is released as body heat. Complete worksheet on Cell Respiration! </li> <li> Slide 22 </li> <li> Aerobic vs. Anaerobic Aerobic = O 2 present Anaerobic = No O 2 present Can organisms break down glucose and release its energy in anaerobic conditions? </li> <li> Slide 23 </li> <li> YES! Fermentation an anaerobic cellular process by which glucose is broken down. Fermentation - used by organisms that need small quantities of energy: unicellular organisms or simple multicellular organisms AND Fermentation used when energy is needed very quickly by muscle cells in animals. </li> <li> Slide 24 </li> <li> Fermentation Two types of fermentation a) lactic acid fermentation b) alcohol fermentation. </li> <li> Slide 25 </li> <li> Lactic Acid Fermentation Stage 1 - Glycolysis occurs. Glucose ____________________ pyruvic acid Stage 2 Lactic acid fermentation Pyruvic acid broken down into lactic acid + NAD + Lact = milk! </li> <li> Slide 26 </li> <li> Lactic Acid Fermentation The NAD + restarts the glycolysis reaction which produces 2ATP molecules from 2ADP molecules. Used by bacteria for the breakdown of glucose. Used to produce yogurt and cheeses. Used by muscles when energy is needed quickly (a sprint), and O 2 is in short supply. Lactic acid build up causes a burning sensation resulting in sore muscles. </li> <li> Slide 27 </li> <li> Alcoholic Fermentation Stage 1 - Glycolysis occurs. Glucose pyruvic acid Stage 2 Alcoholic fermentation - In yeast occurs. Pyruvic acid broken into CO 2 + ethanol alcohol. When yeast is added to bread dough, the CO 2 thats produced is released and trapped in the doughcauses bread to rise.*causes bread to rise. The alcohol produced in the reaction evaporates when the bread is baked! </li> <li> Slide 28 </li> <li> Breaking down Glucose Cellular Respiration Aerobic 3 Stages Glycolysis Krebs Cycle Electron Transport Chain Nets 36 ATP molecules Fermentation </li> </ul>

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