* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Biology_Chapter 8_Cellular_Respiration
Survey
Document related concepts
Gaseous signaling molecules wikipedia , lookup
Carbon sink wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
Metalloprotein wikipedia , lookup
Biosequestration wikipedia , lookup
Citric acid cycle wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Oxidative phosphorylation wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Photosynthesis wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Transcript
Biology – Premed Windsor University School of Medicine and Health Sciences Biology Chapter 8 Cellular Respiration Dr. Uche Amaefuna Pre Med – Biology Chapter 8 Cellular Respiration There is more to lectures than the power point slides! Engage your mind 1 Cellular Respiration 2 THE CONCEPT OF ‘Cellular Respiration’ IS CENTRAL TO ALL LIVING PROCESSES It is worth studying this presentation thoroughly because it is essential for an understanding of all the activities of living cells and organisms 3 All living cells are made up of chemical substances The processes of living involve reactions between the substances A reaction is an event which produces a change in a substance For example, a reaction between carbon and oxygen (such as burning coal in air) changes the carbon in the coal, and oxygen in the air into carbon dioxide This reaction can be represented by the equation C carbon + O2 CO2 oxygen carbon dioxide 5 The reaction between carbon and oxygen also releases energy in the form of heat and light (flames) Living organisms get their energy from reactions like this (but not reactions which are violent enough to produce flames) 7 One of the energy-producing reactions is called respiration (Respiration is not the same thing as breathing) The chemical reactions of respiration take place in all living cells The reaction takes place between oxygen and a substance which contains carbon. The reaction produces carbon dioxide and water, and releases energy 8 The carbon-containing substances come from FOOD The oxygen comes from the AIR (or water) The energy is used to drive other chemical reactions taking place in cells One example of this is the release of energy in muscle cells to make them contract and produce movement 9 One example of an energy-producing reaction in cells is the breakdown of sugar when it combines with oxygen This can be represented by the equation C6H12O6 + 6O2 sugar (glucose) oxygen 6CO2 + 6H2O + carbon dioxide energy water This means that one molecule of sugar reacts with six molecules of oxygen to produce six molecules of carbon dioxide and six molecules of water. Energy is released during this process 10 Some examples of the use of energy in organisms muscle contraction Respiration supplies the energy for germination chemical changes in cells cell division 11 Energy use in muscle contraction shoulder blade The blood stream brings food and oxygen to the muscle cells. Respiration occurs in the cells and releases energy which…… upper arm bone lower arm bones One example of respiration in ourselves 2. The lungs absorb oxygen from the air 2.The stomach and intestine digest food. One of the products is glucose 4 RESPIRATION Glucose and oxygen react to produce energy for muscle contraction 15 1. Air taken in 1.Food taken in 3.The blood stream carries glucose and oxygen to the muscles 5 Carbon dioxide is carried to the lungs by the blood 16 Question 1 What is the most important point about respiration? (a) it uses oxygen (b) It produces energy (c) It produces carbon dioxide (d) It needs food and air 17 Question 2 In which part of the human body is respiration most likely to be occurring? (a) The lungs (b) The heart (c) The muscles (d) All of these 18 Question 3 Which of these are waste products of respiration? (a) Carbon dioxide (b) Water (c) Oxygen (d) Nitrogen 19 Question 4 Which of the following would be reliable indicators of respiration in a living organism? (a) Output of water vapour (H2O) (b) Output of carbon dioxide (CO2) (c) Uptake of oxygen (O2) (d) Production of energy 20 Question 5 Which of the following statements is correct? (a) We breathe in air (b) We breathe in oxygen (c) We breathe out air (d) We breathe out carbon dioxide What Is ATP? Energy used by all Cells Adenosine Triphosphate Organic molecule containing highenergy Phosphate bonds Chemical Structure of ATP Adenine Base 3 Phosphates Ribose Sugar How Do We Get Energy From ATP? By breaking the high- energy bonds between the last two phosphates in ATP What is the Process Called? HYDROLYSIS (Adding H2O) H2O How Does That Happen? An Enzyme! How is ATP Re-Made? The reverse of the previous process occurs. Another Enzyme is used! ATP Synthetase The ADP-ATP Cycle ATP Synthetase ATP-ase Copyright Cmassengale When is ATP Made in the Body? During a Process called Cellular Respiration that takes place in both Plants & Animals Cellular Respiration • Includes pathways that require oxygen • Glucose is oxidized and O2 is reduced • Glucose breakdown is therefore an oxidation-reduction reaction • Breakdown of one glucose results in 36 to 38 ATP molecules Overall Equation for Cellular Respiration C6H12O6 + 6O2 YIELDS 6CO2 + 6H20 + e- + 36-38ATP’s What Type of Process is Cellular Respiration? • An Oxidation-Reduction Process or REDOX Reaction • Oxidation of GLUCOSE --> CO2 + H2O (e- removed from C6H12O6) • Reduction O2 to H2O (e- passed to O2) What Carries the Electrons? • NAD+ • • (nicotinadenine dinucleotide) acts as the energy carrier NAD+ is a coenzyme It’s Reduced to NADH when it picks up two electrons and one hydrogen ion Are There Any Other Electron Carriers? • YES! Another Coenzyme! • FAD+ (Flavin adenine dinucleotide) • Reduced to FADH2 Other Cellular Respiration Facts • Metabolic Pathway that breaks down carbohydrates • Process is Exergonic as High-energy Glucose is broken into CO2 and H2O • Process is also Catabolic because larger Glucose breaks into smaller molecules What are the Stages of Cellular Respiration? • Glycolysis • The Krebs Cycle • The Electron Transport Chain Where Does Cellular Respiration Take Place? • It actually takes place in two parts of the cell: Glycolysis occurs in the Cytoplasm Krebs Cycle & ETC Take place in the Mitochondria Diagram of the Process Occurs across Cristae Occurs in Cytoplasm Occurs in Matrix Glycolysis Summary Takes place in the Cytoplasm Anaerobic (Doesn’t Use Oxygen) Requires input of 2 ATP Glucose split into two molecules of Pyruvate or Pyruvic Acid • Also produces 2 NADH and 4 ATP • Pyruvate is oxidized to Acetyl CoA and CO is removed Glycolysis Diagram Fermentation Occurs when O2 NOT present (anaerobic) Called Lactic Acid fermentation in muscle cells (makes muscles tired) Called Alcoholic fermentation in yeast (produces ethanol) Nets only 2 ATP A Little Krebs Cycle History • Discovered by Hans Krebs in 1937 • He received the Nobel Prize in physiology or medicine in 1953 for his discovery • Forced to leave Germany prior to WWII because he was Jewish Krebs Cycle Summary • Requires Oxygen (Aerobic) • Cyclical series of oxidation reactions that give off CO2 and produce one ATP per cycle • Turns twice per glucose molecule • Produces two ATP • Takes place in matrix of mitochondria Krebs Cycle Summary • Each turn of the Krebs Cycle also produces 3NADH, 1FADH2, and 2CO2 • Therefore, For each Glucose molecule, the Krebs Cycle produces 6NADH, 2FADH2, 4CO2, and 2ATP Krebs Cycle ATP NETS: 3NADH, 1ATP, 1FADH2, & 2CO2 Electron Transport Chain Summary • 34 ATP Produced • H2O Produced • Occurs Across Inner Mitochondrial membrane • Uses coenzymes NAD+ and FAD+ to accept e- from glucose • NADH = 3 ATP’s • FADH2 = 2 ATP’s 23 Anaerobic Respiration 24 The process of respiration described so far has been defined as the release of energy when foodstuffs such as glucose react with oxygen to produce carbon dioxide and water. This form of respiration, which needs oxygen, is called aerobic respiration. There is another form of respiration which does not need oxygen and is called anaerobic respiration. In anaerobic respiration, glucose is still broken down to carbon dioxide with the release of energy, but without the involvement of oxygen The glucose is not completely broken down to CO2 and H2O but to CO2 and alcohol (ethanol). 25 Anaerobic respiration can be represented by the equation C6H12O6 glucose energy 2C2H5OH + 2CO2 alcohol The energy released by anaerobic respiration is considerably less than the energy from aerobic respiration. Anaerobic respiration takes place at some stage in the cells of most living organisms. For example, our own muscles resort to anaerobic respiration when oxygen is not delivered to them fast enough. 26 Micro-organisms Anaerobic respiration is widely used by many micro-organisms such as bacteria and yeasts. Bacteria and yeasts are microscopic single-celled organisms. Bacteria are to be found everywhere, in or on organisms, in water, air and soil Yeasts are usually found in close association with vegetable matter such as fruit 27 Bacteria cell wall there are many species of bacteria and they have different shapes and sizes nucleus cytoplasm 0.002mm a single bacterium 28 Aerobic and anaerobic bacteria Bacteria which need oxygen in order to respire are called aerobic bacteria. Aerobic bacteria are likely to be found in the air, water and soil where oxygen is available Bacteria which can respire without needing oxygen are called anaerobic bacteria Anaerobic bacteria are to be found in situations where oxygen is lacking, such as in stagnant water, waterlogged soils or the intestines of animals 30 Fermentation One form of anaerobic respiration in bacteria and yeasts is called fermentation. During fermentation, sugar is broken down to alcohol and carbon dioxide The reaction described in slide 25 is an example of fermentation Fermentation is involved in brewing and wine-making 29 Yeasts cell wall cytoplasm nucleus 0.005mm vacuole Yeast cells dividing single yeast cell 31 Wine making Grapes are crushed and the sugar they contain is fermented by yeasts to produce alcohol and carbon dioxide. The carbon dioxide usually escapes but if the wine is bottled before fermentation is complete, the carbon dioxide dissolves and escapes as bubble when the bottle is opened This is the case with ‘sparkling’ wines such as Champagne Different varieties of grape produce different types of wine 32 Black grapes growing in a vineyard © Ilan’s Wine Making Brewing In brewing beer, a sugary product (malt) is dissolved out of germinating barley Yeast is added to this solution and fermentation begins, producing alcohol and carbon dioxide Some of the carbon dioxide escapes but the rest dissolves in the beer when it is bottled or put into casks When the bottles or casks are opened, the dissolved CO2 escapes as bubbles 33 34 Beer fermenting ©Stuart Boreham/CEPHAS Baking In baking, yeast is added to a mixture of flour and water, made into the form of a dough The yeast first changes the flour starch into sugar and then ferments the sugar into alcohol and CO2 The CO2 forms bubbles in the dough which cause it to expand (‘rise’) When the dough is baked, the heat evaporates the alcohol but makes the trapped bubbles expand giving the bread a ‘light’ texture 35 Dough rising The yeast is mixed with the dough After 1 hour in a warm place the dough has risen as a result of the carbon dioxide produced by the yeast 36 37 The ‘holes’ in the bread are made by the carbon dioxide bubbles. This gives the bread a ‘light’ texture Question 1 Which statements are correct ? Anaerobic respiration is different from aerobic respiration because a it produces CO2 b it does not need glucose c it does not need oxygen d it produces less energy 38 Question 2 39 In what circumstances do our muscle use anaerobic respiration ? a When insufficient glucose reaches the muscles b When the carbon dioxide level increases c When insufficient oxygen reaches the muscles d When we are asleep 40 Question 3 Anaerobic bacteria are most likely to be found a in the middle of a compost heap b in the air c in fast-flowing streams d on the surface of the skin 41 Question 4 In which of the following is the production of CO2 more important than the production of alcohol ? a Brewing beer b Fermenting grape juice c Making bread d Bottling wine