Cellular Respiration Chapter 9
1.A)Explain where organisms get the energy needed for life processes. Organisms get the energy they need from food. Energy stored in food is expressed as calories. Calorie amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. 1000 calories = 1 kilocalorie, or Calorie. Cells use all sorts of molecules for food: fats, proteins, and carbohydrates. each of these molecules varies because their chemical structures therefore their energy-storing bonds, differ. Cells break down food molecules gradually use the energy stored in the chemical bonds to produce compounds ATP powers activities of the cell
1B)Define cellular respiration. 1C)What is the equation for cellular respiration? Cellular Respiration process in which cells form ATP by breaking down organic compounds Equation for cellular Respiration: 6 O 2 + C 6 H 12 O 6 6 CO 2 + 6 H 2 O + Energy Oxygen + Glucose Carbon dioxide + Water + Energy Why does it have to be broken down this way? cells have to release the chemical energy in food molecules (like glucose) gradually otherwise most of the energy would be lost in the form of heat and light.
1D)What does aerobic and anaerobic mean? Anaerobic no oxygen Aerobic uses Oxygen!
1E) Explain the structure and function of the mitochondrion parts. Outer membrane Allows ions, nutrient molecules, ADP and ATP to pass through Inner Membrane Allows O 2, H 2 O and CO 2 to pass through freely Contained with in the inner membrane: ETC Matrix ATP Synthase Transport proteins Cristae- folds that increase the surface area Contains the enzymes for the Krebs Cycle Contains the H gradient for ATP creation
2A) What happens during the process of glycolysis? http://www.youtube.com/watch?v=3z6dq-t68zs&list=rdsblpt7syh6s Glycolysis (glucose oxidized to produce pyruvic acid) (LEO) 1. occurs in cytoplasm 2. 2 ATP (activation energy) used to form new 6C compound 3. 6C compound split into 2 PGAL (3C) 4. PGAL oxidized 4H removed - joined to coenzyme NAD+ - 2 NADH + 2H formed 5. 4 phosphates removed - joined to ADP to form 4 ATP now have 2 pyruvic acids (3C) C 3 H 4 O 3 (Molecular formula)` 6. net yield of 2 ATP
2B)Explain the differences between lactic acid and alcoholic fermentation. Fermentation (further convert pyruvic acid) (NO OXYGEN) 1. Lactic acid fermentation (occurs in muscle cells) (certain bacteria) a) strenuous exercise uses up O 2 faster than can be resupplied and H accumulates (NAD not available for glycolysis) b) pyruvic acid becomes electron (H) acceptor and is converted to lactic acid (NADH oxidized) c) regenerates NAD+ so glycolysis can continue d) lactic acid accumulates in muscles increased acidity causes less contraction, fatigue, pain, cramps ( increase acid, decrease muscle contractions) diffuses into blood to liver - converted to pyruvic acid when O 2 available http://www.youtube.com/watch?v=dgq94gpkebg
2B)Explain the differences between lactic acid and alcoholic fermentation. 2. Alcoholic fermentation Examples: beer, wine, bread Organisms: bacteria, yeast a. CO 2 removed from pyruvic acid and H added from NADH + H to form ethyl alcohol (C 2 H 5 OH) b. NAD+ regenerated for glycolysis c. alcohol has much energy (can be used as a fuel) http://www.youtube.com/watch?v=4sospuwag7g
2C.)Identify and explain the pathways the body uses to release energy during exercise. How does the body produce ATP during different stages of exercise? For short, quick bursts of energy the body uses ATP already in muscles as well as ATP made by lactic acid fermentation. extra oxygen is required to get rid of the lactic acid produced. For exercise longer than about 90 seconds cellular respiration is the only way to continue generating a supply of ATP. intense exercise, a person will huff and puff for several minutes in order to pay back the built-up oxygen debt and clear the lactic acid from the body. body stores energy in the form of the glycogen (carbohydrate) glycogen stores enough to last for 15 to 20 minutes of activity. After that, the body breaks down other stored molecules, like fats for energy.
Aerobic Respiration Aerobic Respiration Requires oxygen Occurs in the mitochondria Steps of Aerobic Respiration: 1. Glycolysis 2. Forming acetyl CoA 3. Krebs cycle 4. ETC (Electron Transport Chain)
3A)Explain how acetyl CoA is formed. Forming Acetyl Coenzyme A 1. pyruvic acid enters mitochondrial matrix http://science.howstuffworks.com/ life/29543-assignment-discoverycellular-respiration-video.htm 2. CO 2 removed from 3C pyruvic acid 2C acetyl group 3. Coenzyme A joins to 2C acetyl forming acetyl CoA (oxidized) 4. 2H released and NAD+ reduced to NADH TOTAL For 2 pyruvic acids or 1 glucose molecule: 2 CO 2 removed 4H removed(2 NADH formed + 2H) 2 H 2 O used
3B.)Describe the stages and the products of the Krebs cycle. Krebs Cycle: Citric Acid Cycle 1. 2C acetyl CoA attaches to 4C oxaloacetic acid to produce citric acid (6C-C 6 H 8 O 7 )- CoA released 2. During 1 cycle: (1 pyruvic acid) a. 2 CO 2 removed b. series of oxidations removes 8H (6H form 3NADH + 3H and 2H form 1FADH 2 ) c. 1 ATP formed d. 2 H 2 O used TOTAL 2 turns of cycle because there are 2 pyruvic acids or 1 glucose molecule so: 4 CO 2 removed 16H removed (12 H form 6 NADH + 6H and 4H form 2FADH 2 ) 2 ATP formed 4 H 2 O used
3C)Explain how high energy electrons are used by the electron transport chain. Electron Transport Chain (on cristae) animation 1. much energy in electrons held by 10 NADH 2 and 2 FADH 2 2. electrons from 24H move down series of coenzymes and energy from them produces 34 ATP each pair of H from NADH yields 3 ATP (10 NADH = 30) each pair from FADH 2 yields 2 ATP (2 FADH 2 = 4) 3. role of oxygen is final acceptor of electrons (chain keeps operating and forming ATP) a. also accepts protons (H+) O 2 + 4e- + 4H+ 6O 2 + 24e- + 24H+ 2H 2 O 12H 2 O 6H 2 O used in previous steps so net of 6H 2 O
3D)How many molecules of ATP are produced in the entire breakdown of glucose? Where is the ENERGY made? Glycolysis = 4 ATP Kreb= 2 ATP ETC= 34 ATP 40 ATP Formed (2 used in Glycolysis) 38 ATP net yield http://www.mhhe.com/biosci/bio_animations/m H01_CellularRespiration_Web/index.html http://www.youtube.com/watch?v=3azrkdzrd04& list=rdsblpt7syh6s
3E) Compare and contrast the difference between aerobic and anaerobic respiration Anaerobic No O2 required Occurs in the cytoplasm only Called Fermentation Only produces Max. 2 ATP Less efficient Produces alcohol using Prokaryotes Produces lactic acid in eukaryotes Similarities Break down glucose Go through glycolysis Requies glucose Produces Energy involves pyruvic acid Both continuous process Makes at least 2 ATP Use 2 ATP Aerobic Requires O2 Occurs in cytoplasm and mitochondria Steps: forming acetyl coa, Krebs cycle, and ETC Produces 38ATP Efficient Performed by Eukaryotes
3F) What is the relationship between photosynthesis and cellular respiration? Photosynthesis products of P.S. endergonic occurs in chloroplasts stores energy light energy is converted into chemical energy in bonds of carbohydrates occurs in the light autotrophs do it Cellular Respiration are reactants of cell respiration Exergonic occurs in mitochondria releases energy chemical energy from carbohydrate bonds is released and used to make ATP occurs in light and dark autotrophs and heterotrophs do it