Chapter 9 – Respiration. Chapter 9 - Overview. 1. SUN. 2. LIGHT ENERGY. 3. PHOTOSYNTHESIS. 5. RESPIRATION. 6. ATP (CELL ENERGY). 4. CHEMICAL ENERGY. Energy Formation in Cells. Organic Compounds & Oxygen. ATP. Energy for Life. Carbon Dioxide & Water. ADP and P.
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Chapter 9 - Overview 1. SUN 2. LIGHT ENERGY 3. PHOTOSYNTHESIS 5. RESPIRATION 6. ATP (CELL ENERGY) 4. CHEMICAL ENERGY
Energy Formation in Cells Organic Compounds & Oxygen ATP Energy for Life Carbon Dioxide & Water ADP and P
What is Respiration? • The process of respiration is where organisms convert chemical energy into cellular energy, which is known as ATP.
Where does it occur? • In both autotrophs and heterotrophs that depend on chemical energy to make ATP. • The actual process occurs inside a cell’s cytoplasm and the mitochondria.
What does it need? • Carbohydrates, Sugars, Starches (C6H12O6) • Oxygen (O2)
What happens?(respiration equation) Carbon Dioxide ATP Carbohydrates C6H12O6 + 6O2 6CO2 + 6H2O + ENERGY Oxygen Water
How does this happen? • The process of respiration is divided into different stages depending on whether or not oxygen is present. • When oxygen is present more ATP can be made (up to 20 times more).
How does this happen? • Respiration that uses oxygen is called aerobic. • Respiration that does not use oxygen is called anaerobic or fermentation.
Stage 1 - Glycolysis • A 6-carbon molecule of glucose is separated into two 3-carbon pyruvate molecules and makes some ATP and NADH. • This process occurs in 4 steps that take place in the cytoplasm and does not requireoxygen to be present.
Step 1 • Two ATP phosphates are attached to a molecule of glucose to form a new 6-carbon compound.
Step 2 • The 6-carbon compound is split into two 3-carbon compounds each with a phosphate each (PGAL).
Step 3 • A second phosphate is added to each PGAL, this time it comes from NAD+ creating 2 NADHs.
Step 4 • All of the phosphates are removed to produce 2 molecules of Pyruvic Acid. • Each removed phosphate combines with a molecule of ADP to make an ATP.
Glycolysis Summary • 2 ATP were used to start the process. • 4 ATP were produced from this process. • This gives a total net yield of 2 ATP.
A. Aerobic Respiration • If oxygen is present the pyruvic acid produced during glycolysis continues on to aerobic respiration. • Aerobic respiration takes place within the mitochondria.
How does it work? • Aerobic Respiration has 2 stages: • Krebs Cycle • Electron Transport Chain
i) Krebs Cycle - Step 1 • Acetyl-CoA combines with Oxaloacetic acid to form Citric acid and releases coenzyme A .
i) Krebs Cycle - Step 2 • Carbon Dioxide (CO2) is released from citric acid forming a 5-carbon compound. • Electrons are transferred to NAD+ making a molecule of NADH.
i) Krebs Cycle - Step 3 • A CO2 is released from the 5-carbon compound forming a 4-carbon compound and electrons are again transferred to NAD+ making a NADH. • Also a molecule of ATP is produced.
i) Krebs Cycle – Step 4 • The 4-carbon compound is changed to a new 4-carbon compound and FAD is converted to FADH2.
i) Krebs Cycle – Step 5 • The new 4-carbon compound is converted to the original Oxaloacetic acid that began the cycle. • This produces another NADH.
ii) Electron Transport Chain – Step 1 • Electrons donated by NADH and FADH2 pass through the electron transport chain. • The energy from these electrons pumps hydrogen out of the inner mitochondria.
ii) Electron Transport Chain – Step 2 • Hydrogen builds up outside and creates a concentration gradient. • Hydrogen diffuses back to the inside by passing through carrier proteins, which add a phosphate to ADP creating more ATP.
ii) Electron Transport Chain – Step 3 • Hydrogen that reenters the mitochondria combines with used up electrons and oxygen to form water (H2O).
B. Anaerobic Respiration • If oxygen is not present the pyruvate produced during glycolysis continues on to anaerobic respiration. • Anaerobic respiration takes place in the cytoplasm.
How does it work? • Anaerobic Respiration has 2 types: • Lactic Acid Fermentation • Alcoholic Fermentation
i) Lactic Acid Fermentation • Pyruvate is changed to lactate by removing two hydrogen. • This process is by bacteria and fungi to produce foods like yogurt and cheese. • Also used by muscle cells when oxygen is not present (called lactic acid build up.)
ii) Alcoholic Fermentation • Pyruvate is changed to Ethyl Alcohol by first removing CO2 and then 2 hydrogen. • This process is used by yeast to prepare many foods and beverages. • The release of CO2 causes dough to rise.
Aerobic versus Anaerobic • The total amount of energy that a cell can harvest depends on the presence or absence of oxygen. • Aerobic (with oxygen) gains 36 ATP. • Anaerobic (without oxygen) gains 2 ATP.
Any Questions? • “Education is our passport to the future, for tomorrow belongs to the people who prepare for it today.”--Malcolm X • “Living on Earth is expensive, but it does include a free trip around the sun every year.” --Unknown