Cellular respiration Aerobic Anaerobic

From Photosynthesis to Respiration Organic food molecules (sugars) are assembled during photosynthesis The energy stored in the molecular bond of the food is released through respiration Cellular Respiration: the process by which living organisms obtain energy from the bonds in food molecules

The equation Chemical Equation  6O2 + C3H12O6 reacts to form 6CO2 + 6H20 + 36ATP Word Equation  oxygen + glucose reacts to form carbon dioxide + water + energy How are Photo and CR related?  Both processes create a complete cycle - The products of photosynthesis are the reactants in cellular respiration – the products of cellular respiration are the reactants in photosynthesis

Adenosine triphosphate Compound that contains 2 high energy phosphate bonds and is an important source of energy for cells

ATP to ADP and back Start with ATP Break off a phosphate group Energy is released!! Now we have ADP Use energy to put a phosphate group back on Now we have ATP again. Repeat!!

2 types of respiration Aerobic Anaerobic Occurs: in the presence of oxygen Steps: Glycolysis Krebs Cycle Electron Transport Chain Occurs: in the absence of oxygen types: Lactic Acid Fermentation Alcoholic Fermentation

Cellular Respiration The goal of all cell respiration is to make energy from glucose There are 2 types of cell respiration AEROBIC respiration occurs when oxygenis present and makes a large amount of ATP ANAEROBIC occurs when oxygen is NOT present and makes a small amount of ATP

AEROBIC RESPIRATION = 3 stages glycolysis, Krebs Cycle, Electron Transport Chain

Glycolysis Where does this take place? What goes in, what comes out? Cytoplasm (cytosol) of the cell What goes in, what comes out? glucose goes in pyruvate comes out What actually happens? Glucose is converted into 2 pyruvate molecules This produces a small amount of ATP and Electron carriers (FADH2 and NADH) How many ATP?? 2 Video

Krebs Cycle (citric acid cycle) Where does this take place? Matrix of the mitochondria What goes in, what comes out? pyruvate goes in CO2 and Electron Carriers comes out What actually happens? Each pyruvate goes through the Krebs cycle (2 cycles) For each cycle, 3 CO2 are released along with 1 ATP and e- carriers One cycle for pyruvate releases a total of 6CO2 and 2 ATP for step 2 How many ATP?? 2 Video

Electron Transport Chain (ETC) Where does this take place? Along the inner membrane of the mitochondria What goes in, what comes out? Oxygen and Electron carriers goes in Water and ATP comes out What actually happens? E- carrier molecules bring electrons to the mitochondrion inner membrane. The electrons move through a series of reactions to produce a large amount of ATP, between 32 and 34 oxygen is the final electron acceptor and binds with hydrogen to form water How many ATP?? 32-34 (depending on efficiency) Video

Total ATP of Aerobic Respiration Glycolysis = Krebs = ETC = Total =

Anaerobic Respiration - Fermentation How do cells get energy if they run out of oxygen, or if there isn’t enough?

Anaerobic Respiration (fermentation) enables cells to make ATP in the absence of oxygen Not as efficient as aerobic respiration, but still produces ATP Anaerobic respiration is done by muscle cells, bacteria, microorganisms, and a few other types of cells

The Process Fermentation begins with glycolysis, just like aerobic respiration Glucose is broken down into pyruvate in the cytoplasm of the cell Pyruvate never enters the mitochondria Instead, pyruvate is broken down into something else Either lactic acid or ethyl alcohol (depending on the type of fermentation) Only results in 2 ATP molecules (vs 36 from aerobic respiration

2 types Lactic Acid Fermentation Alcoholic Fermentation Occurs in the muscle cells when they use Up all of the available oxygen Muscle cells feel fatigued and sore because the lactic acid forms when oxygen is not present. Examples: yogurt, cheese, pickles Equation: C6H12O6 + 602 ---- pyruvate ---- lactic acid ---- 2ATP Alcoholic Fermentation Occurs in yeast cells (which live in environments w/o oxygen) Yeast cells convert the sugar in dough first to pyruvate and then into ethyl alcohol and CO2 Examples:wine, beer, adding ethanol to gas Equation:C6H12O6 + 602 ---- pyruvate ---- ethanol + CO2 + 2ATP