CH7: Cellular Respiration pg 131

Cellular Respiration All living organisms go through cellular respiration. Series of chemical reactions to make ATP from glucose Equation for Photosynthesis 6CO2 + 6H2O + pigment + sunlight C6H12O6 + 6O2 Equation for Cellular Respiration C6H12O6 + O2 6 CO2 + 6H2O + ENERGY (ATP)

There are 2 scenarios Anaerobic Aerobic (with oxygen) Anaerobic (without oxygen) Anaerobic Glycolysis (only method for some prokaryotes) Occurs in cytoplasm Fermentation allows for this process to keep going 2 ATPs are made

Aerobic Respiration Occurs in the mitochondria Kreb’s cycle Electron Transport Chain

Glycolysis Series of chemical reactions that take place in the cytoplasm and does not need oxygen to work. In glycolysis, enzymes break down one of glucose into two pyruvate/pyruvic acid molecules. *Glue glycolysis illustration into notes

Glycolysis

Glycolysis, pg 133 Step 1, Breaking Down Glucose Glucose is converted back into 2 - G3P (3 carbon molecule).

Glycolysis Step 2 and Step 3, NADH and Pyruvate Each of the G3P go through a series of chemical reactions Converted into Pyruvate (pyruvic acid) 2 molecules NADH are created Important because NADH are Hydrogen ion/proton and e- carriers

Glycolysis Glycolysis produces 2 ATP without O2 it also produces 2 NADH, 2 Pyruvates

Fermentation (anaerobic process) pg 134 To make ATP during glycolysis, NAD+ is converted to NADH. Organisms must recycle NAD+ to continue making ATP through glycolysis. The process in which carbohydrates are broken down in the absence of oxygen is called fermentation. Beneficial because it allows glycolysis to continue supplying a cell with ATP in anaerobic conditions.

Pathway Reaction Lactic Acid Fermentation PYRUVIC ACID + NADH LACTIC ACID + NAD+ *occurs in muscle cells for short term energy production, also used in the production of foods ex. yogurt, Kim chi, sauerkraut Alcoholic Fermentation PYRUVIC ACID + NADH  ALCOHOL+ CO2 + NAD+ *occurs in yeast cells and is used in the production of beer, wine and bread

Two Types of Fermentation

Cellular Respiration illustration

Aerobic Respiration 1st stage is the Krebs cycle a series of reactions that produce electron carriers (NADH and FADH2) 2nd stage electron transport chain takes place in the inner membranes of mitochondria ATP synthase are located here Up to 36 ATP molecules can be produced from one glucose molecule in aerobic respiration.

Kreb’s Cycle Pyruvate (from glycolysis) is broken down and combined with other carbon compounds creating CoA. Releasing CO2 2 ATP, 6 NADH, and 2 FADH2

Electron Transport Chain Takes place in the inner membranes of mitochondria ATP synthase are located here NADH and FADH2 from the Krebs cycle transfer energy in the form of e- and H+ into the electron transport chain. e- are used to pump the H+ across the membrane to create a concentration gradient

Electron Transport Chain ATP Production Hydrogen ions diffuse through ATP synthase, providing energy to produce several ATP molecules from ADP.

The Role of Oxygen At the end of ETC If oxygen is not present, the e- combines with an oxygen atom and two hydrogen ions to form two water molecules. If oxygen is not present, the electron transport chain stops, because hydrogen has no where to go. the electron carriers are not recycled, so the Krebs cycle also stops

Summary Cellular Respiration Reactants Products Location Gycolysis Glucose, 2 ATP 2 Pyruvates, 2NADH, 4 (2) ATP Cytoplasm Krebs Cycle 2 AcetylCoA (CoA) CO2, 6NADH, 2FADH2 ,2ATP Matrix of Mitochondria ETC 6 NADH, 2FADH2, O2 34 ATP, H2O, 6NAD, 2FAD Inner Mitochondrial Membrane