Cellular Respiration

Remember this:  Aerobic  Process that requires oxygen in order to take place  Anaerobic  Process that requires NO oxygen to take place.  Glycolysis  Process that splits glucose (6 carbon) into two 3 carbon molecules and makes 2 ATP. (this must take place before respiration can occur)

Cell Respiration  Chemical energy is released when sugar is broken down to make ATP and oxygen is present.  This process is almost a mirror image of photosynthesis.  This process also has 2 stages.  All this takes place in the mitochondria.

Stage 1  Known as the Krebs Cycle  This is going to produce energy molecules that are used in the 2 nd part of cell respiration. 1. The 3-carbon molecules from glycolysis are broken down. 2. Small amount of ATP is made (for stage 2) 3. Carbon dioxide is given off as a byproduct

Stage 2  Known as the Electron Transport Chain 1. Energy is transferred to here from Krebs Cycle. 2. Oxygen is taken in. 3. Lots of ATP are made. 4. Water and heat are given off as byproducts.

Fermentation Chapter 4.6

Glycolysis  This is where cells break apart 6 carbon sugars into 3 carbon sugars and makes 2 ATP.  This does NOT require oxygen  Anaerobic  This usually stops when oxygen appears.  Fermentation allows this to continue so it can make energy for the cells to use.

Fermentation  Normally you maintain oxygen levels, but when you do hard work, your body can’t keep up the oxygen levels.  This means you need a different energy source so you can still function.  We use fermentation to continue glycolysis for energy.

Fermentation  Comes in two different forms:  Lactic Acid Fermentation  Alcohol Fermentation  Both forms use NADPH as it’s energy source.  Remember: both of these are Anaerobic – They don’t need oxygen to work.

Lactic Acid Fermentation

1. Glycolysis makes ATP (used for energy elsewhere) and NADPH 2. Pyruvates (3 carbon molecules) are formed 3. Energy is added and Pyruvates become Lactic Acid.  This important byproduct is why your muscles hurt after you work them out.

Alcohol Fermentation

1. Glycolysis makes ATP (used for energy elsewhere) and NADPH 2. Pyruvates (3 carbon molecules) are formed 3. The pyruvates are broken apart and CO2 breaks off. 2 carbon molecule left behind Carbon molecule is alcohol.  This is why breads become “fluffy” with time.

Uses  Remember: Fermentation doesn’t make energy, glycolysis does. Fermentation just lets this continue.  Lactic acid fermentation – used for your muscles.  Alcohol fermentation – used for making breads, cheeses, digestive bacteria.