Cellular respiration Chapter 3 section 4

Cellular Respiration When cells break down simple food molecules like glucose and release the energy they contain.

Energy Energy is stored in the molecules that make up food. When you eat you add to your storage. To use the energy, the molecules are broken down and released.

Two stages: 1. Glucose is broken into smaller molecules in the cytoplasm- a few energy rich molecules are created (glycolysis) 2. The small molecules enter the mitochondria and go through a series of chemical reactions using oxygen in which many energy molecules are created. (aerobic respiration)

Energy Rich Molecule Called ATP Adenosine Triphosphate This is the molecule created during cellular respiration Make ATP -> stores energy Break ATP apart releases energy

Chemical Equation C6H12O6 + 6 O2 6 CO2 + 6 H2O +energy Raw materials: glucose & oxygen Products: carbon dioxide, water & energy (ATP)

Comparing Respiration & Photosynthesis If you look at the chemical formulas, they are the opposite of each other. Photosynthesis provides the raw materials for respiration (glucose & O2), and respiration provides the raw material for photosynthesis (CO2 & H2O).

Cellular respiration is also called aerobic respiration because it can not occur without oxygen. If there was no oxygen present then it is called fermentation or anaerobic respiration (without oxygen)

If there is no oxygen present: The first stage in the cytoplasm happens the same way (glycolysis, splits the glucose in two) but then the molecules go through a process called fermentation instead of the second stage of respiration

Two Types of Fermentation Alcoholic fermentation Lactic acid fermentation

Alcoholic Fermentation Occurs when yeast and other single celled organisms break down sugar Produces ethyl alcohol, carbon dioxide and a small amount of energy Important for bakers and brewers, this is how bread rises and alcoholic drinks have bubbles

Lactic Acid Fermentation Takes place in your body when you are working your muscles so much that they are not getting enough oxygen Without enough oxygen lactic acid fermentation occurs to supply your muscles with needed ATP. A buildup of lactic acid in the muscles causes burning or soreness