N-6 Cellular Respiration How do we get energy from food?

Let’s eat! Everyone knows that food provides energy. But not everyone knows how food provides energy. The food you eat does not provide your body with energy immediately after you eat it. First the food must pass through your digestive system where it is broken into small molecules. One of these molecules is glucose. Wait a minute….. doesn’t photosynthesis make glucose in plant cells?

Cellular Respiration During respiration, cells break down simple food molecules (like glucose) and release the energy they contain YOU MAY HAVE HEAR THE TERM “RESPIRATION” USED TO DESCRIBE AIR GOING IN AND OUT OF YOUR LUNGS – this is similar, not the same!!!!

Occurs in MITOCHONDRIA Mitochondria uses: Glucose Oxygen To do Cellular Respiration to produce: Carbon Dioxide Water Energy

Isn’t that the opposite of Photosynthesis? Sunlight (energy) Yes! Photosynthesis Carbon Dioxide + Water  Glucose + Oxygen Cellular Respiration Glucose + Oxygen  Carbon Dioxide + Water + Energy Photosynthesis and Cellular Respiration can be thought of as opposite reactions.

What if there isn’t enough Oxygen? – Anaerobic Respiration Some animals live in areas where there isn’t much oxygen. How do they get energy? The process of Fermentation provides energy for cells without using oxygen. This is MUCH LESS efficient that Cellular Respiration

Alcoholic Fermentation Some single celled organisms – plant, animal, or fungus – can produce a little energy without oxygen Glucose  Alcohol + Carbon Dioxide + Energy

Uses Bakers use yeast to create Carbon Dioxide so dough will rise – it creates the air pockets you see in bread. Most drinkable alcohols are created in the same way - the alcohol is produced by Fermentation.

Lactic-Acid Fermentation If you exercise long enough, your body will ‘run out of’ oxygen. No matter how hard you breathe, you cannot get enough oxygen for your cells to make energy. You will not be able to move anymore. Glucose  Lactic Acid + Carbon Dioxide + energy Because your cells lacked oxygen, Lactic Acid is formed. When it builds up in your body, you feel pain in your muscles.