Mitochondria: Respiration Coulter

What is respiration? Cells break down simple food molecules such as sugar and release the energy they contain. Energy captured during photosynthesis from sunlight is saved in the form of carbohydrates (sugars/starches). When they are eaten by a heterotroph they add energy to the body. respiration: respiration in cells is called cellular respiration .

Two stages of cellular respiration First stage takes place in the cytoplasm. Molecules of glucose are broken down into smaller molecules. Oxygen is not involved only a small amount of energy is released.

Stage two: respiration Takes place in the mitochondria “organelle”. Small molecules are broken down into even smaller molecules. These chemical reactions require oxygen they release a great deal of energy. Mitochondria= ##@###powerhouse!!

Respiration equation C6H12O6 ++++++++ 6O2 -- 6CO2 + 6H2O + energy Sugar + oxygen - carbon dioxide + water Notice that the raw materials for respiration are sugar and oxygen. Plants and other organisms that undergo photosynthesis make their own sugar. Glucose in cells of animals comes from the food they eat. Oxygen comes from the air or water surrounding the organism.

Comparing respiration and photosynthesis Did you notice any similarities between respirations equation and photosynthesis’ equation? These two processes form a cycle that keeps levels of oxygen and carbon dioxide fairly constant in Earth’s atmosphere.

fermentation Provides energy for cells without using oxygen. Some single-celled organisms live where there is no oxygen, such as deep in the ocean or in the mud of lakes or swamps. The amount of energy released from each sugar molecule is much lower than the amount during respiration.

Alcohol fermentation This type of fermentation occurs when yeast and some other single-celled organisms break down sugars. This process is referred to as alcohol fermentation because alcohol is one of the products. This fermentation is important to bakers and brewers. CO2 produced by yeast creates pockets in bread dough, causing it to rise. CO2 also the source of bubbles in drinks.

Lactic acid fermentation Think about a time when you ran as hard as you could for as long as you could. Your breathing was rapid, but no matter how fast your breathe your muscles used more oxygen then you could bring in. Because your cells lacked oxygen, fermentation occurred. Fermentation supplied your cells with the energy needed to go on. The product of this fermentation is an acid known as lactic acid. When lactic acid builds up you feel pain, sore, and weakness.