Cellular Respiration the process of obtaining usable energy (ATP) from food

Respiration occurs in BOTH plants and animals. Respiration is how we, humans, have energy to walk, talk, run and think. With out respiration, we would not be alive because we would not have any energy for our body systems, such as the pumping of your heart and breathing. Plants need energy also- they need energy to grow and reproduce. Although they make glucose, they need to convert that into usable energy (ATP). Plants and Animals

The chemical reaction for respiration is... C 6 H 12 O 6 + O > CO 2 + H energy

These are the reactants

C 6 H 12 O 6 + O > CO 2 + H energy and these are the products.

It is the same as photosynthesis... but backwards! CO 2 + H energy  C 6 H 12 O 6 + O 2 C 6 H 12 O 6 + O > CO 2 + H energy Cellular Respiration: Photosynthesis:

C 6 H 12 O 6 + O > CO 2 + H energy In animals, the glucose comes from the food that they eat. In plants, it comes from the glucose they made in photosynthesis.

C 6 H 12 O 6 + O > CO 2 + H energy In animals, oxygen comes from the air they breathe into their lungs. In plants, the oxygen enters the leaf through the stomata.

C 6 H 12 O 6 + O > CO 2 + H ATP The equation can also be written in the following way. This equation specifically tells you the type of energy (ATP) and the amount made from one glucose molecule (38).

C 6 H 12 O 6 + O > CO 2 + H ATP Carbon Dioxide is expelled when an animal exhales Water is reabsorbed by the body

Autotrophs make carbohydrates like glucose using photosynthesis. Glucose contains energy stored in its bonds. Cellular Respiration breaks these bonds to release this stored energy. The released energy is transferred to ATP.

Glycolysis Cellular Aerobic Respiration has three steps: Glycolysis, Krebs Cycle and the Electron Transport Chain. Glycolysis occurs in the cytoplasm of the cell. During glycolysis, the glucose is taken and broken down into 2 pyruvates. 2 ATP molecules are produced. These pyruvates will be broken down in the following steps to make ATP. cytoplasm Glycolysis Glucose 2 pyruvates 2 ATP

Aerobic Respiration vs. Anaerobic Respiration If oxygen is present, aerobic respiration will occur and the pyruvates will go to the mitochondria to be made into ATP. If oxygen is NOT present, anaerobic respiration will occur. The pyruvates are not made into ATP, but another chemical depending if it is a plant or animal. Anaerobic respiration does not make as many ATP molecules as aerobic respiration and is less efficient. Glycolysis Glucose2 pyruvates Aerobic Respiration Anaerobic Respiration with oxygen without oxygen

The Mitochondria As stated earlier, if oxygen is present aerobic respiration will occur. The second step of aerobic respiration is the Krebs cycle. The Krebs Cycle occurs in the mitochondria. The inner and outer membrane which offers protection to the mitochondria. The cristae is a folded membrane where ATP production occurs. The more folds, means that more energy can be produced at a time. The matrix is the space in between the folds.

The Krebs Cycle During the Krebs Cycle the pyruvates are broken down even more. The carbon molecules in the pyruvate are “unfixed” and the gas CO 2 is produced as a waste product. Kreb’s Cycle pyruvates carbon dioxide CO O H3CH3C C C O O OH H3CH3C C C O O CO O CO O CO O

The Electron Transport Chain The third and final step of aerobic respiration is the Electron Transport Chain (ETC). During this step, oxygen is taken in and the majority of the 38 ATP is made. A by-product of water is also produced during the ETC. If oxygen is NOT present, the ETC can not occur and not many ATP are made. ETC oxygen water ATP O H H O O O O O H H

Summary Aerobic Respiration powers your muscles and creates all of the energy your cells need. When you use more energy, such as exercising, you breathe harder to get more oxygen so your body can make more ATP. Aerobic Respiration is summarized below. glucosecarbon dioxide oxygenwater ATP Glycolysis Kreb’s Cycle ETC But what happens if the cells do not get enough oxygen? oxygen

Anaerobic Respiration Anaerobic Respiration occurs when there is a lack of oxygen. This process still breaks down the pyruvates but does not make as much ATP as aerobic respiration. In plants, anaerobic respiration is called alcohol fermentation and in animals, anaerobic respiration is called lactic acid fermentation. glucose Glycolysis 2 pyruvatesAnaerobic Respiration NO oxygen in plants in animals Alcohol Fermentation Lactic Acid Fermentation

Lactic Acid fermentation often takes place in muscle cells. When you exercise, your cells are using oxygen to make ATP. When your body can not supply your muscles with enough oxygen, it begins lactic acid fermentation. Instead of making lots of ATP, your muscles make lactic acid. When lactic acid builds up in your muscles, they feel sore. To relieve this soreness you must wait for the lactic acid to diffuse out of the muscles and into the blood stream where it can be disposed of. It takes a couple of days to get rid of the lactic acid and during this time, you have sore muscles.

Alcoholic Fermentation Alcoholic fermentation takes place in plant cells. When a plant is deprived of oxygen, it begins to make ethanol, a type of alcohol. Different types of plants will produce different types of alcohols. Yeast cells, tiny fungi that live just about everywhere, also goes through alcoholic fermentation. Yeasts break down sugars anaerobically to meet their ATP needs. This also produces ethanol and CO2. In breweries, the yeast is used to make beer and in bakeries the yeast’s production of CO2 is used to make bread rise. In wineries, the yeast is used the ferment grape juice into wine. The yeasts eventually poison themselves in ethanol and die. If the bottle is sealed, the wine becomes champagne.