Cellular Respiration

Cellular Respiration Respiration is the process by which plant and animal cells get energy from glucose (sugar). The glucose came from? A product from photosynthesis in plants. During respiration cells break down simple food molecules such as sugar and release the energy that is contained. There are 2 stages just as in photosynthesis.

Respiration Stage 1 The first stage in the cytoplasm. There, molecules of glucose are broken down into smaller molecules. Oxygen is not involved, and only a small amount of energy is released.

Stage 2 The second stage of respiration happens in the mitochondria. There, the small sugar molecules are broken down into even smaller molecules. These chemical reactions require oxygen, and they release a great deal of energy. This is why the mitochondria are sometimes called the “powerhouses” of the cell.

Cellular Respiration Note that energy is released in both stages. Two other products of respiration are carbon dioxide and water. These products diffuse out of the cell going from the high concentration in the cell to the low concentration in the blood. In most animals, the carbon dioxide and some (not all) water leave the body during exhalation, or breathing out. So when you breathe in, you take in oxygen—a raw material for respiration. When you breathe out, you release carbon dioxide and water—products of respiration. These products become the raw materials of photosynthesis.

Cellular Respiration and Food

Cellular Respiration Notice that the raw materials/reactants for respiration are sugar and oxygen. Plants and other organisms that undergo photosynthesis make their own sugar. The glucose in the cells of animals and other organisms comes from the food they eat. The oxygen used in respiration comes from the air or water surrounding the organism. Resource: http://portageparkschool.net/apps/pages/index.jsp?uREC_ID=393583&type=u&termREC_ID=&pREC_ID=435520

Mitochondria Structure Mitochondria are shaped perfectly to maximize their productivity. They are made of two membranes (like chloroplasts). The outer membrane covers the organelle and contains it like a skin. The inner membrane folds over many times and creates layered structures called cristae.

Mitochondria Structure Cristae are the folds of the inner membrane. They are like booths in a restaurant allowing more seating. This means more energy can be produced. The fluid contained in the mitochondria is called the matrix. Video Clip

Respiration Equation C₆H₁₂O₆ + 6O2 6CO2 + 6H2O + energy

Comparing Photosynthesis and Respiration What do you notice about the equation for respiration? It is the opposite of the equation for photosynthesis.  During photosynthesis, carbon dioxide and water are used to produce sugars and oxygen. During respiration, the sugar glucose and oxygen are used to produce carbon dioxide and water.

Comparing Photosynthesis and Respiration Photosynthesis and respiration can be thought of as opposite processes. Together, these two processes form a cycle that keeps the levels of oxygen and carbon dioxide fairly constant in Earth’s atmosphere. Living things use both gases over and over again.

Respiration Raw Materials What are the raw materials of respiration? Glucose and oxygen Where does the glucose come from? Plants that animals eat Animals we eat that ate plants Where does the oxygen come from? A product of photosynthesis It leaves a plant through its stomata

Respiration Products What are the products of respiration? Carbon dioxide and water and energy Where does the carbon dioxide go? Into the air for plants to “breathe” in through their stomata Where does the water go? Into the water cycle to be absorbed by plant roots Where does the energy go? Used as fuel for plant and animal cells Burned while moving, breathing, eating, etc.

Don’t Forget!

Matter Cycle - Elements How do respiration and photosynthesis work together as a cycle?

Energy Cycle http://www.youtube.com/watch?v=hJFySkAi-ZA

Photosynthesis vs. Respiration Feature Photosynthesis Respiration Raw Materials Products Is energy required or released? Requirement of sunlight Fate of Carbon Dioxide and Oxygen Main Function Occurs in which organisms? Water and Carbon Dioxide Sugar (glucose) and Oxygen Sugar (glucose) and Oxygen Water and Carbon Dioxide Required Released Can only occur in presence of sunlight Occurs AT ALL TIMES without sun CO₂ is absorbed while O₂ is released O₂ is absorbed while CO₂ is released Production of food, capture of energy Breakdown of food, release of energy Plants, protista (algae), and some bacteria Occurs in ALL living organisms (plants AND animals)