unit 4 chapter 3 lessons 3 and 4 photosynthesis and cellular respiration
TRANSCRIPT
Unit 4Chapter 3 Lessons 3 and 4
PhotosynthesisAnd
Cellular Respiration
How Do Living Things Get Energy from the Sun?
• every living things needs energy-The Sun as an Energy Source
-photosynthesis- process by which a cell captures energy in the sunlight and uses it to make food.
-nearly all living things obtain energy either directly or indirectly from the energy of sunlight.-Producers and Consumers
• -autotroph/producers- organisms that make own food
-heterotroph/consumer- organism that cannot make own food
What Happens During Photosynthesis• During photosynthesis plants and some
organisms absorb energy from the sun and use energy to convert carbon dioxide(CO2) and water(H2O) into sugar
and oxygen.
Stage One: Capturing the Sun’s Energy-energy from the sun is captured by the leaves-chloroplasts are green organelles inside plant cell. The green color comes from pigment called chlorophyll-chlorophyll captures the energy in light and converts it to a form used later-water is split into hydrogen and oxygen. The oxygen is given off as a waste product. The hydrogen is used in stage 2.
Stage Two: Using Energy to Make Food-carbon dioxide is absorbed by small openings on bottom of leaf called stomata-sugar is produced by a series of chemical reactions between hydrogen and carbon dioxide. The sugar that is produced is glucose (C6H12O6)
-Oxygen is a waste product produced. It is released through the stomata.
The Photosynthesis Equation
-CO2 and H20 are the raw materials-glucose and oxygen are products-plants use the sugar for energy to carry out life’s functions, others are stored for later use
As summer ends and autumn comes, the days get shorter and shorter. This is how the trees "know" to begin getting ready for winter. During winter, there is not enough light or water for photosynthesis. The trees will rest, and live off the food they stored during the summer. They begin to shut down their food-making factories. The green chlorophyll disappears from the leaves. As the bright green fades away, we begin to see yellow and orange colors. Small amounts of these colors have been in the leaves all along. We just can't see them in the summer, because they are covered up by the green chlorophyll. The bright reds and purples we see in leaves are made mostly in the fall. In some trees, like maples, glucose is trapped in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn cause the leaves turn this glucose into a red color. The brown color of trees like oaks is made from wastes left in the leaves. It is the combination of all these things that make the beautiful colors we enjoy in the fall.
Photosynthesis
Producing FoodThe second stage of photosynthesis makes food for a plant. How can the information for Stage 1 and Stage 2 be completed?
Lesson 4
Cellular respiration
What Happens During Cellular Respiration?
• What is Cellular Respiration?-cellular respiration- process by which cells obtain energy from glucose-During cellular respiration, cells break down glucose and other molecules for food in the presence of oxygen, releasing energy.
• Storing and Releasing Energy-excess glucose is stored in the body. When energy is needed glucose is broken down through cellular respiration
• Breathing and Respiration-breathing brings oxygen to lungs which is carried to cells for cellular respiration.-breathing also removes the wastes products of cellular respiration.
The Two Stages of Cellular Respiration
• -First Stage-Occurs in the cytoplasm-glucose molecules are broken down in smaller molecules-oxygen is not involved and only a small amount of energy is released
-Second Stage-takes place in the mitochondria-molecules are broken down even smaller-requires oxygen and a great deal of energy is released
Cellular Respiration
Releasing EnergyCellular respiration takes place in two stages. What terms will complete the sentences?
The Cellular Process Equation
ATP= adenosine triphosphate (energy)
Cellular RespirationComplete the concept map about cellular respiration.
Cellular Respiration
Comparing Two Energy Processes• -Photosynthesis and Cellular Respiration can be
thought of as opposite processes.-Together they form a cycle that keeps oxygen levels and carbon dioxide levels fairly constant in Earth’s atmosphere.-both carbon dioxide and oxygen are used over and over-The energy released through cellular respiration is either used or lost as heat
•
Opposite ProcessesProducers carry out photosynthesis, but producers and consumers both carry out cellular respiration. Use the word bank to complete the blank boxes.
Cellular Respiration
What Happens During Fermentation
• -fermentation- energy releasing process that doesn’t require oxygen
• - one drawback is that far less energy is released than during cellular respiration
Alcoholic Fermentation
• -occurs in yeast and single celled organisms-produces alcohol, carbon dioxide, and small amount of energy
• -uses: yeast creates gas pockets in bread, causing the bread to rise. Source of bubbles in beer and wine
Lactic Acid Fermentation• -when the muscle cells are using oxygen faster than
it can be replaced, muscle gets energy by breaking down glucose without oxygen.-lactic acid is a product of this, causing pain and muscle soreness and weakness
Cellular Respiration
Energy for LifeEnergy processes in living things include photosynthesis, cellular respiration, and fermentation. How would you complete these statements?