Photosynthesis Respiration 1 of 29 Boardworks Ltd 2004

Photosynthesis Respiration 1 of 29 © Boardworks Ltd 2004

What is needed for photosynthesis? 2 of 29 © Boardworks Ltd 2004

How do plants get the food they need? All living organisms need food to grow and survive. Plants are known as producers because they provide food for many other organisms. Plants cannot move very much, so how do they get the food that they need? 3 of 29 © Boardworks Ltd 2004

Nutrition in green plants Green plants are amazing because they actually make their own food! Green plants are the only living organisms that are able to do this. All other organisms rely on plants because of the food that the plants make. What is the name of the process by which plants make their own food? 4 of 29 © Boardworks Ltd 2004

What is photosynthesis? Plants make their own food by photosynthesis. This process is a chemical reaction that uses light energy to produce chemical energy (in the form of glucose). light energy The word photosynthesis comes from the Greek language: “photo” means “light” “synthesis” means “putting together” Photosynthesis just means “putting together with light”. What do green plants “put together” to make their food? 5 of 29 © Boardworks Ltd 2004

Photosynthesis: raw materials The raw materials for photosynthesis come from the air and the soil. What are these raw materials called? What else do plants need to turn carbon dioxide and water into food? 6 of 29 carbon dioxide water © Boardworks Ltd 2004

Photosynthesis: energy for the reaction Photosynthesis is a chemical reaction between carbon dioxide and water. light energy Energy is needed for this reaction to take place. Where do plants get this energy from? carbon dioxide water 7 of 29 © Boardworks Ltd 2004

Photosynthesis: where it happens Plants use light energy from the Sun to power photosynthesis. light energy Where in the leaf does this reaction take place? Photosynthesis takes place in what part of plant cells? carbon dioxide water 8 of 29 © Boardworks Ltd 2004

Photosynthesis: where it happens Photosynthesis takes place in plant cells with chloroplasts. light energy Chloroplasts contain the green chemical called chlorophyll. Chlorophyll absorbs the energy from sunlight that allows carbon dioxide and water to react. What are the products of this reaction? 9 of 29 chlorophyll carbon dioxide water © Boardworks Ltd 2004

Photosynthesis: products of the reaction The products of the reaction between carbon dioxide and water are glucose and oxygen. light energy chlorophyll Which of these products is used by plants? What happens to the ‘waste’ product? carbon dioxide oxygen glucose water 10 of 29 © Boardworks Ltd 2004

Photosynthesis: products of the reaction Glucose is the useful product for plants. Some glucose is used straightaway by plant cells, some is converted to starch for storage and later used for food. light energy chlorophyll carbon Oxygen is the ‘waste’ dioxide product. This gas is transported out of the leaf into the air. Why is this important for humans and other living things? 11 of 29 oxygen glucose water © Boardworks Ltd 2004

What do plants use glucose for? What do plants do with the glucose made by photosynthesis? Some glucose is used straight away in cellular respiration - to release the energy they need glucose Some glucose is changed into starch for storage Some glucose is used to make proteins, sugars and fats 12 of 29 © Boardworks Ltd 2004

Photosynthesis: summary Summarize the process of photosynthesis in one sentence. Photosynthesis is a chemical reaction that takes place in the chloroplasts in green plant cells, where light energy is used to convert carbon dioxide and water into glucose and oxygen. Photosynthesis is a chemical reaction which means it can also be summarized in a word equation. What is the word equation for this vital chemical reaction? 13 of 29 © Boardworks Ltd 2004

Photosynthesis: word equation light energy carbon dioxide water glucose oxygen chlorophyll light energy chlorophyll carbon dioxide oxygen glucose water 14 of 29 © Boardworks Ltd 2004

Photosynthesis: word equation activity 15 of 29 © Boardworks Ltd 2004

Word equation to chemical equation 16 of 29 © Boardworks Ltd 2004

Photosynthesis multiple-choice quiz 17 of 29 © Boardworks Ltd 2004

Testing leaves for starch 18 of 29 © Boardworks Ltd 2004

Multiple-choice quiz 19 of 29 © Boardworks Ltd 2004

Anagrams 20 of 29 © Boardworks Ltd 2004

Parts of the chloroplasts • Thylakoid 21 of 29 • Stroma • Granum © Boardworks Ltd 2004

Two types of reactions in Photosynthesis • Light. Dependent • Light. Independent (also known as the Calvin cycle) 22 of 29 © Boardworks Ltd 2004

Light-Dependent Reactions • Occur in the thylakoid membrane. • Water and sunlight are needed. 1. Chlorophyll absorbs energy from sunlight, and this energy is transferred to molecules that carry energy, such as ATP and NADPH. 2. Water molecules are broken down by enzymes and oxygen is released. 23 of 29 © Boardworks Ltd 2004

Light-Dependent Reactions 24 of 29 © Boardworks Ltd 2004

Light-Independent Reactions (Calvin Cycle) • Occur in the stroma. • Carbon dioxide is needed. 3. Carbon dioxide enters the Calvin cycle. 4. Energy from the light-dependent reactions (carried by ATP and NADPH) is used to make glucose. 25 of 29 © Boardworks Ltd 2004

Light-Independent Reactions (Calvin Cycle) 26 of 29 © Boardworks Ltd 2004

To sum it all up: • The main function of the light-dependent reactions is to capture and transfer energy. • The main function of the light-independent reactions is to build sugars (glucose). 27 of 29 © Boardworks Ltd 2004

Energy for life Every living cell in your body needs energy. The average adult has about 50 million cells – that’s a lot of energy! energy Where does all this energy come from? 28 of 29 In body cells, the energy needed for life comes from the chemical energy stored in glucose. We eat to obtain energy from food (plants). © Boardworks Ltd 2004

What is needed for releasing energy? Burning is a chemical reaction in which energy is released in the form of heat. What other substance is needed for energy to be released from this fuel? fuel 29 of 29 oxygen ? © Boardworks Ltd 2004

What does the body need for releasing energy? The body’s energy-releasing process depends on the digestive system and the respiratory system. What are the substances supplied by these systems? glucose is the fuel supplied ? by the digestive system oxygen ? is supplied by the respiratory system How does the body’s energy-releasing process compare with releasing energy from wood? 30 of 29 © Boardworks Ltd 2004

Transport around the body Glucose and oxygen enter the body in different ways, but are needed at the same destinations. Where are these substances needed and how do they get there? Glucose and oxygen are transported around the body by the circulatory system. Blood flowing in blood vessels takes these important substances to where they are needed – the body’s cells. 31 of 29 © Boardworks Ltd 2004

The body’s energy-releasing process In the body’s cells, the chemical energy stored in glucose is usually released by a chemical reaction with oxygen. What is this energy-releasing process called? respiration glucose oxygen energy Why does every living cell need a constant supply of glucose and oxygen? 32 of 29 © Boardworks Ltd 2004

What is respiration? Respiration is the process that occurs in the mitochondria and used by the body’s cells to release the chemical energy stored in glucose. When oxygen is involved in this energy-releasing process, it is called aerobic respiration. What do you think aerobic means? aerobic = ‘with oxygen’ Aerobic respiration is an efficient process that generates enough energy to supply the whole body. Our bodies perform aerobic respiration most of the time, as long as the supply of oxygen remains high enough. 33 of 29 © Boardworks Ltd 2004

Aerobic respiration: summary Summarize the process of aerobic respiration in a sentence. Aerobic respiration is a chemical reaction that takes place in all living cells, in which glucose reacts with oxygen to produce carbon dioxide and water, and stored chemical energy is released. Aerobic respiration is a chemical reaction so it can also be summarized in a word equation. What is the word equation for this vital chemical reaction? 34 of 29 © Boardworks Ltd 2004

Aerobic respiration: word equation activity 35 of 29 © Boardworks Ltd 2004

Waste products of aerobic respiration Aerobic respiration releases energy that is useful. This process is a chemical reaction between glucose and oxygen which also generates waste products. glucose oxygen ? ? energy Breathing in obtains the oxygen needed for aerobic respiration. How does the body get rid of the waste products? Breathing out removes the waste products of aerobic respiration. How can the waste products of this reaction be identified? 36 of 29 © Boardworks Ltd 2004

Aerobic respiration: word equation glucose oxygen carbon dioxide water energy glucose oxygen 37 of 29 carbon dioxide water © Boardworks Ltd 2004

• Parts of cellular respiration (Glycolysis, anaerobic respiration, Aerobic respiration) – ATP numbers – NAD, FAD, etc. 38 of 29 © Boardworks Ltd 2004

Photosynthesis and respiration Only green plants photosynthesize, but respiration occurs in the cells of all living things to release energy. Photosynthesis (energy needed) light energy carbon dioxide water glucose oxygen chlorophyll Respiration (energy released) carbon glucose oxygen dioxide water Compare the reactants, products and energy results of these two chemical reactions. How are they connected? 39 of 29 © Boardworks Ltd 2004

Photosynthesis and respiration How will the amounts of oxygen and carbon dioxide in the air vary over 24 hours? amount of oxygen amount of gas in the air amount of carbon dioxide 12 a. m. 12 p. m. 12 a. m. What overall effect do photosynthesis and respiration have on the levels of oxygen and carbon dioxide in the air? 40 of 29 © Boardworks Ltd 2004