© Boardworks Ltd 2004 1 of 29 Photosynthesis Respiration.

© Boardworks Ltd 20041 of 29

Photosynthesis

Respiration


All living organisms need food to grow and survive.

How do plants get the food they need?

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?


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?

Nutrition in green plants


Plants make their own food by photosynthesis.This process is a chemical reaction that uses light energy.

What is photosynthesis?

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?


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?

Photosynthesis: raw materials

carbondioxide

water


Photosynthesis is a chemical reaction between carbon dioxide and water.

Energy is needed for this reaction to take place.

Where do plants get this energy from?

Photosynthesis: energy for the reaction

carbondioxide

water

light energy


Plants use light energy from the Sun to power photosynthesis.

Where in the leaf does this reaction take place?

Photosynthesis takes place in what part of plant cells?

Photosynthesis: where it happens

carbondioxide

water

light energy


Photosynthesis takes place in plant cells with chloroplasts.

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?

Photosynthesis: where it happens

carbondioxide

water

light energy

chlorophyll


The products of the reaction between carbon dioxide and water are glucose and oxygen.

Which of these products is used by plants?

What happens to the ‘waste’ product?

Photosynthesis: products of the reaction

carbondioxide

water

glucose

oxygen

light energy

chlorophyll


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.

Oxygen is the ‘waste’ product. This gas is transported out of the leaf into the air.

Why is this important for humans and other living things?

Photosynthesis: products of the reaction

carbondioxide

water

oxygen

light energy

chlorophyll

glucose

oxygen

glucose


Photosynthesis: summary

Summarize the process of photosynthesis in one sentence.

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?

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: word equation

carbondioxide

water

oxygen

light energy

chlorophyll

glucose

glucose

light energy

chlorophyll

carbondioxide water oxygen


Photosynthesis: word equation activity


Word equation to chemical equation


Photosynthesis multiple-choice quiz


Energy for life

Every living cell in your body needs energy. The average adult has about 50 million million cells – that’s a lot of energy!

In body cells, the energy needed for life comes from the chemical energy stored in glucose. We eat to obtain energy from food (plants).

energy

Where does all this energy come from?


What is needed for releasing energy?

What other substance is needed for energy to be released from this fuel?

Burning is a chemical reaction in which energy is released in the form of heat.

?fuel oxygen


What does the body need for releasing energy?

The body’s energy-releasing process depends on the digestive system and the breathing system.

How does the body’s energy-releasing process compare with releasing energy from wood?

What are the substances supplied by these systems?

? ??glucose is the fuel

supplied by the digestive system

oxygenoxygen is supplied by

the breathing system


Glucose and oxygen enter the body in different ways,

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.

Transport around the body

but are needed at the same destinations.


In the body’s cells, the chemical energy stored in glucose is usually released by a chemical reaction with oxygen.

The body’s energy-releasing process

What is this energy-releasing process called?

glucoseoxygen

energy

respiration

Why does every living cell need a constant supply of glucose and oxygen?


Respiration is the process 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 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.

What is respiration?

aerobic = ‘with oxygen’


Waste products of aerobic respiration

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?

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


Aerobic respiration: summary

Summarize the process of aerobic respiration in a sentence.

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?

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: word equation

carbondioxideglucose oxygen water

carbondioxide

wateroxygenglucose

energy

energy


Aerobic respiration: word equation activity


Respiration is the process 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 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.

What is aerobic respiration?

aerobic = ‘with oxygen’


Photosynthesis and respiration

Only green plants photosynthesize,

glucose

light energy

chlorophyll

carbondioxide water oxygen

Compare the reactants, products and energy results of these two chemical reactions. How are they connected?

carbondioxideglucose oxygen water

Photosynthesis

Respiration

but respiration occurs in the cells of all living things to release energy.

(energy needed)

(energy released)


12 a.m. 12 p.m. 12 a.m.

Photosynthesis and respiration

How will the amounts of oxygen and carbon dioxide in the air vary over 24 hours?

What overall effect do photosynthesis and respiration have on the levels of oxygen and carbon dioxide in the air?

amount of gas

in the air

amount of oxygen

amount of carbon dioxide

© Boardworks Ltd 2004 1 of 29 Photosynthesis Respiration.

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Transcript of © Boardworks Ltd 2004 1 of 29 Photosynthesis Respiration.