Presentation on theme: "9C Plants and Photosynthesis"— Presentation transcript:
19C Plants and Photosynthesis KS3 Biology9C Plants and Photosynthesis
29C Plants and Photosynthesis Contents9C Plants and PhotosynthesisWhat is photosynthesis?Leaves and glucoseRoots and waterSummary activities
3How do plants grow?Many years ago people thought that plants ate soil and that made them grow.Think about it, if that really happened then there wouldn’t be any soil left!Plants actually grow by making their own food, not by eating soil!So where does the stuff that plants are made of come from?
4How do plants make their own food? One of the raw materials that plants need to make food does come from the soil, the other comes from the air.What are these two raw materials called?carbon dioxide(from the air)water(from the soil)Plants use carbon dioxide and water to make their own food in a chemical reaction. What is the name of this reaction?
5How do plants make their own food? Plants make their food from carbon dioxide and water in a chemical reaction called...photosynthesis.carbon dioxide(from the air)glucoseoxygenwater(from the soil)The food made by photosynthesis is the sugar glucose.Oxygen gas is also made as a by-product of photosynthesis.
6How do plants grow? light energy carbon dioxide (from the air) glucose Plants need energy for photosynthesis to take place.Where does this energy come from?light energycarbon dioxide(from the air)glucoseoxygenwater(from the soil)The energy for photosynthesis comes from the Sun.Where in a plant does photosynthesis take place?
7How do plants grow? light energy carbon dioxide (from the air) glucose Plant cells in the upper surface of leaves have chloroplasts which contain the green pigment called chlorophyll.light energycarbon dioxide(from the air)chlorophyllglucoseoxygenwater(from the soil)It is chlorophyll that absorbs light energy from the Sunto make photosynthesis happen.
8Photosynthesis summary Plants make their own food by the process of photosynthesis.In this chemical reaction, chlorophyll in plant cells absorbs light energy to change carbon dioxide and water into glucose and the by-product oxygen.What is the word equation for photosynthesis?light energycarbondioxidewaterglucoseoxygenchlorophyllThis equation can be read as:“carbon dioxide and water, in the presence of light energyand chlorophyll, produces glucose and oxygen”.
119C Plants and Photosynthesis Contents9C Plants and PhotosynthesisWhat is photosynthesis?Leaves and glucoseRoots and waterSummary activities
12How are leaves adapted?Leaves are small ‘factories’ that produce food for plantsby photosynthesis.Leaves are adapted so that photosynthesis can take place.Plants need carbon dioxide, water, sunlight and chlorophyll to carry out this important process.What features of leavesmake them suitable for photosynthesis?
13How are leaves adapted?The features of leaf that make it suitable for photosynthesis are:A leaf is broad and flat to capture lots of sunlight.carry water to the leaf and take food from the leafto the rest of the plant. Veinsalso help to support the leaf.Certain plant cells contain chloroplasts with chlorophyll.Small holes called stomata in the underside of a leaf allow gases in and out.Veins
15What do plants use glucose for? What do plants with the glucose made by photosynthesis?Some glucose is used straight away in respiration. Plants also carry out respiration torelease the energy they need for life processes.glucoseSome glucose is converted into starch and othersubstances for storage. These stores of energycan be used later when the plant needs them.Some glucose is used to make new chemicalssuch as proteins, sugars and fats that the plantalso needs to function properly.
179C Plants and Photosynthesis Contents9C Plants and PhotosynthesisWhat is photosynthesis?Leaves and glucoseRoots and waterSummary activities
18How does water enter a plant? Water is one of the raw materials needed for plants to carry out photosynthesis.How does water enter a plant?Water from the soil enters a plant through the roots.You can’t normally see them butroots are a very important part of a plant.Why are roots branched and spread out through the soil?
19How are roots adapted? water Roots are branched and spread out for two reasons:to absorb water (and mineral salts)from a large amount of soil.to anchor the plant in the soil.Taking a closer look, roots arecovered in root hair cells.Root hair cells have thin wallsand a large surface area to helpthem absorb lots of water.How are roots adapted to their job?water
20Why do plants need water? Water is needed by plants for photosynthesis but this important liquid is also used in many other ways:to provide dissolved minerals that keep the plants healthy;to transport substances around the plant;to keep the plant rigid and upright;to keep the plant cool;to allow other chemical reactions to occur in plant cells.What happens to a plant if it does not get enough water?
219C Plants and Photosynthesis Contents9C Plants and PhotosynthesisWhat is photosynthesis?Leaves and glucoseRoots and waterSummary activities
22chlorophyll – The green pigment inside chloroplasts Glossarychlorophyll – The green pigment inside chloroplaststhat plants need for photosynthesis to take place.chloroplast – The part of a plant cell where photosynthesis occurs.glucose – The sugar plants make during photosynthesis.palisade cell – A type leaf cell with lots of chloroplasts.photosynthesis – The process by which plants use carbon dioxide and water to produce glucose and oxygenin the presence of light and chlorophyll.starch – Extra glucose from photosynthesis is stored as this substance which can be tested for with iodine.stomata – Small holes in the lower surface of a leafthat allow gases in and out.xylem – Tubes in veins that carry water around a plant.