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Plants and photosynthesis
 

Plants and photosynthesis

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  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation Teacher notes The oxygen from this process formed the ozone layer which now protects us from the harmful rays of the sun.
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Teacher notes Plants and Photosynthesis Worksheet 1 accompanies this slide. This worksheet could alternatively be used alongside a practical. The second part of the worksheet could be given to higher level students to investigate photosynthesis further.
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Teacher notes Plants and Photosynthesis worksheet 2 accompanies this slide. Correct answers for the table: plant 1 - potassium plant 2 - phosphorus plant 3 - potassium plant 4 - nitrogen
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation Teacher notes Students may have heard of the term pesticide. It might be helpful to explain that a pesticide is any substance that provides plants with protection against harmful organism. So this will include insecticide, herbicide and any substance used to kill mammalian pests.
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis Photo credit: Jupiterimages Corporation
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis chlorophyll – The green pigment inside chloroplasts that plants need for photosynthesis to take place. chloroplast – The part of a plant cell where photosynthesis occurs. competition – The demand by two or more organisms for limited shared resources, such as nutrients, space or light. crop – A plant that is grown for food or other products. fertilizer – A chemical that is added to soil to provide plants with the minerals needed for healthy growth. glucose – The sugar plants make during photosynthesis. herbicide – A chemical used to kill weeds. insecticide – A chemical used to kill insects. organic – An alternative farming method that involves fewer artificial chemicals. palisade cell – A type of leaf cell with lots of chloroplasts. pest – An animal that damages crops and competes with humans for food. photosynthesis – The process by which plants use carbon dioxide and water to produce glucose and oxygen in 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 leaf that allow gases in and out. toxin – A poisonous chemical. weed – A plant growing in the wrong place that competes with a crop.
  • Boardworks KS3 Science 2008 Plants and Photosynthesis
  • Boardworks KS3 Science 2008 Plants and Photosynthesis

Plants and photosynthesis Plants and photosynthesis Presentation Transcript

  • Plants and photosynthesis1 of 47 © Boardworks Ltd 2008
  • What is photosynthesis?2 of 47 © Boardworks Ltd 2008
  • How do plants grow?Many years ago, peoplethought that plants ate soiland that made them grow.But think about it, if thatreally happened then therewouldn’t be any soil left!Plants actually grow bymaking their own food,not by eating soil.So where does the stuffthat plants are made ofcome from? 3 of 47 © Boardworks Ltd 2008
  • How do plants make their own food?One of the raw materials that plants need to make fooddoes come from the soil, the other comes from the air.What are these two raw materials? carbon dioxide (from the air) water (from the soil)Plants use carbon dioxide and water to make their own foodin a chemical reaction. What is the name of this reaction? 4 of 47 © Boardworks Ltd 2008
  • What is the name of the process?Plants make their food from carbon dioxide and water ina chemical reaction called photosynthesis.The food made by photosynthesis is the sugar, glucose. carbon dioxide (from the air) glucose water (from the soil) oxygenOxygen gas is also made as a by-product of photosynthesis. 5 of 47 © Boardworks Ltd 2008
  • Where does the energy come from?Plants need energy for photosynthesis to take place.The energy for photosynthesis comes from the Sun. carbon dioxide (from the air) glucose water (from the soil) oxygenWhere in a plant does photosynthesis take place? 6 of 47 © Boardworks Ltd 2008
  • Where does photosynthesis happen?Plant cells in the upper surface of leaves have chloroplastswhich contain the green pigment called chlorophyll. chlorophyll carbon dioxide (from the air) glucose water (from the soil) oxygenIt is chlorophyll, which absorbs light energy from theSun, that enables plants to carry out photosynthesis. 7 of 47 © Boardworks Ltd 2008
  • What is the equation?Plants make their own food through photosynthesis.In this chemical reaction, chlorophyll in plant cells absorbslight energy to change carbon dioxide and water intoglucose and the by-product oxygen.What is the word equation for photosynthesis? light energy carbon dioxide + water glucose + oxygen chlorophyllThis equation can be read as:“Carbon dioxide and water, in the presence of light energyand chlorophyll, react to form glucose and oxygen”. 8 of 47 © Boardworks Ltd 2008
  • What is needed for photosynthesis? 9 of 47 © Boardworks Ltd 2008
  • What is the word equation? 10 of 47 © Boardworks Ltd 2008
  • Photosynthesis and the atmosphereBefore plants the atmospherewas mainly made up of carbondioxide and water vapour.Gradually carbon dioxide wasconverted into oxygen asphotosynthesis in plants andalgae evolved.The increased level of oxygenslowly made the planet moresuitable for other forms of life. 11 of 47 © Boardworks Ltd 2008
  • Leaves and glucose12 of 47 © Boardworks Ltd 2008
  • How are leaves adapted?Leaves can be thought of as small ‘factories’ that producefood for plants by 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 leaves make them suitable for photosynthesis? 13 of 47 © Boardworks Ltd 2008
  • What are the useful features of leaves?Leaves often have many features that make them suitablefor photosynthesis, including: A leaf is broad and flat to capture lots of sunlight. Veins carry water to the leaf and take food from the leaf to the rest of the plant. Veins also help to support the leaf. Certain plant cells contain chloroplasts filled with chlorophyll. Small holes called stomata in the underside of a leaf allow gases in and out. 14 of 47 © Boardworks Ltd 2008
  • Inside a leaf 15 of 47 © Boardworks Ltd 2008
  • What do plants use glucose for? 16 of 47 © Boardworks Ltd 2008
  • Testing leaves for starch 17 of 47 © Boardworks Ltd 2008
  • Does light affect photosynthesis? 18 of 47 © Boardworks Ltd 2008
  • Photosynthesis 19 of 47 © Boardworks Ltd 2008
  • Photosynthesis 20 of 47 © Boardworks Ltd 2008
  • Roots and water21 of 47 © Boardworks Ltd 2008
  • How does water enter a plant?Water is one of the raw materialsneeded for plants to carry outphotosynthesis.How does water enter a plant?Water from the soil enters a plantthrough the roots.You can’t normally see them but rootsare a very important part of a plant.Why are roots branched and spread out through the soil? 22 of 47 © Boardworks Ltd 2008
  • How are roots adapted?Roots are branched and spread out fortwo 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 tohelp them absorb lots of water.How are roots adapted to their job? 23 of 47 © Boardworks Ltd 2008
  • Why do plants need water?Water is needed by plants for photosynthesis but thisimportant liquid is also used in many other ways: to provide dissolved minerals that keep the plant 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? 24 of 47 © Boardworks Ltd 2008
  • 25 of 47 © Boardworks Ltd 2008
  • Humans in food chainsHumans eat many different foods andso are at the top of many food chains.What are the food chains for theingredients in a slice of pizza? tomato human onion human wheat human (bread) cow’s milk grass human (cheese) 26 of 47 © Boardworks Ltd 2008
  • Plants as producersAll food chains start with a producer.Plants are called producers because they produce thefood that humans and all other consumers depend on.How do plants make their food?Plants use light energy to carry out photosynthesis: light energy carbon dioxide + water glucose + oxygen chlorophyllThe glucose produced by plants is converted into starch forstorage or used to make proteins, fats and other substances.Which parts of plants can be eaten? 27 of 47 © Boardworks Ltd 2008
  • Food from plantsPlants provide food in many different forms – some foodsare the leaf, the stem or the root of a plant, others are theseed or the fruit.Which plant parts are these foods from? 28 of 47 © Boardworks Ltd 2008
  • Food from plants 29 of 47 © Boardworks Ltd 2008
  • Other uses of plantsPlant material can be used to make other products, including: drugs – medicines, such as aspirin, are made from plants. construction – wood is an important building material for houses and furniture. clothing – materials, such as cotton, are made from plants. Some dyes are also made from plant extracts. paper – wood pulp is used to make paper. 30 of 47 © Boardworks Ltd 2008
  • 31 of 47 © Boardworks Ltd 2008
  • Healthy plant growthPlants need carbon dioxide and water for photosynthesis,but they also need small amounts of mineral salts forhealthy growth.Where do plants get mineral salts from?Minerals are dissolved in water in the soil and so plantsabsorb these nutrients in the water they take in from the soil.The three main elements in mineral salts are: nitrogen (N) – needed for healthy leaves phosphorus (P) – needed for healthy roots potassium (K) – needed for healthy flowers and fruit. 32 of 47 © Boardworks Ltd 2008
  • Healthy plant growthWhat happens when plants use up all the minerals in thesoil, what do they look like? low low low low phosphorous potassium magnesium nitrogenCan you explain why potted plants often look sickly? 33 of 47 © Boardworks Ltd 2008
  • Healthy plant growth 34 of 47 © Boardworks Ltd 2008
  • Fertilizers and plant growthPlants take in mineral salts from the soil and over timethere are fewer nutrients available in the soil.Farmers and gardeners often addmanure or chemicals, called fertilizers, tosoil to make sure that their crops getenough mineral salts.Manufactured fertilizers help crops to growwell and so increase the farmer’s cropyield, but they can be very expensive.If fertilizers aren’t used responsibly they canrun into rivers, causing water pollution. 35 of 47 © Boardworks Ltd 2008
  • Competition between plantsOrganisms that share ahabitat have to competewith each other for limitedliving resources.A weed is any plant that isgrowing in the wrong place.Weeds are a problem forfarmers as they competewith the crops for resourcessuch as light, water, livingspace and mineral salts.How does competition affect the growth of crops? 36 of 47 © Boardworks Ltd 2008
  • Controlling weedsWeeds compete with crops for living resources and this canreduce crop yield. What can farmers do to control weeds?One way farmers can controlweeds is to use chemicalscalled herbicides (orweedkillers).Weeds are part of the foodweb. How might usingherbicides affect otherorganisms in the food web? 37 of 47 © Boardworks Ltd 2008
  • Types of herbicidesNon-selective herbicides kill most of the plants that they aresprayed on. This type of herbicide can be used to clearlarge patches of ground.Selective herbicides only kill specific types of plants.Many of the weeds that are killed using herbicides areimportant sources of food or shelter for consumers likeinsects and butterflies.As the number of weedsdecline, competition betweenthe consumers increases.Is this thistle a weed to a farmer? 38 of 47 © Boardworks Ltd 2008
  • Controlling insectsInsects can cause a huge amount of damage to crops. Theyare thought of as pests as they compete with humans for food.One way farmers can controlinsects is to use chemicals calledinsecticides. Insecticides can killthe adult insect or prevent insectlarvae hatching.However, nearly all types ofinsecticides can cause damageto local ecosystems and manyare toxic to humans. 39 of 47 © Boardworks Ltd 2008
  • Alternative farming methodsOrganic farming is an alternative farming method. It isthought that this method may have less impact on theenvironment as fewer artificial chemicals are used. Artificial fertilizers can be replaced with natural fertilizers and crop rotation to keep the soil rich in nutrients.  As an alternative to insecticides farmers may encourage the insects’ natural predators, such as birds and other insects, to feed on them.  Instead of using herbicides weeds are removed by hand or mechanically. 40 of 47 © Boardworks Ltd 2008
  • The pros and cons of organic farmingThere are both advantages and disadvantages of organicfarming.Using fewer artificial chemicals may decrease the risk of toxicsubstances remaining on food and could reduce the impactfarming has on the environment.However, organic farmingis more labour-intensive andmay result in a lower yield.This means that organicfarming requires more labourand space, making organicfood more expensive. 41 of 47 © Boardworks Ltd 2008
  • Organic food 42 of 47 © Boardworks Ltd 2008
  • Which chemical? 43 of 47 © Boardworks Ltd 2008
  • Summary activities44 of 47 © Boardworks Ltd 2008
  • Glossary 45 of 47 © Boardworks Ltd 2008
  • Anagrams 46 of 47 © Boardworks Ltd 2008
  • Multiple-choice quiz 47 of 47 © Boardworks Ltd 2008