hey guys in this video there are loads of short sharp quickfire questions that will help you with your in Excel IGCC plant physiology if you want to copy these questions so you can fill in your answers as we going along then you can get that from the free written guide which you can download for website or you can get abs in to print it out for you what is the word equation for photosynthesis the plants take in carbon dioxide and water and they make glucose and oxygen what is the chemical symbol for carbon dioxide it is co2 Big C Big O and little - what is the chemical symbol for water big H for hydrogen two of those and an oxygen what is the chemical symbol for oxygen gas Big O little - what is the chemical symbol for glucose c6h12o6 what is the balanced symbol equation for photosynthesis well you've got carbon dioxide and water giving you glucose and oxygen in order to balance it just remember that the molecules without a six in it get a six in front of it like that how is energy transferred in photosynthesis energies transferred from the Sun lighter absorbed by chlorophyll to create glucose in the cell what factors might affect photosynthesis you've got three main ones light intensity temperature and carbon dioxide concentration how does temperature affect photosynthesis the lower the temperature the slower the rate of photosynthesis up to the optimal level the optimal temperature once the optimal temperature is reached of course the rate of reaction Falls quickly downwards as the temperature increases because too high a temperature denatures enzymes and further synthesis stops all right how does light intensity affect photosynthesis light intensity again is that higher the light intensity eat faster the rate of photosynthesis again up to optimal level at optimal light intensity within the reaction plateaus how does carbon dioxide concentration affect photosynthesis the higher the concentration carbon dioxide the faster the rate of photosynthesis up to the optimal where the reaction plateaus now all you need to remember is that lower slower the higher it is the faster it goes the higher is the faster it goes so you sketch a graph to show how light intensity affects photosynthesis light intensity is the amount of light shining on the leaf during the day when the sun is shining what happens is the graph light intensity and this is rate of photosynthesis now during the day as the rate of photosynthesis increases obviously light intensity is greater and then eventually the graph will plateau now this is the plateau this is the steady rate of photosynthesis so it can't increase its rate of photosynthesis at the plateau what the upward part means is that as the light intensity increases rate of photosynthesis increasing the enzymes the molecules are working together much much faster and plateaus at this point over here which we call the optimal light intensity level sketch the graph to show how temperature affects photosynthesis so at the bottom axis we'd have temperature and we have rate of photosynthesis going up the slide and this graph is a little bit unusual because it doesn't look like the other two the rate of photosynthesis will increase as the temperature increases increase increase increase then it will reach an optimal level and then or very quickly drop down to zero so a rate of zero photosynthesis are over here on the upward curve of the graph the temperature is increasing right over here at that peak you've got the optimal temperature for photosynthesis now what that means is that that is the rate at which all the enzymes are functioning at their absolute peak anything beyond that you're looking at higher temperatures over here which means enzymes are denaturing which means rate of photosynthesis is going to fall because the enzymes can no longer function appropriately they've changed their shape sketch the graph to show how carbon dioxide concentration affects photosynthesis see you'd have in dioxide concentration down the bottom here and you have rate of photosynthesis across the side there now this one happens exactly like the light intensity graph the rate of photosynthesis will go up is the carbon dioxide concentrator increases and then will reach an optimal level and it'll plateau right so there is the optimal level of co2 and plateaus only because the enzymes can't create or break down molecules any faster than they already are there's a biological problem going any faster so there has to be a plateau in this kind of graph is photosynthesis EXO or endothermic photosynthesis is endothermic label the parts of a leaf the top part is the waxy cuticle underneath that you've got the xylem here I've got the phloem these two make up the vein underneath is the god cell and you've got these DOMA very bottom there you got the waxy cuticle again this is the lower epidermis so the spongy mesophyll this is the palisade cells and the very top you've got the upper epidermis what is epidermal tissue is the tissue on the outside of the leaf what is palisade mesophyll it's a rectangular plant cell found near the top belief containing many chloroplasts what is spongy mesophyll let's say it's a round or circular little square killer plant cell found near the bottom of a leaf and it's below the palisade mesophyll and it also contains chloroplasts what is the xylem xylem is the water transport vessel in the plant leaf what it does is it moves water from root to leaves okay what does xylem do from roots to leaves and as a transport water from roots sillies water moves in one direction so water always moves upwards what is the phloem phloem is the sucrose transport vessel and phloem transport sucrose for one path of the plant to another part of the plant phloem is responsible for something called trance location what does phloem do it moves sucrose by translocation within the plant translocation implies that the movement is in two directions so it can take sucrose from the leaves down to the root and then it can break down sucrose from the root and take it up to the leaves the most important thing to know is that phloem has companion cells and sieve tubes whereas xylem is a dead tissue so there are no nuclei in xylem what is the waxy cuticle the waxy cuticle is the waterproof layer on the surface of the leaf and as per its name it's made of a waxy substance what does the waxy cuticle do it's transparent to allow light through but it is also waxy which means that is waterproof to prevent water loss what a stomata they are pores on the bottom surface of a leaf surrounded in God cells and they allow gases to move into and out of the leaf how can we test a starch in a leaf you start with place leaf in boiling water to soften it second thing you do is you turn the Bunsen off this is because the next step is to dip the leaf into methylated spirits or ethanol why do we turn the Bunsen burner off because ethanol and methanol spirits are both quite flammable so if you don't if you don't turn the Bunsen burner off you're going to find yourself with a little bit of a fire so you dip the leaf into methylated spirits and ethanol you dip the leaf back into the warm water to rinse the ethanol off and then you put it on to a surface and you drip a few drops of iodine onto the leaf now if the leaf has starch in it the ID turns blue-black the leaf has no starch in it the iodine stays red run okay now importantly in this we did the leaf into methylated spirits a ethanol this removes the chlorophyll so that you leaf is no longer green it's kind of a a light whitish color and that's important because if we don't do that we can't see what color the leaf turns when we add iodine to it in what form is glucose transported in the plants as sucrose what is phototropism it's the growth movement two really important words the growth movement of a plant in response to light so phototropism tropism growth movement photo light remember photosynthesis is to make with light and what is geotropism it's the growth movement of a plant in response to gravity what is the role of Oksana's auxins create growth movements implants what is the role of gibberellins gibberellins do a couple of things to help seeds germinate the override photoperiodism which is basically plants having a cycle that they open their flowers during the day and close their flowers at night they can cause fruits to develop without seeds so your seedless fruits are a result of gibberellins and gibberellins can also make bigger fruits what is the role of cytokinins cytokinins cause cell growth and differentiation and then what is the role of ethene gas ithi and gas is a plant hormone that ripens fruit now sometimes in papers you will see this written as ethylene gas it's exactly the same thing they both ripen fruit describe the effect of the lack of magnesium on a plant the plant lacks magnesium its leaves turn yellow and that's because magnesium forms part of the chlorophyll molecule describe the effect of the lack of nitrates on a plant and nitrates that's protein and we know in humans protein is for growth and repair so in plants you're going to get stunted growth and the older leaves will turn yellow describe the effect of the lack of phosphates on a plant now phosphates and cause poor root growth and they also create younger leaves turning purple okay now a great way to remember it is phosphates begins of the pee so does poor read growth growth and so does purple from there we've got describe the effects of the lack of potassium on a plant the symbol for potassium is cave alright so leaves turn yellow with dead spots that's because potassium means enzymes of respiration photosynthesis aren't getting produced dead spots means it kills part of the plant okay for potassium k4 kills what are the differences between a wind pollinated flower and an insect pollinated flower right so wind pollinated flower is also known to have feathery stamens and also feathery stigmas because the pollen needs to be able to catch the wind and travel to the next flower the feathery Stegman's would then pick them up the pollen grains will be light so that they can travel by wind there will be no nectar in these flowers because you don't need it because of the insects on the side of insect pollination you're going to have stamens that are within the flower you're going to have sticky stigma so that when an insect that has flower and flower pollen on its back comes along and burrows into the flower it's going to collect that the sticky stigma will collect the pollen onto itself the pollen grains are larger here and they sometimes are spiky or have hooks and that's to grab onto insect fur you'll also have nectaries next three is a little well of nectar down at the bottom of the bottom of the flower to make sure that the flower is the flower is attractive to insects and is quite sweet-smelling sometimes you'll have colorful petals majority of times you'll have color for petals this one has no colorful petals so when pollinated flowers don't need colorful petals because they're not trying to attract anything label the parts of a flower I'll start with the simple ones this is petal down the bottom here these are sepals then the female part of the flower flower you've got the stigma style and the ovary and together these make up the female part called the carpel on the other side you've got the male part of the flower which is the anther and the filament and they together make up the stamen and right at the bottom inside of the ovary you've got the ovules and the ovules are where the ovum or over arc it and that's where the flower gets its seeds fertilized when is the pollen tube start and where does it grow to well if you remember the female part of the flower looks like that the pollen grain will attach here on the stigma so pollen attaches to the stigma and then the pollen tube will grow all the way down the style all the way to the ovary the ovary is shaped like that so it's open on the bottom so the pollen tube needs to grow down attach a stigma grows down the style to the ovary now where does fertilization take place in a plant the answer is in the ovary in the ovary of the flower now there's an entirely different answer if you were asked that question where does fertilization take place in a animal the answer there is oviduct how do you seed germinate or during germination the seed contains a food store so when the conditions are optimal and the warmth water and oxygen are predict presented so it needs warmth water and oxygen the seed will then burst open and the plumie 'el and the radical will begin to grow and they'll use the energy stores of the seeds how can plants reproduce by asexual reproduction there are several ways the first the first natural ways are by making itself runners so strawberry plants are famous for their strawberry plants have runners tubers daffodils have tubers and bulbs artificially humans can make plants asexually reproduce by taking cuttings you define gas exchange using the word diffusion gas exchange is the movement of particles by diffusion from an area of high concentration to an area of low concentration how do stomata help with gas exchange stomata open and close because of the god cells that surround them and they help with gas exchange because carbon dioxide moves into the leaf by diffusion obviously and oxygen and water vapor move out of the leaf again by diffusion now gas exchange is literally the movement of gases so carbon dioxide moves into leaf from the surrounding environment oxygen water vapor move out of the leaf from the air space how will the parts of the leaf adapted for gas exchange as I've written here this is a really popular six mark question that'll only be found in a triples paper so you've got guard cells on the bottom of the leaf and they help the stomata to open and close depending on the water level inside the guard cells from there we've got spongy mesophyll and they contain chloroplasts which is basically made up of chlorophyll and they are loosely packed creating air spaces around the bottom of the leaf now the palisade cells the spongy mesophyll and the guard cells all photosynthesize as they've all got chloroplasts and they produce oxygen and glucose now the oxygen moves out of the leaf along with the water vapor and the carbon dioxide moves into the leaf both by diffusion what are the color changes of hydrogen carbonate indicates in a hydrogen carbonate measures atmospheric oxygen left as carbon dioxide level so if there are normal levels of carbon dioxide your hydrogen carbonate indicator starts off as orange but if there is slightly more co2 than is needed your hydrogen carbonate indicator turns yellow and if there is slightly less co2 your hydrogen carbonate indicator will turn purple now that means that hydrogen carbonate indicates very useful for respiration and photosynthesis practicals here slightly more more co2 the top here that means that you'd use it when something is respiring so you'd use you'd see hydrogen carbonate attorney up a indicator turn yellow when they were slightly more co2 in the atmosphere because respiration uses oxygen slightly less co2 will turn purple you'd use that for photosynthesis because there's more oxygen given off by photosynthesis which means that the hydrogen carbonate indicator would go purple how is water absorbed by the root hair cells it's absorbed by osmosis what is transpiration it's the movement of water as vapour from the inside of the leaf to the outside of the leaf how can we measure transpiration we'll use either a weight pedometer or a commercial potometer what factors affect transpiration you've got the usual things humidity in air wind speed temperature light intensity because light intensity will increase photosynthesis levels so humidity levels in air the more humid the less transpiration wind speed the more windy more transpiration the more temperature the higher the temperature the more transpiration because more photosynthesis there's more light intensity you're gonna have more transpiration the only one you need to think about is that more humidity will bring the less transpiration [Music]