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Investigation Into The Factors That Affect The Rate Of Photosynthesis In Elodea Essay, Research Paper

Investigation into the factors that

affect the rate of photosynthesis in Elodea Introduction? ? Photosynthesis is the chemical

process, which takes place in every green plant to produce food in the form of

glucose.? Plants use the suns energy to

join together water and carbon molecules to make the glucose, which is sent

around the plant to provide food.? Cells

in the root or stem can use the glucose to make energy, if the plant does not

need to use all the glucose immediately then it is stored which is difficult

because glucose is hard to store in water.?

Plants solve this problem by joining hundreds of glucose molecules

together to make starch.? Starch does

not dissolve in water very well so it makes a better food store. ? Photosynthesis takes place

mainly in leaves and depends on an important green pigment called chlorophyll,

which is found in chloroplasts.? To

obtain the most sunlight as possible, leaves have a large surface area and the

more sunlight the plant receives, the better it can photosynthesize.? Chloroplasts are found in palisade cells in

large numbers and to allow as much light to get in as possible, the cells are

arranged like a fence.? This helps the

energy entering the surface of the leaf to travel a long way through the

palisade cells. ? Glucose can provide energy or

carbon, which can manufacture other molecules in the plant.? Which can make new living matter and this is

called biomass.? The chemical equation for

photosynthesis is: ??????????? Carbon dioxide +

Water??? =?? Glucose and Oxygen??????????? 6CO2? +?

6H20? =? C6H1206? +? 6O2Key Factors:? CO2 is vital in photosynthesis because the plant takes in

CO2 from the air and joins with water molecules to make glucose.? The CO2 comes in through the stomata pores

on the surface of the leaf and only 0.03 % of the air around is CO2 so it?s

pretty scarce.Temperature has to be kept at a certain level because if it gets

too hot, about 45`C then the enzymes in the chlorophyll will be killed and

photosynthesis will stop altogether.? If

the temperature is too cold then temperature becomes a limiting factor and the

enzymes will stop working.Light As chlorophyll uses light energy to perform

photosynthesis, it can only do it as fast as the light is arriving.? Chlorophyll only absorbs the red and blue

ends of the visible spectrum but not the green light in the middle, which is

reflected back.? If the light level is

raised the rate of photosynthesis will increase steadily but only to a certain

point.Water is important because it is needed

to join with CO2 molecules to make glucose and the amount of chlorophyll needs

to be enough so that the plant can photosynthesize to the best of its

abilities. Investigation Prediction I predict that the plastic sheets

coloured green, yellow and orange will produce the least amount of bubbles

because the light will be transmitted.?

Whereas placing red and blue sheets in front of the Elodea will result

in the greatest amount of bubbles because the light is absorbed.? Certain colours of light can limit the rate

of photosynthesis depending on how well it is absorbed into the plants

chlorophyll to photosynthesize.? Also

the wavelength can change the rate of photosynthesis.? If the lamp supplying heat for the plant were placed twice as far

away, I predict that there would be half as many bubbles.? Also if it were moved twice as far closer

then there would be twice as many bubbles.?

This is backed up with knowledge from previous experiments and ones done

by other people and scientific understanding.Diagram ??????????????????????????????????????????????????????????????????????????????????????????????? ???? Previous experiment Method ? For our experiment we chose as accurate

equipment as possible to give us the most accurate results.? The equipment is as follows:? 1 lamp ????????????????????????????????????????????????????????????????????????????????????????????????????? A boiling tube ??????????????????????????????????????????????????????????????????????????? A

small piece of Elodea ??????????????????????????????????????????????????????????????????????????? Plastic

sheets of different colours ??????????????????????????????????????????????????????????????????????????? A

beakerThe boiling tube was filled

with water and the Elodea placed in.?

The boiling tube was placed in the beaker and the lamp placed at a set

length away.? He plastic sheets were individually

wrapped around the beaker with an elastic band.? For every new plastic sheet we counted the number of bubbles each

time for a minute.? It was important to

keep the experiment the same each time to ensure it was fair test for example:

The lamp stayed the same distance from the beaker, we used the same plant each time

and the plastic sheets were all the same size.?

The experiment was repeated three times and the results were averaged to

ensure they were regular and as expected.?

Results were recorded each time and patterns observed.? Previous results for an experiment of this

kind have been recognized and compared.?

Throughout the experiment we made observations for a number of

distinctive things:???????????????????????????????????????????????? ??????????????????????????????????????????????? ·?? Increase/Decrease in

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