Extracting Chlorophyll From Various Plants In Order to Determine Cellular Anatomy, Fluorescing Properties, and Pigments CompositionEsha Jesha876728SBI4UO-AMonday, January 8th, 2018DISCUSSIONAnswer the questions asked in the procedure. Part A – Leaf AnatomyStep 8: Record your observation of the cell structure in a chart. (eg.
shape, colour) EnvironmentShape of CellColour of CellSize of CellRegularcircular asymmetricalthe cell itself has a faded yellow-green colournucleus is yellow-brownsmallSaltylongasymmetricalthe cell itself is whitenucleus is brown or blackmediumColdlongrectangularasymmetrical the cell itself has a faded yellow-green colournucleus is brownlargeStep 9: Make an accurate sketch of one (1) lettuce cell & label appropriately.EnvironmentLabelled Sketch of CellRegularSaltyColdStep 11: Describe characteristics of the chloroplasts.The characteristics of the chloroplasts seem to be dependent upon their environment. For example, the chloroplasts of the lettuce leaf in regular water are small but easily visible as individual granules around the edges of the of the cell. The chloroplasts of the lettuce leaf in salty water are visible in large clusters in various corners of the cell, as opposed to small, individual granules. The chloroplasts of the lettuce leaf in cold water are similar to the chloroplasts of the lettuce leaf in regular water, as they are easily visible as small, individual granules around the edges of the of the cell.
Step 13: Make an accurate sketch of two stomata & label the parts appropriately on one.EnvironmentLabelled Sketch of StomataRegularSaltyCold Part B – Chlorophyll Fluorescence PropertyStep 3: Pour in boiling water until the level covers the leaf sample. Note the colours.When the green spinach leaves were boiled, the colour did not change much; the leaves remained green, but the shade of green became lighter after being boiled.
When the purple kale leaves were boiled, the colour changed; the leaves went being purple before boiling to the same shade of green as the spinach leaves after boiling.Step 5: Explain why the leaves need to be boiled.The leaves need to be boiled in order to remove any excess dirt, bacteria, chemicals, or preservatives that may have previously come into contact with the lettuce leaves. The presence of dirt or any other chemicals can alter the results when the solvent is later added.Step 6: Explain why the petiole and major veins are not important for extracting chloroplasts.Chloroplasts are more likely to be found in parts of the leaf that undergo photosynthesis, such as the main leaf itself. The petiole and main veins are considered vascular tissue and are responsible for the transportation of nutrients and water throughout the leaf, therefore, they don’t necessarily contain as many chloroplasts as the main part of the leaf.Step 10: Explain why you need to grind the leaf pieces.
You need to grind the leaf pieces so that they can be as small as possible. This this is necessary because it is easier for solvents to extract chlorophyll from smaller leaf pieces than larger leaf pieces.Step 14: Explain why you need to add solvent and shake the mixture. (Cite your sources for what the chemical do to plant cells)Adding the solvent to the ground leaf powder and then shaking the mixture is what allows the chlorophyll to be extracted from the leaf powder. Isopropyl is a polar molecule, and it can only form bonds with other molecules.
Chlorophyll is also a polar molecule, so shaking the mixture allows the isopropyl molecules to bond with the chlorophyll molecules, and this is how chlorophyll is extracted from the leaf powder.Step 16: Describe your observations and indicate which layer is the chlorophyll extract.After letting the test tubes sit for 15 minutes, two distinct layers were formed in the tubes. The top layer was the solvent, which had turned a bright green colour, and the bottom layer is the leaf powder. The top layer was the chlorophyll extract because the chlorophyll from the leaf powder had turned it green.Step 19: Explain why the test tubes are stored in a dark cool place overnight.The test tubes containing the chlorophyll extract are stored in a dark cool place overnight so that they don’t absorb any of the sun’s light. Part C – Pigments CompositionStep 4: Note why the chlorophyll extract is dropped in the same spot.
The chlorophyll extract is dropped in the same spot, because that spot is considered the “starting point” for the absorbency of the extract. Usually, the use of chromatography paper involves a stationary phase and a mobile phase. In the stationary phase, the pigment is dropped onto one part of the chromatography paper until the colour is clearly visible, and in the mobile phase, the chromatography paper is dipped in a solvent; this is called the mobile phase because the absorbance property of the chromatography paper causes the solvent to move upwards. The movement of the solvent and the colour of the pigment is reflective of how small or heavy the substance is.Step 10: Record the distance the solvent travelled. Chlorophyll Extract CompositionDistance Solvent Travelled (cm)Green Leaf + Water5.1Green Leaf + Isopropyl6Purple Leaf + Water5.3Purple Leaf + Isopropyl5.
7Step 12: Record your observation by sketching the filter strip and labelling the lines with coloured pencils.Chlorophyll Extract CompositionSketch of Chromatography StripGreen Leaf + WaterGreen Leaf + IsopropylPurple Leaf + WaterPurple Leaf + IsopropylPart A – Leaf AnatomyCompare cells from different parts of the lettuce leaf.Cells From LeafCells From Petioleround clustered, arranged randomlychloroplasts are visible around the edges of the cellcells are generally the same sizeroundclustered, arranged in a circlechloroplasts are not visiblevein-like structures are presentcells are smaller around the center of the petiole, and larger around the outsideExplain the functional significance of the differences in shape. (Cite your references)Cells present in the leaf are shaped the way they are so that photosynthesis can occur and the leaf can sustain itself. This is why there are many chloroplasts clustered around the cell.
The cell is also generally round so that cell division can occur within the leaf. In regards to petiole cells, they are shaped the way they are so that they can allow water, carbon dioxide, and nutrients to easily flow to the rest of the leaf. This is why the petiole has a generally round, vein-like structure. Also, the petiole does not contain very many chloroplasts and this is because photosynthesis does not occur in that part of the leaf; it only occurs in the leaf itself, which is why there are more chloroplasts in the leaves than in the petiole.Compare the cellular states (structural cells and stomata) of lettuce leaf from 3 different conditions.Cellular StatesRegular WaterSalty WaterCold WaterStructural Cellsroundlargenucleus is visiblemany chloroplasts are visiblelongslightly rectangular shapenucleus is partly visiblemany chloroplasts are visiblerectangularlargenucleus is visible, attached to the cell wallmany chloroplasts are visibleStomatasurrounded by odd shaped cellsstomata is party openfew chloroplasts are visiblestomata is completely openfew chloroplasts are visiblestomata is partly open, most of them are closedfew chloroplasts are visibleProvide an explanation for these observations.One explanation for the presence of chloroplasts in both structural cells and the stomata is that chloroplasts are used more in structural cells for photosynthesis, as opposed to stomata, which deals mostly with gas exchange during photosynthesis.
As shown in the above, the cellular states change based on their environment, and this is so that they can survive in their new environment. Part B – Chlorophyll Fluorescence PropertyExplain briefly how UV light works to enable us to see different sets of colours.UV light, also known as black light is converted into visible light via phosphors. Phosphors are substances that absorb energy, and then emit it as light that is visible to the human eye. Phosphors are naturally present in teeth and fingernails, and that is why they glow under UV light.Compare the colours of your two samples of chlorophyll extract.
One sample of chlorophyll extract we used contained water as the overall solvent. The colour of this chlorophyll extract was very murky and had a yellowish tint. Under the UV light, this sample of chlorophyll extract took on a faint, opaque grey-blue colour.
Another sample of chlorophyll extract we used contained isopropyl as the overall solvent. The colour of this chlorophyll extract was transparent and it had a bright green colour. Under the UV light, this sample of chlorophyll extract took on a bright, opaque red colour.Hypothesize a factor that influence the colours observed.According to the experimental design, the independent variable for this part of the experiment was the solvents used, and the dependent variable was the colour of the chlorophyll extract. Therefore, I hypothesize that the factor that influenced the colours observed was the solvent used.
Compare your results with other teams to determine which solvent was the best for extraction use.After discussing with other teams, we got to know that other solvents used in this experiment were acetone and water. After discussing the results of the use of acetone and water as solvents, I came to discover that isopropyl is the better solvent for the following reasons. First of all, the chlorophyll extracts that were acquired using water and acetone were not as green as the chlorophyll extract acquired using isopropyl. Second of all, when viewed under the UV light, the chlorophyll extracts that were acquired using water and acetone were not as brightly coloured as the chlorophyll extract acquired using isopropyl. Therefore, isopropyl was the best solvent to use for extraction. Part C – Pigments CompositionCalculate the Rf value of each pigment observed.
Chlorophyll Extract CompositionDistance Pigment Travelled (cm)Distance Solvent Travelled (cm)Rf value (Distance Pigment Travelled / Distance Solvent Travelled)Green Leaf + Water2.45.10.47058823529Green Leaf + Isopropyl1.260.2Purple Leaf + Water2.55.30.
4716981132Purple Leaf + Isopropyl1.55.70.26315789473Identify the pigments found in your leaf by referring to the standard values chart.Chlorophyll Extract CompositionRf valueName of PigmentGreen Leaf + Water0.
47058823529chlorophyll bGreen Leaf + Isopropyl0.2xanthophyll 2Purple Leaf + Water0.4716981132chlorophyll bPurple Leaf + Isopropyl0.26315789473xanthophyll 2Explain why some leaves are green even though other pigments are present.Our perspective of leaf colours is largely based upon the type of light absorbed and reflected by that specific leaf. For example, chlorophyll is known to absorb only red and blue light, and since it can’t really absorb green light, the green colour is reflected back to our eyes, and that is why we perceive certain leaves as green. Other pigments may absorb and reflect other colours of light, causing us to perceive the leaf as a different colour. Although other pigments are present alongside chlorophyll in leaves, they act as accessory pigments to the main pigment, which is chlorophyll a.
Most land plants are green because their accessory pigments are also different forms of chlorophyll.Provide some advantages and limitations for plants to have different pigments.One advantage of plants having different pigments is that they can use these pigments to make their own foods. For example, chlorophyll can be used by plants to help them make their own food, therefore, they can be self-sufficient and do not require external sources for food. One limitation of plants having different pigments is that the presence certain pigments in plants is not sufficient for the plant’s survival; in the case of autumn leaves, chlorophyll is broken down when there is a lack of sunlight and nutrients, and this causes the leaves to turn orange or yellow, however, these orange and yellow pigments are not able to photosynthesize and make food for the plant, so the leaves dry out and die very quickly.
Based on what you have learned, explain why leaves tend to change colours in the fall.Based off of what I have learned, leaves change colours in the fall autumn is what triggers this breakdown in chlorophyll, and this allows orange and yellow pigments to become visible. Also, since photosynthesis cannot occur without sunlight or nutrients, glucose present in the leaves becomes trapped in the leaves, and this produces a red pigment which becomes visible in leaves.Discuss two key errors that could have affected your results.One key error that could have affected the results of our experiment was the amount of time during which the green leaves were boiled. In regards to the boiling of the purple leafs, we kept on boiling them until we noticed the leaves turn from dark purple to light green, and this seemed to be an indication as to when to stop boiling. However, in regards to the boiling of the green leaves, there was no visible indication as to when to stop boiling. This may have lead to over-boiling or under-boiling of the green green leaves, and this could have possibly lead to inaccurate results.
Another key error that could have affected the results of our experiment was the heating of the leaves on the tin foil. Given how small the pieces of the leaves were cut, it was almost impossible to completely heat the leaves without burning them to ash. In order to avoid this from happening, our group heated the leaves for an extremely short amount of time, and even then the leaves were not completely dried out. Our inability to properly heat the leaves without burning them completely may have lead to inaccurate results.Provide one general conclusion to this lab.In conclusion, plant cells may behave differently based on their environment. As proven in Part A of the experiment, plant cells have different characteristics based on what type of water they’re exposed to, and plant cells undergo these changes so that they can survive in their new environment. Another general conclusion to this experiment is that plant cells contain many different pigments that dictate their colour, and their colour is also dependent upon their environment.
Plants on land are mostly green due to the various combinations of chlorophylls contained within them, and the visibility of these pigments can fluctuate based on access to sunlight and nutrients.ReferencesGCSE Bitesize: Functions of the leaf. (n.d.).
Retrieved January 08, 2018, from http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/green_world/leavesrev1.shtmlPlant Life: Chromatography. (n.d.
). Retrieved January 08, 2018, from http://lifeofplant.blogspot.
ca/2011/05/chromatography.htmlOn the Hidden Colors in Leaves: What are the Functions of Those Yellow and Orange Pigments We See in the Fall?. (2017, September 21). Retrieved January 08, 2018, from https://biology.appstate.edu/fall-colors/hidden-colors-leaves-what-are-functions-those-yellow-and-orange-pigments-we-see-fall
