Bioenergetics Photosynthesis & Respiration

Bioenergetics Photosynthesis & Respiration
Laboratory Report
Exercise 6
PBIO101

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Gina Dedeles
Minda Dimaano-Kho

Group 5
Felicita, Haniel
Paulo, Gisselle Mildred V.

Aniseta, Carmelus*Absent but present in the first day of activity
Corpus, Kristine *Absent at the 2nd day of activity
Shinotsuka, Hideki *Absent

Introduction
Energy is the capacity to do work. According to the first law of Thermodynamics, energy can never be created nor destroyed, but can only be transformed. Thus, the sun burns up its mass to release light and mass to release light and heat energy that reach the earth. It is this light energy that Chlorophyll plants, protists (algae) and monerans (bacteria and cyanobacteria) capture and convert to chemical energy through photosynthesis (photo-light; synthesis-building up) , the key process by which energy that ultimately comes from sunlight is supplied to nearly all living systems. Such photosynthetic organisms,themselves, use part of this chemical energy to grow and reproduce, but they are also eaten by animals and decomposed by fungi and the dominant achlorophyllous bacteria, thus supplying these organisms’ energy needs.
Not all organisms on earth depend on sunlight as source of energy; small ecosystems have been recently discovered in dark ocean depths which rely on the energy provided by chemical substances spewed out by small volcanic vents. This is an example of a unique biological process of unusual energy conversion called chemosynthesis.
But unlike carbon dioxide, oxygen, or water, energy does not cycle in biological systems. It is gradually lost as heat as the chemical bonds of the plant biomass are broken and reformed in animal biomass. Only about 10% of the energy available in ingested food during respiration is used to make new biomass; the remaining 90% dissipates as low-grade heat entropy. Thus, photosynthesis and respiration are opposed but interlinked energetic processes necessary for the maintenance of life. The overall equation of photosynthesis (left to right) Photosynthesis CO2 + 12H2O respiration C6H12O6 + 6H12O + 6O2 Carbon dioxide water glucose water oxygen

Respiration not only makes energy in chemical bonds of biomass that are convertible into the various forms of energy in chemical bonds of biomass that are convertible into the various forms of energy needed in metabolism. It also recycles carbon dioxide to fuel which furnaces photosynthesis

Objectives: 1. To study the role of light, chloroplast pigments, and carbon dioxide in photosynthesis 2. To demonstrate the process of aerobic respiration in germinating mongo seeds based on intake of oxygen and evolution of carbon dioxide. 3. To demonstrate abaerobic respiration (fermentation) in the yeast Saccharomyces cereviseae
Materials:
1. Live Specimens a. fresh or frozen leaves of any plant – spinach, petchay, etc. b. 2 potted mayana variegated plants (1 kept in the dark for 48 hours and the other as long as in the light) c. germinated mongo seeds d. Hydrilla sprigs e. pure culture of Saccharomyces cereviseae

2. Chemicals/Solutions * acetone * petroleum ether * I2KI (potassium iodide)in 70% alcohol * KOH (potassium hydroxide) pellets * NaOH (sodium hydroxide) pellets * Ba(OH)2 (barium hydroxide) * Methylene blue dye (0.15g in 100ml distilled water) * C6H12O6 (glucose)

3. Laboratory Equipment * 250 ml beakers * 250 & 500 ml flasks * 1 ml pipettes * separatory funnel * 50 ml test tubes * regular-sized tubes * petri dishes * fermentation tubes * mortar & pestle * small vial * chromatographic paper * prism * water color paint brush * glass & rubber tubing * lamp with 100 watts bulb * cork & rubber stoppers with holes 250 & 500 ml flasks * cotton * iron stands * iron clamps * rings * transparent rulers * absorbent tissue papers

I. Photosynthesis A. Role of Light and Chlorophyll 1. Starch Test – Felicita, Haniel 2. Nature of chloroplast pigments– Paulo, Gisselle B. Role of Carbon Dioxide – Aniseta, Carmelus II. Respiration A. Aerobic Respiration – Felicita, Haniel B. Oxygen Consumption: Quantitative - Aniseta, Carmelus C. Anaerobic Fermentation – Paulo, GisselleIntroduction & Guide Questions – Corpus, Kristine |

I. Photosynthesis A. Role of Light and Chlorophyll 1. Starch Test According to the Home Science Tools, any extra food a plant makes through photosynthesis is stored in its tissue as starch. Testing a leaf for starch is one way to test whether it has been performing photosynthesis or not. Starch is a carbohydrate consisting of a large number of glucose units joined by glycoside bonds. This polysaccharide is produced by all green plants as an energy store. 1. Detach 2 leaves from the “light” plant and “dark” plant. Include the leaf stalk (petiole) in the “light” leaf to distinguish it from the “dark” leaf, which should be detached from the latter without the attendant petiole 2. Untreated group. Describe the appearance of the “light” and “dark” leaves based on the distribution of the pigments or coloration from the blade of the leaf. 3. Treated with cold water.Place “light” and “dark” leaves in a beaker of cold water. Let stand for 5 minutes. 4. Treated with boiled water. Blanch the “light” and “dark” leaves in a beaker of boiling water for 5 minutes 5. Treated with alcohol and IKI. Carefully transfer the boiled leaves in a beaker of hot alcohol (70% ethyl alcohol). Heat the beaker of alcohol in a pan of boiling water. As soon as the leaves become whitish, spread them out in separate petri dishes and flood with enough alcoholic solution of iodine for one minute and dip in a beaker of distilled water.

| Treatment | Mayana Leaves | | | “Dark” | “Light” | 1 | None | The color is pale. | Its color is dark (lively). | 2 | Cold H2O 5 minutes | Same color | Same color | 3 | Boiling H2O5 minutes | Its color got more pale and weak. | Its color also got lighter and weaker. | 4 | Hot alcohol several minutes | It turned white / colorless. | It turned white but it has still a little light green color. | 5 | IKI | It has not spots compared to the “light” leaf | It has black spots,which shows the presence of starch(see the picture above right) |

Explain the cancellation of the pattern of variegation in the “dark” leaf after treatment with alcohol and IKI. The “dark” plant wasn’t able to collect enough light and store it as an energy that is why on the process of boiling, it was easy to kill the leaf because it has no enough energy, and when it was boiled on the beaker of alcohol its color turned white faster than the “light” leaf. It has no dark spots compared to the “light” leaf, which indicates the presence of starch.

2. Nature of chloroplast pigments Light energy must first be transformed into chemical (bond) energy before living cells can use it. Because only absorbed light can transfer this energy, the colored component of the plant cells in the leaves must be absorbing visible light. Substances that have the ability to absorb selectively are called pigments. Chlorophylls a & b and carotenoids (xanthophylls and carotene) are the major component of the chloroplasts. These pigments can be extracted from plant cell tissues with lipid solvents and demonstrated in paper chromatography. 1. Select two fresh or frozen leaves (10g soft-tissued spinach, pechay, Chinese cabbage). Remove the fleshy portion, chop or cut into small pieces the remaining portion. 2. Pound and grind the cut leaves with a mortar and pestle in 10ml acetone until the liquid turns green. 3. Pour the liquid in a small vial. Allow to stand for 15 minutes for the suspended solids to settle. 4. Cut a strip of chromatography paper to fit lengthwise into a 50ml test tube without touching the glass walls. At one end of the strip, make a pointed cut (V-shaped) one inch from that end. Draw a pencil line 1 cm above this V-shaped cut. Draw a small circle in the center of the line.

5. With a capillary tube held along its length, dip it into the acetone plant extract. See the green liquid rise inside the capillary tube. Touch briefly on the pencil drawn circle. Let dry the spot for 2 minutes and apply again on the circle. Do this 5 times. Dry the paper thoroughly.

6. Place 5 ml developing solvent (9 parts petroleum ether, 1 part acetone) into the 50ml test tube. Insert the treated chromatography paper with V-shaped cut first. 7. Stopper the tube tightly with a cork and let the paper string hand from the cork. Let the tube stand undisturbed for the solvent to rise up in paper. Examine the chromatogram periodically for the next several minutes. When the solvent front reached about 1 cm, remove the cork and gently withdraw the paper to allow it to dry, How long does it take for the solvent front to reach the indicated top limit?

It took 2 minutes and 30 seconds for the green pigment (chlorophyll a) to reach a 1 mm displacement.

8. In the petroleum ether-acetone solvent, the carotenes (yellow, orange, red) move the fastest, followed by the xanthophylls and then the chlorophylls a & b. Mark the outline of the individual visible spots with a pencil and a label each with corresponding color before it fades. B. Role of Carbon Dioxide *to be submitted separately

II. Respiration A. Aerobic Respiration By-products of Aerobic Respiration: CO2 and Water. The term “respiration” originally meant the transfer of gases between organism and its environment. This process requires oxygen and yields much more energy than glycolysis. Aerobic respiration is divided into two processes: the Krebs cycle, and the Electron Transport Chain, which produces ATP through chemiosmosis phosphorylation. In this experiment we will see which has more CO2 by using our own breath, by blowing the aspirator and so by using a rubber bulb. 1. Put 50 ml limewater in the 250 ml flasks. Using a pipette aspirator (rubber bulb) assembly, bubble 30-aspirator full air into flask A,be sure the end of pipette is dipped in limewater when the bulb is squeezed, and must be out of the limewater when the bulb is released. Pour the aerated limewater into a test tube, and let it stand for 10 minutes.

2. Using a straw tube, exhale 30-mouthful of your breath into the limewater in flask B. Each mouthful (or half mouthful) should approximately the volume of one bulb full of air blown into flask A. Again, pour the aspirated limewater into another test tube, and let it stand for 10 minutes.

3. Calcium hydroxide [Ca(OH)2] reacts with CO2 to form a white, insoluble precipitate of calcium carbonate. Based on the seen amounts of precipitate in the two test tubes, is your breath richer, or poorer, than air in CO2? By how much (indicate height of precipitate)? The test tube with the exhaled breath is richer than the air in CO2.
…
4. Also exhale into a clean glass slide held close to your open mouth. Does your breath also contain water in vapor form? Yes, it also contains water in vapor form.

B. Oxygen Consumption *to be submitted separately

C. Anaerobic Respiration (Fermentation) This Louis Pasteur’s “Life without air”; it provides energy in the absence of oxygen. The essence of this process is the rearrangement of the atoms of sugar to yield a compound of lower energy, making the difference in energy available to the cell. Saccharomyces cervisiae, a yeast, is capable of respiration and fermentation as a trait called the “Pasteur Effect”. When O2 is plentiful, it breaks down glucose via respiration but when it is deficient then the organism switches to fermentation.
Yeast Fermentation:

Other micro-organisms ferment sugar to different products (e.g. butyric acid, butanol, lactic acid, acetone, etc.), but the principle is always the same. Animal cells also ferment glucose during periods of oxygen deficiency to produce lactic acid. Muscle cells, for example, are often required to work rapidly than they can be supplies with oxygen.
1-4. Dissolve … solution. (prepared by the technician)

(arranged from 1-6) 5. After several minutes, observe the tubes carefully and note the evolution of bubbles in the straight portion of the tube. This results to the accumulation of carbon dioxide and the subsequent displacement of liquid at the top of the tube. 6. Compare the rate of bubble evolution, liquid displacement and scent.

7. Test for the presence of carbon dioxide by adding a pinch of phenol red indicator- a yellow color indicates presence of CO2.

8. Is there fermentation in tube #6? Why? What is the effect of high concentration of copper on cells?

Fermentation tube | # | Color | Rate of Bubble Evolution | Volume of Displacement | Scent | | 1 | Transparent orange | No bubbles | Evident volume of displacement | No smell | | 2 | Orange | Less bubbles | Small volume of displacement | Rice wine like smell | | 3 | Yellow orange | Many bubbles | Greater than #2 | Strong smell | | 4 | Dark orange | Many bubbles | More displacement | Stronger smell | | 5 | orange | Less bubbles | less displacement | Milder smell | | 6 | Blue green | No bubbles | less displacement | Foul smell |

Guide questions
1. Explain the statement “life on earth runs on solar energy”
Solar Energy is the energy generated by the sun. All life on earth depends ultimately on the sun 's radiation. It warms the earth and provides the energy that green plants use to make their food. (Without plants, there would be no animals, since all animals must feed on plants or on plant-eating organisms.)
2. What is fermentation? Name some products resulting from this processes (the so- called fermented products you see in grocery stores). The conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a combination thereof, under anaerobic conditions. Fermentation in simple terms is the chemical conversion of sugars into ethanol. Some products are sour cream, yogurt, and soy sauce.
3. What organisms other than members of the plant kingdom can perform photosynthesis? Where in nature do they occur?
Cyanobacteria and protists like algae. During photosynthesis, it uses chlorophyll (and carbon dioxide and water) to gather light and convert it to energy. Once the conversion is complete, the organism stores that energy as sugar, while releasing oxygen as a byproduct.
4. What substance accumulate in tired muscles, and why? Why does massaging ease in this condition?
As the muscles get tired they tend to respire anaerobically (without oxygen) to produce energy. Such kind of respiration produces a byproduct called Lactic Acid. Messaging the muscle alows more blood to reach it and clean this acid
5. Explain the need for an animal to breathe. Do plants also breathe?
Breathing is important to organisms because cells require oxygen to move, reproduce and function. Breath also expels carbon dioxide, which is a by-product of cellular processes within the bodies of animals. Yes, plants do breathe.
6. Photosynthesis and aerobic respiration to take place,respectively , in chloroplast and mitochondria. But monerans lack these organelles; does this mean they can neither photosynthesize nor undergo aerobic respiration? Explain.
Monerans don 't have chloroplast but some have pigments which allows them to do photosynthesis. | | |
References:
http://www.hometrainingtools.com/starch-test/a/1497/
http://www.cd3wd.com/cd3wd_40/vita/ethanol/en/ethanol.htm

References: http://www.hometrainingtools.com/starch-test/a/1497/ http://www.cd3wd.com/cd3wd_40/vita/ethanol/en/ethanol.htm