When substances are brought in contact with each other they intermix, this property is known as Diffusion. This property of diffusion takes place very rapidly in case of gases and to a lesser extent in case of liquids, whereas solids do not show this process of diffusion with each other. But what we can observe in case of solids is that the diffusion of solids in liquids takes place at a very slow rate. Molecules of solute are in constant random motion due to the collision between molecules Of solute and that of the solvent.
II. OBJECTIVES . Describe how diffusion takes place. 2.
Distinguish between diffusion and osmosis. 3. Demonstrate osmosis in cells. 4. Describe hypotonic, isotonic, and hypertonic solutions. 5. Explain the effect of the different salt concentrations on cells Ill. PROCEDURE A. Diffusion of Solid in Water A pinch of potassium permanganate was dropped into a 250ml beaker containing water. The beaker was left undisturbed and was observed for 10 minutes with an intervals of every 2 minutes.
B. Diffusion through Membrane A cellophane was filled with a starch solution up to a height of about 1 inch. The cellophane bag was tied tightly assuring of no air was traps inside.
Then the cellophane bag with starch solution was immersed in a beaker containing Lugol’s iodine solution. The set up was observed and timed until the change in color was observed within the cellophane bag from white to blue black solution. C. Osmosis in Cells About 1/4 of the broad end part of the egg was broke out, and the whole egg was then immersed into a beaker containing water in upright position with the membrane exposed by supporting the egg by a pebbles. The egg immersed into the water was observed for an hour on observing its changes. D.
Effect of the Different Salt Concentration of plant Cells A Rheo discolor mounted in to a glass slide was first examined under LPO with water as its solvent and the distribution of the pigments was noted. Without removing the slide from the stage a 10% salt solution was dropped twice into the edge of the cover. The three neighboring cells as they was appeared under CPO was drawed one minute after the addition of the 10% salt solution. A new Rheo discolor slide was again prepared and examined under LPO but the solution added was 50% salt solution and the three neighboring cells was then again drawed.
These procedure was again epeated but the slide used was a Hydrilla leaf and was examined under HPO. IV. RESULTS AND OBSERVATIONS 5. a At the end of 10 minutes, describe what took place in the beaker. 1-2 Minutes – Some of the solid KMn04 dissolved while most of it did not and was settled in the bottom of the beaker. 2-4 Minutes – A very light pink cover was found at the upper portion of the solvent. At the bottom of the beaker were found to contain the undissolved KMn04. 4-6 Minutes – The cover of the solvent changes from light pink to pink. There were still undissolved KMn04 found in the beaker. -8 Minutes Some of the undissolved KMn04 at the bottom of the beaker rose which turns the color of the solution to a light pink. 8-10 Minutes – More solid KMn04 rose from the bottom of the beaker which turns the color of the solution the dark pink. There was still undissolved KMn04 in the beaker. 5. b Suggest at least 3 ways of speeding up the rate of diffusion of the potassium permanganate crystals. 1. Stir 2. Agitate 3. Heat the solution B. Diffusion through Membrane 5c. What was the cover of the two solutions at the beginning of the experiments? Iodine is black red; Starch solution in color white Sd.
Describe any changes in color that you observed in both chemical solutions. The Iodine solutions remains black red while the starch solution turned blue black in color. Se. How long did it take for the color to change. It took 4 Minutes. Sf. From the results, which substance was able to diffuse through the cellophane? Explain. Its the Iodine, because the iodine solution was more concentrated compared to the starch solution. 5g. What would be the expected result if the both chemical solutions were able to diffuse through the cellophane. The solution changes its color from white to blue black due to the Iodine-starch reaction. After about an hour, lift the egg from the beaker. What happened to the exposed membrane? The exposed membrane of the egg was smooth and prominent compound to its original form due to the entry of water through the membrane. 4. Explain how osmosis took place in the egg. The selective permeable membrane Of the egg allows the entry Of Water but prevents the passage of other solutes. Since the water has a high concentration than that with the all causes the net osmotic movement of water into the cell, making it swell and bulky. D. Effect of the Different Salt Concentration on Plant Cells Figure 3. der LPO (100x) A. before adding Salt solution B. after adding 1 0%salt solution adding 50% salt solution C. after a. Explain the change in the distribution of the violet pigment in the cells of Rheo discolor before and after adding the 50% salt solution. Before the addition of 50% salt solution, the violet pigments are still distributed but on the addition of 50% salt solution, the violet pigments were concentrated and found on the side part of the which is near the cell wall. b. What is the importance of diffusion in the transport of solutes in cells?
Hypertonic; 50% salt solution Hypotonic; 10% salt solution V. DISCUSSION When solids like potassium permanganate are brought in contact with liquids such as water, intermixing Of substances, i. e. diffusion takes place. But what we can observe in case of solids is that the diffusion of solids in liquids takes place at a very slow rate. Diffusion across this membrane is the net movement of molecules in a fluid from the regions of high concentration to regions of low concentration. This is driven by the concentration gradient. The greater this gradient is the faster the rate of diffusion will be.
If no other forces intervene, the diffusion will go ntil the gradient is zero. No work needs to be done to get this process to occur. Because it decreases the amount of free energy, diffusion is a spontaneous process. Animal cells has partially permeable cell membrane. The cytoplasm of the egg was stronger solution than the pure water, water will pass into the cells by osmosis. This brought the cell of the egg to bulk and swell. When a salt is added to the plant cell their concentration contrast to each other depending upon the concentration of the salt added.
Osmosis happens when the cell wanted to have equal concentration to the salt solution. When the solution is in the hypertonic solution, the cell shrinks and could even be die, and swell or burst if it is in hypotonic solution. VI. CONCLUSION Diffusion results in the overall (net) movement of particles from an area of high concentration to an area of low concentration down a concentration gradient. If there is a big concentration difference diffusion will take place more rapidly than if there is only a small concentration difference. The difference in concentration is known as the concentration gradient.
Diffusion and osmosis are related concepts, both involves the movement of aterials from a highly concentrated area to areas of low concentration. Diffusion is the spreading out ofthe particles of a gas or any substance in solution. It is caused by the random movement of the particles. The higher the temperature, the faster the particles move and the faster diffusion takes place while osmosis takes place when two solutions are separated by a partial permeable membrane. A partially permeable membrane lets some particles through but not others. Cell membranes are partially permeable.
Water can move freely through them but other particles, such as sugar molecules, cannot. Hypotonic solutions are less dissolved particles outside of cell than inside of cell. At these solution, cells merely expands or may burst. Isotonic solutions has the concentration of the solute is equal to the cell. At these solution no net water movement occurs. Hypertonic solutions has the concentration of the solutes higher than the cell and has more dissolved particles outside of cell than inside of cell. At these solution, water moves out of cell into solution which make the cell shrink Vil. ANSWERS TO QUESTIONS 1 .
Can a liquid substance diffuse in another liquid substance? Explain. A gas in a gas? Example. A gas in a liquid? Explain. – Liquid substance diffuse with Liquid substance; it depends upon the nature of the substance and its polarity to the another substance. Like blood and water they can be diffuse, unlike oil and water it wouldn’t. – Gas in gas; yes, because of the rapid motion of its molecules, a gas will diffuse, or spread uniformly. In diffusing, it can mix with another gas or with certain liquids and solids. When a gas is confined to a container, the moving gas molecules continually strike the container’s inside walls, exerting pressure. Gas in Liquid; The property of diffusion takes place ery rapidly in case of gases and to a lesser extent in case of liquids, whereas solids do not show this process of diffusion with each other. 2. What is the importance of diffusion in the transport of solutes in cells? – Diffusion allows the small particles to be transported into the cell without the cell having to spend energy that’s how the soluble solutions move through the cell membrane. VIII. REFERENCE https://ph. answers. yahoo. com/question/ D httpwscience. howstuffworks. comcas- su bstance-info. htm http://projects. cbse. com/chemistry-254 http://www. virginia. edu/bohr/mse209/chapter5. htm http://www. abpischools. rg. uk/page/modules/homeostasis_kidneys/ kidneysg. cfm http://www. rpi. edu/dept/chem-eng/Biotech-Environ/ Membranes/wilbarg. html http://www. uic. edu/classes/bios/bios 1 00/ lecturesf04am/lect09. htm http://www. passmyexams. co. uWGCSE/biology/ osmosis-in-cells-html Western Mindanao State university Group No. : 02 Date Performed: April 22, 2014 Activity No. : 5 Effect of Light Intensity on Photosynthesis The primary source of energy for nearly all life is the Sun.
The energy in sunlight is introduced into the biosphere by a process known as photosynthesis, which occurs in plants, algae and some types of bacteria. Photosynthesis can be defined as the physico-chemical process by which photosynthetic organisms use light energy to drive the synthesis of organic compounds. The photosynthetic process depends on a set of complex protein molecules that are located in and around a highly organized membrane. Through a series of energy transduction reactions, the photosynthetic machinery transforms light energy into a stable form that can last for hundreds of millions of years.
Photosynthesis has been applied to organisms that depend on chlorophyll (or bacteriochlorophyll) for the conversion of light energy into chemical free energy. These include organisms in the domains Bacteria (photosynthetic bacteria) and Eucarya (algae and higher plants). General equation of Photosynthesis 6 +7 H20 C6H1206 +6 02 + H20 The overall equation for photosynthesis is deceptively simple. In fact, a complex set of physical and chemical reactions must occur in a coordinated manner for the synthesis of carbohydrates. 1 . Correlate the number of bubbles produced to the rate of photosynthesis under different light intensities.
A three (3) healthy looking sprigs of Hydrilla was cute about 1 inch long from the sprig and was placed in each three (3) 25ml test tubes which was ompletely filled with tap water. These test tubes was then after placed inverted inside in each three (3) beakers containing water which was blown with breath through a straw in order to increase the concentration of the dissolved carbon dioxide in the water. Beaker 1 was placed under direct sunlight, the other beaker labeled 2 was placed under the shade of the tree, and lastly the third beaker labeled 3 was placed inside the laboratory room.
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