This is because water potential and solute potential are inversely proportional. Ans: There is only 1 type of cell present. Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. The controlled variables in the experiment were: constant temperature, the type of onion, and the microscope. Slowly lower the upper edge of the cover slip onto the water. Ans: They have a different function than leaves bulbs are an emergency energy storage organ, whereas leaves convert solar energy to glucose for immediate use by the plant 3. Replace the sodium chloride solution with distilled water in the same way that the salt solution was added Observation and drawings The drawings above depict what happened during the osmosis in an onion cell experiment.
For a cell to be able to have that kind of attribute, it permits us to conclude that cell tissues contribute significantly in passive transport. In part 1, red blood cells were suspended in four different solutions of NaCl Sodium Chloride and timed to see if and how long it would take for hemolysis to occur. The purpose of this lab is to compare the three different types of solutions affect on the relative size of the vacuole to the cell, the outer membrane of onion red cells tunics are used to figure out the different types. Hypothesis: If a saline solution is added to the outer membrane of a red onion cell, then based on the amount of the solution, it will cause the vacuole inside the cell to become hypertonic thus shrinking in size. What will happen to the onion cell if it is placed in distilled water? The control group that the experiment was based upon was a slice of the outer membrane without any solutions added to it. The solution with the most rapid hemolysis time was 0. Osmosis in Red Onion Cells By: Youssef Gharib Brief Description of Osmosis in Red Onion cells: Osmosis is the diffusion of water from an area of low concentration to an area of high concentration across a semi-permeable membrane.
Were you able to see individual cells? Light microscopes use light as a source of radiation. Put each bag into a beaker of distilled water and let stand for half and hour. What will happen to the onion cell if it is placed in distilled water? Ans: There is only 1 type of cell present. Two cells will be observed, one from the skin of an onion, and the other from a common aquarium water plant anacharis. Sketch a drawing of the cells.
Materials: The following materials are required: onion, microscope, glass slide, cover slip, and iodine Note: iodine is toxic and will stain - handle with care. Lab 1B — Table 1. For example, when the bag contained a 0. What structure surrounds the cell membrane in plants and gives the cell support. The type of onion used in this experiment was a red onion, and the purple outer membrane was used to record data.
Plant cells are distinct from animal cells: plant cells have rigid cell walls, rather than the more flexible cell membranes of animal cells. Lawrence Biology 0983 By Zane Jeffels Partners: Lily Juno, Huynh, and Lin Yan Sun Preformed: October 11th, 2010 Due: October 25th, 2010 King Edward Campus- Rm. What magnification did you use to observe your specimen? In this investigation, you will observe the effects of placing plant cells in solutions of various concentrations. If two solutions have the same solute concentration, the solutions are said to be isotonic. Purpose: To study the structure of the onion epidermal cell, with particular emphasis on the nucleus and nucleoli. Hypothesis 4: If 20 % of saline concentration is added to the membrane of the red onion cell then, that vacuole will rapidly shrink because that the solute will be higher, thus causing that water to move out of the cell towards that higher solution making that cell smaller. This would be good supporting evidence since the role of the bulbs is to store starch as an emergency energy source.
What biological function do onion bulbs serve for the onion plant? Place 2 drops of the 5% salt solution on the slide at the edge of the cover slip. Observe the slide to see the effects of the saline salt solution on the onion cells. Ans: If you used iodine to stain the cells, it would have bound to and stained the starch granules in the cytoplasm. Given that iodine tends to bind to starch, it stains the starch granules when the two come in to contact making them visible. Answer the following questions: 1. Day 2: How to do biological drawings 3. Unlike animal cells, students will also notice that the plant cells have a more regular shape.
If the solutions differ in concentration, the area with the higher solute concentration is hypertonic and the area with the lower solute concentration is hypotonic. Sandwiched between the vacuole and the cell wall is the cytosol. Replacing the water in room temperature to warm water did the same procedure. They also use light rays which have a long 2 objects if they are 0. Ans: Answers will vary depending on how much cell biology has been covered prior to the experiment. Likewise, the cells are large, regular, easily seen and conform very well with the standard generic elements of all plant cells. Going Further Once students have mastered the above procedure, advanced students should be able to design and carry out similar investigations using yellow or white onion iodine can be used to stain the cells, as it binds to the starch granules in the cytoplasm and nucleus or other plant cells for comparison.
What changes would you observe in the cells of an Elodea plant that was suddenly moved from fresh water to salt water? The thin layer of skin found on the inside of an onion scale one layer of onion lifts off without effort and can be wet mounted on a slide with no need for extreme skill. Plant cells also have chloroplasts: these are organelles containing chlorophyll in systemic arrays to capture light and convert it to glucose. Describe the test below, and if you have time conduct the test. Take a dropper and add several drops of salt solution to one side of your cover slip while placing a small piece of paper towel along the opposite edge of the cover slip. Get a glass slide and cover slip for yourself and make sure they are both thoroughly washed and dried.
As the slide warms from the light of the microscope, you may see the chloroplasts moving, a process called cytoplasmic streaming. Ans: Answers will vary depending on the type of microscopes used, but it is recommended that students use magnifications ranging from 40-60x and up to 100-200x 8. Variables What is the variable you are going to change in the experiment? Cell Walls Give Structure Cell walls in plants are rigid, compared to other organisms. Images are used with permission as required. In each nucleus, are round bodies called nucleoli.