Which observations or evidence from this experiment supports this? Optional: Show the following video, which demonstrates how to obtain a thin layer of onion epidermis, make a wet mount and how to stain it with iodine 3. Do not use encyclopedias Internet or otherwise , dictionaries Internet or otherwise , or personal web pages as sources for the report, this includes Wikipedia. Determine the mass of the four cylinders. Mullins Date: January 20, 2011 Introduction This lab was designed to explain the different things osmosis does. In a redox reaction, two half-reactions occur; one reactant gives up electrons undergoes oxidation and another reactant gains electrons undergoes reduction. The onion elodea cells were both plants, so they had a cell wall. Because a plant cell has cell wall which is to maintain.
Lab 1B — Obtain the six strips of dialysis tubing and fill each with a solution of a different molarity. Question: How will the vacuole inside the cells of the outer membrane of a red onion react when deionized water, a 1%, and a 10% saline solution are added to the cells? One slice was used as negative control, and salt was sprinkled on the other slice. Only the plant cells were together in a large group. The drawing on the right shows what happened when I then replaced the salt solution with distilled water. Introduction — The purpose of this experiment is to answer questions associated with the onion root tip photos that are pictured in the lab. Cancer, Cell cycle, Cell division 377 Words 2 Pages Lab 4 — The Cell Answer Key Procedure 4.
Each membrane layer is composed of a phospholipid layer, which is semi-permeable and possesses the ability to control the movement of diffusion. You can make the investigation quantitative by using different concentrations of sodium chloride solution e. Particularly in this experiment we use onion cells. The type of onion used in this experiment was a red onion, and the purple outer membrane was used to record data. Bacteria, Cell, Cell membrane 573 Words 2 Pages Epidermis Cells Aim: To see if rhubarb changes when it is placed in solutions of different concentrations.
In this investigation, you will observe the effects of placing plant cells in solutions of various concentrations. Use a model to illustrate the role of cellular division mitosis and differentiation in producing and maintaining complex organisms. In this case use tissue paper to withdraw water from one side of the cover slip while adding the salt solution at the other side. Chlorophyll and responsible for photosynthesis are therefore only present in the leafy part of the onion above ground and absent in the bulb which grows below ground. The water molecules moved down concentration gradient from an area of higher to lower water potential.
The evidence is that the cells are fairly uniform in size and shape, suggesting they are the same type of cell. We need a single layer of pigmented cells. Lab 1B — Table 1. 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. Make a wet mount of the red onion epidermis.
Students may note that the onion cells lack chloroplasts and chlorophyll or you can point this out to younger students. If you connect a water hose to spray your grass, the water will come out faster than a device that attaches to water your grass. This produced basically the identical view as the original, since it was back to being mainly water again, with the cell wall and membrane very close to each other. How does iodine work to make onion bulb cytoplasm and nucleus visible? 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. Ans: Answers will vary depending on how much cell biology has been covered prior to the experiment.
Osmosis will occur resulting in either turgid cells or plasmolysed cells. The observation showed a large number of onion cells. See the diagram in your lab manual. Teaching notes This experiment could be run as a qualitative investigation of the effects of water and sodium chloride solution on the contents of plant cells. Which plant organ is modified to produce onion bulbs? Introduction: Plant cells have a cell wall and cell membrane which animal cells do not have. Animal cells usually burst at this point as they do not have the strong cell walls that plant cell do.
When the water potential is high, the cell is most full of water and is at its maximum volume. This… teabag was placed into a beaker of water. The salt water should flow beneath the cover slip. Cover it with a drop or two of distilled water. Chromatins are structures that are loosely coiled in the cell. Lab 1C — sing the potato core borer, obtain 24 cylindrical slices of potato, four for each cup. Because of this, the root tip is an excellent system in which to observe the entire cell cycle, including the processes of nuclear division mitosis and cell division cytokinesis.
This is because they have a cell wall made up of cellulose which maintains its shape. Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction. Make sure that you do. Unlike animal cells, students will also notice that the plant cells have a more regular shape. Put each bag into a beaker of distilled water and let stand for half and hour.