Hobbies And Interests
Plant Cell Models
Plant cells include many components such as the cell wall, cytoplasm, golgi bodies, chloroplast, and membranes. Identifying these parts is important to understanding how plant cells work. Find diagrams of these parts in biology text books and then construct a model to show this inner structure. A diorama using the box as the cell walls and inserting the inner structures constructed from clay or other materials such as yarn, toothpicks, gummi or candies is one of the simplest models. Other options include clay models or edible models made with cake, frosting and candies.
Demonstrate Osmosis
Part of osmosis is the passage of liquid through a semi permeable membrane. To demonstrate this, cut the bottoms from a fresh celery stalk and an old celery stalk and compare the differences between the cells within each stalk end. Place both stalks into a cup of water colored with food coloring. The color will move up the celery stalks because tubes called xylem, carry liquid to the plant's stem. Remove the stalks from the water and examine the bottoms. You'll see small circles colored by the water. These are the xylem. Note differences in how quickly the cells in the fresh and old celery sent the liquid up.
Plant Cell Regeneration
Special roots called adventitious roots develop from the broken pieces of multicelled organisms like plants, making regeneration possible. To demonstrate, fill two jars about 3/4 full with water. Cut four healthy stems with leaves from a geranium plant. Place the cut ends of two stems into each jar and set the jars in direct sunlight. Observe daily for about two weeks, and then transfer them into pots filled with soil. Roots will grow from the ends of the stems in about 10 days. After a few months, the stems will grow into plants. Repeat the experiment with a leafless stem and then with stems that have more leaves than the original experiment to see if the leaves increase growth speed.
Plasmolysis
Plasmolysis is the shrinking of the protoplasm from the cell wall due to water loss from osmosis. This results in gaps between the cell wall and membrane. To see this process, cut a red onion into wedges and peel a thin layer of tissue from the thickest part of a wedge. Place a drop of water on two slides then add the onion tissue to each and add a drop of water and a drop of iodine (to stain) over the tissue. Top with a glass cover and allow the air bubbles to escape. Set the second slide aside. Examine the first slide under a compound microscope and identify the structures you see. Dissolve 5 grams of salt to 100 milliliters of water. Make a second solution using 10 grams of salt to 100 milliliters of water. Add a few drops of the 5 gram solution to the first slide and examine the effect under the microscope and record. Add the 10 gram solution to the second slide and examine the effects. The salt should cause the protoplasm to shrink, causing clear differences between the slides.