The Cell 67 Experiment 1: Investigating Plant Cells (con\'t) Part 1: Onion epide

Question

The Cell 67 Experiment 1: Investigating Plant Cells (con't) Part 1: Onion epidermis The skin (epidermis) between the dormant leaves of an onion are a single cell thick, and serve as a great representation of the internal structure of plant cells. While you can not see all the organelles of the plant cell with a compound light microscope, you will be able to visualize certain cellular characteristics. Your instructor will provide you several images of an onion skin wet mount that you would visualize under a microscope in the lab. Use these images from www.thebiologyprimer.com/cell- lab to complete the questions below 5. Sketch a single onion cell and label the 6. Do the onion cells have chloroplasts? following: cell wall, cell membrane, nucleus, and nuclear membrane. 7. Why would you (or why would you not) expect to find chloroplasts in an onion cell? Part 2: Cytoplasmic streaming in Elodea cells Elodea is an aquatic plant (Fig. 2) with the unique quality of having leaves that are only two cells thick. This characteristic makes this plant a good model to study the living plant cells in action. In this exercise, you will see chloroplasts moving in the Elodea cells as the cells begin to photosynthesize. This movement is known as cytoplasmic streaming View the video of cytoplasmic streaming in an Elodea leaf at www.thebiologyprimer.com/cell-lab. Identify the major organelles of the Elodea cell and label them in Fig. 3. The space inside of the cell is known as the cytoplasm. In the cytoplasm, there are several green oval organelles, known as chloroplasts. In the center of the cell is a large vacuole used to store water and other molecules. Surrounding the cell is the cell wall, which appears as relatively thick boundaries between the Elodea cells. Fig. 2. Elodea www.thebiologyprimer.com

Explanation / Answer

Gram positive bacteria have very thick wall of peptidoglycan therefore they retain stain showing violet colour

gram negative also has peptidoglycan but has very thin layer so they cant retain violet colour

And counterstained with pink stain safranin

Gram negative has peptidoglycan but very less (10% of cell envelope)

And gram positive has more peptidoglycan ( 50-90% of cell envelope)

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