Laboratory activity 3 (post lab)
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This document summarizes a lab activity where students observed plant cell structures using a microscope. The objectives were to locate, identify, and describe parts of the plant cell. Two specimens - fanwort leaf and onion leaf - were used. For fanwort, the cell wall and chloroplasts were observed, while onion showed a cell wall and nucleus. The purpose of crystal violet dye was to enhance contrast and highlight organelles. Thin sections of specimens were needed for light to pass through and provide clear images under the microscope.
Laboratory activity 3 (post lab)
- 1. A POST LABORATORY DISCUSSION
- 2. OBJECTIVES OF THE LAB. ACT. At the end of the laboratory period, you should be able to: Locate the parts of the plant cell. Identify the parts of the cell. Describe the parts of the plant cell.
- 3. RESULTS Cellular organelles seen in Fanwort Leaf (Cabomba caroliniana) 1. Cell wall - it is the outer most layer of the cell. 2. Chloroplastids or chloroplasts – it was observed as a spherical or globular green structures inside the cell. Cellular Organelles seen in Onion Leaf (Allium cepa) 1. Cell wall – it is the outermost layer of the cell. 2. Nucleus – a dark small spherical staining body inside the cell.
- 4. DISCUSSION 1. Review: Give two differences/distinctions between a plant and an animal cell? (2 points) Possible answers could be the presence of cell wall in plants but absence in animals, the presence of chloroplastids in plants but absence in animals.
- 5. DISCUSSION 2. What are the specimens used in this experiment? Give the scientific name and common name of each. Cabomba caroliniana – Fanwort Kingdom: Plantae Subkingdom: Tracheophyta Division: Magnoliophyta Subclass: Magnoliidae Order: Nymphaeales Family: Cabombaceae Genus: Cabomba Species: Cabomba caroliniana Gray Common Name: Carolina fanwort, fanwort
- 6. DISCUSSION Allium cepa L. – Garden onion Kingdom: Plantae Subkingdom: Tracheobionta Division: Magnoliophyta Class: Liliopsida Subclass: Lilidae Family: Amaryllidaceae Genus: Allium L. Species: Allium cepa L. Common name: Garden onion
- 7. DISCUSSION 3. What is the purpose of the crystal violet dye? Explain. The crystal violet dye is used to enhance the contrast in the microscopic image seen. It was used to highlight the biological structures (organelles) in the specimens. The dye reacts with certain organelles only.
- 8. DISCUSSION 4. Why do you need very thin sections of the specimens to be observed in each specimen? We need to make the specimens thin enough to allow light to pass through. If the specimen is thick, not enough light will be able to pass through resulting to a blurry image.
- 9. DISCUSSION 5. What cell parts have you observed in the specimen? Fanwort – Cell wall, cell membrane and Chloroplastid. Garden onion – Cell wall, cell membrane and Nucleus.
- 10. Fanwort – Scanner – 40x
- 11. Fanwort– LPO – 100x
- 12. Fanwort – MPO – 400x
- 13. Fanwort – OIO – 1000x Anacharis sp. 1000x (oil) magnification Observable parts: chloroplasts, cell wall
- 14. Garden Onion – Scanner – 40x
- 15. Garden Onion – LPO – 100x
- 16. Garden Onion – MPO – 400x
- 17. Garden Onion – OIO – 1000x Allium cepa 1000x (oil) magnification Observable parts: nucleus, cell wall
- 18. GARDEN ONION – OIO – 2000x Allium sepa 2000x (oil) magnification Observable parts: nucleus Nucleolus?