Prepare and examine microscopically the transverse section of a dicotyledonous stem Flashcards
Define the term cotyledon.
A cotyledon is a seed leaf in a plant embryo that stores food and aids in early plant growth.
Name a dicotyledonous plant.
Sunflower, bean, or oak tree.
When using the light microscope, which objective lens will you use first?
The low-power objective lens (usually 4x) to get a wide field of view and focus on the specimen before increasing magnification.
Why will you use a thin slice of stem?
A thin slice is used to allow light to pass through for better visibility of internal structures under the microscope.
Explain how you cut a thin section of stem.
Used a sharp blade (scalpel or razor). Placed the stem on a cutting board for stability. Cut a thin, even section using a back-and-forth motion. Placed the section in water to prevent dehydration.
Name three tissue types in plants, giving the functions of each.
(a) Dermal tissue: Protects the plant and prevents water loss (e.g., epidermis). (b) Vascular tissue: Transports water, minerals, and food (e.g., xylem and phloem). (c) Ground tissue: Supports, stores nutrients, and carries out photosynthesis (e.g., cortex and pith).
If preparing a slide of a transverse section of a dicotyledonous stem, state the reason why you used an herbaceous stem rather than a woody one.
An herbaceous stem is softer and easier to cut into thin sections, while a woody stem is too hard to section properly.
Why was the stem cut between the nodes?
Cutting between the nodes ensures that the vascular bundles are evenly distributed, making it easier to study their arrangement.
Name two of the tissues that are not vascular tissues.
(a) Epidermis (dermal tissue) (b) Cortex (ground tissue)
Describe how you examined your section of stem with the microscope.
Placed the thin section on a glass slide with a drop of water. Added a coverslip to prevent air bubbles. Started with the low-power objective lens (4x) and focused using the coarse focus knob. Switched to a higher magnification (10x or 40x) for a more detailed view. Adjusted the diaphragm for better contrast.
