Microscope Techniques and Onion Cells

The video tutorial demonstrates how to prepare a wet mount slide of stained onion epidermal cells. It covers obtaining the specimen, peeling the onion layer, and placing it on the slide. An alternative method for placing the onion skin is shown, followed by staining with iodine and applying a cover slip. The video also explains examining the specimen under different magnifications and adjusting light for better contrast. Observations of onion cells at high magnification are discussed, highlighting cell structures.

What is the first step in preparing a wet mount slide of onion epidermal cells?

• Placing the cover slip on the slide

• Applying iodine to the slide

• Obtaining the specimen from one layer of onion bulb

• Breaking the onion layer towards the rough side

What is the best way to obtain a large flat sheet of onion epidermal cells?

• Use a knife to cut the onion layer

• Use a microscope to view the onion layer

• Peel the layer of onion skin off directly onto the slide

• Apply pressure to flatten the onion layer

Why is iodine used in the preparation of a wet mount slide?

• To magnify the specimen

• To clean the slide

• To dry the specimen

• To stain the cells and make them easier to see

How should the cover slip be applied to minimize air bubbles?

• Place it flat on the specimen

• Hold it at a right angle and let it drop

• Press it down firmly

• Slide it across the specimen

What does the par focal feature of a microscope allow?

• Automatic adjustment of light levels

• Automatic staining of specimens

• Magnification beyond 1000x

• Switching objectives without losing focus

At what magnification do onion epidermal cells appear like misshapen bricks?

• 10x

• 40x

• 100x

• 400x

What is one method to improve the contrast of a specimen under a microscope?

• Increase the magnification

• Change the slide

• Adjust the light level

• Use a thicker specimen

What is the total magnification when using the high dry power lens?

• 400x

• 300x

• 100x

• 200x

What can be seen in onion epidermal cells at 400x magnification?

• Only the cell membrane

• Cell walls and elongated cells

• The entire onion bulb

• No details, just a blur

What is the purpose of adjusting the iris diaphragm on a microscope?

• To change the color of the specimen

• To clean the lens

• To adjust the amount of light passing through the specimen

• To increase the size of the specimen