Answer the following questions with reference to the microscope - Leaving Cert Biology - Question 8 - 2014

To find the actual diameter of the cell, we utilize the formula:

diameter_{actual} = rac{diameter_{image}}{magnification}

First, we identify that the total magnification using both lenses is given by multiplying their magnifications:

magnification = 10× (from lens E) × 40× (from lens O) = 400×

Next, substituting the values:

diameter_{actual} = rac{0.8 ext{ mm}}{400} = 0.002 ext{ mm}

To obtain a sample of cells, I rubbed the inside of my cheek with a clean cotton swab. This method collects epithelial cells from the inner lining, which are then transferred to a glass slide for examination.

I used methylene blue as the stain on the sample to enhance the visibility of the cells under the microscope.

I placed the coverslip at an angle over the sample on the slide and then gently lowered it to avoid air bubbles, ensuring the specimen was protected and evenly covered.

A coverslip is used to protect the sample from drying out, which helps preserve it for observation. It also protects the microscope lens from coming into direct contact with the specimen, preventing contamination.

To examine the cells, I first focused using the coarse focus knob with the lowest power objective lens to locate the specimen. Once located, I switched to a higher power objective for a more detailed view, using fine focus to adjust for clarity.

The labelled diagram should include the following components of the cells:

• Cell membrane
• Cytoplasm
• Nucleus
• Any visible organelles

*Label each part clearly to describe the structure of the cell seen at high magnification.