Electron microscopy, and the size and scale of cells | Exit Quiz | Oak National Academy

Which type of microscope uses electrons to view specimens in 3D?

• light microscope

• compound microscope

• scanning electron microscope

• transmission electron microscope

Answer explanation

A scanning electron microscope uses electrons to scan the surface of a specimen to produce 3D images.

In microscopy, what does the term 'resolution' refer to?

• the brightness of the light source

• making small objects appear larger in order to see more detail

• the distance at which two distinct points of a specimen can still be seen

• the size of the microscope stage

Answer explanation

The resolution of a microscope is the distance at which two distinct points can still be seen.

Which microscope would be most suitable for observing detailed structures within a cell, such as chloroplasts?

• light microscope

• compound microscope

• scanning electron microscope

• transmission electron microscope

Answer explanation

A transmission electron microscope is most suitable for observing detailed structures within a cell, such as chloroplasts.

A typical human hair has a diameter of approximately 60 micrometres (µm). What is its diameter in nanometres?

• 60 nm

• 600 nm

• 6000 nm

• 60 000 nm

Answer explanation

There are 1000 nanometres in a micrometre. 1000 × 60 = 60 000 nm

The nucleus of a cell measures 5 micrometres (µm) in diameter. In an image, the nucleus appears as 20 millimetres. What is the magnification of the nucleus in the image?

• 40x

• 400x

• 4000x

• 40 000x

Answer explanation

Image size: 20 × 1000 = 20 000 µm Real size of nucleus: 5 µm magnification: 20 000 ÷ 5 = 4000x

A plant cell has a length of 20 µm, while a bacterium measures 2 µm in length. How many times longer is the plant cell compared to the bacterium?

• 5 times

• 10 times

• 15 times

• 20 times

Answer explanation

The plant cell is 10 times longer than the bacterium.