Observing mitosis in plant cells using a light microscope | Exit Quiz | Oak National Academy

Which part of the microscope is the line pointing towards?

• eyepiece lens

• coarse focus wheel

• objective lens

• stage

Answer explanation

The line is pointing towards the objective lens. There are usually three of these that magnify the image for example x4, x10 and x40.

In which two places does mitosis take place in an onion?

• tips of shoots

• outer layer of skin

• tips of roots

• inner layer of skin

Answer explanation

Mitosis takes place in the tips of roots and shoots in onion cells. These cells can be used to view the stages of mitosis when viewed under a microscope.

Put these stages in order to show how a microscope should be used?

• Turn the objective lens to a higher power to increase the magnification.

• Use the coarse focus wheel to roughly focus the image.

• Turn the objective lens to the lowest power.

• Use the fine focus wheel to get a sharp focus.

• Clip the specimen onto the stage and turn on the light.

Answer explanation

There are a specific sequence of steps to follow when using a microscope to make sure the image is magnified and focussed correctly to produce a clear image.

The image has circled a stage of the cell cycle, what is happening?

• Cell growth; DNA and sub-cellular structures are being copied.

• Chromosomes are lining up along the middle of the cell.

• Cytoplasm and cell membrane are dividing.

Answer explanation

The image shows the chromosomes lining up along the middle of the cell. After this the chromosomes are pulled to either end of the cell.

The image has circled a stage of the cell cycle, what is happening?

• The cytoplasm and cell membrane are dividing.

• Cell growth; DNA and sub-cellular structures are being copied.

• The chromosomes are being pulled to either end of the cell.

Answer explanation

The image shows the first stage of the cell cycle; cell growth. In this stage the DNA and sub-cellular structures are copied.

Which statements describe what has happened to the circled cell?

• The DNA is decondensed and held within a nucleus.

• The DNA has condensed to form visible chromosomes.

• The nuclear membrane is formed around the DNA.

• The nuclear membrane has broken down.

Answer explanation

After cell growth the DNA condenses to form visible chromosomes and the nuclear membrane breaks down.