Microscopy

Blood contains different types of cell.

Complete the sentences.

Choose answers from the box.

White blood cells defend the body against

Some white blood cells release chemicals that neutralise toxins. These chemicals

Figure 3 shows a white blood cell.

The image of the white blood cell in Figure 3 is magnified 4000 times.

Calculate the real width of the white blood cell.

Complete the following steps.

Measure width W in millimetres (mm).

Convert your measurement to micrometres (µm).

1 millimetre (mm) = 1000 micrometres (µm).

Calculate the real width of the white blood cell.

Use the equation:

Table 3 shows information about different types of blood vessel.

The width of a red blood cell is 8 µm.

Figure 4 shows red blood cells in one type of blood vessel.

Which type of blood vessel is shown in Figure 4 ?

Use Table 3.

Tick () one box.

Explain why arteries need to have thick walls.

Use Table 3.

Coronary arteries in the heart can become narrowed.

What happens inside coronary arteries to cause them to become narrowed?

Explain why narrowed coronary arteries can be dangerous.

Treatments are available for some cardiovascular diseases.

Draw one line from each cardiovascular disease to a treatment for the disease.

Why is coronary heart disease described as a ‘non-communicable disease’?

This question is about the human circulatory system.

Blood plasma transports blood cells around the body.

Give one other function of blood plasma.

Do not refer to oxygen in your answer.

Figure 5 shows a red blood cell.

The image of the red blood cell in Figure 5 is magnified 7200 times.

Calculate the real diameter of the red blood cell.

Give your answer in micrometres (µm).

Figure 6 shows the heart.

Blood pressure is a measure of the force of the blood against the walls of the blood vessels.

Table 5 shows information about the different types of blood vessel shown in Figure 6.

Complete Table 5 using the correct letters from Figure 6.

One row has been completed for you.

Name blood vessel D in Figure 6.

Describe the structure of the walls of an artery.

An athlete ran on a running machine.

The athlete:

• reached their maximum intensity of exercise and then stopped exercising

• had their use of oxygen recorded

• had the lactic acid concentration in their blood recorded.

During the exercise the athlete respired aerobically and anaerobically.

Explain why anaerobic respiration is less efficient than aerobic respiration.

Figure 7 shows the athlete’s use of oxygen and the lactic acid concentration of blood during exercise and after exercise.

Explain why the use of oxygen remained high after the athlete stopped exercising.

Some athletes regularly exercise in conditions that increase the number of red blood cells.

Explain why having an increased number of red blood cells is an advantage to an athlete.

Cancer occurs when there is uncontrolled cell division.

Which two factors can cause cancer?

Tick () two boxes.

What type of cell division occurs in cancerous cells?

Tick () one box.

Complete the sentences.

Choose answers from the box.

Figure 4 shows the cell cycle.

What percentage of the time taken for the cell cycle does the cell growth stage take?

Use Figure 4.

Tick () one box.

What happens during stage X of the cell cycle in Figure 4 ?

Tick () one box.

Figure 5 shows an animal cell during cell division.

Name structure Z in Figure 5.

The image of the cell in Figure 5:

• is magnified 800 times

• has a width of 50 mm.

Calculate the real width of the cell in Figure 5.

Give your answer in micrometres (µm).

Use the equation:

1 mm = 1000 µm

Some drugs can treat cancer.

Complete the sentences.

Choose answers from the box.

In drug trials some patients are given a tablet which does not contain the drug.

What name is given to the tablet that does not contain the drug?

Cancer is caused by changes in cells that result in uncontrolled cell division.

Before a cell begins to divide, its DNA replicates to form two copies of each chromosome.

Describe one other change that occurs in a cell before the cell begins to divide.

Figure 8 shows a cell during one of the stages of cell division.

Name structure Z in Figure 8.

Structure Y in Figure 8 is a cylinder.

For structure Y:

• real volume = 24 500 000 nm³

• real radius = 125 nm.

The length of a cylinder is calculated using the equation:

The length of the image of structure Y in Figure 8 is 4 mm.

Calculate the magnification of structure Y in Figure 8.

Use π = 3.14

Magnification = ×

Figure 9 shows some of the stages of cell division.

Some cancer drugs prevent cell division.

Drug X prevents the fibres from attaching to the replicated chromosomes in stage 1.

Explain why a cell cannot complete division when affected by drug X.

Give the reason why a drug that stops cell division helps to treat cancer.

New cancer drugs are tested in clinical trials.

Preclinical testing happens before clinical trials.

What is involved in preclinical testing of drugs?

Tick (✓) one box.

Figure 3 shows a microscope.

Draw one line from each part of the microscope to the function of the part.

Part of the

A student prepared some onion cells.

The student viewed the onion cells using a microscope.

This is the method used.

1. Cut an onion into pieces using a sharp knife.

2. Peel off a thin layer of cells from one piece.

3. Place the layer of cells onto a microscope slide.

4. Add three drops of iodine solution to the layer of cells.

5. Cover with a cover slip.

6. Place the slide on the stage of the microscope.

Why was iodine solution added to the layer of onion cells?

Tick (✓) one box.

Why was a thin layer of onion cells used?

Tick (✓) one box.

The student was worried about using a sharp knife to cut the onion.

The student wrote a risk assessment for using a knife.

Draw one line from each part of the risk assessment to the description of the part.

Part of risk assessment
Description

Figure 4 shows what the student saw using the microscope at a magnification of ×400.

Line A – B in Figure 4 shows the length of cell Z.

Calculate the real length of cell Z.

Complete the following steps.

Measure the length of line A – B in millimetres (mm).

Give your measurement of the length of line A – B in micrometres (µm).

1 mm = 1 000 µm

Calculate the real length of cell Z.

Use the equation:

How would onion cells look different if they were seen using an electron microscope?

Tick (✓) two boxes.

Figure 4 is repeated below.

Figure 5 shows the student’s drawing of Figure 4.

What two improvements could the student make to the drawing in Figure 5 ?

Tick (✓) two boxes.

A student prepared some onion cells. The student viewed the onion cells using a light microscope. This is the method used.

1. Cut an onion into pieces using a sharp knife.

2. Peel off a thin layer of onion epidermis from one piece of onion.

3. Place the onion epidermis onto a microscope slide in a single flat layer.

4. Add three drops of iodine solution.

5. Slowly lower a cover slip at an angle onto the onion epidermis.

6. Place the slide on the stage of the microscope.

Table 4 shows a risk assessment for this experiment. Complete Table 4.

Give a reason for each of the following steps in the method.

A thin layer of onion epidermis is used.

Iodine solution is added to the onion epidermis.

The cover slip is lowered onto the onion epidermis at an angle.

Figure 3 shows what the student saw under the microscope at a magnification

of ×400.

The length of cell Z in Figure 3 is 4.8 cm. Calculate the real length of cell Z. Give your answer in micrometres (µm).

Figure 4 shows the student’s drawing of Figure 3.

Give two ways the student could improve the drawing in Figure 4.

Onion cells can be seen using an electron microscope. Give two ways onion cells would look different when seen using an electron microscope.

This question is about cells.

Figure 1 shows a cell.

What type of cell is shown in Figure 1 ? Tick (✓) one box.

Figure 2 shows an algal cell.

What is the function of the cell wall? Tick (✓) one box.

The algal cell is green. Which part of the algal cell makes it green in colour? Tick (✓) one box.

Cells contain sub-cellular structures. Draw one line from each structure to its function.

A student prepared a microscope slide of cheek cells.

The student looked at one cell using a microscope. Figure 3 shows the image the student saw.

What should the student do to get a clear image? Tick (✓) one box.

The student then obtained a clear image.

Figure 4 shows the clear image.

Measure the length of the nucleus (A) and the length of the cell (B) in millimetres (mm).

How many times longer is the cell (B) than the nucleus (A)?

The student looked at another cell. The image width of the cell was 40 mm The real width of the cell was 0.1 mm Calculate the magnification of the cell. Use the equation:

Magnification = × 12

Figure 12 shows an animal cell viewed using a microscope.

The cell contains a nucleus.

What is the function of the nucleus?

Name one type of cell that does not contain a nucleus.

Draw a simple diagram of the cell in Figure 12.

Label two parts of the cell.

Name one structure found in a plant cell but not found in an animal cell.

Figure 13 shows some different cells.

The real length from point X to point Y is 0.06 mm

Calculate the magnification.

Use the equation:

The cells shown in Figure 13 were viewed using a light microscope.

Give two advantages of using an electron microscope instead of a light microscope.

Figure 1 shows an animal cell viewed using a microscope.

The cell contains a nucleus.

What is the function of the nucleus?

Name one type of cell that does not contain a nucleus.

Draw a simple diagram of the cell in Figure 1.

Label two parts of the cell.

Name one structure found in a plant cell but not found in an animal cell.

Figure 2 shows some different cells.

The real length from point X to point Y is 0.06 mm

Calculate the magnification.

Use the equation:

The cells shown in Figure 2 were viewed using a light microscope.

Give two advantages of using an electron microscope instead of a light microscope.

Plants are made up of cells, tissues and organs.

Draw one line from each level of organisation to the correct plant part.

Level of organisation
Plant part

Figure 3 shows a plant cell drawn to scale.

Where in a plant would the cell in Figure 3 be found?

Tick one box.

Calculate the length of the chloroplast labelled in Figure 3.

Cells in plant roots do not photosynthesise.

Give one reason why.

As a plant grows, new root hair cells are formed from unspecialised cells.

How does an unspecialised cell become a new root hair cell?

Tick one box.

Scientists can clone plants using tissue culture.

Figure 4 shows the process of tissue culture.

Why might scientists want to clone plants?

Tick one box.

What is the advantage of cloning plants using tissue culture?

Tick one box.

The growth medium in Figure 4 helps the plants to grow.

Name one substance in the growth medium.