Cancer

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.

Viruses cause disease.

What name is given to microorganisms that cause disease?

Tick (✓) one box.

The body has defences to stop viruses entering.

Draw one line from each defence to the part of the body that provides the defence.

Part of the body that

Some viruses can cause tumours to develop.

Complete the sentence.

Choose the answer from the box.

A tumour can form when changes to cells cause uncontrolled

cell.

Malignant tumours are cancers.

Which two sentences describe malignant tumours?

Tick (✓) two boxes.

HPV is a virus that can cause one type of cancer in females.

In the UK since 2008, most 12 to 13-year-old females have been vaccinated against HPV.

Scientists investigated the percentage of 16 to 18-year-old females with HPV.

Table 2 shows the results.

What does Table 2 show about the percentage of females with HPV from 2010 to 2016?

Suggest the reason for the change you described in Question 02.5.

The HPV vaccine contains an inactive form of the virus.

The inactive form of the virus is injected into the body.

Which part of the blood responds to the inactive virus?

Tick (✓) one box.

What is produced by the body in response to the inactive virus?

Tick (✓) one box.

Suggest one reason why some parents refuse to allow their children to have the HPV vaccine.

Do not refer to the pain of the injection in your answer.

Figure 11 shows where three of the same type of tumour were found in a patient.

Malignant tumours are cancers.

Describe what happens to cells when a tumour forms.

What evidence is there in Figure 11 to suggest that the tumour in the lung is malignant?

Some types of cancer can cause the numbers of blood components in a person’s body to fall to a dangerously low level.

A person with one of these types of cancer may experience symptoms such as:

• tiredness

• frequent infections

• bleeding that will not stop after the skin is cut.

Explain how a very low number of blood components in the body can cause these symptoms.

Some patients with a very low number of blood cells may be given a blood

transfusion.

A blood transfusion is where a patient receives blood from a donor.

Different people have different blood groups.

Figure 12 shows:

• the red blood cells found in people with different blood groups

• the antibodies that can be made by people with different blood groups.

Antibodies can bind to antigens that have complementary shapes.

When antibodies bind to the antigens on red blood cells, many red blood cells begin to clump together.

Each red blood cell is about 8 µm in diameter.

Many capillaries have an internal diameter of about 10 µm.

In one type of blood transfusion, only red blood cells from a donor are transferred to

the patient.

It is dangerous for a patient with blood group A to receive red blood cells from a donor with blood group B.

Explain why.

Explain why blood group O red blood cells can be given to patients with any blood group.

Table 4 shows some of the risks associated with blood transfusions.

Which risk has the lowest probability of occurring?

Tick (✓) one box.

A person has a tumour blocking the tube leading from the gall bladder to the small intestine.

Explain why this person would have difficulty digesting fat.

Pancreatic cancer develops when a malignant tumour grows inside the pancreas.

The pancreas produces digestive enzymes. What is an enzyme?

Carbohydrase is an enzyme produced by the pancreas.

Name two other organs in the digestive system that produce carbohydrase.

One symptom of pancreatic cancer is weight loss. Explain how pancreatic cancer may cause a person to lose weight. Do not refer to hormones in your answer.

Enzyme A and enzyme B are involved in controlling cell division in pancreatic cancer cells. Most cancer cells produce both enzyme A and enzyme B. Some people have a gene mutation that stops cancer cells producing enzyme B.

Figure 9 shows how cell division is controlled in pancreatic cancer cells.

Scientists have developed a drug that inhibits enzyme A. The drug is given to pancreatic cancer patients who have the gene mutation that stops cancer cells producing enzyme B. The drug only targets cancer cells.

Explain why the drug can be used to treat pancreatic cancer in patients with the gene mutation.

Use information from Figure 9.

Explain why the drug could not be used to treat pancreatic cancer in a patient that produces both enzyme A and enzyme B.

The drug was trialled before it was licensed for use. To improve validity of the results in the trial:

• some patients were given a placebo

• a double-blind trial was used.

Give reasons why a placebo and a double-blind trial were used.

A double-blind trial

One stage in a drug trial is to test the drug on healthy volunteers.

What is the next stage in the drug trial?

Tick (✓) one box.

A monoclonal antibody has been produced to treat pancreatic cancer.

Explain how the monoclonal antibody works to treat pancreatic cancer.