Stem cells

This question is about cells.

Figure 1 shows a muscle cell.

The nucleus and cytoplasm are parts of a muscle cell.

Draw one line from each part of the muscle cell to the correct label from Figure 1.

What is the function of the nucleus?

What part of a cell controls the movement of substances into the cell?

Figure 2 shows a bacterial cell.

What type of cell is the bacterial cell in Figure 2 ?

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Which are two features of bacterial cells?

Tick () two boxes.

Stem cells are cells that are not specialised.

Stem cells can be collected from human bone marrow.

What type of stem cells are found in bone marrow?

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Which process produces stem cells in humans?

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Stem cells can be used to produce blood cells.

A blood transfusion is when a patient is given blood cells.

Table 1 compares two different methods of providing blood cells that can be given to a patient.

A scientist stated:

‘Blood cells produced from stem cells are better to use for a blood transfusion than blood cells from a donation.’

Suggest two reasons that support the scientist’s statement.

Ciliated cells have small hair-like structures called cilia on the cell surface.

Ciliated cells are found in the trachea and in the oviducts.

Oviducts are part of the female reproductive system.

Figure 7 shows cilia lining an oviduct.

Give one piece of evidence that an electron microscope was used to produce the image shown in Figure 7.

Do not refer to colour in your answer.

Describe the function of ciliated cells in the oviduct.

The mean length of the cilia in an image was 6 mm.

The cilia were viewed at a magnification of 1.5 × 10³

Calculate the real mean length of the cilia.

Give your answer in micrometres (µm).

Red blood cells are a type of cell found in humans.

People with anaemia do not have enough red blood cells.

Explain why a person with anaemia is likely to experience muscle fatigue.

Scientists have produced red blood cells from stem cells in a laboratory.

The scientists:

• collected a sample of blood from a donor

• extracted 5 × 10⁵ stem cells from the sample.

Each stem cell was developed into 100 000 red blood cells.

35% of the red blood cells made from stem cells are suitable to use in a patient.

Calculate the number of red blood cells made from the donor’s sample that could be used in a patient.

Give your answer in standard form.

Patients with anaemia are sometimes given a blood transfusion.

A blood transfusion is when a patient is given blood.

The patient can be given red blood cells:

• produced from stem cells in a laboratory or

• from a whole blood donation.

Table 2 gives information about the two sources of red blood cells.

Evaluate the use of red blood cells:

• produced from stem cells in a laboratory

• from a whole blood donation.

You should refer to costs in your answer.

This question is about photosynthesis.

What is the symbol equation for photosynthesis?

Tick (✓) one box.

A student investigated the relationship between temperature and the rate

of photosynthesis.

The student measured the volume of gas produced by an aquatic plant in 1 hour.

The student collected the gas in a measuring cylinder.

Table 2 shows the results.

Describe the effect of increasing temperature on the rate of photosynthesis.

Use data from Table 2.

Explain why no gas was produced by the plant at 45 °C.

How could the student increase the accuracy of the results?

Tick (✓) one box.

A person grows tomatoes in a greenhouse.

The mean temperature of the greenhouse is 15 °C.

A heater would keep the temperature of the greenhouse at 25 °C.

Suggest two reasons against using a heater set at 25 °C in the greenhouse.

Do not refer to cost in your answer.

The person cut a stem from one of the tomato plants.

The cut stem was placed in soil to grow new roots.

Which tissue in the cut stem will differentiate into new root cells?

Tick (✓) one box.

Antibiotics are drugs used to treat bacterial infections.

Mutations in bacteria produce new strains.

Some strains of bacteria are resistant to antibiotics.

Where do mutations happen in a bacterial cell?

A scientist investigated which antibiotics (A, B, C, D and E) killed Staphylococcus aureus (S. aureus) bacteria.

This is the method used.

1. Grow S. aureus bacteria in a Petri dish.

2. Cut five small discs of paper.

3. Soak each paper disc in a different antibiotic solution.

4. Put the five paper discs into the Petri dish.

5. Keep the Petri dish at 37 °C for 24 hours.

Figure 9 shows the results.

A clear area around a disc shows where the bacteria have been killed.

The scientist concluded:

‘ S. aureus is resistant to antibiotics C and E ’.

Explain the evidence for this conclusion.

Use Figure 9.

The scientist later discovered that S. aureus is not resistant to antibiotic E.

Suggest how the method was developed and showed that S. aureus is not resistant to antibiotic E.

Broken bones are sometimes repaired using a metal implant.

The area around an implant can become infected with S. aureus bacteria. The infection is usually treated with a long-term course of antibiotics.

Long-term use of antibiotics has led to the development of antibiotic resistant bacteria. Research is being carried out into alternative treatments.

Stem cells from bone marrow and from fat tissue have antimicrobial properties.

A scientist investigated the effect of four treatments on the area of infection around metal implants. Each treatment was injected into the area around the implant.

The four treatments were:

• unreactive solution

• antibiotic solution

• stem cells from fat tissue

• stem cells from fat tissue containing antibiotic.

Each treatment was tested on 5 patients where an infection had developed around their metal implant.

After 7 days of treatment, the scientist calculated the ratio:

area of infection: total tissue area

What was the independent variable in this investigation?

Tick (✓) one box.

Suggest one advantage of using stem cells from fat tissue, rather than using stem cells from bone marrow.

Stem cells containing antibiotic were produced by growing the cells for 24 hours in a solution containing the antibiotic.

How did the antibiotic enter the stem cells from the solution?

Give a reason for your answer.

Tick (✓) one box.

Figure 10 shows the results.

What is the range of results for the treatment with stem cells only?

A student looked at the results and concluded:

‘Injections of stem cells containing antibiotic should be used to treat all implant-related infections’.

Evaluate the student’s conclusion.

Use Figure 10.

Figure 5 shows the human heart.

Which blood vessel transports blood with the highest oxygen concentration into the heart? Tick (✓) one box.

Blood pressure is a measure of the force of the blood against the walls of the blood vessels. Which blood vessel transports blood at the highest pressure? Tick (✓) one box.

What is the correct order for blood flowing through the heart to the lungs? Tick (✓) one box.

Every year thousands of people in the UK have heart attacks.

A heart attack is caused when the heart muscle cells do not get enough oxygen, causing the cells to die.

Statins and stents are two treatments used to reduce the risk of someone having a heart attack. Evaluate the use of statins compared with the use of a stent to reduce the risk of a heart attack.

Many people who survive a heart attack get out of breath easily when they exercise gently. Explain why heart attack survivors get out of breath easily.

Scientists have developed patches of beating heart cells to repair damaged

heart tissue. The patches are placed onto areas of the heart where cells have died. New cells grow to replace the dead cells. The patches are made using a person’s own cells that are converted into stem cells.

Explain why stem cells are used to make the patches.

The scientists could have used human embryonic stem cells to make the patches. Give two advantages of using stem cells made from the person’s own cells, rather than using embryonic stem cells.

Cells divide in a series of stages called the cell cycle.

Stage 2 of the cycle is mitosis.

Figure 10 shows a simplified cell cycle for a human body cell.

Draw one line from each stage in the cell cycle to what happens during that stage.

What happens during that Stage in the cell cycle stage

The mass of DNA in a human body cell at the start of the cell cycle is 6 picograms.

What mass of DNA will be in each of the new cells produced by this cell division?

Tick one box.

Stem cells are undifferentiated cells.

Which statement about stem cells is correct?

Tick one box.

Stem cells from human embryos can differentiate into most types of human cell.

Research is being done into the use of embryonic stem cells in medical treatments.

The long-term effects of using embryonic stem cells in patients are not well understood.

In therapeutic cloning, human embryos are produced using a donated human egg cell and a cell from the patient.

• The embryo produced contains the same genetic information as the patient.

• Stem cells are taken from the embryo and stimulated to divide to form cells the patient needs.

• The embryo is then destroyed.

Suggest two advantages of therapeutic cloning.

Suggest two disadvantages of therapeutic cloning.

This question is about stem cells.

Give one place in a plant where stem cells are found.

What is one economic use of plant stem cells? Tick one box.

Embryonic stem cells divide by mitosis. Figure 9 represents a cell cycle for a human embryonic stem cell.

The mass of DNA in the cell at the start of the cycle is 6 picograms.

Convert 6 picograms to grams. Give your answer in standard form.

The time taken for this complete cell cycle is 15 hours. Calculate how many hours the cell spent in mitosis. Give your answer to 3 significant figures.

Describe what happens in each of the three stages of the cell cycle.

Figure 10 shows how embryonic stem cells are produced in therapeutic cloning for use in patients.

Give two advantages and two disadvantages of therapeutic cloning in medical treatments. Use Figure 10 to help you.

Disadvantage 2