Stem cells

In people with severe liver disease the liver stops working correctly.

A person with severe liver disease can be treated with:

• an injection of embryonic stem cells or

• a liver transplant from a donor.

The person’s body can reject embryonic stem cells and can reject a liver transplanted from a donor.

What property of embryonic stem cells makes them suitable to treat liver disease?

Suggest one ethical reason why a person may not want an injection of embryonic stem cells.

Drugs can be used to reduce the risk of liver rejection after a transplant.

One drug contains monoclonal antibodies.

The monoclonal antibodies are specific to an antigen on the surface of liver cells.

Figure 9 shows part of the process used to create the monoclonal antibodies.

Name the three types of cell in Figure 9.

How is the mouse stimulated to produce cell type A ?

A patient with severe liver disease was given a liver transplant.

The drug containing the monoclonal antibody is given to the patient.

Explain how the monoclonal antibody stops the patient’s white blood cells from attacking the cells of the donor liver.

Give one other use of monoclonal antibodies.

Do not refer to pregnancy tests.

The liver produces bile.

Bile is needed for efficient digestion.

Where is bile stored in the human body?

Tick () one box.

Explain why a person with severe liver disease has difficulty digesting fats.

A root is a plant organ.

Plant roots contain many different types of tissue.

What is a tissue?

Tissue in the tip of a plant root contains stem cells.

Stem cells can differentiate into any type of cell.

Name the type of tissue in plants that contains stem cells.

In the past many drugs were extracted from plants.

Aspirin is a painkiller.

Which plant does aspirin originate from?

Scientists have extracted chemical A from the deadly nightshade plant.

Chemical A can be used as a painkiller.

Table 5 shows information about where chemical A is found.

The scientists usually extract chemical A from the berries of the deadly nightshade plant.

Suggest one reason why berries are used instead of leaves or roots.

A deadly nightshade plant has chlorosis (yellow leaves).

The mass of chemical A found in the leaves of the plant is 60% of the mass shown in Table 5.

Calculate the mass of chemical A in 200 g of the leaves with chlorosis.

Give your answer in mg.

Suggest one reason why the leaves of the deadly nightshade plant have chlorosis.

Chemical A has not been tested in large-scale clinical trials in the UK.

It is important for drugs to be tested in clinical trials before the drugs are approved for use by the public.

Give two reasons why.

There are many online reports making claims about the effects of chemical A.

Some of these reports are biased.

Suggest one reason why a report making claims about the effects of chemical A may be biased.

How can scientists be sure that claims about new drugs are valid?

Tick (✓) one box.

A root is a plant organ. Plant roots contain many different types of tissue.

What is a tissue?

Tissue in the tip of a plant root contains stem cells. Stem cells can differentiate into any type of cell. Name the type of tissue in plants that contains stem cells.

In the past many drugs were extracted from plants.

Aspirin is a painkiller. Which plant does aspirin originate from?

Scientists have extracted chemical A from the deadly nightshade plant. Chemical A can be used as a painkiller. Table 1 shows information about where chemical A is found.

The scientists usually extract chemical A from the berries of the deadly nightshade plant. Suggest one reason why berries are used instead of leaves or roots.

A deadly nightshade plant has chlorosis (yellow leaves).

The mass of chemical A found in the leaves of the plant is 60% of the mass shown in Table 1.

Calculate the mass of chemical A in 200 g of the leaves with chlorosis. Give your answer in mg.

Suggest one reason why the leaves of the deadly nightshade plant have chlorosis.

Chemical A has not been tested in large-scale clinical trials in the UK.

It is important for drugs to be tested in clinical trials before the drugs are approved for use by the public. Give two reasons why.

There are many online reports making claims about the effects of chemical A. Some of these reports are biased.

Suggest one reason why a report making claims about the effects of chemical A may be biased.

How can scientists be sure that claims about new drugs are valid? Tick (✓) one box.

Figure 1 shows animal cells.

Some of the cells are dividing by mitosis for growth and repair.

What fraction of the cells in Figure 1 is dividing by mitosis?

Tick (✓) one box.

The cells which are not dividing in Figure 1 each contain 10 chromosomes.

One of these cells divides by mitosis to produce two new cells.

How many chromosomes will each new cell contain after mitosis?

Tick (✓) one box.

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

Complete the sentences.

Choose answers from the box.

After the chromosomes have been pulled to each end of the cell, the

Figure 2 shows the time taken to complete different stages of the cell cycle.

Which stage of the cell cycle takes the most time?

Tick (✓) one box.

What percentage of time in the cell cycle is stage A ?

Tick (✓) one box.

Stem cells divide by mitosis.

Scientists can use stem cells from an embryo to create heart cells in a laboratory.

Which organ system contains heart cells?

Tick (✓) one box.

Name one medical condition that could be treated using heart cells created from an embryo.

Give one reason why a patient may not want to be treated with heart cells created from an embryo.

Turn over for next question

This question is about cell division.

Which process makes two identical new body cells for growth and repair? Tick (✓) one box.

Figure 5 shows the three stages of a cell cycle.

Draw one line from each stage of the cell cycle to what happens during that stage. Stage of cell cycle What happens during that stage

What percentage of the total time for the cell cycle is taken by stage 1?

A cell divides to form two new cells every 24 hours. How many days will it take for the original cell to divide into 8 cells? Tick (✓) one box.

The chromosomes contain the genetic material. Name the chemical which the genetic material is made from.

The genetic material is made of many small sections. Each section codes for a specific protein. What is one section of genetic material on a chromosome called? Tick (✓) one box.

Stem cells are cells which have not yet been specialised to carry out a particular job. Bone marrow cells are one example of stem cells. Explain how a transplant of bone marrow cells can help to treat medical conditions.

An animal called an axolotl lives in water.

Figure 3 shows an axolotl.

Oxygen enters the axolotl’s bloodstream through the gills by diffusion.

What is diffusion?

Tick (✓) one box.

Describe how one feature of the axolotl’s gills increases the rate of diffusion of oxygen.

Use information from Figure 3.

If a gill of an axolotl is removed, stem cells in the damaged area will divide and a new gill will grow.

Complete the sentence.

Choose the answer from the box.

When stem cells specialise to produce gill cells, this process is

known as.

Complete the sentence.

Choose the answer from the box.

To grow a new gill the stem cells divide by.

Which one of the following does not contain stem cells?

Tick (✓) one box.

Axolotls are small animals. Axolotls are used in stem cell research.

What are two advantages of using axolotls in stem cell research?

Tick (✓) two boxes.

Oxygen uptake in humans takes place in the lungs.

Figure 4 shows the human breathing system.

Where does oxygen enter the bloodstream?

Tick (✓) one box.

Name part E on Figure 4.

Which blood vessel carries blood to the lungs?

Tick (✓) one box.

A small animal called an axolotl lives in water. The axolotl has a double circulatory system.

Define the term double circulatory system.

Figure 7 shows the double circulatory system of the axolotl.

Figure 7

The following figure cannot be reproduced here due to third-party copyright restrictions.

The heart of the axolotl has only one ventricle.

Label the ventricle on Figure 7.

Explain why having only one ventricle makes the circulatory system less efficient than having two ventricles.

Figure 8 shows an axolotl.

Explain why an axolotl may die in water with a low concentration of oxygen.

If a gill of an axolotl is removed, a new gill will grow in its place.

Scientists hope to use information on how axolotls grow new gills to help with regenerating human tissue.

Name the type of cell that divides when a new gill grows.

Name one condition that could be treated using regenerated human tissue.

Suggest one reason why an axolotl is a suitable animal for research in the laboratory.

An axolotl may not be a suitable animal to study when researching regeneration in human tissue.

Suggest one reason why.

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.