Stem cells

Figure 6 shows the bones in the limbs of a bird and a whale.

The bird and the whale have evolved from a common ancestor.

Give one way the structure of these limbs provides evidence for this evolution.

Charles Darwin developed the theory of evolution by natural selection.

Which scientist worked with Darwin on the theory of evolution by natural selection?

DNA is found in bones and stem cells.

Suggest one reason why DNA is found in bones.

Describe how stem cells help animals to grow.

Scientists have transplanted stem cells into the retina of the eye.

Name one type of light sensitive cell found in the retina.

Explain one reason for transplanting stem cells into the retina.

Figure 8 shows a diagram of a mouse sperm cell.

Which row of the table shows the functions of structure A and structure B?

The diploid chromosome number for a mouse is 40.

State the number of chromosomes in a mouse sperm cell.

After a mouse egg cell is fertilised, cell division produces a ball of genetically identical stem cells.

Which is the correct order for the stages of one cell division?

The genetically identical stem cells produce the cells that develop into an embryo.

Describe how stem cells produce the cells of an embryo.

Scientific research has made many discoveries and developments allowing stem cells to be used in medical treatments.

Figure 9 shows a timeline for some of these discoveries and developments.

2006 cells with
2014 cells that make 1963 discovery 1981 mouse embryonic stem cell insulin produced by of stem cells in embryonic stem properties produced generating stem cells bone marrow
cells isolated from adult body cells from skin cells

1968 bone marrow 1998 human 2009 embryonic transplant from a
embryonic stem stem cells used to sister to her brother
cells isolated treat spinal injury

Figure 9

Give one scientific reason why the bone marrow transplant in 1968 was from a sister to her brother.

Give one scientific reason why some people are opposed to the isolation of human embryonic stem cells.

Stem cells, with the properties of embryonic stem cells, can be produced from a patient’s own skin cells.

Discuss the benefits of using these stem cells to treat the patient.

Figure 12 shows a height percentile chart for boys.

The numbers on the right-hand side of the graph show the percentiles of the population for each growth curve.

A 10-year-old boy has a height of 140 cm.

Which is the percentile range for height for this boy?

State how percentile charts are used.

As we grow, we make new cells by mitosis and meiosis.

The cells that are made can become specialised.

Figure 13 shows a diagram of a sperm cell.

Describe two ways that the sperm cell is specialised.

Complete the table to show the results when a cell divides by mitosis or meiosis in humans.

Human body cells, except gametes, have 23 pairs of chromosomes.

The tips of plant roots are where many cells are dividing by mitosis.

Which term describes the area of a root where many cells are dividing by mitosis?

Plant root cells contain an enzyme that joins glucose molecules together to make starch.

Devise a plan to investigate the effect of pH on the activity of this enzyme.

State why the embryo of the pig must be engineered so it does not grow pig kidneys.

Explain why human stem cells are used for this process.

Figure 9 shows the number of organ transplants needed and the number of donors available in the USA from 1991 to 2018.

Compare the number of donors available with the number of organ transplants needed from 1991 to 2018.

Use information from the graph to support your answer.

State why scientists are genetically engineering animals for organ transplants.

*(c) Bacteria have been genetically engineered to produce human insulin since 1978.

Explain how bacteria can be genetically engineered to produce human insulin.

5 (a) Figure 7 shows cells from an onion root tip as seen using a light microscope.

(Source: © Rattiya Thongdumhyu/Shutterstock)

Figure 7

(i) Identify the stages of mitosis shown in cell Q and cell R.

(ii) Describe two processes that occur in cells during prophase.

(iii) State the term used to describe the process which occurs after mitosis, when the cell divides into two.

(iv) The diameter of one cell in Figure 7 is 0.075 mm. Which is this diameter in µm?

(b) A student placed a prepared slide on the stage of a light microscope. Describe how to adjust the microscope to view the slide at a magnification of ×400.

(c) Arthritis is a condition that occurs when cells in joints get damaged or destroyed. Stem cell therapy can be used to treat arthritis. Discuss the benefits and risks of using stem cell therapy to treat arthritis.

Figure 14 shows a banana plantation.

After the bananas have been harvested, the old plants are cut down.

The suckers then develop into mature plants producing the next crop of bananas.

The tip of each sucker contains a group of cells called a meristem.

Describe the function of a meristem in the growth of a plant.

A student took a sample of cells from a meristem to view under a light microscope.

Describe how the student would prepare a microscope slide using these cells.

Figure 15 is a drawing of a eukaryotic cell.

Structure Z is found in plant leaf cells.

Name structure Z.

Give one function of the mitochondrion.

*(c) DNA is found in the nucleus of cells.

Describe the structure of DNA and how it can be extracted from plant cells.

Figure 2 shows a banana plantation.

After the bananas have been harvested, the old plants are cut down.

The suckers then develop into mature plants producing the next crop of bananas.

The tip of each sucker contains a group of cells called a meristem.

Describe the function of a meristem in the growth of a plant.

A student took a sample of cells from a meristem to view under a light microscope.

Describe how the student would prepare a microscope slide using these cells.

Figure 3 is a drawing of a eukaryotic cell.

Structure Z is found in plant leaf cells.

Name structure Z.

Give one function of the mitochondrion.

Describe how a prokaryotic cell is different from the cell in Figure 3.

A student cut a piece of onion and placed it on a microscope slide.

The student then placed this slide on the stage of a light microscope and looked through the eyepiece.

No cells could be seen in the piece of onion.

Explain two ways this method could be improved to see details of the onion cells.

Figure 7 shows mitosis occurring in some plant cells.

The cells in Figure 7 were taken from a rapidly growing part of a plant.

Which part of a plant has rapidly dividing cells?

Which stage of mitosis is shown in cell R?

Describe two genetic similarities of the new cells that would be produced by cell Q in Figure 7.

The cells in Figure 7 were heated in hydrochloric acid.

State two safety precautions that should be taken when heating hydrochloric acid.

Explain one advantage of using an electron microscope to observe plant cells.

In 2012, two scientists were awarded the Nobel prize for their research on stem cells.

They showed that adult cells could be reprogrammed to become cells with the properties of embryonic stem cells.

Describe the possible benefits of this research.

Figure 11 shows four stages of mitosis, labelled P, Q, R and S.

Which is the correct order for these stages?

The stage of mitosis labelled S in figure 11 is

Interphase is part of the cell cycle.

Describe what happens during interphase.

Figure 12 shows a root tip with cells in different stages of mitosis.

The image was magnified 400 ×.

Explain how a magnification of 400 × can be obtained using the lenses on a light microscope.