Unit 3 Sht_2

HWrkSht 3_2

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1. Identify the following specialised cells. Name each one, and describe the specialised structure indicated by the arrow and its function.

Cell 1

Cell 2

2. The table below shows the number of cells of different length in a sample of onion epidermis.

a) In your jotter, draw a bar graph above showing the information on the table.

b) What percentage of cells have a length greater than 55micrometres?

3.

a) What is meant by the term stem cell?

b) What type of blood disorders can be treated using blood stem cells from the umbilical cord?

c) Many researchers hope to be able to produce embryonic stem cells derived from the patient’s own cells. The Figure below outlines the process they would use.

i) Why is it a significant advantage to make the embryonic stem cells from the patient’s own cells in the way shown in Figure 1 ?

ii) Why is this process called cloning?

iii) Use the information from the diagram to suggest why researchers choose to harvest the cells for culturing at six days and not a week later when there would be far more cells?

4. Many people are opposed to the use of embryonic stem cells on ethical grounds. Others feel there are good ethical reasons for doing this research. In your jotter, outline the two main arguments used on both sides and explain your own position.