1 Draw up a table (like the one below) of the different organisms mentioned in these articles and classify them. One entry has been started for you, as an example.
Name of organism Group to which it belongs Characteristics
Pig Mammal Diaphram separates thoracic and
abdominal cavity
Presence of body hair / fur
Female has mammary glands
2 Make a list of the different ways that the organisms discussed in these articles are used by humans.
3 a) Why are relatively few heart and liver transplants undertaken?
b) The greatest problem that doctors have encountered in any type of transplant operation is rejection. What is meant by rejection, and how have doctors tackled the problem to date?
c) Why were the pigs'hearts not rejected by the monkeys in this study?
d) If this technique is found to be successful with humans, what
ethical dilemmas might be raised?
4 a) What is a stroke?
b) Why is the herpes virus particularly good at introducing a gene into human cells?
c) What do you understand by the term 'viral vector'?
5 a) What is meant by the term 'biological control'?
b) Which common garden pests can be controlled by this means?
c) Whitefly is a serious pest in commercial glasshouses, where the numbers can rise dramatically. Why? What makes a glasshouse an ideal place for whiteflies?
d) The parasitic wasp Encarsia is used to control whitefly. How does it control the whitefly population?
e) Why are sticky cards also suspended throughout the glasshouse?
f) Using the organisms mentioned in the article, write out two different
food chains with at least three organisms in each.
g) Why might it be better to use biological control rather than chemical methods to limit pests in a glasshouse?Name of Group to which Characteristics of group organisation organism belongs
Pig Mammal Diaphragm separates thoracic and abdominal cavity Presence of body hair/fur Female has mammary glands
6 a) Why is it ad vantageous for a crocodile to be able to stay submerged in
the water for long periods of time?
b) Give one advantage of using 'artificial blood'with genetically altered human haemoglobin.
c) When oxygen binds to haemoglobin, it causes its three-dimensional shape to change. What name is given to this type of change in a protein, when brought about by a small molecule?
d) What is the name of the oxygen-storing molecule related to haemoglobin that is found in the muscles of diving mammals such as seals?
e) If scuba divers dive too deep or for too long, what condition may
develop as they return to the surface? What are the symptoms of this condition?
7 a) Throughout history, flies and other insects have been notorious in the spread of disease. Draw up a list of diseases that are spread by insects, and for each one name the insect responsible for its spread.
b) Why would the use of maggots to clean wounds and infections be particularly useful in developing countries?
c) Why do the maggots need to be sterilised? How might this be done without killing them?
8 a) Fungi have been used by humans for a long time. What was the earliest recorded use of a fungus?
b) Chitin is a natural polymer. What does the ter m 'polymer'mean?
c) What sub-units make up chitin?
d) How does chitin differ from cellulose?
e) What are crustacea? Give an example of a fresh water crustacean.
f) How do the chitin bandages seem to help the healing of wounds?
9 The late twentieth century has seen the rise of new human 'plagues'.
They represent new challenges to doctors and scientists. The article
'Plague worse than Aids turns bodies to water' reports on one of these.
a) As humans have travelled further afield, so have disease-causing organisms. Give three examples of diseases that have spread with humans.
b) How can disease-causing microbes enter the body?
c) How does i) the Ebola virus and ii) HIV gain entry to the body?
d) Compare the effects and symptoms of Ebola and HIV infection.
e) What measures can be taken to limit i) an outbreak of the Ebola virus and ii) the spread of HIV?
