1 Read the passage below. Use the information in the passage and your own knowledge
to answer the questions that follow.
Micropropagation: good or bad?
Plant cells have the ability to produce a genetically identical copy of their parent
plant. They can do this because the information is coded in the sequence of
bases in their DNA. Micropropagation involves taking small pieces, known as
explants, from a plant with the desired characteristics. The explants are sterilised
5 and then put into a growth medium containing sucrose, amino acids and a
variety of minerals as well as growth promoting chemicals.
All the young plants produced from the original cell or piece of tissue are clones.
The sterile conditions in which they have been grown allow these plants to
be disease free. Micropropagation can also produce plants which are free of
10 pathogens such as viruses.
Micropropagation is used to produce commercial quantities of plants. Large
quantities of flowers are cloned in this way. The quality and characteristics
of the flowers produced can be controlled more easily than when using
sexual methods of reproduction. With rare or endangered plant species,
15 micropropagation may be the last chance of reproducing them if more
conventional methods have failed.
The process has been used to create large numbers of palm oil plants. The oil
extracted from these plants can be used in a wide variety of food and consumer
products. It can also be used to make biofuel for use as a sustainable energy
20 source in cars.
The increased demand for the use of palm oil has had serious environmental
consequences, with huge areas of rainforest being destroyed to make way
for fresh plantations. Today, Malaysia and Indonesia account for 90 per
cent of global production. Indonesia already has six million hectares of oil
25 palm plantations, with plans for another four million by 2015 dedicated to
biofuel production. This destruction of habitat will result in more rainforests
disappearing, pushing several species such as the orangutan towards extinction.
Name one base found in DNA (line 3).
(1)
....................................................................................................................................................................................................................................................................................