Extras I

Question 1

Immobilised enzyme

Answer 1

A technique in which
enzymes are bound to membranes or set in gel
before being used. There are several advantages
in doing this. It makes biotechnological
processes cheaper because the enzyme can be
separated from the product easily and used
again. In addition, immobilised enzymes are
more tolerant of higher temperatures and
extremes of pH.

Question 2

In vitro

Answer 2

Referring to a process carried out in test
tube conditions rather than inside a living
organism. In vitro fertilisation (IVF) is often
used to treat infertility. In this technique, the
fertilisation of egg cells by sperms takes place
outside the body. If fertilisation is successful one
or more of the resulting embryos is implanted
into the uterus of the mother where it will
develop normally.

Question 3

Insecticide

Answer 3

A type of pesticide used to kill
insects. Pyrethrins are substances found in
pyrethrum, a plant belonging to the daisy family.
They are an ingredient of many insecticides.

Question 4

Insightful learning

Answer 4

A form of learning in which
an animal solves problems by insight or
reasoning. In a series of experiments, Wolfgang
Kohler placed a banana just out of reach of a
chimpanzee in a cage. The chimpanzee joined
two sticks together and used these to pull the
banana into the cage. Kohler used the term
insightful learning to describe this behaviour

Question 5

Integrated pest management

Answer 5

Managing pests by
combining use of chemical pesticides with other
methods of control. One of the advantages of
this approach is that much less pesticide is
needed. This saves on cost as well as minimising
environmental damage. For example, corn
borer larvae are important pests of maize crops.
Many farmers control corn borers with a system
of integrated pest management. They combine
the use of biological control and chemical
sprays.

Question 6

Invertebrate

Answer 6

Animals may be divided into
vertebrates and invertebrates. Invertebrates are
animals that do not have a skull and vertebral
column. They include worms, snails and insects

Question 7

Isoenzyme

Answer 7

Isoenzymes are slightly different
forms of a particular enzyme. These differences
help organisms to survive changing conditions.
For instance, acetylcholinesterase is an
important enzyme found in the nervous system.
Trout produce slightly different forms of this
enzyme, each with a different optimum
temperature. In this way they can live both in
lowland rivers and mountain streams

Question 8

Junk DNA

Answer 8

A complete set of human DNA
contains approximately three thousand million
nucleotide bases. This DNA includes all the
30 000 genes we need to produce the proteins
which determine our characteristics. A lot of our
DNA, however, does not code for proteins. This
non-coding DNA is sometimes called junk
DNA.

Question 9

Knock-out studies

Answer 9

Experiments in which
organisms, such as mice, are bred with a
particular gene switched off. These are used to
investigate the role of individual genes, for
example the role of genes in normal brain
activity.