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Module 2 Making Use of Biology
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11.1 Enzymes may be isolated from 3.6 Downstream
microorganisms and have important applications processing is described
in biotechnological processes 17.7 in relation to
penicillin, but the same
Isolation of enzymes 18.10
principles apply to the
production of enzymes
The distinction between intracellular and
by microorganisms.
extracellular enzymes.
See also spread 18.10
A suitable example should be chosen to show that which describes
the commercial production of enzymes from cloning which can be
microorganisms involves: useful for the
manufacture of
the growth of large numbers of microorganisms enzymes.
using specific media and aseptic conditions
the isolation and purification of the enzyme
product by downstream processing
Application of enzymes in biotechnological 3.6 Figure 2, spread 3.6
processes shows different
3.7 methods of enzyme
The applications of enzymes should be linked to a immobilisation
consideration of their functions (Module 1, Section
10.5) Table 1, spread 3.7
gives examples of
Suitable examples should be selected to demonstrate industrial applications
that: of enzyme.
because of their high sensitivity and specificity,
enzymes may be used as analytical reagents
industrial processes require a high degree of
thermostability
immobilised enzymes can be separated easily
from reactants and products and can thus give a
higher degree of control; they are also more stable
11.2 Genetic information is passed from cell to 4.11 Staining techniques are
cell during division not covered in the
book. Aceto-orcein,
Mitosis acidified with
concentrated
The process of mitosis emphasising the behaviour
hydrochloric acid, is
of chromosomes, the role of the spindle and the
commonly used to
genetic identity of the products.
stain squashes of onion
Use of appropriate staining techniques in the study root tips so that the
different stages of
of mitosis in suitable plant material. mitosis can be
identified.
The cell cycle 4.10 Figure 3 shows the
stage in which DNA
Mitosis and the cell cycle. replication takes place.
The relationship between DNA replication and the
events of the cell cycle.
Meiosis 4.10 Details of chromosome
behaviour are covered
The importance of meiosis in halving the in spread 4.12.
chromosome number in gametes so that, after
fertilisation, the diploid chromosome number is
restored in the resulting zygote.
Details of chromosome behaviour are not required.
This is covered in section 14.1 of Module 5.
11.3 Genes incorporate coded information which 2.11 2.11 gives a simple
determines the metabolism of organisms introduction to
18.1 nucleotides and
The structure of DNA, mRNA and tRNA in terms nucleic acids; 18.1
of nucleotides, base pairing and hydrogen bonding. 18.7 considers the structure
of DNA; 18.7
considers mRNA and
tRNA.
DNA as genetic material 18.4 This spread considers
the work of Griffith,
Evidence that DNA is the genetic material. Avery and co-workers,
and Hershey and
Candidates will not be expected to link workers’
Chase.
names with particular pieces of work or to be
familiar with the details of techniques. The exercise
for candidates should be one of analysis and
deduction using evidence derived from experimental
work.
The structure of nucleic acids 2.11
This topic should be covered in sufficient detail to 18.1
provide an understanding of the roles of nucleic
acids in coding information, protein synthesis and 18.7
the replication of DNA.
Replication of DNA 18.3 Figure 1a shows semi-
conservative
The semi-conservative replication of DNA. replication
Protein synthesis 18.6 18.6 describes the
features of the genetic
The genetic code as a non-overlapping, degenerate 18.7 code (see Appendix for
code. Introns as non-coding DNA. the full code); 18.7
gives an account of
introns.
The mechanism of protein synthesis involving the 18.7 18.7 covers
roles of mRNA, tRNA and the ribosomes. transcription; 18.8
18.8 covers translation
Enzymes as proteins whose synthesis is controlled 18.5 This spread describes
by DNA. They control metabolic pathways and thus Beadle and Tatum’s
influence the phenotype of an organism. experiment and the one
gene – one polypeptide
hypothesis.
11.4 Gene technology has many applications in a 18.9 General principles of
modern world genetic engineering
18.10 including the key
Recombinant DNA enzymes involved, are
covered in spread 18.9.
The production of recombinant DNA and its use in
the production of human insulin and other proteins. Figure 1, spread 18.10
shows how insulin is
Consideration should be given to the:
produced by
isolation of the gene coding for the required recombinant DNA
protein technology
use of the enzymes: reverse transcriptase, The moral and ethical
restriction endonuclease and ligase issue of human cloning
is touched on in Food
sticky ends; insertion of the gene into a vector and for thought, spread
its subsequent introduction into host cells; plasmids 18.10, and the issue of
and viruses as examples of vectors Genetically Modified
Organisms is included
use of genetic markers such as genes conferring in spread 23.3, but
antibiotic resistance to detect genetically modified students will need to
organisms consult reports in
newspapers and
multiplication of host cells science magazines,
The moral and ethical issues associated with such as the New
recombinant DNA technology. Scientist for up-to-date
accounts of issues.
11.5 Forensic examination of blood may draw on 15.5 Antigens in spread
the principles of blood grouping and genetic 15.5, in which B-
fingerprinting 15.6 lymphocytes, plasma
cells, and memory
Principles of immunology cells are also
described.
Definition of antigen and antibody. The
immunological response of B-lymphocytes to Antibodies defined in
stimulation by the appropriate antigen in terms of
production of plasma cells, memory cells and spread 15.6
antibodies.
ABO blood groups can be distinguished by antigens 15.8 Figure 2 shows how
present on the plasma membranes of red blood cells. blood groups can be
determined by the
Agglutination occurs when blood of a specific antibody-antigen
group is mixed with an appropriate antibody. This reaction.
reaction forms the basis of blood grouping.
The inheritance of ABO blood groups is not
required.
Genetic fingerprinting 18.11 Figure 1, spread 18.11
gives the main stage of
The technique of genetic fingerprinting may be used making a genetic
to identify individual blood samples. fingerprint (=DNA
fingerprint) by DNA
This process should be considered in such detail as
profiling; restriction
to show that:
endonuclease =
restriction enzymes are used to cut DNA into restriction enzyme.
fragments
Gel electrophoresis is
electrophoresis is used to sort DNA fragments described in the
according to size Appendix.
radioactive DNA probes are used to locate specific Figure 2 describes the
DNA fragments Polymerase Chain
Reaction (PCR)
Polymerase chain reaction
The polymerase chain reaction and its importance in
obtaining increased amounts of DNA for analysis.
11.6 Cultivated plants are adapted to survive in 22.15 Rice is an example of
particular environments. Humans can hydrophyte; details of
manipulate the environment of these plants to its cultivation are not
increase productivity included in this book is
its adaptations are only
Adaptations of cereals briefly discussed.
Cereals form an important part of the human diet.
Different species of cereal show structural and
physiological adaptations which enable them to
grow in different parts of the world.
Consideration should be given to each of the cereals
named below:
rice as a swamp plant with hollow aerenchyma
and a tolerance to ethanol produced by anaerobic
respiration
sorghum as a plant which grows in hot, dry 22.15 Sorghum is an
conditions; its xerophytic modifications include the example of xerophyte,
presence of an extensive root system, a thick cuticle described in spread
and a reduced number of sunken stomata; both the 22.15. Details are
adult plants and the embryos can tolerate high sorghum cultivation
temperatures are not included.
maize as a tropical plant with a specialised method 5.6 Maize is an example of
of photosynthesis; the advantages of this method of a C4 plant, described
photosynthesis in increased efficiency at high in spread 5.6
temperature and low carbon dioxide concentrations.
The biochemical details of photosynthesis are not
required.
Controlling the abiotic environment 23.3 Spread 5.5 deals with
the factors affecting
Humans can change the abiotic environment of crop the rate of
plants. The effect of light intensity, temperature and photosynthesis; spread
carbon dioxide concentration on rate of 23.3 considers
photosynthesis and productivity. greenhouse cultivation
of plants, but only
Enhancement of these factors in commercial
briefly.
glasshouses.
Spread 23.6 includes a
description of the
greenhouse effect
which enhances the
temperature in
greenhouses (and
within the Earth’s
atmosphere)
Fertilisers 23.1 Fertilisers are
considered in spread
Harvesting removes nutrients from the soil. The use 23.1, but the
of fertilisers to replace these. The advantages and quantitative
disadvantages of organic and inorganic fertilisers. relationship between
The relationship between yield and the quantity of yield and quantity of
fertiliser added. The environmental issues arising fertiliser is not dealt
from the use of fertilisers. Leaching and with.
eutrophication.
Leaching and
entrophication are
dealt with in spread
23.1 and 23.7
respectively.
See also nitrogen
cycle, spread 22.11.
Pesticides 23.2 See spread 22.5 for a
definition of
Interspecific competition between weeds and crop interspecific
plants. Reduction of crop yield by insects either competition.
directly, or indirectly by reducing the
photosynthetic tissues of the plant. See also 23.1 for soil
management
The principles of using chemical pesticides, techniques (such as
biological agents and integrated systems in crop rotation and
controlling pests of agricultural crops. tillage) which prevent
the build-up of weeds
The environmental issues associated with pest
and pests.
control. Toxicity and bioaccumulation.
The Fact of Life in
Candidates should be able to evaluate the issues
spread 22.3 describes
involved in using different methods to control the
how bioaccumulation
pests.
of DDT can occur.
See also spread 14.10
for an account of the
use of herbicides to
control weeds (in Food
for thought)
11.7 Biotechnology allows the manipulation of 12.4 Detection of oestrus in
reproduction in humans and domestic animals pigs is considered in
12.5 spread 12.5.
Reproduction and its hormonal control
The development of ovarian follicles and corpora
lutea and changes in the uterine endometrium
during the sexual cycle in a female mammal.
The hormonal control of the female sexual cycle in
a mammal.
The roles of FSH, LH, oestrogen and progesterone.
The detection and significance of oestrus in a
named farm animal.
Manipulation and control of reproduction 12.6 12.6 focuses on human
contraceptives, but the
The use of extracted and synthetic hormones as 19.10 same principles apply
contraceptives and in controlling human infertility. to other mammals, but
23.3
the synchronisation of
In domestic animals, the role of hormones in:
breeding behaviour in
producing large numbers of embryos for sheep is not dealt with
transplanting specifically.
synchronising breeding behaviour in sheep Cloning of sheep is
considered in spread
increasing milk production 19.10.
The moral and ethical issues associated with using Spread 23.3 deals with
biotechnology to manipulate reproduction. bovine somatotrophin.
See also spread 20.7
for artificial selection
in cattle.
Moral and ethical
issues are touched on,
but not dealt with
fully. Students are
advised to consult
newspapers and
science magazines for
up-to-date debates
about these issues.
