Edexcel Biology Specification
NCBE ‘Illuminating DNA’
Subject content
Part of booklet / Practical exercises
Unit 1: Molecules and cells
1.1
Molecules
Lipids
...
understand the structure and properties of
phospholipids and their role in the structure
and properties of cell membranes.
...
Nucleic acids
understand that ribonucleic acid (RNA) and
deoxyribonucleic acid (DNA) are composed of
mononucleotides; recall the basic structure of a
mononucleotide; thymine, uracil and cytosine
as pyrimidines; adenine and guanine as purines;
understand that condensation reactions are
involved in the formation of mononucleotides
and polynucleotides (DNA and RNA);
recall the structure and understand the roles of
messenger and transfer RNA;
recall the structure of DNA; understand base
pairing; understand the double helix;
understand the mechanism of replication of
DNA (semi-conservative); understand the
nature of the genetic code; understand that a
gene is a sequence of bases on the DNA
molecule which codes for a sequence of amino
acids in a polypeptide chain; understand the
processes of transcription and translation in the
synthesis of proteins; understand that amino
acid sequences are specified by DNA, and
know the function of the ribosomes;
understand codons and anticodons in relation
to messenger and transfer RNA;
appreciate the Human Genome Project in the
light of the structure and roles of nucleic acids;
consider the spiritual, moral, ethical, social and
cultural issues of this project.
1.3
The DNA extraction protocol (pp. 20–21), and the plasmid
extraction protocol (pp. 26–27) will help to reinforce this
content.
Most of this content is dealt with briefly in the background
information in the booklet. In some areas, more detail will
be required, but it is easily found in all biology textbooks.
The DNA model-making (pp.18–19) will be useful here.
Issues arising from the Human Genome Project are not dealt
with in the booklet, but several of the EIBE units may be
helpful here. They can all be downloaded from http://www.
reading.ac.uk/EIBE
Cellular organisation
Prokaryotic cells
describe the structure of a bacterial cell and its
inclusions as illustrated by Escherichia coli;
understand the roles of the cell wall, cell surface
(plasma) membrane and its invaginations,
flagella, bacterial chromosomes, plasmids,
glycogen granules and lipid droplets... etc.
Eukaryotic cells
... describe the structure and understand the
roles of the nucleus, nucleolus, rough and
smooth endoplasmic reticulum, Golgi
apparatus, lysosomes, chloroplasts,
mitochondria, ribosomes, centrioles and
microtubules, the cellulose cell wall... etc.
The various practicals involving E. coli may be useful, including
β-galactosidase induction (pp. 24–25); extraction of plasmid
DNA (pp. 26–27); ttransformation (pp. 28–29).
This material is covered briefly in the introduction, although
greater detail will be required. The DNA extraction
protocols (pp. 20–21) may help to reinforce this content.
Edexcel Biology Specification
NCBE ‘Illuminating DNA’
Subject content
Part of booklet / Practical exercises
Option A: Microbiology and biotechnology
A.1 Diversity of microorganisms
Bacteria
recall the structure of a bacterial cell and its inclusions, as
illustrated by Escherichia coli;
The introduction section gives very brief details of bacterial
cell structure.
Viruses
understand that the classification is based on virus structure Phage lambda is described on page 12, and used in several
and nucleic acids types as illustrated by λ (lambda) phage of the practical exercises (restriction site mapping, pp.32–33
(DNA)...
and PCR, pp. 34–35).
A.2 Culture techniques
...
Methods for culturing
understand the principles and techniques involved in
culturing microorganisms; describe the use of different
media (solid and liquid media, selective media, indicator
media);
Those practical exercises involving the growth of
microorganisms require some of these techniques, namely:
β-galactosidase induction (pp. 24–25);
extraction of plasmid DNA (pp. 26–27);
bacterial transformation (pp. 28–29)....
Practical work to include preparation and sterilisation of
media, agar plate pouring and inoculation using sterile wire
loops, pipettes and spreaders;
A.3 Use of microorganisms in biotechnology
...
understand antibiotic resistance and the reasons for its
spread.
There are several facets here:
the occurance of genes conferring resistance to the
effects of antibiotics;
the transfer of these genes between microorganisms;
selection pressures which result in the widespead
occurrance of those genes in microbial populations.
These ideas are touched on in the transformation protocol
(pp. 28–29) and are considered in more detail in the forthcoming NCBE publication, The Transformer Protocol.
Edexcel Biology Specification
NCBE ‘Illuminating DNA’
Subject content
Part of booklet / Practical exercises
Unit 5B: Genetics, evolution and biodiversity
Unit 5H: Genetics, human evolution and biodiversity
5B.4
Gene technology
describe and understand the roles of reverse transcriptase,
endonucleases and DNA ligase in the manipulation of
DNA;
This is explained on page 6, with a restriction and ligation
protocol on pages 30–31.
describe the insertion of DNA into a host cell and the
multiplication of the host cell;
Transformation is described on pages7–9, with a practical
protocol on pages 28–29.
appreciate the use of marker genes to indicate that new
genes have been incorporated into host cells;
The use of markers in explained on page 10, and there are
clear links with the transformation protocol (pp. 28–29).
understand how protein synthesis is switched on and the
synthesis of a new product by the host cell as illustrated
by the production of new genes into plants using the
bacterium Agrobacterium tumefaciens;
Induction of β-galactosidease production is described briefly
on page 11; the practical protocol is on pages 24–25.
The use of Agrobacterium is described on page 8, but this
phrase in the syllabus doesn’t make sense!
understand the production of chymosin from genetically
modified yeast and its use as a substitute for mammalian
rennin in the dairy industry;
This will be dealt with in another booklet in the series —
Fermented foods.
discuss the potential of genetically modified organisms
illustrated by the development of crop plants resistant to
herbicides, the improvement of crop quality and the
development of pharmaceutical products such as human
hormones and new drugs;
This will be touched on in another booklet in the series,
Plant tissue culture.
discuss the social, ethical and economic implications of the Such issues are covered in the Transformer protocol, which
development of genetically modified organisms;
will be available from the NCBE in due course.
understand how the polymerase chain reaction (PCR)
amplifies genetic material;
This is described on page 10 and in a practical protocol on
pages 34–35.
describe genetic fingerprinting as a diagnostic tool.
Strictly speaking, genetic fingerprinting is not a ‘diagnostic’
tool (unless one regards identity or genetic relationships as
something to be diagnosed).
Genetic profiling is described in EIBE Unit 2, DNA
Profiling, while the diagnosis of inherited ‘disease’ by
similar genetic techniques is described in EIBE Unit 4,
Issues in human genetics. Both are available from http://
www.reading.ac.uk/EIBE
A future NCBE publication will deal with human genetics.