Download Mark scheme for essay

Mark scheme for essay: What are PCR and gel electrophoresis and how are
they used in the process of DNA profiling?
Content
Explain the procedures
Students must explain the procedure for PCR 2
marks and for gel electrophoresis 2 marks
Explain what the procedures actually do
Students must have explained that PCR is used to
increase the amount of copies of DNA so that it is
easier to test, and, that gel electrophoresis is a way
of separating out cut pieces of DNA in order to
identify specific genes using gene probes
 Explain DNA profiling and what it is for
 Explain the process of constructing a DNA profile
incorporating PCR and gel electrophoresis
 Explain gene probes and what they are for
 Explain restriction enzymes and what they are
used for
Explained how the techniques are used in the process of DNA
profiling
4
4
2
2
2
2
Structure & Style
Student needs to have a good structure to the report. Explain how
antibiotics and antibiotic resistance work and then use this to
support information on infection control
Student needs good use of scientific terminology and to show
understanding for the wording that they use. They also need to
spell these terms correctly consistently. Grammar also needs to be
of good standard. Species names in italics. -1 mark if not in italics
Student has a clear, good structure to the essay
5
Student has an adequate structure to the essay
3
Student has poor structure to the essay
1
Good use of scientific terminology, good spelling
and good grammar,
Adequate terminology, spelling and grammar
Poor terminology, spelling and grammar
5
3
1
Referencing
Students need to have used a variety of sources showing that they
have read around the subject.
References need to be linked into text and all pictures need to be
referenced as well
Students need to evaluate the quality of the sources that they have
used. They need to assess the reliability of the information that
they have researched and decide whether their evidence is
supported.
Total content
/16
A* = 37
Total Structure &
style
/10
A = 33
B = 29
Student has used a variety of sources including
books and websites, at least 4
Student has used a variety of 1 type of source (i.e.
only websites or only books), at least 4
Student has used only a few sources
(1 or 2)
All references linked into text either as footnotes
or numbering relating to bibliography. All pictures
referenced
Some references linked into text, some cut and
pasting. Not all pictures referenced
No linking references in text although bibliography
present. No referencing of pictures
Student has evaluated at least 3 of their sources
clearly and evaluated for reliability with reasons!
Student has evaluated 1 or 2 of their sources with
reasons
An effort has been made to evaluate sources
however no reason
Total referencing
Total
/15
/41
C = 25
D = 21
E = 16
5
3
1
5
3
1
5
3
1