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Weekly plan 21
Studying and working with DNA
Student book links
Specification links
Link to GCSE/AS specification
Suggested time allowed (includes contact and non-contact time):
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5 hours
2.2.8
2.2.9
2.2.10
5.2.3 (a)–(b); (f)–(h)
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GCSE DNA, genes and
chromosomes
Evolution
Classification
Genetic disease
Enzymes
AS 1.1.1 Cell structure
2.1.1 Biological molecules
2.1.2 Nucleic acids
2.1.3 Enzymes
Suggested teaching order
1.
2.
3.
4.
5.
6.
Outline techniques involved when working with DNA
Genome sequencing
Comparative gene mapping
Electrophoresis
Probing DNA
Polymerase chain reaction (PCR)
Weekly learning outcomes
Students should be able to:
 Outline the steps involved in sequencing the genome of an organism.
 Outline how gene sequencing allows for genome-wide comparisons between individuals and
species.
 Outline how DNA fragments can be separated by size using electrophoresis.
 Describe how DNA probes can be used to identify fragments containing specific sequences.
 Outline how the polymerase chain reaction (PCR) can be used to make multiple copies of
DNA fragments.
Key words
Genetic fingerprinting
Comparative genome mapping
Coding
Genetic engineering
Clone libraries
Microsatellites
DNA probes
Polymerase chain reaction (PCR)
How Science Works
Gene
Gene therapy
Genetic sequencing
Non-coding
Bacterial artificial chromosomes
Genomics
Mapped
Annealing
Amplified
Primer
Electrophoresis
DNA fragments
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HSW 7b Outline how gene sequencing allows for genome-wide
comparisons between individuals and species.
HSW 3 Outline how DNA fragments can be separated by size
using electrophoresis.
HSW 3 & 4 Outline how genetic disease can be diagnosed and
carriers identified by using DNA probes on a DNA micro array.
HSW 7 Outline the aims, approaches and outcomes of the Human
Genome Project.
The web links referred to here are some that the author has found personally helpful but are not intended to be a comprehensive list, many other
good resources exist.
© Pearson Education Ltd 2009
This document may have been altered from the original
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Weekly plan 21
Learning styles (S = Starter activities, M = Main activities, P = Plenary activities)
ICT activities
Kinaesthetic
Activity S3
Activities M1–2
Activity P2
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Interpersonal
Activities S1–3
Activities M1–3
Activities P1–3
Auditory
Activities S1–3
Activities M1–3
Activities P1–3
Suggested starter activities
Visual
Activities S1–3
Activities M1–3
Activity P2
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See Activities M1 and M2 below – using a word processor to write
up the investigations.
See Activity P2 below – using an interactive whiteboard (IWB).
Equipment
Teacher notes
1. Write the definitions of: genetic fingerprinting; genomic
sequencing; genetic engineering; and gene therapy on the
board.
As a class, students have to decide which definition
matches which technique and agree on the odds that they
are correct.
2. In pairs, students undertake a risk assessment for using
PCR.
Go online to the National Centre for Biotechnology
Education to purchase a practical kit.
3. Revise DNA structure and replication.
From memory, pairs of students have to draw the process of
DNA replication.
Suggested main activities
Equipment
Teacher notes
1. Practical activity 19: DNA electrophoresis
See technician worksheet.
See teacher worksheet.
See Activity S2.
2. Undertake a PCR investigation.
3. Ask students to create a model to represent the process of
probing DNA.
Velcro, card, plastic bottles, Sellotape®,
any other relevant materials
Students have to evaluate the strengths and weaknesses of
each other’s models.
Suggested plenary activities
Equipment
Teacher notes
1. Play Tip of my tongue.
2. In groups, rearrange cards showing the main steps in DNA
sequencing.
3. Play What am I?
Read out the steps involved in any aspect of DNA
sequencing – the students interrupt when they can guess
what you are going to say next.
Cards showing the main steps in DNA
sequencing
You take the role of an aspect of this topic – e.g. bacterial
artificial chromosome, DNA probe, etc. The students ask
you questions that you may only answer yes or no to
ascertain what you are.
© Pearson Education Ltd 2009
This document may have been altered from the original
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Weekly plan 21
Homework suggestions
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Find out 10 things about the Human Genome Project – add them to a class wiki.
Produce a time line to show the steps involved in DNA sequencing.
Create a concept map which outlines the applications of comparative genome mapping.
Write a job advert for a technician to run a DNA sequencing programme.
Write a lonely hearts column for an Escherichia coli seeking a bacterial artificial chromosome.
Cross-curriculum links
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PSHE – ethics of DNA manipulation, Human Genome Project
Religious studies – ethics of DNA manipulation, Human Genome Project
Physics – electricity and charge, radioactivity, light
Stretch and Challenge
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The links to the AS specification stated on page 1 are a good opportunity to develop Stretch and Challenge skills.
Many non-protein coding sections of DNA are now known to code for the production of a variety of short mRNA strands which are involved in silencing genes and
have a natural role in genome control. Research and explain: (a) how such silencing can occur; (b) how investigations into natural RNA interference may lead to
treatments for cancer; and (c) why the silencing of genes in an organism is an important part of cellular differentiation.
Potential misconceptions
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Some students may confuse genes and genomes.
Students may have a pre-existing negative view of genetic technologies.
Understanding that most DNA is non-coding can be very counter-intuitive for students.
When covering microsatellites, present the topic using a series of diagrams to help students understand this concept.
When covering how PCR works, present the topic using a series of diagrams to help students understand this concept.
Some students may have difficulties understanding why DNA would move during electrophoresis, and may confuse the cathode and anode along with their charges.
The protocol surrounding electrophoresis and probing can appear abstract and difficult to understand, without firsthand experience.
Carefully and repeatedly explain the terms: antiparallel; 5 ’(prime); 3’ (prime); template strand; antisense strand; and coding strand.
Students can confuse the terms: primer; and probe.
Notes
© Pearson Education Ltd 2009
This document may have been altered from the original
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