TOPIC:
Inheritance, chromosomes, DNA and genes
What to do:
Things you’ll
nee
d
two lengths
of liquorice
of about
30cms (you
can join fond
ant
filled liquoric
e using cock
tail sticks)
20 or so so
ft sweets of
4
different colo
urs
cocktail stick
s or wooden
tooth
picks - abou
t 20
Arrange the sweets into groups to represent the 4 organic
bases: A, C, T, G. Pair up your sweets so that one colour always
goes with another. This represents the nitrogenous bases
where C will always pair with G and T will pair with A.
Skewer pairs of sweets with cocktail sticks, making sure to
leave enough at either side to push into the liquorice. Then
arrange the pairs on a flat surface in any order you want.
(Although you can have any pattern or repetition of paired
sweets, you can’t mix the colours between the two sets of
pairs). (This represents the hydrogen bonding between the
base pairs. In real DNA, the precise order of the base pairs
is unique to you and gives you your characteristics, a bit
like a human bar code). Attach your sweets, evenly spaced,
to the long flexible liquorice pieces; this shows how the nucleotides are attached to the sugar-phosphate
backbone. Pick up your own DNA molecule and gently twist it to form the double helix.
Complete this paragraph using the words below:
DNA stands for______________________. It is the genetic code that makes you, you.
DNA is passed on to the next ______________ and nobody else on the planet will have
the same DNA as you unless you have______________________ or you have been
______________. DNA is a large molecule in the shape of _________________.
It’s made up of repeating units called ______________. Each of these contains a sugar
and phosphate molecule, and one of four ________________. These bases are
adenine (A), guanine (G), ______________ (C) and ______________ (T). It’s the
specific order of A, G, C and T within a DNA molecule that makes it unique to you and gives
you your characteristics.
thymine organic bases double helix an identical twin deoxyribonucleic acid
generation cloned nucleotides cystosine
Science Technology Engineering Maths
For more resources like this,
this visit
visitww.baesystemseducationprogramme.com/resources
www.baesystemseducationprogramme.com/resources
7
GENETICS AND EVOLUTION
Heredity is the process by which genetic information is
transmitted from one generation to the next. Hereditary
material is passed on in the form of a code, contained
uniquely for each individual, within their DNA. In the shape
of a double helix (like a ladder that’s been twisted many
times), DNA is a large molecule that carries genetic
information in a chromosome.
KS3
TOPIC:
Inheritance, chromosomes, DNA and genes
Within the nucleus of cells, DNA is arranged
into structures called chromosomes. Human
cells contain 23 pairs of chromosomes, so
46 per cell, 22 pairs are autosomes, which
contain most of the hereditary information,
and one pair are sex chromosomes, which
can be x or y and determine gender.
NATURE or NUTURE?
Finding out that some behavioural traits are
inherited is not the end of the challenge to
scientists and geneticists, but just the beginning! We need to know not just that genes affect behaviour,
but also to establish which genes are do this and how they affect the biochemistry of brain cells in ways
that influence behaviour.
The makeup of our chromosomes is important in human psychology. Females typically have two x
chromosomes, while males have an x and y chromosomal structure. The x chromosome is thought to be
much more active than y and to affect behaviour. However, because social and environmental factors affect
brain activity and behaviour, it is difficult for researchers to assess whether or not behavioural differences
between males and females are genetic or just learned behaviour. WHAT DO YOU THINK?
Science Technology Engineering Maths
For more resources like this,
this visit
visitww.baesystemseducationprogramme.com/resources
www.baesystemseducationprogramme.com/resources
7
GENETICS AND EVOLUTION
How does it work?
KS3
TOPIC:
Inheritance, chromosomes, DNA and genes
ME
O
N
Working scientifically...
Janet Shibley Hyde, Professor of Psychology
and Gender at University of
Winsconsin-Madison has conducted research
to explore the differences between male and
female, based on a set of psychological
variables: her research found that 78% of
gender difference results were either small, or
close to zero.
Among the few exceptions, where there were
the greatest differences between male and
female, results included throwing distance and
speed of throw.
What to do
Select, plan and carry out an experiment
which tests this. Ensure that you work
scientifically and make and record
observations and measurements.
STEM
W
Arrange yourself into groups of about 6 or 8,
which are as mixed as possible across gender,
but also varied because of different
personalities and interests both inside and
outside of school. One person in each group is
responsible for making sure that everyone has a
chance to speak, another for making brief notes,
and another for reporting back to the other
groups. Allow yourselves up to ten minutes for
each discussion.
Rosalind Franklin
You will probably have heard of Watson and Crick, biophysicists,
who were credited with ‘cracking the DNA code’ and were awarded
a Nobel Prize in 1962 for their work on discovering the structure of
the DNA molecule.
“Science and
everyday life
cannot and
should not be
separated.”
ROSALIND FRANKLIN
However, few will have heard of Rosalind Franklin who produced the
key x-ray images and for writing the reports that helped to direct
Watson and Crick’s research. She died, at the age of only 37 of
ovarian cancer in 1958 and was therefore ineligible for the Nobel
Prize in 1962 as prizes are not awarded posthumously.
Key to Watson and Crick’s breakthrough was their use of Rosalind
Franklin’s photograph (x-ray diffraction image) of DNA that
resembled an ‘x’ seen through the slats of a Venetian Blind –
fuzzy to our eyes now, but at that time - 1953 - among the sharpest
and most informative of DNA x-ray pictures. Rosalind Franklin was a
biophysicist and an expert in x-ray crystallography.
Science Technology Engineering Maths
For more resources like this,
this visit
visitww.baesystemseducationprogramme.com/resources
www.baesystemseducationprogramme.com/resources
7
GENETICS AND EVOLUTION
What to do
KS3