Download gene

Monday, 31 July 2017
Inheritance and Variation
Objective: Describe how features are inherited using
WALT:
DNA
A/A* Explain that genes exist in
formats called alleles.
B
Describe the relationship between
chromosomes and genes.
C Identify where chromosomes are found
within cells
Key Words:
Inheritance. Genes. Alleles.
Peter Griffin
Lois Griffin
Meg Griffin
Chris Griffin
Stevie Griffin
What
features do
Lois and
Meg share?
How are
they
different?
What features do Peter and Chris
share? How are they different?
VARIATION

How do we get variation?
DNA Structure
• How is DNA Structured?
Match up the name of the structure, to the
picture and the information about it.
Try and get them in order from biggest to
smallest!
Cells
All living organisms are
made up of cells.
Cells contain genetic
information in a place
called the nucleus.
Genes, Chromosomes and DNA
Cell membrane
A single
chromosome
cytoplasm
nucleus
A pair of
chromosomes
Animal cell
(one from each
parent)
The nucleus of human cells
23 pairs of chromosomes
A chromosome
A gene = a short
section of the
chromosome
A gene
DNA molecule =
DOUBLE HELIX
Cross sections made up
of Base Pairs
The DNA is
coiled to form the
arms of the
chromosome
The gametes
• Are the sperm and egg cells
• They contain half the genetic
information of a normal body cell
• When joined together the fertilised
egg will have a complete set of genetic
information (a complete genome)
• This is why we might look a bit like our
parents!
Key Fact:
Genes control the features of the organism.
A gene makes a protein that provides a
physical feature.
E.g. brown hair colour
Alleles
Extracting DNA Practical
© Association for Science Education and Centre for Science Education 2011
METAHUMAN : ENGINEERING 2 : MODIFIED
Extracting genetic material
1 Pulp 2–3 strawberries in a pestle
and mortar.
2 Add 10 cm3 of extraction buffer
and mix thoroughly but gently.
3 Filter into a test tube.
Collect about 3 cm3 of filtrate.
4 Carefully pour about 6 cm3 of cooled
ethanol down the side of the test tube
so that it forms a layer on top of the
filtrate.
5 After about a minute carefully
remove the white material that
forms between the layers by
twisting it round a glass rod.
6 Put a small piece on microscope slide
and tease it into a thin layer using
toothpicks.
7 Examine under a microscope.
© Association for Science Education and Centre for Science Education 2011
SS3
CAN YOU
DESCRIBE WHAT EACH STAGE OF
THE PRACTICAL DID?

Crushing it with a pestle and mortar?

Adding extraction buffer?

Filtering the mixture?

Adding ice cold ethanol?
TASK: CAN YOU COME UP WITH AN ANALOGY TO
REMEMBER THE ORDER OF THE WORDS

E.g. I think of a book:
Each letter is the base pair
 Each word is a piece of DNA
 Each sentence is a gene.
 Each chapter is a chromosome


Each book is the genome / cell
WRITE YOUR OWN DEFINITION OF THE KEY
WORDS:

Genome

Chromosome

Gene

DNA

Alleles
Monday, 31 July 2017
Inheritance and Variation
Objective: Describe how features are inherited using
WALT:
DNA
A/A* Explain that genes exist in
formats called alleles.
B
Describe the relationship between
chromosomes and genes.
C Identify where chromosomes are found
within cells
Key Words:
Inheritance. Genes. Alleles.
SIZE