Transcript Molecules of Life

Proteins and Mutations
Part 1
Learning Objectives
• Learn about different types of proteins.
• Learn about the functions of different
proteins.
• Understand what mutations are.
• Learn why some proteins are not made
by all the cells in the body.
Starter
What do all of these animals
have in common??
They’re MUTANTS!
Use your knowledge of DNA
to explain the colours of the
budgie and tiger.
Proteins
• We learnt last lesson that DNA codes for proteins.
• You need to know the names and functions of a few
proteins in particular.
Use page 14 of the student book to find out the
function of collagen, insulin & haemoglobin and
complete worksheet 1
Stick the sheet in your book.
Collagen
• Collagen is a structural protein.
• It is found in artery walls.
• It is also found in skin, bone and even teeth.
Insulin
• Insulin controls blood
glucose levels.
• It belongs to s group of
proteins called hormones.
• It is produced in the
pancreas.
• Not all cells produce insulin!
Only the cells of the
pancreas.
• Do plant cells make insulin?
Haemoglobin
• Haemoglobin is only found in red blood cells.
• It is the reason red blood cells carry oxygen.
• Remember, only red blood cells need haemoglobin,
so brain or liver cells wouldn’t make it.
Mutations
• The DNA of an organism codes for it’s features and
characteristics.
• But what if something went wrong with the code?
not likely!
it happens!
- Having a sixth finger is called
polydactyly. Caused by a mutation.
Mutations
• Gene mutations or spontaneously (randomly).
• The chance of a mutation happening can increase
due to:
– RADIATION
– CHEMICALS (such as tar in cigarettes).
• Mutated genes normally code for a different shaped
protein.
• The new protein may be harmful and even cause
death (cancer).
• Sometimes a mutation can be beneficial (evolution).
• Sometimes a mutation can be neutral (blue budgies).
Examples of Mutations
Haemophilia
Haemophilia is caused by a
mutated gene.
The blood of a person with
this condition does not clot
because a clotting protein is
not produced.
It is dangerous because
bleeding does not stop.
Sickle Cell Anaemia
In this condition, the shape
of the red blood cells is
different.
This stops them carrying
oxygen efficiently.
However, people with sickle
cell anaemia cannot get
malaria.
Task
• In groups, discuss if you think the following mutations would
benefit or harm a species:
Albino rabbits – The gene that gives skin colour mutates; the result is a white
rabbit.
Cystic fibrosis – A gene for an important protein is changed; the result is a
human with breathing problems.
Dark moths – A type of moth that is normally peppered in colour becomes
dark; the result is better camouflage on dark-coloured trees but they show up
on most light-coloured trees. During the industrial revolution, many trees were
dark due to pollution; now most trees are light in colour.
Resistant bacteria – Some bacteria have mutated to become resistant to
antibiotics.
Sickle cell anaemia – A mutation that makes people ill but stops them catching
a fatal disease called malaria.
Task
• Using what you have learnt over the last few lessons,
create a poster, or information leaflet on DNA and
Proteins.
• You may include ideas on the following:
DNA Structure
Genes & Genetic Code
Base Sequences
Protein Synthesis
Proteins & Mutations
• Use your notes and pages 10-15 to help you create
your poster or leaflet.
HIGHER
Protein Shapes
• Proteins are made of amino acids.
• The number and sequence of amino acids in a
protein is important, and is known as the protein’s
primary structure.
Final shape
• Mutations cause the primary structure of a protein to
fold into the incorrect shape.
• The protein can then no longer carry out its function
properly.
Switched On or Off
• Every cell in your body has the exact same DNA.
• But cells in different parts of your body look different
and don’t make the same types of protein.
• This is because cells only ‘switch on’ the genes they
need!
• A pancreas cell produces insulin, so switched on the
insulin gene.
• A cell in your kidney does not need insulin, so the
insulin gene is switched off.
Task
• Answer questions 7-9 on page 15 of the student
textbook.
ANSWERS:
7. Because it codes for the order of amino acids in a
protein and therefore the primary structure of a
protein.
8. Because the gene fore insulin aren’t switched on.
9. An incorrect primary structure, which then didn’t fold
into the correctly shaped protein (haemoglobin).
Learning Objectives
• Learn about different types of proteins.
• Learn about the functions of different
proteins.
• Understand what mutations are.
• Learn why some proteins are not made
by all the cells in the body.