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B1 L1
Learning Objective
To be able to decribe how can become immune to pathogens
Key words: Immunity, White blood cells,
Starter activity: why do you think this boy lives in this bubble?
He would not survive outside
the bubble because he has no
defense against pathogens he
isn’t immune to them
Success Criteria
At the end of this lesson it will be:
Best
Better
Good
Able to explain how White blood cells
protect us.
Able to explain how we become immune to
pathogens
Able to state how bacteria and viruses make you
ill
What do pathogens do when they are
inside your body
• Once Bacteria are inside your body they
multiply rapidly by cell division, doubling in
number once every 20 minutes.
Bacteria
• Viruses multiply by entering the cells in your body.
They use chemicals inside the cells to make copies of
themselves
The new viruses then burst out of the cell ready to
invade other cells, this can damage and even
destroy the cell
How viruses invade and multiply
How do Pathogens make you feel ill?
• Bacteria and viruses
– release poisonous chemical called toxins
– Or prevent cells from working properly
• From these you will get symptoms such as a
headache and fever.
Learning objective check
Good
Able to state how bacteria and viruses make you
ill
How does our body protect us
• Your body has many different ways to protect you:
• WHITE BLOOD CELLS are specialised cells that defend your body
against pathogens and also release Antitoxins to combat the
toxins given by the pathogen.
White blood cells
Phagocytes
Ingest pathogen
Lymphocytes
Release chemicals
called antibodies
Phagocytes – Ingest pathogen
• Phagocytes ingest (eat) the pathogen taking the pathogen
into the cell.
• Once inside the white blood cell releases enzymes to digest
and destroy it.
Lymphocytes – release antibodies
• Lymphocytes release chemicals known as antibodies.
• Antibodies can only destroy a particular bacterium of virus,
so lymphocytes need to produce different antibodies for
different pathogens. So wbcs learn to make different types
of antibody.
Immunity
• Once your white blood cells destroy a type of
pathogen, you are unlikely to develop the same
disease again.
• This is because the white blood cells recognise
the pathogen the next time it invades the body
and the correct antibodies will kill it very quickly
before it can affect you.
• This makes you Immune to the disease and is
known as Immunity.
Science skills activity (5 minutes)
How do Bacteria multiply in the body?
How do viruses multiply when in the body?
How do bacteria and viruses
make you ill?
Explain how each type of white blood
cell protects you from disease.
What are the 2 types of white
blood cell?
Once your white blood cells have destroyed a
pathogen , you are unlikely to become ill again
from the same pathogen, why?
Plenary
• Discuss and Identify 3 important points from
this lesson which you will need to revise
Good revision
video of
pathogens