Transcript Disease - Science

Year 9 Biology
Micro-organisms
and Disease
Year 9 Biology
Task 1: Notes
• A disease is anything
that causes your
body to stop working
properly
• One cause of disease
is bacterial
infection.
• Bacteria are a type
of micro-organism
Year 9 Biology
Micro-organisms
• Micro organisms are
the tiny living things
that can only be seen
using a microscope.
• They are everywhere,
including the food you
eat and you!
Year 9 Biology
Ignaz Semmelweiss
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Ignaz Semmelweiss was a doctor in the mid 1800s
He wondered why so many women died of ‘childbed fever’ soon
after giving birth.
He also noticed that student doctors carrying out work on
dead bodies did not wash their hands before delivering a baby.
When he got them to wash their hands in calcium chloride
solution before delivering babies, fewer women died.
He concluded that something was carried by the doctors from
the dead bodies to the women.
Year 9 Biology
Doctors / Scientists Pasteur
and Lister
• Pasteur proved that there
were ‘germs’ in the air and
that they carried infection
and disease.
Chemicals that are used to clean wounds or get rid of
sores are called antiseptics.
• Lister developed a special
soap called carbolic soap.
• He insisted that all medical
instruments, dressings and
even surgeons should be
cleaned with it before any
operation.
• Lister’s patients stayed
healthy.
Year 9 Biology
Task 2:
Hospitals
• Why is it important
to keep them clean?
• What is an antiseptic
/ disinfectant?
• What is now used on
wards for visitors?
Why?
Year 9 Biology
Bacteria
• Bacteria are examples of
decomposers that convert
dead plant and animal
matter into nutrients that
make plants grow
• In some animals bacteria
can help with digestion
• Bacteria that cause disease
are called pathogens
• Infectious diseases are
diseases that can spread.
Year 9 Biology
Task 3: microbes
• List the 3 main types of microbe and
a disease they cause
• Bacteria
(cause cholera, boils, MRSA, typhoid, tuberculosis)
• Viruses (cause warts, herpes, polio, flu, mumps, measles,
smallpox)
• Fungi (cause athlete’s foot, ringworm)
A disease causing organism is called a
pathogen
Year 9 Biology
Questions
1. What is a disease?
2. What are the main causes of
disease?
3. What is a decomposer?
4. What is a pathogen?
5. What does infectious mean?
Year 9 Biology
First line of defence
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skin
fluids
hairs in nose
Acid in stomach
vomiting/diarhoea
Year 9 Biology
Second line of defence
• Neutrophils (large WBC) consuming
bacteria causing pus
• Lymphocytes and macrophages (other
WBC) are release from lymph nodes
• Macrophages engulf/destroy bacteria
• Lymphocytes make antibodies that
provide future protection.
Year 9 Biology
Year 9 Biology
Micro-organisms also have
enzymes
• Temperature is increased
during an infection so
pathogens cannot
function as efficiently
Year 9 Biology
Summary task
• The _______ which cause infectious diseases are
known as ________
• Once __________ and __________ get inside your
body they _________ rapidly.
• They ________ your tissues and may produce _______
of disease.
• Bodys first line of defence include _________
• Lymphocytes produce _________. Macrophages
_______ pathogens. A __________ can also reduce
the activity of a pathogen.
Skin Toxins
temperature viruses acid engulf
micro organisms
reproduce pathogens Antibodies
damage
symptoms bacteria