Transcript Microbes and Diseases

Microbes and Diseases
Microbes or micro-organisms can only be seen using a m
They can infect our bodies and cause d
.
Bacteria

single celled organism


are not always h
.
(useful for making c
and
y
and for decomposing sewage
and dead plants and animals)
grow and reproduce inside your b
.
can release poisons (toxins) or damage cells
are destroyed by a
.
numbers can double every 20 mins
Examples of diseases they cause:
f o od
po
t
w
cough
s
t
ch





.
Viruses




are not cells - contain genetic information
are very s
.
infect cells – don’t survive long out of body
multiplies by making copies of itself inside
the cell then bursts out of cell killing it and
releases lots of viruses to infect more cells



can release p
making you feel ill
antibiotics don’t affect them
Examples of diseases they cause:
co
f
c
p
G
m
p
c
s
A
foot and
food poisoning colds
flu
chicken pox
whooping cough
German measles tetanus
sore throats
polio
cold sores
foot and mouth disease
AIDS
cholera
yoghurt
microscope cheese
harmful
disease
poisons body antibiotics small
Questions - write the answers in your book
1. Name 3 things which can damage your health.
2. There are millions of bacteria everywhere - in the air, water, soil and you. Some are
important and are useful (e.g. production of yoghurt), but others cause disease. List 3 ways in
which bacteria can enter your body.
3. Explain why it is important to cover your mouth or nose when you cough or sneeze.
4. When bacteria enter our body and start to multiply, what do we say we have?
5. Why shouldn’t we eat food which is undercooked?
6. Bacteria can get into drinking water and make you ill when you drink it. Which disease can
be spread in this way?
Microbes and Diseases
Microbes or micro-organisms can only be seen using a m
They can infect our bodies and cause d
Bacteria

single celled organism


are not always h
.
(useful for making y
and for
decomposing sewage
grow and reproduce inside your b
.
can release poisons (toxins) or damage cells
are destroyed by a
.




Examples of diseases they cause:
f o od
poisoning
w
cough
s ore
t
.
.
Viruses




are not cells
are very s
.
infect cells
makes copies of itself inside the cell



can release p
making you feel ill
antibiotics don’t affect them
Examples of diseases they cause:
colds and flu
chicken
p
G
m
cold
sores
A
chicken pox
whooping cough
German measles
sore throats
yoghurt
microscope
harmful
disease
poisons
body
AIDS
antibiotics
cholera
small
Questions - write the answers in your book
1. Name 3 things which can damage your health.
2. There are millions of bacteria everywhere - in the air, water, soil and you. Some are
important and are useful (e.g. production of yoghurt), but others cause disease. List 3 ways in
which bacteria can enter your body.
3. Explain why it is important to cover your mouth or nose when you cough or sneeze.
4. When bacteria enter our body and start to multiply, what do we say we have?
5. Why shouldn’t we eat food which is undercooked?
6. Bacteria can get into drinking water and make you ill when you drink it. Which disease can
be spread in this way?
Antibiotics
Antibiotics are substances which can kill bacteria.
Alexander Fleming was a Scottish scientist who studied the bacteria that stopped soldiers wounds
from healing. In 1928 he discovered the first antibiotic by accident! He noticed some mould
(fungus) growing on jelly which had stopped the bacteria growing on it. The mould was called
Penicillin notatum and it produced a substance which killed bacteria. From this discovery
Howard Florey then used this substance - penicillin to treat patients.
Why can’t antibiotics be used to treat the common cold?
Fighting disease
Your body has a defence system against microbes. You have a protective wrapping - your s______.
Your body recognises ‘enemy’ microbes which do get in and fights against them.
It is the job of the i___________ system to fight disease.
Some types of white blood cells surround the microbes and destroy them by ‘eating’ them.
Another type of white blood cell makes antibodies. Each type of antibody is designed to
attack and kill a certain type of microbe.
Questions - write the answers in your book.
1. If you catch a disease like measles, you don’t get it again - you become immune.
Explain how you think you become immune to diseases.
2. You can become immune by vaccination. A vaccine is a weak or dead form of the disease microbe.
Try to explain how vaccination works.
3. Your body can make millions of different antibodies. Why do you think this is?