Download Antibiotics - Noadswood Science

Which drugs do you take when
you are ill? Why?
Antibiotics
Antibiotics
L.O:
To understand how antibiotics
work and the advantages and
disadvantages associated with
them.
Defence against disease quiz
Fleming video
How do doctors treat bacterial, fungal and viral infections?
• Often drugs relieve the symptoms of a disease but do
not kill the pathogens e.g.____________
• Antibiotics are chemicals which kill bacteria and fungi
e.g.__________
• Antibiotics do not kill _______
• Antibiotics do not damage your own cells
• If used too frequently bacteria can become resistant to
_____________
• It is very difficult to find drugs for viruses because they
reproduce rapidly and inside ________, it is difficult to
develop drugs that kill viruses without damaging your
cells
Investigating the growth of bacteria.
Predict which plate will have the biggest
growth bacteria and explain why.
Using discs on agar covered with bacteria : this
technique is used in hospitals on samples of
urine blood and stools to work out which
antibiotic to use
• Which antibiotic is the
best?
• Which antibiotic are
the bacteria most
resistant to?
• What is the difference
between antiseptics
and antibiotics
A
B
C
D
E
Antibiotics
Advantages
• Cures a lot of diseases
• Usually relieves
symptoms in a few days
• Reduces deaths from
diseases
Disadvantages
• Resistant bacteria can
develop
• Diseases become more
difficult to treat
• Not taking the full course
causes more resistant
bacteria to survive
Results
A. Collect your agar plates.
B. Examine the agar surface, looking for clear areas
around the discs (where the bacteria have been killed).
Measure the radius of any clear areas.
C. Design and draw up a table in which to record your
results, and also those from the rest of the class.
D. You may wish to determine the mean results for the
class.
Conclusion
• Hypothesis: ‘the survival and growth of the
micro-organisms depends on the type of
antibiotic used’
• Do your results support the hypothesis? 1 mark
• Which antibiotic was best at killing E.Coli?
Which antibiotic was best at killing
M.Luteus?
• Were the results repeatable or reproducible?
•
2 marks
2 marks
Context
If you were working in a hospital
laboratory, and you had just carried out
this test on bacteria isolated from sick
patients, would you always choose the
antibiotic that gave the biggest
inhibition zone? Are there any other
factors you would need to consider?