Transcript 4.3 using drugs to treat disease and MRSA - science

GCSE Core Science
Human Biology
Key Words
ANTIBIOTIC, PENCILLIN, PAINKILLER,
NATURAL SELECTION, PANDEMIC,
EPIDEMIC, MUTATION
GCSE Core Science
Objectives
Human Biology
By the end of the lesson I will:
•Know that antibiotics can be used to kill bacteria inside your body
•Know that it is very difficult to kill viruses because they reproduce
inside the bodies cells (so destroying the virus means destroying the
cell!)
•Know that painkillers can relieve the symptoms of a disease
• Know that it is difficult to control a pathogen that changes through
mutation (occurs in an instant) or natural selection (occurs over time
and is a gradual process)
•Know that bacteria DO NOT have a ‘brain’ so they do not ‘want’ to
develop a resistance to antibiotics they just do!
•Know what MRSA is and why it is a concern. (Multiple resistant
Staphylococci Aureus)
•Be able to read graphs
GCSE Core Science
Starter
Human Biology
I know HOW TO USE ASEPTIC TECHNIQUE
GCSE Core Science
How do we effect change?
Human Biology
We are going to grow some yeast…..
AND THEN KILL IT!
1. Using ASEPTIC TECHNIQUE infect a petri dish with a
yeast solution.
WHAT DID
YOUonto the centre of the agar
Place a full drop of antiseptic
plate.
FIND OUT?
2. Wait for the solution to slightly dry (perhaps 1hour)
3.
4. Incubate for 24-48hours.
WHAT ARE YOU TRYING TO FIND OUT?
WHAT DO YOU EXPECT TO FIND OUT?
GCSE Core Science
Human Biology
GCSE Core Science
Alexander Fleming
Human Biology
Alexander Fleming is attributed to discovering penicillin in his lab.
One day after a holiday he returned to his untidy lab to find a ring in
the agar around a mould. He tried unsuccessfully to extract the
juice (the penicillin).
10 years later he finally gave up and another scientist pair ‘Ernest
Chain and Howard Florey’ discovered a way to extract and produce
the drug in industrial amounts.
This was first used in the second world war and still is used today
GCSE Core Science
How do they work?
Human Biology
Antibiotics work by damaging the bacterial cell wall without
harming your cells.
What is a mutation?
A mutation is caused when you get ill, you take an
antibiotic and most of the bacteria is killed except for a
few who survive as they are resistant to the antibiotic.
Since there are only a few remaining, the body is able to
remove these or ingest them.
GCSE Core Science
What is natural selection?
Human Biology
When you are ill you are given a antibiotic to kill the
bacteria.
To prevent
there
arestart to
The antibiotic
kills most this
of thetrend
bacteria
and you
feel well and
takingthat
the medication.
This leaves a
twostop
things
we can do;
number of bacterial cells that are resistant to the
antibiotic. These resistant bacteria reproduce and you get
1. Only take antibiotics for
sick again.
bacterial infections
You get given
a different
stronger
antibiotic
2. Take
the full
course
of which kills
most of the bacteria and you start to feel well and stop
antibiotics that have been
taking the medication. This leaves a number of bacterial
prescribed
cells that are
even more resistant and you fall ill again.
GCSE Core Science
Human Biology
Antibiotic resistance
Antibiotics have been used to control
bacterial diseases for some time.
Erythromycin was first available in the UK
in 1954 to control infections, caused by
Staphylococcus bacteria, in young babies.
GCSE Core Science
Antibiotic resistance
Human Biology
The graph shows the development of Erythromycin resistance
in bacteria.
GCSE Core Science
Antibiotic resistance
1 What important event took place in the bacterial
population sometime during 1956?
Human Biology
GCSE Core Science
Human Biology
Antibiotic resistance
Answer to question 1
1) Erythromycin resistance started to
develop in Staphylococcus as a result of a
mutation.
GCSE Core Science
Antibiotic resistance
Human Biology
2 What decision did Hospital E and Hospital W take concerning
the use of Erythromycin in 1959 and 1961 respectively?
GCSE Core Science
Human Biology
Antibiotic resistance
Answer to question 2
2) Hospital E stopped using Erythromycin in
favour of an alternative antibiotic in 1959.
Hospital W stopped using Erythromycin in
favour of an alternative antibiotic in 1961.
GCSE Core Science
Antibiotic resistance
Human Biology
3 What effect did the action taken in 1959 and 1961 have on
the percentage of organisms resistant to Erythromycin?
GCSE Core Science
Human Biology
Antibiotic resistance
Answer to question 3
3)In the case of Hospital E, the percentage of
Erythromycin-resistant Staphylococcus fell
straight away. In Hospital W, it fell after a
delay of more than one year.
GCSE Core Science
Antibiotic resistance
Human Biology
4 If resistance is inherited and the decision to withdraw Erythromycin
use had not been taken, what long-term change in the
Staphylococcus population would take place?
GCSE Core Science
Human Biology
Antibiotic resistance
Answer to question 4
4)Eventually all the Staphylococcus would be
resistant to Erythromycin.
Antibiotic resistance by natural selection
GCSE Core Science
Human Biology
Bacteria – a few will have mutations that make them
resistant to antibiotics
Antibiotic 1 given – only those bacteria that are resistant
survive to breed
Antibiotic 2 given – only those bacteria that are resistant
survive to breed
Now bacteria are resistant to two antibiotics
GCSE Core Science
Extension
Human Biology
Use page 69 to answer this
A* question
What problems do mutations cause
in modern hospitals?
What Principles can we use
to affect change?
5 marks
GCSE Core Science
Objectives
Human Biology
By the end of the lesson I will:
•Know that antibiotics can be used to kill bacteria inside your body
•Know that it is very difficult to kill viruses because they reproduce
inside the bodies cells (so destroying the virus means destroying the
cell!)
•Know that painkillers can relieve the symptoms of a disease
• Know that it is difficult to control a pathogen that changes through
mutation (occurs in an instant) or natural selection (occurs over time
and is a gradual process)
•Know that bacteria DO NOT have a ‘brain’ so they do not ‘want’ to
develop a resistance to antibiotics they just do!
•Know what MRSA is and why it is a concern. (Multiple resistant
Staphylococci Aureus)
•Be able to read graphs