Unit 6 Investigative project: The effect of penicillin on bacterial growth.
P3
Start date:
After a discussion with the school’s laboratory technicians and my teacher, we decided to
arrange the date of the practical on 2 nd February 2022. The practical will take place around 9:00
until 11:00. I would say that the time given is enough for me to gather the equipment and set up
my workspace. I’m planning on spending 20 minutes on ensuring that the aseptic technique is
safely done before I will begin the experiment. The methods that I have investigated involves the
use of bacterial solution and an antibiotic (penicillin) to observe how bacteria grows when a fixed
concentration of the antibiotic is provided considering different concentrations of bacterial
solution.
Because the experiment requires 24 hours to obtain the results, I will expect to gather all the
evidence, analyse the results, and present them therefore I will observe if my hypothesis was
correct. If I found that my results were not accurate as I would expect them to be, I will leave the
product for another 24 hours to sit or I could potentially repeat the experiment using the other
methods that I have using a lower concentration of the bacterial solution or different solution of
bacteria.
Milestones:
- Getting method to the school’s technicians on the 12 January 2022 to check if it is correct
and may any adjustments be made.
- Ensure a bacteria bottle is ordered before the experiment, making sure that the volume is
enough when using it also an extra bottle is ordered in case the initial one breaks. I will
ensure that this is done a week before the experiment begins on the 27th of January 2022.
- Ensuring that all equipment is checked and functions correctly. This will be done on 28th of
January 2022 as well as ensuring before 20 minutes the experiment begins on the 2 nd of
February that all the equipment is set and works correctly.
- Being cautious of any potential hazards and risks that can be involved before during and
after the experiment on 2nd February 2022. This is done throughout the experiment having
alongside a safety regulation sheet. Making sure that safety protocols and risk assessments
are established to minimise the potential errors that might happen such as using PPE when
handling glassware, substances such as bacteria.
- Collecting the results with accuracy then analyse them to be presented in a correct way.
This is done after 24 hours the experiment finished which is on the 3rd of February or if the
petri dishes needed an extra 24 hours, the results can be collected on the 4th of February.
Completion:
I think that 4th of February will be a final date of completion of my experiment only if the experiment
will need an extra 24 hours to be completed. Otherwise, I will be collecting and finishing my
experiment on the 3rd of February 2022. This will allow me to analyse my results also completing an
evaluation and therefore complete my report in the following week.
Hypothesis: A lower concentration of bacterial solution will allow a fixed concentration of penicillin
to kill the bacteria more quickly.
, Method 1 (the method that I am going to test): Investigating the effect of a fixed concentration of
penicillin on different concentrations of bacteria solution to see how bacteria grows.
1. Prepare equipment to be sterilized using the aseptic technique:
the workspace and Petri dish must be sterilized using antibacterial cleaner before and after
the experiment.
Using the Bunsen burner flame to heat the neck of the bacteria bottle.
The windows and doors need to be closed to limit the air currents.
The Bunsen flame should be at safety flame so that it creates a sterile environment.
2. Set up 5 different agar plates. Label each petri dish with how much concentration needs to
be used, the date and name.
3. Light up a Bunsen burner, set it to an orange flame and place the agar plates near the
Bunsen burner, this ensures that no contamination will take place. The agar plates must be
closed. MAKE SURE THAT ANY BOTTLES OF ANTIBACTERIAL SOLUTION OR FLAMMABLE
SUBSTANCES ARE CLOSED BEFORE TURNING ON THE BUNSEN BURNER.
4. Switch the flame of the Bunsen burner to a safety blue flame and heat the neck of the bottle
of the E. coli bacterial solution. Switch again the orange flame of the Bunsen burner.
5. Then using a sterile micro pipette, measure different concentrations of bacterial solution
when adding in each petri dish. Open the lid of the Petri dish near the Bunsen orange flame
placing the different concentrations of bacteria solution. Increase concentration of bacteria
by 10 micro ml each time. For example, use 10 micro ml, 20 micro ml,30 micro ml, 40 micro
ml and 50 micro ml.
6. A wire hoop should be heated in the Bunsen blue flame to remove any contamination. Open
each petri dish at a time making streaks on the agar plate.
7. The Bunsen blue flame should be used again to heat the forces to pick up the paper disc
soaked in antibiotic. Again, open the lid of each petri dish and insert the disc carefully.
8. Close the lid of each petri dish and seal them around using Sellotape, do not tape them all
the way around. Place the plates in an oven at 25°C and allow the bacteria to grow over the
next 24 hours.
9. After 24 hours, do not open the petri dish, measure the diameter of the inhibition zone
around the penicillin in each petri dish using a ruler.
Evaluation of the working plan:
I consider that the working plan that I have produce might work to observe the effect of an antibiotic
on bacterial growth as I produced a hypothesis; changing the concentration of bacterial solution
when a specific concentration of penicillin (antibiotic) is provided in the agar plates. In particular for
this experiment, I will use 5 different agar plates in which I will put different concentrations of
bacterial solution. Generally, to test this experiment only the antibiotic is changed so the agar plate
can be split into sections and so the bacteria can grow in colonies. However, with bacterial solution,
which is in the liquid form, it will spread in the agar plate the different concentrations. This is going
to be more stressful as I will have to ensure that in each agar plate the concentrations are measured
correctly so my results are not affected and when I place the different concentrations in each plate, I
need to make sure that the plate is open slightly near the Bunsen burner and then quickly closed as
contamination can occur. The timing that I have to complete this experiment is enough however if I
do not fit in the time given, I could only remain with one or two samples.
P3
Start date:
After a discussion with the school’s laboratory technicians and my teacher, we decided to
arrange the date of the practical on 2 nd February 2022. The practical will take place around 9:00
until 11:00. I would say that the time given is enough for me to gather the equipment and set up
my workspace. I’m planning on spending 20 minutes on ensuring that the aseptic technique is
safely done before I will begin the experiment. The methods that I have investigated involves the
use of bacterial solution and an antibiotic (penicillin) to observe how bacteria grows when a fixed
concentration of the antibiotic is provided considering different concentrations of bacterial
solution.
Because the experiment requires 24 hours to obtain the results, I will expect to gather all the
evidence, analyse the results, and present them therefore I will observe if my hypothesis was
correct. If I found that my results were not accurate as I would expect them to be, I will leave the
product for another 24 hours to sit or I could potentially repeat the experiment using the other
methods that I have using a lower concentration of the bacterial solution or different solution of
bacteria.
Milestones:
- Getting method to the school’s technicians on the 12 January 2022 to check if it is correct
and may any adjustments be made.
- Ensure a bacteria bottle is ordered before the experiment, making sure that the volume is
enough when using it also an extra bottle is ordered in case the initial one breaks. I will
ensure that this is done a week before the experiment begins on the 27th of January 2022.
- Ensuring that all equipment is checked and functions correctly. This will be done on 28th of
January 2022 as well as ensuring before 20 minutes the experiment begins on the 2 nd of
February that all the equipment is set and works correctly.
- Being cautious of any potential hazards and risks that can be involved before during and
after the experiment on 2nd February 2022. This is done throughout the experiment having
alongside a safety regulation sheet. Making sure that safety protocols and risk assessments
are established to minimise the potential errors that might happen such as using PPE when
handling glassware, substances such as bacteria.
- Collecting the results with accuracy then analyse them to be presented in a correct way.
This is done after 24 hours the experiment finished which is on the 3rd of February or if the
petri dishes needed an extra 24 hours, the results can be collected on the 4th of February.
Completion:
I think that 4th of February will be a final date of completion of my experiment only if the experiment
will need an extra 24 hours to be completed. Otherwise, I will be collecting and finishing my
experiment on the 3rd of February 2022. This will allow me to analyse my results also completing an
evaluation and therefore complete my report in the following week.
Hypothesis: A lower concentration of bacterial solution will allow a fixed concentration of penicillin
to kill the bacteria more quickly.
, Method 1 (the method that I am going to test): Investigating the effect of a fixed concentration of
penicillin on different concentrations of bacteria solution to see how bacteria grows.
1. Prepare equipment to be sterilized using the aseptic technique:
the workspace and Petri dish must be sterilized using antibacterial cleaner before and after
the experiment.
Using the Bunsen burner flame to heat the neck of the bacteria bottle.
The windows and doors need to be closed to limit the air currents.
The Bunsen flame should be at safety flame so that it creates a sterile environment.
2. Set up 5 different agar plates. Label each petri dish with how much concentration needs to
be used, the date and name.
3. Light up a Bunsen burner, set it to an orange flame and place the agar plates near the
Bunsen burner, this ensures that no contamination will take place. The agar plates must be
closed. MAKE SURE THAT ANY BOTTLES OF ANTIBACTERIAL SOLUTION OR FLAMMABLE
SUBSTANCES ARE CLOSED BEFORE TURNING ON THE BUNSEN BURNER.
4. Switch the flame of the Bunsen burner to a safety blue flame and heat the neck of the bottle
of the E. coli bacterial solution. Switch again the orange flame of the Bunsen burner.
5. Then using a sterile micro pipette, measure different concentrations of bacterial solution
when adding in each petri dish. Open the lid of the Petri dish near the Bunsen orange flame
placing the different concentrations of bacteria solution. Increase concentration of bacteria
by 10 micro ml each time. For example, use 10 micro ml, 20 micro ml,30 micro ml, 40 micro
ml and 50 micro ml.
6. A wire hoop should be heated in the Bunsen blue flame to remove any contamination. Open
each petri dish at a time making streaks on the agar plate.
7. The Bunsen blue flame should be used again to heat the forces to pick up the paper disc
soaked in antibiotic. Again, open the lid of each petri dish and insert the disc carefully.
8. Close the lid of each petri dish and seal them around using Sellotape, do not tape them all
the way around. Place the plates in an oven at 25°C and allow the bacteria to grow over the
next 24 hours.
9. After 24 hours, do not open the petri dish, measure the diameter of the inhibition zone
around the penicillin in each petri dish using a ruler.
Evaluation of the working plan:
I consider that the working plan that I have produce might work to observe the effect of an antibiotic
on bacterial growth as I produced a hypothesis; changing the concentration of bacterial solution
when a specific concentration of penicillin (antibiotic) is provided in the agar plates. In particular for
this experiment, I will use 5 different agar plates in which I will put different concentrations of
bacterial solution. Generally, to test this experiment only the antibiotic is changed so the agar plate
can be split into sections and so the bacteria can grow in colonies. However, with bacterial solution,
which is in the liquid form, it will spread in the agar plate the different concentrations. This is going
to be more stressful as I will have to ensure that in each agar plate the concentrations are measured
correctly so my results are not affected and when I place the different concentrations in each plate, I
need to make sure that the plate is open slightly near the Bunsen burner and then quickly closed as
contamination can occur. The timing that I have to complete this experiment is enough however if I
do not fit in the time given, I could only remain with one or two samples.
