purpose : how concentration can affect the performance rate of disinfectants in killing micro-organism
hypothesis: I predict that the higher the concentration of the disinfectant ,the larger the rate of killing off the bacteria.
fair test:
Independent Variables: Concentration of Savlon.
How will it be changed?: by diluting the water with the savlon.
Suitable Range: 0%, 1:10, 1:100, 1:1000
Dependent Variable: We measured the zone of inhibition (diameter (mm)). We used the same type of bacteria on the agar plate. We used diluted yoghurt.
How will it be changed?: by diluting the water with the savlon.
Suitable Range: 0%, 1:10, 1:100, 1:1000
Dependent Variable: We measured the zone of inhibition (diameter (mm)). We used the same type of bacteria on the agar plate. We used diluted yoghurt.
Reliable Data: I can ensure my data is reliable because I sealed the agar plate and every time I'm not using it I put the lid on the agar I sterilized the tweezers each time with ethanol.
Controlled variables : We also kept the type of antiseptic used (Savlon) the same and the size of the filter paper
Controlled variables : We also kept the type of antiseptic used (Savlon) the same and the size of the filter paper
equipment:
Agar plate
marker pen
filter paper
hole puncher
10ml measuring cylinder
savlon
ruler
bacteria
cotton bud
plastic pipette
tweezers
Ethanol
lighter
diluted yoghurt
Ethanol
lighter
diluted yoghurt
bunion burner
method:
1. With a permanent marker ,label your agar plate as a quadrant (see diagram)
2. Take a cotton bud ,dip it into the diluted yoghurt and the diluted yoghurt is in a breaker. pour over the agar plate, clean up with paper towel. Don't touch the jelly.
3. Use a plastic spotting tile and a pipette and Take the Savlon and diluted the Savlon
- for %0 Savlon put water in the first hole in the spotting tile and use the pipette to drop the water ,10 drops. This is called "control"
-for 1:10 savlon , take one drop of savlon that you used in the first spotting tile hole and put that one drop in a second hole ,put 9 drops of water in the second tile.
-for 1:100 savlon , take one drop of the 1:10 solution then put the one drop into the third tile and then put 9 more drops of water in the third tile.
-for 1:1000 savlon , take one drop of 1:100 solution next put the one drop into the fourth tile and then put 9 drops of water in the fourth tile.
4. Get the filter paper to hole punch 4 circles .
5. Turn on the Bunsen burner. Get the tweezers and put the top of the tweezers in Ethanol then run it over the flame to sterilizes the tweezers. Don't put the ethanol close to the flame.
6. Pick up the circles with the tweezers and put the first circle in the %0/control savlon ,put it in the first quadrant then sterilizes the tweezers again and put the second circle in the 1:10 , put it in the second quadrant then do the same step with the 1:100 and the 1:1000.
7. Put the lid on the agar plate and leave it for 24 hours.
-for 1:1000 savlon , take one drop of 1:100 solution next put the one drop into the fourth tile and then put 9 drops of water in the fourth tile.
4. Get the filter paper to hole punch 4 circles .
5. Turn on the Bunsen burner. Get the tweezers and put the top of the tweezers in Ethanol then run it over the flame to sterilizes the tweezers. Don't put the ethanol close to the flame.
6. Pick up the circles with the tweezers and put the first circle in the %0/control savlon ,put it in the first quadrant then sterilizes the tweezers again and put the second circle in the 1:10 , put it in the second quadrant then do the same step with the 1:100 and the 1:1000.7. Put the lid on the agar plate and leave it for 24 hours.
Conclusion
I predicted that the higher the concentration of the disinfectant ,the higher the rate of killing off the bacteria. By analyzing my table and graph I can see my hypothesis is right. On my graph there is a trend line. I can see an increase trend forming, that's another evidences that my hypothesis was correct.
The trend is that the higher the concentration of savlon the larger the inhibition zone.
I concluded that by increasing the concentration of savlon the larger the inhibition zone around the filter paper because the bacteria was unable to grow.
Savlon is an antiseptic brand with two antiseptics, cetrimide and chlorhexidine
cetrimide is antiseptic substance and destroys certain type of bacteria that can infect the skin It helps maintain cleanliness of the skin . Chlorhexidine is a disinfectant and antiseptic that is used for skin disinfection before surgery and to sterilize surgical instruments.Savlon helps perverts infection , burns , small wounds etc. The structure of the bacteria. Capsule is the outer layer which protects the cell and aids in defense against immune system. Cell wall stronger layer which protects and provides the shape of the cell. Cell membrane a flexible barrier which controls what enters and exits the cell. Pili not all bacteria have it. It helps to attached to other bacteria. Cytoplasm gel-like material inside the cell which holds the cells organelles. Ribosomes location of protein synthesis. Nucleoid cell genetic information codes essential life processes. Flagellum tail which aids in cell movements. plasmid small circular piece of DNA which codes for additional non-essential processes. bacteria
The bacteria reproducing is by binary fission.In the process its started off as one then divides or splits into two identical daughter cells. The bacteria divides every 20 mins. So the bacteria stop growing around the filter paper because higher the concentration of savlon higher the killing of the bacteria, the inhibition zone would be bigger.
http://leavingcertbiology.net/uploads/3/4/3/2/34323540/8719358.jpg?454
My experiment was reliable because I sterilizer my tweezers each time before using it so I don't contaminate the other filter paper and I sealed my agar plate. The only thing that went wrong is when I put my filter paper to close together and I though it will ruin the experiment but it didn't. My anomalies were my control ( only water ) had killed little of the bacteria around the filter paper. I was thinking if we used office paper instead than filter paper will it changed the experiment? My other question are, what happens when we let the bacteria grow in a warm room for a week will it changed massively or changed slightly than 24 hours. What happens when we didn't use diluted yoghurt and we use something else like meat or fruit?
I predicted that the higher the concentration of the disinfectant ,the higher the rate of killing off the bacteria. By analyzing my table and graph I can see my hypothesis is right. On my graph there is a trend line. I can see an increase trend forming, that's another evidences that my hypothesis was correct.
The trend is that the higher the concentration of savlon the larger the inhibition zone.
I concluded that by increasing the concentration of savlon the larger the inhibition zone around the filter paper because the bacteria was unable to grow.
discussion
Savlon is an antiseptic brand with two antiseptics, cetrimide and chlorhexidinecetrimide is antiseptic substance and destroys certain type of bacteria that can infect the skin It helps maintain cleanliness of the skin . Chlorhexidine is a disinfectant and antiseptic that is used for skin disinfection before surgery and to sterilize surgical instruments.Savlon helps perverts infection , burns , small wounds etc. The structure of the bacteria. Capsule is the outer layer which protects the cell and aids in defense against immune system. Cell wall stronger layer which protects and provides the shape of the cell. Cell membrane a flexible barrier which controls what enters and exits the cell. Pili not all bacteria have it. It helps to attached to other bacteria. Cytoplasm gel-like material inside the cell which holds the cells organelles. Ribosomes location of protein synthesis. Nucleoid cell genetic information codes essential life processes. Flagellum tail which aids in cell movements. plasmid small circular piece of DNA which codes for additional non-essential processes. bacteria
growth
phase 1 : lag phase
Bacteria initially placed in the culture begin to take in nutrients, synthesize their RNA and their protein they are not ready to replicate yet.
Phase 2: exponential phase
bacteria replicate quickly, using the readily available nutrients in the broth.
Phase 3: stationary phase
depletion of an essential nutrients cause the bacteria growth rate and death rate to be equal during this phase.
Phase 4 : Death phase
bacteria dies as the nutrients are no longer readily available.
Nutrients
Bacteria absorb nutrients to grow and secrete wastes through cell membrane, cell wall, capsule. Active transport helps with the nutrients. It uses kinetic energy and the Membrane proteins to move materials against their concentration gradients from a area of an lower to an higher concentration.
http://leavingcertbiology.net/uploads/3/4/3/2/34323540/8719358.jpg?454
My experiment was reliable because I sterilizer my tweezers each time before using it so I don't contaminate the other filter paper and I sealed my agar plate. The only thing that went wrong is when I put my filter paper to close together and I though it will ruin the experiment but it didn't. My anomalies were my control ( only water ) had killed little of the bacteria around the filter paper. I was thinking if we used office paper instead than filter paper will it changed the experiment? My other question are, what happens when we let the bacteria grow in a warm room for a week will it changed massively or changed slightly than 24 hours. What happens when we didn't use diluted yoghurt and we use something else like meat or fruit?
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