Bacteria and Disinfectants

Bacteria and Disinfectants

Purpose:

How concentration can affect the performance rate of disinfectant in killing micro-organisms.

Hypothesis:
I predict that when the concentration of Savlon is increased that the clear zone size will also increase.

Equipment:

• 3 Agar Plates
• Savlon
• Tweezers
• Filter Paper
• Ethanol
• Bunsen Burner
• Yoghurt (for the bacteria)
• Permanent Marker
• Sellotape
• Pipette
• Water
• Spotting Tile

Concentrations:

One control 0% - Water

Savlon

One 100%

One 50%

One 10%

Variables:

• Independent Variable: The concentration of the disinfectant, in this case Savlon
• Dependant Variable: The clear zone. Or the area where the bacteria was not able to grow. We will measure the diameter in mm
• Control Variables: 1) Size of filter paper, used a hole punch of the same size, (2) type of disinfectant, only used savlon and no other type of disinfectant (3) size of agar plate used three of the exact same agar of the exact same size.

Possible factors for a source of error

• Contamination of Agar plate
• Cracking the agar
• Not sterilising tweezers
• amount of yoghurt differing agar to agar

Method:

• With a permanent marker, mark out four sections on the bottom of the plate on the side where the gel is located. These four sections will hold the different concentrations of Savlon and the Control.
• Spread some yoghurt acting as bacteria on top of the gel inside the agar plate.
• once the yoghurt has covered the agar we will drain the excess.
• we will then dilute the Savlon into three concentrations of 100% 50% and 10% using the pipette and Spotting Tile place 10 drops of Savlon in 1 spot of the tile, 5 drops of savlon and 5 drops of water in another spot, then 1 drop of savlon and 9 drops of water in another spot and then 10 spots of water in another one. you should have 4 spots in the tile filled with these solutions.
• using filter paper and a hole punch cut out 12 circles, 4 for each plate
• using these circles and sterilising the tweezers by dipping in ethanol and running through the Bunsen burner after each time, dip the circles into the different concentrations and water then place in the different sections.
• after this we will tape it up, put our initials on it and place it in incubation.
• Then measure the diameter of the clear zone in millimetres. 

Outcome:

Concentration	Clear Zone (mm)	Clear Zone 2 (mm)	Clear Zone 3 (mm)	Clear Zone average (mm)
0%	0	0	0	0
10%	13	18	20	17
50%	22	25	25	24
100%	28	29	35	30.6

Conclusion:

After analysing the results of our experiment and placing them in a table and a line graph we have concluded that when the concentration of Savlon is increased the size of the clear zone also increases. The savlon worked by not killing the bacteria but actually preventing it to grow and as we increased the Savlon it worked better and prevented more bacteria from growing.

Discussion:
The active ingredient in Savlon is chlorhexidine. Chlorhexidine is used as a disinfectant and an antiseptic. Savlon is bacteriostatic meaning that it prevents the growth and reproduction of bacteria. bacteriostatic disinfectants work by interupting the growth and reproduction cycle. They do this by interfering with the protein growth within the cell and also the DNA replication. By doing this the cell is not able to create offspring because they are unable to pass on their DNA.

Bacteria is made up of a capsule, cell wall, cell membrane, chromosome, plasmids, ribosomes, pili and a flagellum. The capsule helps keep the cell safe, the cell wall holds the structure of the cell, the cell membrane controls the nutrition and excretion of the cell, the chromosome hold the DNA of the cell, the plasmids hold extra DNA, the ribosomes are where protein is produced, the pili is used for transferring DNA between cells and the flagellum is used to move the cell. Since the cell membrane is what controls what comes in and out this means that the disinfectant breaks through the Cell wall, enters through the cell membrane and destroys the Chromosome which holds the DNA making the Bacteria cell unable to reproduce. Bacteria cells excrete and gain nutrition through their cell membranes. They do this by using active or passive transport. 

Bacteria grow by replicating the DNA of the parent cell, after this they grow/elongate, after this stage they then split into two seperate cells and the reproduction cycle is complete. Bacteria reproduce very rapidly as they split into two from every parent cell. This means that the Bacteria is asexual. Since the Bacteria is self producing, when one Bacteria's DNA is destroyed there is no way for any more Bacteria to be reproduced from that certain cell. When the disinfectant is spread through a whole colony all of those Bacteria are rendered unable to reproduce. Passive transport is when there is a high concentration of molecules outside of the cell and a low concentration inside and the cell naturally diffuses the high concentration inside of the cell. Active transport is when there is a low concentration outside of the cell and a high concentration inside and the cell has to use energy to transport the molecules. So when a disinfectant is introduced to a bacteria cell it will enter the passive transport cycle and naturally diffuse into cell causing the chromosome to be destroyed.

Evaluation:
The Method we used was very effective, they were easy to follow and nothing went wrong. The method was reliable as the size of the clear zone varied because of the different concentration which is what we wanted. The size of the clear zones from each concentration on the different agars differed slightly  but they remained relatively close. The averages are probably a little close together which could come down to not enough time letting the bacteria grow or putting to much Savlon on the filter paper resulting in the results not being extremely varied.

Research:
https://en.wikipedia.org/wiki/Chlorhexidine
https://en.wikipedia.org/wiki/Bacteriostatic_agent
https://en.wikipedia.org/wiki/Savlon

Reading Log 5

Title: AI Learns Gender and Racial Biases From Language

Author: Jeremy Hsu
Text Type: Article

In this article Jeremy Hsu speaks about how AI is learning about gender and racial biases from existing English texts and how these AI could possibly exhibit these biases found in the texts.

Part of the text says that the AI are more likely to associate words such as flower and music with being pleasant and words such as insects and weapons with being unpleasant. But the AI was also more likely to associate European American names rather than African American names with being pleasant. It would also associate women with jobs in the arts rather than with mathematics. I think this is a problem because when we eventually introduce these AI robots into our world they will already hold preconceived prejudices. This will lead to even more gender and racial problems that future generations will have to endeavour. If these AI's can pick up different prejudices that the human race holds against each other then it is possible that the racial and gender problems we have right now will only worsen. Since these AI's effectively think for themselves, these preconceived ideas that they've gained by analysing us as a race and our language, may actually become the ideas that they will follow and try to implement. If the AI's become a race of their own then they could also feed off each other's information like we do. If they did this then they would begin to form their own prejudices amongst their race against our race.

Another part of the text I found interesting was this quote “The worry is that if machine learning is replicating human biases, it's also reflecting that back at us. Perhaps it would further create a feedback loop in perpetuating those biases." I found this to be a extremely true statement. I made a similar point on my first paragraph, if these AI's are recreating these biases then they will feed off each other's information just like we do. This world is run by opinions and power, if a leader thinks something needs changing, that is their opinion and they have the power to implement that change. Prejudices are built upon opinions of other people because of their religion, cultural background, gender etc. Over the years these opinions have become preconceived thoughts that people now already know and already think are normal, because they are so common. Now since AI are picking up on all of our prejudices that we hold against each other, these prejudices will become even more common and out of control, because not only are we reinforcing them, but the AI are picking up our ideas and making them their own. Reinforcing these prejudices and only making them worse.

Link for Article
https://spectrum.ieee.org/tech-talk/robotics/artificial-intelligence/ai-learns-gender-and-racial-biases-from-language

Composition 2

Composition Ideas
Me, Cody, Cameron
Guitar and Drums Instrumental

I was sick for a week, but the boys had a intro sorted out, so once I had learnt that and gotten the vibe of the song the next day me and Cody sat down, and we exchanged riff ideas for the rest of the song and we ended up finishing the guitars apart from a solo.

We need to spend more time working on drum beats to accompany the guitars, but what Cameron has come up with so far has been awesome. We may include some sort of guitar harmony outro, and maybe a drum intro.

This song has a very upbeat feel and is extremely groove based and melodic, some vocals would go great over it but unfortunately we do not have a singer. All we need to do now is write some solo sections, write the rest of the drums and tweak the song so it is perfect to our ears.

This will be me and Cody's 5th composition but only our second with Cameron on Drums, so hopefully by the end of this year we will have all of our songs with guitars and drums, so we can eventually gain a bass player and a singer then record it all for our first E.P.

Artist Model: Marc Chagall

Marc Chagall was born 6th of July 1887 in Liozna, Russian Empire and died on the 18th of March 1985.
March Chagall was an early modernist. He used many different artistic styles and worked in almost every artistic format including painting, book illustrations, stained glass, stage sets, ceramic, tapestries and fine art prints. My favourite part about Marc Chagall's paintings in particular are his backgrounds. Such as in these paintings.










For my first board I focused on Rene Magritte's idea of surrealism, simplicity and morphing objects together, so for my second board I am going to focus on Marc Chagall and using his ideas of using backgrounds that a very eclectic have a lot of texture and are often very disorientating.

Second Board

For my second board, I am going to focus on using naturally occurring objects such as birds plants etc as metaphors. For the top of my board I am going to do a progression of roses form dead to live to wrapped around someones hands. I will use the vines of the rose as a reoccurring theme for my second board which will link to the first board as it is similar to the chains. I will also do a raven flying away from another with some vine wrapped around it's leg and the other raven possibly wrapped up in it. These two birds are a continuation of the "two people" in my first board and one will have a key in it's mouth and I might use the prison bars through the middle of the piece with the two ravens and possibly have the raven flying away casting a shadow. and the roses are representations of the at this stage I am still thinking about the rest of my board. Here are some sketches and notes on these ideas.

Start of my Artwork with two ravens, debating on keeping it drawn, painting it or using mixed media.

First Page of ideas for second board.

Second Page of Second Board Ideas.