Bacteria and Disinfectants

Purpose: How concentration can affect the performance rate of disinfectants in killing micro-organisms

Savlon

What is a disinfectant?

- bacteriacidal

What does it do?

- inhibits the growth of bacteria

Why does it do that?

- cetrimide

- chlorhexidine gluconate

Structure of a cell

Binary Fission - reproduction

Aim: I want to investigate how to kill bacteria using different concentration of Savlon.

Hypothesis: I think that the higher the concentration of Savlon the more bacteria killed.

Variables:

What is your independent variable? The concentration of savlon

What is your dependant variable? The clear zone

Describe a suitable range of values to be used for the independent
variable and how these values will be changed? The range of the concentrations i used were 0, 1/10, 1/100, 1/1000

Describe how the dependent variable will be measured and give its units? we measured the diameter of the clear zone with a ruler in millimetres

Identify any other variables that might influence your investigation and
describe how they will be controlled or kept the same to make your results
more accurate? A variable that could influence the investigation is the size of the filter paper disks, we ensured that they were keep the same size by using a hole punch. Another variable is the fact that we used savlon for the investigation instead of detol, we used salvlon because it tested better and another variable is the temperature that the agar plates were kept at, we controlled this by putting them in an incubator. 

Describe how you will ensure that your results are reliable and that you
have enough data? I ensured that my data was reliable because we did the experiment three times and took an average, we also removed an outlier.

Equipment:

• Agar Plate
• Vivid
• Yoghurt
• Cotton Bud
• Discs of filter paper - hole punched
• Tweezers
• Ethanol - alcohol
• Bunsen Burner
• Pipette - Dropper
• Dimple Tray

Method:
1. Label the agar plate into quarters.
2.Pour some of the diluted yoghurt into the agar plate
3.Drain the excess
4.Use a paper towel to soak up the unwanted yoghurt left on the rim of the agar plate
5.Use a pipette to do the dilutions on a spotting tile
6.Clean the pipette after each dilution
-10 drops of savlon, (0)
-9 drops of water, 1 drop of savlon, (1/10)
-9 drops of water, 1 drop from the solution above, (1/100)
-9 drops of water, 1 drop from the solution above, (1/1000)
7. Hole punch the filter paper into 4 small discs x3
8. Dip tweezers in ethanol
9. make sure to put the lid back on the ethanol each time
10. pass the tweezers through the flame to make sterile
11. use the tweezers to pick up the filter paper circles
12.soak the filter paper circles in each of the different concentrations
13. place the filter paper that was soaked in the different concentrations of savlon into the quarters of the agar plate
14. tape the agar plate closed
15. label with your initials
16.leave overnight

Concentration of savlon resulting in clear zone
		Clear zone diameter (mm)		Average
Concentration	1	2	3
0	0	0	0	0
1/1000	12	10	10	10.67
1/100	14	26	15	14.5
1/10	21	20	24	21.67

Trend Line

This data showed

- That the line is increasing

My conclusion

- My hypothesis was correct, I conclude that the higher the concentration of savlon used the more bacteria is killed, therefore the clear zone is bigger.

Discussion
The purpose of the Savlon was to stop the growth and reproduction of the bacteria. Bacteria are very small microorganism's, which have cell walls. For example the Capsule is the outer layer, cell wall is the middle layer and the cell membrane is the inner layer. Savlon kills bacteria because it contains Cetrimide and Chlorhexidine Gluconate. These layers protect, keep the structure and the cell membrane controls what enters and exits the cell. The chemical in Savlon is Chlorhexidine and it is bactericidal and bacteriostatic and kills bacteria by breaking down the cell membrane. 

Structure

Reproduction of bacteria

1. Cell replicates it's DNA


2. The cytoplasmic membrane gets bigger, separating DNA molecules. 

3. Membrane closes in, a cross wall is formed


4. Daughter cells.

The Chlorhexidine in savlon affected the structure of the bacteria so they  were no longer able to reproduce, which is why they created the clear zones in the agar plates.
Growth

Phase 1: Lag Phase
Bacteria begin to take in nutrients, synthesize, their RNA and there proteins, but they are not ready to replicate/reproduce yet.
Phase 2: Exponential Phase
Bacteria replicate quickly.
Phase 3: Stationary Phase
Bacteria death rate and growth rate are the same.
Phase 4. Death Phase
Nutrients are no longer available so the bacteria dies


Evaluation
 If something went wrong, what was it and how did you fix it? On one of the agar plates we spread the yoghurt to thin so it left a patch, we didnt use this measurement because it would effect the overall result.

Were there any anomalies? We had one outlier from when we spread the yogurt to thin.

What were some of the problems and how could you fix them in the future? We struggled getting all the agar plates finished before the period ended, so some of the yogurt didn't set properly, we could have started the investigation earlier in the period.

Has your investigation raised any challenging questions? Is there any way possible that we could speed the process up

Reading Log 6 - Thirteen Reasons Why

Title: Thirteen Reasons Why
Text Type: Extended text
Author: Jay Asher

"Thirteen Reasons Why" is a young adult fiction book written by Jay Asher. The book is about a teenage boy named Clay Jensen who comes home from school one day and finds a box full of tapes addressed to him on his front door step. He listens to the tapes to discover that they were recorded by his classmate/crush Hannah Baker who had committed suicide recently. The tapes explained the thirteen reasons why she committed suicide.

In my opinion this book really makes you reflect on how we as people treat and talk to each other. This book really made me reflect on my actions in the sense that i realized how oblivious i really am of my surroundings. Especially the little things, like walking through the corridor at school i would walk past people without a single thought about who they were or what they might be going through. After reading this book I've realized that it is the little things that are most important, like smiling at people. It might make someone going through a hard time feel appreciated even if it's just for a second. For example i love this quote that Clay said about people being oblivious and not wanting to accept the fact that things like suicide happen "This is the type of school we go to, everyone is just so nice until they drive you to kill yourself".

In my opinion the most impact full chapter in Hannah Baker's whole story is when she went to the school counselor. Hannah baker was heavily depressed and her last resort was talking to the school counselor. She told him about a very person subject and instead of helping her or even asking her if she was okay he said "You can dwell over the fact that this happened or move on". This chapter hurt me so much because everyone, especially children look for authority figures when they need guidance and help. I felt as though he let her down when she needed reassurance the most. There were so many red flags he could have picked up. For Example Hannah said to him "I need everything to stop.Just...People.Life."

I think that we can learn a lot as a society from this novel. We need to make sure that people especially kids realize that it is healthy and acceptable to talk about your feeling. Things will always get better.

Reading Log 5 - Dunkirk

Title: Dunkirk
Text Type: Film
Director: Christopher Nolan

"Dunkirk" is a World War II film directed by Christopher Nolan. The film is telling the story of when Germany advanced into France in May 1940, trapping allied troops on the beaches of Dunkirk.

In my opinion i think it was so sad that when the soldiers from England were returning from Dunkirk that they felt ashamed of how they fought in the war. The soldiers really underestimated themselves and didn't give themselves enough credit. A soldier called Alex in the film, when returning home from the battlefield on Dunkirk beach said "I can't look them in the eye, there going to spit at us in the streets". I think it is heartbreaking that after everything they went through all that trauma and distress they still saw themselves as cowards.

In my opinion the thing i find most interesting about the troops on Dunkirk beach is that they were so close to home, but i bet it felt like a life time away. There family and friends were literally only a train ride away, that is how close they were to the violence and fighting. Every time that they would get close to evacuating a bomb would be dropped by the enemy. Almost all of the boats that were sent to collect the soldiers went down. Commander Bolton said in the film "You can practically see it from here, home". I cant even imagine being so close to something but so far away at the same time.

Folio Panel 1 Plan

This is my folio plan for panel 1. My artist model who i got inspiration from is Barbara Kruger, i like that she tells a story with her photography. My favourite group of photos are probably the mirror ones because it was really fun working with reflection and perception.

Shutter Island

The film Shutter Island directed by Martin Scorcese demonstrates the theme 'the causes and consequences of madness' in several ways. The causes of madness in the film include guilt and trauma. Whereas the consequences ranged from creation of a double self to destruction of self. The main character Andrew Laeddis creates a delusional world in which he can escape the fact that he feels responsible for the death of his wife and children. An example of

Reading Log 4 - Walt before Mickey

Title: Walt before Mickey
Text Type: Film
Director: Khoa Le

"Walt before Mickey" was released on 8th December 2015, it was directed by Khoa Le. The movie is set about Walt Disney's life 10 years before his creation of Mickey Mouse. It explains the struggles he went through to become the most legendary animator of all time.

Walt Disney went through a lot of struggles when trying to enter into the animation film industry because it had not been done before. Every theatre he went to turned him away. Even when his first contract fell through he still kept trying. I think in order for someone to be successful they have to fail first.In my opinion failing is part of the reason Walt Disney became so famous, even when he couldn't pay his employee cartoonists and was on the verge of going bankrupt they kept pushing. Walt proves this in the movie when he says "All the adversity I've had in my life, all the troubles and obstacles, have strengthened me... You may not realise it when it happens, but a kick in the teeth may be the best thing in the world for you".

I have a lot of respect for Walt Disney because his father was not the most supportive parent of his love for drawing. When he was young his father would constantly tell him that it would be impossible to make a living from drawing and that he should just move on with his life. Even though his father did not approve he never stopped doing what he had a love and passion for. In my opinion when it comes to things like this it is okay to be a little bit selfish, because its your life your living not what your parents would ideally like you to do. I think it is definitely possible to have a career or job that you love, Walt said in the movie "The real problem with the world, to many people grow up".

Reading Log 3 - Beauty and the Beast

Title: Beauty And The Beast Book Of The Film
Text Type: Extended text
Author: Parragon Publishing

"Beauty And The Beast Book Of The Film" was published by Parragon on 31st January 2017. Belle is so sick of her boring life in her little village town, until she becomes prisoner to a terrifying beast in a mysterious magical castle. But as time goes by she learns to look past the Beasts appearance and sees a very different side of him.

In my opinion I think the majority of people judge a person by their physical appearance without even realising that there doing it. For example in the book the reason the man becomes a Beast is because he won't let an old lady into his castle based on her appearance. He says "Why would I let someone like you enter my castle". The lady puts a curse on him as a punishment for judging someone by the way they look, the only way he can turn back into a human is if someone falls in love with him as a the Beast.

The Beast becomes very lonely and depressed, he gives up hope on becoming human again because he doesn't think it is possible for someone to love him the way he is. In my opinion i think the Beast is the most relatable character in the whole book because sometimes i think i have judged someone to quickly without even giving them a fair chance, also when i feel down and self conscious i have to remind myself that it really is whats on the inside that counts. Proof of this from the book is " If he could lean to love another, and earn her love in return by the time the last petal fell, then the spell would be broken. If not he would be doomed to remain a beast for all time. As the years passed, he fell into despair and lost all hope.For who could ever learn to love a beast ?". Belle falls in love with the beast for who he really is and is super understanding about him previous actions, " She wanted him not to be deceived by appearances, for beauty is found within."

The beast definitely learnt his lesson about not judging a book by its cover. I think a quote that really sums up the way Belle pictured the beast is " When you change the way you look at things, the things you look at change. I think society could definitely learn something from this fairy tale because it has been proven that 93% of how someone judges you is based on non-verbal communication.