Antibiotics | Biology A-Level Revision

• In normal cells water enters by osmosis - too much water, the cells burst (osmotic lysis)
• Bacterial cells have a tough cell wall which prevents the cell from expanding
• Antibiotics stop the bacterial cell wall from forming correctly so the wall is weaker. 
• This weakened cell wall means that the cell can burst due to osmotic lysis so the bacteria doesn't spread

Although there's a new problem, antibiotic resistance:

• Shortly after antibiotics were discovered, small groups of people were developing resistance due to a chance mutation. 
• The mutation caused the production of a new enzyme which broke down the penicillin. 
• The gene that coded for this mutation then is passed to the next generation (through vertical gene transmission) 
• The antibiotic resistance gene carries plasmids so it can pass onto other bacterial species via horizontal gene transmission. 

Why do bacteria need to adapt?

Similarly to what Darwin said, only the fittest survive, so to increase their chances of survival, they need to adjust to suit their environment. What this does mean however is that antibiotics can quickly become useless as the bacteria adapt to become resistant to them.

Conjugation

1. A donor cell produces a thin conjugation tube between its cell and the recipient cell. 
2. The donor cell replicates its plasmids
3. The plasmid is unwound so it's now straight and can fit through the conjugation tube
4. The replicated plasmid moves through the conjugation tube and enters the recipient cell
5. The plasmid which has just entered the recipient cell now returns to a circular shape
6. The bacteria has now replicated. 

Key terms:

1. Mutations: A random change in the quantity or structure of DNA (one base is added,deleted or replaced)
2. Conjugation: The fastest method of evolution where DNA of existing individuals is combined - horizontal gene transmission
3. Plasmids: A circular piece of DNA

Vertical Gene Transmission - DNA passed to the next generation of the SAME species

Horizontal Gene Transmission - DNA passed to different species via CONJUGATION

British Science Week 2016

Science week is a ten day celebration of all things Science, Technology, Engineering and Maths. Across the UK more than 1.6 million people get involved with events nationwide - getting inspired. Over this week, I'll be posting some of my favourite parts of science.

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Happy New Year! | 2015 Review

Welcome back to my blog! I hope you all had a great Christmas and an  amazing new year!

So much in science happened last year. Until last year, Pluto was a place we knew pretty much nothing about but in 2015, we finally made it to Pluto, the images came back and the results where simply stunning. Scientists formulated a computer generated face of our past - shaking up the history of our origin. There was also a record breaking effort to travel around the world in a solar plane -  a journey however which was not difficulty free. Scientists also put in place some radical plans to protect endangered animals and to put poachers off of them. This involved things like marking shells of tortoises so they'd no longer be sell-able by poachers. Paris also held a major climate summit to formulate a deal to finally attempt to combat the growing issue of global warming. Finally, in December the UK had its first official British Astronaut, Major Tim Peake, who took off from Kazakhstan to spend 5 1/2 months on board the ISS. This event brought to a close a momentous year in science, although one which can hopefully be bettered this year!