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Degree: Biochemistry (Bachelors) - Bristol University
A bit about me:
I am currently studying Biochemistry at Bristol and I'm absolutely loving it! Although I know science can be really difficult, I've always been enthusiatic about it and hopefully I can pass some of my enthusiasm on in my tutorials and make learning a little bit easier! I have 3 younger sisters, and so I have a lot of experience with tutoring at GCSE and A-level. As well as Biology and Chemistry A-level and GCSE, I'm happy to help with GCSE Maths.
You decide exactly what we do in the sessions. I've found explaining concepts and topics using pictures, diagrams and analogies the most effective, but I'm happy to use whatever method you find the most helpful. My aim is to make the sessions enjoyable - learning is so much better when it's fun!
I'm also really happy to help with Uni applications and personal statements, so please get in touch if you want help with that!
Please send me a 'WebMail' or book a 'Meet-the-Tutor Session' if you have any questions, I am more than happy to help! Please tell me the exam board and the topics you want help with too :)
I can't wait to meet you!
|Biology||A Level||£20 /hr|
|Chemistry||A Level||£20 /hr|
The nitration of benzene is an example of an electrophilic substitution reaction - where one of the hydrogens (or other group attached to the benzene ring) is removed and replaced by another group. There are 3 steps in the nitration of benzene:
1. First an electrophile needs to be formed. This is done be reacting nitric acid with sulfuric acid. Sulfuric acid is the stronger acid (it dissociates more in solution) and so nitric acid acts as the base in this reaction.
H2SO4 + HNO3 ---> H2NO3+ + HSO4-
The H2NO3+ formed then quickly breaks down into water and a nitronium ion (NO2+) - this is the electrophile that can then attack the benzene ring.
H2NO3+ ----> H2O + NO2 +
2. The nitronium ion attacks the benzene ring, breaking the stable ring of delocalised electrons.
3. Now one of the carbons in the structure is attached to both the nitrate and the hydrogen it was first bound to. This structure is now unstable and so the benzene ring forms the delocalised ring again, by breaking the carbon and hydrogen bond, using the electrons in that bond to reform the delocalised ring. The hydrogen is released as a H+ and is picked up by the HSO4- (formed in step 1) forming the sulfuric acid (therefore the sulfuric acid acts as a catalyst in this reaction)see more
The humoral repsonse removes the pathogenic microorganisms which don't enter the cells and requires antibodies produced by B lymphocyctes. Different B lymphocyte cells produce different antibodies, each of which is complementary to (i.e. fits the shape of, like jigsaw pieces) a signle type of antigen (present on the surface of pathogens). The B lymphocyte cell is activated once its antibody has bound to an antigen and it replicates itself to produce many clones, all producing the same antibody. The large amount of antibodies can then target and lead to the break down of the pathogen. This repsonse pathway leads to the formation of memory cells.
The cell-mediated repsonse is required when the pathogenic microorganism has entered the body cells and does not require antobodies. Once the pathogen has entered the cells it is much harder to remove and so the infected cell has to be destroyed. This is done by macrophages engulfing the invading pathogen, and presenting its foreign antigen on its surface (this is why macrophages are called antigen presenting cells). T helper cells recognise the antigen and activate cytotoxic T cells (or T killer cells) which then kill the infected cell.see more