Mahuta ♥

BiO FrEaK, on Apr 14, 2012 - 14:35, said:

Hi,

A metabolic pathway is made up a series of chemical reactions, each catalysed by an enzyme. However, sometimes the product formed from the last reaction will inhibit the enzyme of the first reaction; this is known as end-product inhibition and involves non-competitive inhibitors.

If the end product binds to the enzyme of the first reaction, it will act as a non-competitive inhibitor and will NOT bind to the enzyme's active site but to an allosteric site. The effect of it binding to the allosteric site is that it distorts the shape of the enzyme's active site, meaning that that enzyme is unlikely to be able to catalyse any more chemical reactions. (Note: removing the inhibitor from the allosteric will allow the enzyme's active site to return to its original shape.)

In terms of uses, end-product inhibition is useful to control metabolic pathways, e.g. when there is an excess of a product, the metabolic pathway can be shut down until more of the product is required, at which stage the inhibitor is removed from the allosteric site to restart the metabolic pathway. The term negative feedback is often used as the process opposes a change in the environment and therefore is vital for homeostasis.

Hope this helped,
brofessional (not Mahuta, unfortunately)

Conduct of the Examinations.pdf

*TOPIC 11 (11.1.4) -Production of antibodies

For the IB all you need to know is that

1. Phagocytes come across pathogens, ingest them by phagocytosis and break them down into their constituent parts ('antigens') and then display these antigens using MHC (major histocompatibility complex) proteins on their membranes.

2. A T-Helper Cell which binds that specific antigen comes across and binds to the antigen being displayed by the phagocyte on its MHC (one example of a phagocyte is a Macrophage, if you need to name a specific cell type, but there are many different types). Binding of the T-Cell Receptor to its antigen presented by the phagocyte serves to activate the T-Cell via intracellular signals.

3. The activated T-Helper Cell can then activate a B-Cell that is specific for the same antigen as the T-Helper cell  (i.e. the B Cell which produces the correct antibody for that antigen).

4. The B Cell rapidly divides by mitosis to form B Memory Cells (later used as part of long-term immunity) and also B Plasma Cells which have lots and lots of rough endoplasmic reticulum to synthesise antibodies and act as antibody factories.

5. These antibodies attach to the antigen, and thereby disable viruses/pathogens/anything evil. Two of the ways they do this (although there are many others) is by binding to and thereby preventing viruses/bacteria from docking to new cells and also by causing agglutination, so viruses/bacteria stick together in a lump and can't do anything useful.

That's more or less all you need to know. Check it against a textbook, but I reckon that's the whole thing. In other words, your second statement is correct, I just reckon it's easier to remember these things in the context of the whole (which is after all how you write about them!).

Tsaren, on Mar 10, 2012 - 14:10, said:

To give a slightly more specific set of answers that slightly alter details given by previous posters:

Antigen: a molecule that triggers an adaptive immune response. This doesn't necessarily always involve the production of antibodies, although that is one possible outcome. There are many ways besides antibodies that the adaptive immune response may take action, including generation of killer cells etc. Antigens also aren't necessarily on invading pathogens - they CAN be, but they could also be elsewhere. You can in fact (through a failure to delete these cells during development, or a failure to stop them from working peripherally - a process known as tolerance) have adaptive immune cells that respond to your molecules on your OWN cells. Or to things you don't actually want to respond to (e.g. grass pollen, which isn't an invading pathogen...). This is the basis for autoimmune disease, allergy etc. So whilst the body is MEANT to (and generally does) recognise only foreign molecules as antigen to generate an adaptive immune response, it can also recognise itself (self-antigen) and non-pathogenic molecules.
Also, the molecules it recognises don't have to be extracellular on the cell surface (this is only necessarily for antibody-type adaptive immune responses), they can also be intracellular (what happens is the cell chomps up the intracellular proteins and then displays them on its surface, so killer cells can come along, recognise it, and destroy the cell). If you think about it, this must be the case because viruses don't live on the outside of cells - only inside! So we'd all die of viral disease if intracellular things couldn't be recognised as well.

Antibody: these are part of the adaptive immune response. These are Y shaped proteins produced by B Cells (which are categorised as lymphocytes, which are categorised as white blood cells - WBCs - just to make that clear) and they consist of are two parts. Part of it is for recruiting other cells, molecules etc. to come along and help to destroy the cell which is affected (the body sees cells displaying antigen as bad and to be killed). The other part is special in shape and designed to recognise a specific antigen. A bit like the lock and key enzyme theory. When antibodies encounter that antigen, they bind to it - and then that first part (the recruiting part) gets recruiting many other powerful things like killer cells, inflammatory mediators etc. and the immune response goes on from there.

These are very complex things and there's tonnes to know about them, but obviously you don't need to know it all for IB Probably just that antibodies are made by B Cells and 'stick' onto the antigen they are specific for, and that an antigen is a molecule that triggers an adaptive immune response.

Pathogen: exactly what Mahuta said

There are many people who inspire me,usually in little ways,for example my friends all have qualities I admire.
But I have to pick 2 solid role models

My dad - The type of success story that people often hear about.He came from extreme poverty,educated himself and is now very successful.What I really like about him is his work ethic and the fact that he still really values principles like generosity,kindness and humility.He's a social,confident person whereas I am very shy and for that too,I admire him.


Oprah Winfrey  - I like Oprah because she is honest about herself.She's an extremely compassionate person.She's optimistic.She overcame a lot of adversity in her life and she uses herself to help other people learn.She has opened herself up to be used as an instrument and she serves the world as far as her abilities will allow her.She tries to be the best person she can.

I'm afraid I can't do the first.

I will try to implement the second and third though.

Does Observation Creat Reality?

Main WoK / AoK: Sense Perception
Minor WoK / AoK: Emotion / Science, Mathematics

Key words: consciousness, observation, reality, senses, perception, relativity, infinite probability
Please have a look at the following video:

Introduction - A very good video on sense perception



This video may excite many of you physicists and chemists out there. But, the importance of this video in relation to ToK is the the physical or chemical aspects of atoms or quantum theory. The most important thing you should take away from this video is an understanding of how sense perception is constructed from a physical reality; that although sense perception is a product of physical reality, it does not represent the full physical world.

If you are looking for the main message of this video or if you don’t understand it very well, listen to what the monk and the lecturer have to say at 5:44, 7:02 and 7:26 for a concise summury.

Knowledge Issues and Questions:

• How are our sense perceptions useful and what are their limitations?
  
• To what extent is it possible to obtain knowledge of reality through sense perception? Distinguish between physical reality and conscious reality.
  
• "If a tree falls in a forest and no one is around to hear it, does it make a sound?"
  
• How does reality change when sense perception is changed?
  
• Why is “illusion” maybe not the right word to describe the reality we perceive?
  
• Debate: If we can never know absolute reality or if everything “an illusion” or “a mental construction”; is there any point of pursuing reality?
  
• Are you a consciousness within reality or are you reality within a consciousness?

Robert Anton Wilson said:

Anais Nin said:

---

How does this work?

There are no limits to discussion apart from the topic title and that it is related to ToK. All the resources above are there to try to start discussion; by all means contribute your own of you find anything different or interesting. The knowledge issues and questions are there for you to respond to. When replying to a particular question remember to quote it so others can see what you are responding to. if you wish to add your own, simply follow on from the last numbered question and label it in your post. e.g.
4. How does reality change when sense perception is changed?
Response...

8. Can it be true....?
Response.........

Once some of these questions are attempted we can roll into more interesting discussions.

Thank you for your support. The first one of these has now started. Feel free to join in: http://www.ibsurviva...create-reality/

If you wish to recommend a topic for next week please send me a PM.

Kreyszig, on Oct 24, 2011 - 22:13, said:

I know that it is good to have a comparison between the difference in lit. Value and your value, but i don't think that it is a "must' since IB knows that some labs like enzyme or reaction activity has no lit. value.

RIGHT this post is being made because there's an almost endless supply of people who pick very bad TOK presentation titles and it's always for the same reason: they don't really understand what the TOK presentation is about! SO listen up everybody and pay close attention to my attempts to dispel the TOK myths and stop people putting loads of effort into a presentation which is doomed from the start!

1. What do they mean when they say to pick a Knowledge Issue?
The answer is frankly that the phrase 'knowledge issue' is very misleading, in my opinion. I certainly didn't have any idea what one was for most of the time I did TOK. Just think of 'knowledge issue' as a complicated way of saying 'a topic which can be analysed using the TOK pentagram thingy'. What is the TOK pentagram thingy? Well by that I mean the Ways of Knowing (emotion/reason/sense-perception/language) which in the IB diagram is surrounded by the Areas of Knowledge (Humanities, Human Sciences etc.). So a 'knowledge issue' is any topic which can be discussed or analysed in the context of the Ways of Knowing (and the Areas of Knowledge).
Confused?
You may well be. Keep reading! Or just skip the next heading and go to no. 3.

2. Do they mean to pick an ethical dilemma?
No, no and NO. Thousands of IB students misunderstanding TOK up and down the land seem to have a thought process which (understandably but also wrongly) goes along the lines of:
TOK = Philosophy = ...ethics = are things right or wrong??
This is not good. TOK is supposedly a branch of Philosophy but that's as far as it goes. A knowledge issue is not "is _____* right or wrong?"
* = abortion, nuclear war, creationism... and so on.
Don't write about ethics, don't touch ethics, don't go near ethics. Ethics and TOK are like oil and water. They do not mix. An area of knowledge may well be ethics but I guarantee you that almost anybody trying to put ethics into their TOK presentation will fail to write about the TOK aspects and just start writing about ethics. So take Kant, Utilitarianism, Relativism and anything else you may have proudly learnt the rudiments of, and stuff them in a bag for later. Or if you take IB Philosophy, they'll go down well there

3. Okay so what DO they want from me??
This is the best question because it's not about what they MEAN by knowledge issue etc. that is going to help you do well, but rather what they want from you which is the key to success and being able to pick a good TOK essay title. Always think of it in these terms and you'll be able to tell whether you're on the right lines or drifting dangerously off course.
Effectively they want you to answer the following question: How do we know what we know? specifically using their method of the Ways of Knowing/Areas of Knowledge in your explanation.

4. So... what do they mean by how do we know what we know?
How do we know what we know about X? = using the 4 ways of knowing (reason, sense-perception, emotion, language), how do these 4 things interact and come together to form the knowledge that we have about subject X.
For instance, how do we know that this pen is yellow?
This isn't an endlessly deep philosophical question (in this instance) because this is a TOK lesson so they want you to copy/paste from the TOK pentagram. So think to yourself: what are the 4 ways of knowing and how do we use those to know the pen is yellow? Well, maybe somebody told you it was yellow (language), maybe you were told that it was the third colour of the rainbow (reason), maybe you were just shown it (sense-perception). I'm not sure how you'd emotionally find out it was yellow, but you get my gist - basically you are applying the 4 ways of knowing to something and then claiming that those ways of knowing form the "How" of the question "How do we know what we know?".

5. I get it now, but how is "this pen is yellow" a knowledge issue?
Yeah, it's not a knowledge issue. Or rather, technically it is, but it's such a simple one that you couldn't do a presentation on it. Now that you've got the hang of the fact we're looking for SOMETHING to which to apply the 4 ways of knowing, we can look for a proper issue to get your teeth into. My advice is to think of something which is either an assumption or a decision that we make relatively unthinkingly. For instance, "How do we know which charity to donate to?" or "How do we know whether literature is 'good'?".
THEN think your way through the 4 ways of knowing to see whether you can apply them (in which case, congratulations, you're going down the right lines!). Can you think of a way in which we use that way of knowing to come to a conclusion about your new 'knowledge issue'?

6. How does it become an 'issue' exactly? I seem to just be narrating things...
In many ways this is the crux of the essay and the whole point of TOK (to get you to consider this). This is the point at which you say "Well, I know about whether literature is good or not via reason because I assume that anything which has sold 10,000 copies MUST be good..." and then go "actually wait, reason requires things to follow logically - but actually, does this logically follow?".
Well that's what you have to discuss! Your argument as it stands is:
1. People only buy books if they're good
2. 10,000 people have bought this book
3. Therefore the book is good.

...but does number 1 really make sense? What about advertising? 10,000 people might buy a really bad book if they see loads of adverts for it. Was the book a set text for the national curriculum? Plenty of people would have to buy it then And so on. Basically it's looking at the knowledge we have and checking it for mistakes and THAT is why it's an 'issue' and why TOK is meant to be helpful. If you're the kind of person who never questions why they think things, or thinks "hang on a sec, maybe I'm just assuming something which might not be true..." then TOK may be a revelation to you.
This is where you go crazy with stuff like appeals to emotion, bias, censorship etc etc. and start looking into how the way in which we have come about the knowledge might fail to give us a complete picture of the 'truthful' version of that knowledge. Reason, emotion, sense/perception and language have a lot of issues in terms of ways in which they can help and hinder you, and it is now your job to suss these out and make them into a presentation! Essentially: How do they help you/let you down in terms of finding the 'truth' for the knowledge you've chosen as knowledge issue?
BUT make sure you talk about the 4 ways of knowing (or however many apply, you might not need/be able to use all 4) and not just about bias/censorship/any key words other than the ways of knowing if you want to get your marks!

7. So do all TOK titles have to be in the format "How do we know what we know about X?"
Nope, have free rein and go wild. Just make sure you can apply the 4 ways of knowing and that you're examining HOW we come to know about the issue.

8. Link it to a real-life scenario/example wherever possible.
Okay, this isn't a suggestion, this is a command. Find an example, invent an imaginary example, whatever. You get bonus points for this, so do it 'cause it's easy. For the "How do we know what literature is good?" scenario, I might look at the real-life scenario of literature picked to be taught in schools or literature put in the 'Classics' section of a bookshop, or perhaps literary prizes. All scenarios where we have to ask about good literature, and all real-life examples which you can theme your presentation around. The TOK examiners get very sad when they realise that TOK is essentially just another random overlay of bull**** onto real life, so they are made VERY happy indeed by seeing you give a real-life example to prove that TOK is indeed relevant to reality. Even if it isn't. If you fail to link the TOK pentagram to a real-life issue, you can wave goodbye to a hefty chunk of marks. Bonus points if it's a personal example of an issue or uses personal experiences (even if you make them up).

9. Did I mention... DON'T TOUCH ETHICS!!!!
Because honestly this is the hardest one for people to accept. TOK teachers might ask you ethical questions in lessons because they're trying to engage you and make you interested (and let's face it, once you stop pretending it's relevant to ethical dilemmas it becomes about 110% less interesting...), but they WILL NOT AWARD YOU MARKS for talking about ethics rather than TOK - no matter how insightful and interesting your presentation on ethics may or may not be.


In Short...
In summary, the answer to the question "Is this a good TOK presentation title?" can be solved via a simple litmus test.
- Can you attach it to a real-life example?
- Can you discuss it in the context of the 4 Ways of Knowing? (Or if not all 4, in the context of a few of them).

If yes: Excellent work!

If no: Think again, find a new topic. Go to jail, do not pass GO, do not collect £200 etc. and give up on this idea with immediate effect.

MOST IMPORTANTLY: Do not select an ethical dilemma! ...or if you do, can't say I didn't warn you.

Hopefully this helps. TOK is quite a big and ill-defined subject so if anybody has any other ideas or techniques to get good TOK presentations, please do contribute them and I'll add it in. This is just my version. I apologise that the format of this is perhaps not so useful, but if you DO read all the way through it in order, then it does make sense. I promise

Oh and remember ALWAYS READ THE MARKING CRITERIA!

Now please kindly read this thread which has loads of helpful tips for getting on with your TOK Presentation after you've come up with a title! - TOK PRESENTATION GUIDE http://www.ibsurviva...entation-guide/

Alright, you have a golden flute. There are three people you can choose from based on who you want to give this golden flute to (it;s made form gold and can be played):

-A poor man
-A flute maker
-Or a flute player


State your assumptions too make your point more clear.

I'd give it to the poor man. With this flute the poor man would eventually learn how to play the flute. With this new skill he could refine it and become excellent at playing the flute. He could then make a living by becoming a musician. He would then really appreciate the flute and begin this new life with a new passion.

The school only having one diploma recipient each year indicates that the school is not very used to the ways of the IB. Therefore it is important that you students make efficient use of the syllabus documents; read through them and make sure that you know everything you are supposed to know. Read through the assessment criteria (especially those for the Internal Assessments) in order to secure as many marks as possible.

The key to doing well in the exams is to do all the past papers you can find. You have to get used to the kind of questions asked, and doing old exam questions will also help you ensure that you are focusing on the right things.

Also, use IBSurvival!

You know you're in IB if you've made an account on IBS O.0

Something like 94% of people think they're of "above average" intelligence

Also, come on. It's pretty sad to talk about your penile length on the internet. That's like the one place you can get away with saying anything.