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futureless

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Posts posted by futureless

  1. Hey, I was learning about the enthalpy of hydration today and it went *whoosh* right over my head. :embarass: Have a look at this paragraph from my textbook

     

    "For ions to dissolve in water they need to be seperated from one another. The ions in an ionic lattice are attracted by strong forces, so separating them is an endothermic process. For any compound to dissolve in water, a large amount of energy is needed to compensate for this endothermic change. Part of the energy is released when the ions become surrounded with water molecules. Ions and water molecules are attracted to each other so this process releases energy."

     

    Erm okay, I have several questions

     

     

    • Why is energy released when a bond is formed?
    • How does the attraction of water molecules to ions release energy?
    • Is hydration where water molecules break down a lattice by attraction and then water molecules end up surrounding a single ion OR is this solvation OR a special water case of solvation?
    • Whats the difference between the enthalpy of solvation, the enthalpy of solution and the enthalpy of hydration?
    • The paragraph says "Part of the energy is released...", so there's still some of the energy still needed, where does this come from?

     

     

    As you can prabably tell, I'm totally confused and I'd appreciate any help you can give, thanks

  2. Hi, I'm applying for a Biochemistry course at Uni, and was looking to read some good books on Biochemistry that I could mention on my personal statement.:) I'm having a hard time finding anything good at the library and I have taken books home, only to find they are too difficult/boringly wriiten, more than once. Has anyone got any suggestions?

     

    I am curently reading The Thread of Life from Cambridge University Press, and that's quite interesting.:cool:

  3. Unless I'm mistaken, that article talks of a future where we grow new plants and animals, but we're currently heading towards growing our own 'special humans'. I think the idea that parents may be able to choose what characteristics their child has is the scariest. It goes against my "loving me for my virtues and faults " principle.:-(

     

    I agree though, the worst thing that Biotechnology could ever do is stop death. :eek: That would mess up the whole planet. More people, more polution, more demands, less space, less progress...never mind the moral arguments!

  4. Any preserved specimen won't have a good quantity of DNA. Skins are tanned' date=' bodies are boiled or fed to bettles to skeletonize, then often treated with whitening and sealing agents. Teeth don't have that much DNA in anyway. Preservation in alcohol or formaldehyde will similarly mess up the DNA. Add on that DNA decays fairly rapidly except under remarkable conditions while most specimens are kept at room temperature (hence the preservation).

     

    Basically, any method of preserving animal bits involved getting rid of the bits that rot, and DNA is a bit that rots. You'd find traces, of course, but never a whole genome.

     

    Mokele[/quote']

     

    Good point! I'm not familar with the preservation process, but what about bones? Or possibly bone marrow?

    Is it not possible that certain cells in the body can tolerate a range of conditions?

    :confused:

  5. I believe there are two strands, beacuse this structure gives DNA stability and complementary base pairing means each strand is a mirror image of the other. There are two strands, but only one is used in protein synthesis- the sense strand, which has promoter codons for transcription.

    Also if you think about it, this way every time DNA replication occurs the new DNA strand will be the same as the original DNA! :)

  6. Well, I suppose I should start by introducing myself. I'm Aggy and I'm due to start A2 Level Biology, Chemistry, and either/or both, Physics and Psychology.

    I'm having a lot of trouble deciding on a degree for myself.

     

    I originally did not want to take a Biology AS, I wanted to take Maths, but it clashed with my timetable so I took Bio. I had a good experience and I got an A in the first module exam.

    AS Chemy was interesting, but difficult.

    AS Physics, I loved, but I'm not sure if its because of the content or because of...erm...other things (or shall I say people ;) )- it sounds stupid I know.

    AS Psychology, I just had to take. I always thought I would love it, and although its intersting, I wouldn't say its lived up to my expectations.

     

    Originally I wanted to take Physics, but EVERYONE said I needed Maths, and I didn't have it. I felt kinda gutted. So I though "Psychology is perfect", but I looked at the courses and was put off by all the written work. Then I thought "Hey I like Bio, I'll go for that!" As I researched I came across Biochemistry and thought it was right for me, I should've known I would start to doubt the choice. Looking through the prospectus of a uni I came across 'Physics with a preliminary year' which taught maths to A- level standard so you could enter physics and fell in love again. But, alas, the class sizes are small, and I really wanted to start off uni with my degree- kinda like starting with a BANG.

     

    As for careers, I had a few in mind, all surrounding a central theme. A flexible, ever changing job, which is challenging and allows to make a difference (yes I know its cheesy).

    The careers I had in mind were teaching, forensic science, and science research.

     

    So, god help you, I'm asking a HUGE favour of you. Please help me by giving me good IMPARTIAL advice. Please don't try top sell careers or courses to me, I want you to be unbiased. I'm really confuzzled....At the moment I hate school, and can't decide if I like something or not...Thanks guys! :)

  7. OMG! Its turned into a HP discussion! Yipee!:)

    In case you hadn't noticed I'm a huge fan and I think as there is so much evidence pointing towards it, Dumbledore wanted Snape to do the "thing" and snape didn't want to. That's what they were arguing about (see excerpt above). Anyways I don't think we're allowed to be so off topic, so call it shameless self promotion if you will, but you can carry on these discussion on my site forums here. :D

  8. Seriously guys! I don't see what the big fuss is about....shes allowed to have fun! And the pic is real, and even if you don't believe me there are plenty of other pics.. I wish people would just stop bashing emma. I'm a HUGE harry potter fan, and on all the harry potter sites, people are always criticising her. It must be hard being famous...your every move being watched...cut her some slack!:rolleyes:

  9. Well I've always just found science interesting. The idea that there is an explanation for everything around us. You can just see the scientific processes going on around you everyday -respiration, the doppler effect, diffusion, magnetism, forces etc. I think its amazing. I've always been good at science and always get A's, I think its because I love it so much and plus I have had many science teachers who are passionate about science.

  10. lmao @ davey jones

     

    I'm a sixth form student, I don't know what I want to do in the future, hence the username, so I'm heading into the fog and just going with the flow. I find science interesting, particlarly Physics (but I only got a C in my exam so fat chance of me getting a degree in that), and everyone's saying I should go into medicene, but I don't find the area appealing.

     

    Anyways, I found this forum through a search engine and I find it very helpful for my work. It's cool because you can be looking for something to help you, and get completely sidetracked and learn something at the same time! :D

  11. Yes, it is on my calculator. I'm sure many people would agree that a lot has been removed from the syllabus and moved up to learn at a later date. :) My chemistry teacher says the very same thing

     

    In this case, 0% ethanol will not necessarily mean 100% transmission. Although in theory this should be true, there may be other factors which will decrease trasmission at 0% ethanol. If you want, however, you may be able to set the 0% ethanol reading to 100% by adding a constant to all the data points such that the 0% ethanol reading is 100% transmission (however, this is really only a good idea if you expect a linear relationship between conc. ethanol and % transmission, in my opinion it would be best just to plot your raw data).

     

    by linear realtionship you mean if they are proportional right? They are proportional to each other just not directly.

     

    Thanks for everyones help, these forums are so friendly!:)

  12. I am trying to see the effect of increasing concentrations of ethanol on the leakage of pigment in beetroot. I know that increasing concentration DOES break down the cell membrane and so pigment leaks out and hence transmission decreases, but I have to draw a graph of the results to show this. I don't have to work anything out. Really 0% ethanol should be 100% transmission (as it is clear) so what should I do? Should I draw the line starting at that point on the axis, even if I haven't actually got a result like that?

     

    Oh and Tartaglia, erm I think that is a bit advanced for me, as I have nooo idea what "ln(transmittance)" is. Thanks for trying anyway!

  13. Hello, I'm an AS Biology student, I was drawing my graph for my coursework and wanted to know whether the lines of best fit (for the 4 repeats) on the graph should start from a point level with the 100% transmission mark on the axis, even if the actual point to plot for 10% ethanol is lower than that or doesn't it matter. Also, it is a *line* of best fit isn't it? or is it a curve? Furthermore, do the lines of best fit (or curves) have to touch the vertical axis?

    I'd be grateful if anyone could help as it's really quite urgent...thanks!:D

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