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AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011

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Original post by laura123
are receptors proteins?


Yeah the majority of them are trans-membraine proteins. I'm not too sure about the pacinian corpuscle though.
can someone explain the stuff about partial digest and things please. I just don't understand it!
Reply 1842
the worst thing about this exam is that we can revise our ass's off and then get questions on application and nothing we have actually been taught. anybody got any tips about what last minuet essays to look at before tomorrow. also any topics that didnt come up last year that might be in this years paper. im **** at all the dna stuff so im bascially screwed for the exam tomorrow anyway. :frown:
Reply 1843
Original post by User12399
can someone explain the stuff about partial digest and things please. I just don't understand it!


Which bits don't you understand? :smile:
Partial digest is when its not fully digested, so you'll get more sections as some bits aren't cut up. So say you had 2 small sections, in the partial digest you could have 2 small sections and a big section (the 2 small sections still attached) showing :smile:
If that makes sense or helps at all :smile:
Reply 1844
Original post by Jeshiii
Hello there guys, does anyone have some notes or tips on remembering the stuff for the control of the heartbeat? The book i've got doesn't explain it that well and I forgot to ask my teacher about it earlier :/


Just some tips in short

Chemoreceptors- detect changes in blood pH (too much CO2)
Baroreceptors (or pressure receptors)- detect blood pressure

Too low pH and small pressure lead to an increase in heart rate
Too high pH and high pressure lead to a decrease in heart rate.

All controlled by medulla oblongata which conveys all of the action potentials.

Parasympathetic nerves are responsible for slowing down heart rate (think of paralys thats how I remember it :/) acetlycholine is secreted onto the receptors on the SAN
SYmpathetic nerves are responsible for speeding up heart rate. And Noradrenalin is the neurotransmitter which binds to the SAN
(edited 12 years ago)
Sooo do we need to learn about cystic fibrosis specifically? :frown:
hey im confused, are the glycoprotein receptors that insulin combines with the glucose channels that this binding opens??? hence whats the significance of them being 'glyco protein' recptors? i get that being protein recptors they can bind with insulin but what about the 'glyco' bit?
Reply 1847
What's some good "Extra knowledge" stuff to say about bacteria?
Original post by User12399
can someone explain the stuff about partial digest and things please. I just don't understand it!


From what I understand, if something is partially digested the fragments remaining are similar to sticky ends and can join together again to form larger fragments.

The whole thing about what sequence fragments are in is weird aswell but the example I remember there was a size 7 fragment on the gel and it gave you a sequence asking which fragment comes next, already giving you 4 and the answer was 3 as obviously 4+3 = 7 fragment.

I wouldn't take my word entirely for this stuff though, it's not very well explained in the books I'm just going from what I remember my teacher telling us.
Reply 1849
What are 3 key difference between DNA, mRNA and tRNA, excluding size, location, stability.
So, what are the chances of DNA technology coming up? Nothing will stick in my head! I've never been so nervous about an exam before. :frown:
Reply 1851
Original post by Vidja
What's some good "Extra knowledge" stuff to say about bacteria?


MRSA highly resistant strains.


What are 3 key difference between DNA, mRNA and tRNA, excluding size, location, stability.
(edited 12 years ago)
Original post by OriginOfShowbiz
So, what are the chances of DNA technology coming up? Nothing will stick in my head! I've never been so nervous about an exam before. :frown:


Very likely, it's the biggest chapter of all. I really hate it too. :frown: Just a question, do we need to know about cystic fibrosis and the CFTR gene annd adenoviruses?
hey people, can someone explain restriction mapping to me in a clear why: what I know is that several restriction endonucleasea are used to cut DNA in several different places and the primers are attached put under a gel electrophoresis machines to separate fragments and it can be used to see what the sequence of bases are?? accordingto where re primers have attached????
Original post by Sparkly-Star
Very likely, it's the biggest chapter of all. I really hate it too. :frown: Just a question, do we need to know about cystic fibrosis and the CFTR gene annd adenoviruses?


I doubt you need to specifically know about it, any questions they ask will most likely explain which gene causes cystic fibrosis.
Reply 1855
Original post by Sparkly-Star
Very likely, it's the biggest chapter of all. I really hate it too. :frown: Just a question, do we need to know about cystic fibrosis and the CFTR gene annd adenoviruses?


Not specifically although it may help you in the essay, just learn germ line , somatic and how somatic isn't effective as cells die etc.
Reply 1856
Original post by Stirlo
Just some tips in short

Chemoreceptors- detect changes in blood pH (too much CO2)
Baroreceptors (or pressure receptors)- detect blood pressure

Too high pH and small pressure lead to an increase in heart rate
Too low pH and high pressure lead to a decrease in heart rate.

All controlled by medulla oblongata which conveys all of the action potentials.

Parasympathetic nerves are responsible for slowing down heart rate (think of paralys thats how I remember it :/) acetlycholine is secreted onto the receptors on the SAN
SYmpathetic nerves are responsible for speeding up heart rate. And Noradrenalin is the neurotransmitter which binds to the SAN

Too low pH increases heart rate so you can remove as much CO2 in the lungs as possible to raise the pH again
Reply 1857
Original post by NRican
MRSA highly resistant strains.


What are 3 key difference between DNA, mRNA and tRNA, excluding size, location, stability.


Shape, what bases are in each, and number of nucleotides long I'd say. Or would you class number of nucleotides as size
Original post by Ramin Gorji
hey people, can someone explain restriction mapping to me in a clear why: what I know is that several restriction endonucleasea are used to cut DNA in several different places and the primers are attached put under a gel electrophoresis machines to separate fragments and it can be used to see what the sequence of bases are?? accordingto where re primers have attached????


That's pretty much all you need to know, the primers are labelled radioactively or fluorescently so we can find the sequences as primers attatch to complimentary base sequences.
Reply 1859
Original post by Ramin Gorji
hey people, can someone explain restriction mapping to me in a clear why: what I know is that several restriction endonucleasea are used to cut DNA in several different places and the primers are attached put under a gel electrophoresis machines to separate fragments and it can be used to see what the sequence of bases are?? accordingto where re primers have attached????


Yes the radioactive or fluoro. labelled primers will show you a banding pattern, and you use the distance between bands, easiest when you do a question on it some on end of chapter I think?

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