The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

AQA A2 Biology BIOL5 - 17th June 2015

Scroll to see replies

Original post by ecornwell97
anyone got a link to unit 5 practise questions? (that aren't in textbook)


This thread has lots of PPQ's :smile:
So what does tropomyosin do, exactly? I'm very unclear, the best I can come up with is "inhibits actin binding sites without an AP triggering Ca2+ release in the sarcoplasm".
Original post by djhodnett
oh, i thought the grade boundaries would be higher in this one compared to last years but by peoples responses maybe not?


I thought last years was so nice! I found this year's considerably harder and more time-stretching (although that said I don't think I did too badly according to the unofficial mark scheme, but I definitely was not happy leaving the exam hall!)
Anyone know if we need to know the stuff on p86+87 of the cgp guide?
20150612_153606.jpg
Attachment not found

can someone mark these for me the importance of protein structure to its function
20150612_153612.jpg562.3KB
When an action potential arrives, Ca2+ ions are released and move through t tubules to myofibrils. The presence of Ca2+ in high enough concentrations causes a conformational change in the trypsin molecules that lie between the actin molecules and the tropomyosin molecules. The change in the shape of trypsin causes tropomyosin to move, exposing the myosin head binding sites on the actin molecule, allowing the sliding filament mechanism to proceed. Hope that helped:smile:)
when you have a psych and maths exam the day before biol5.... basically 3 exams in one go!
sorry i am a bit late, could someone kindly just repost mentioning what the predicted titles are for this years essay?? Good luck to everyone!!!
Reply 568
Avatar for Ozy96
Ozy96
5
Original post by Azurefeline
So what does tropomyosin do, exactly? I'm very unclear, the best I can come up with is "inhibits actin binding sites without an AP triggering Ca2+ release in the sarcoplasm".


During contraction Tropomyosin is removed in order to expose the binding site on the actin filament to form cross-bridges with the myosin head by the release of Ca2+ ions from the sarcoplasmic reticulum in response to the arrival of an action potential at the neuromuscular junction.

During relaxation Ca2+ are actively reabsorbed back into the Sarcoplasmic reticulum using energy produced from the splitting of ATP to ADP via ATPase.
This causes the tropomyosin to re-block the binding site on the actin filament because no contraction is taking place.
Is anyone else seriously scared for this exam!?
Original post by PurpleJag
Is anyone else seriously scared for this exam!?


Yes, literally terrified, got several exams around it as well, might just do a few past paper now...
Me too ive got chem and psych mon and tues before this exam
will someone please read over my essay
Original post by nualamurphy5
will someone please read over my essay


Its difficult for another student to mark a bio5 essay because the mark schemes are so bare, its best if you ask a teacher to do it who has a better understanding of how to use the marksheme
my teacher is crap:frown: does anyone have a good teacher that they could ask to look at it
Original post by foureyes_
when you have a psych and maths exam the day before biol5.... basically 3 exams in one go!

i have 4 content heavy exams next week, my brain is going to explode
Has anyone got brief bullet points for DNA technology as i missed all lessons due to hospital appointments and i'm terrified.

Also,

any brief bullet points for essays?

thank you!
Original post by sn4kebiteheart
Has anyone got brief bullet points for DNA technology as i missed all lessons due to hospital appointments and i'm terrified.

Also,

any brief bullet points for essays?

thank you!


https://chemstuff.files.wordpress.com/2014/12/unit_5_notes.pdf
Does anybody know if we need to know the differences in protein synthesis between prokaryotes and eukaryotes?
Can someone explain resting potential and action potential

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you