AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011

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Reply 1740

Carpet21

If I pass this exam it's going to be thanks to you guys for getting me through this, seriously!

Reply 1741

mrt23498

Original post by aj2010

Just wondering, I though for A* you had to get over 90 ums in unit 4, over 126 ums in unit 5 and an A in As? :smile:

It is a 90% average in the A2 modules (unit 4,5,6) hence you need 270/300 for A2
and 480/600 ums for your overall A Level

Reply 1742

Sparkly-Star

Original post by Carpet21

The book doesn't really tell us much about troponin does it?

The NT book? Nope. :p:

I only know about tropomyosin really. =/

Reply 1743

yellowpurpleyellow

I'm really struggling with keeping resting/action potentials straight in my head, i keep forgetting when which gates open :/ does anybody know how to remember something so long and complex?

Reply 1744

Stirlo

Original post by Tericon

Histamines must be released when allergens enter the body as allergy medication contains 'antihistamines'.

They both contribute to the inflammatory response however.

Thats what my originally thought too, but the CGP definitions are:

Histamine is a chemical mediator thats stored in mast cells and basophils. It's released in response to the body being injured or infected. It increases the permeabilty of nearby capillaries to allow more immune system cells to move out the blood to the infected area

Prostaglandins are a group of chemical mediators produced by most cells in the body. They're involved in things such as immflamation, fever, blood pressure regulation and blood clotting

Which is the other way round to what the other poster put I believe

(edited 12 years ago)

Reply 1745

Sparkly-Star

Do we really need to know how DNA are introduced to host cells? When plasmids get mixed together in a medium with calcium cells and all that? =/

Reply 1746

User12399

Original post by Stirlo

Thats what my originally thought too, but the CGP definitions are:

Histamine is a chemical mediator thats soted in mast cells and basophils. It's released in response to the body being injured or infected. It increases the permeabilty of nearby capillaries to allow more immune system cells to move out the blood to the infected area

Prostaglandins are a group of chemical mediators produced by most cells in the body. They're involved in things such as immflamation, fever, blood pressure regulation and blood clotting

****! NT says this! Also googled this and Histamine is for allergies.

Reply 1747

User12399

Original post by Sparkly-Star

Do we really need to know how DNA are introduced to host cells? When plasmids get mixed together in a medium with calcium cells and all that? =/

yep.

and replica plating and stuff.

Reply 1748

Stirlo

Original post by Sparkly-Star

Do we really need to know how DNA are introduced to host cells? When plasmids get mixed together in a medium with calcium cells and all that? =/

Yeh I think you need to know about both the heat shock, (ice cold calcium chloride solution heated quickly to ~40) and about adenoviruses (Inject their plasmids into a cell along with restriction enzymes)

(edited 12 years ago)

Reply 1749

Tericon

Original post by yellowpurpleyellow

I'm really struggling with keeping resting/action potentials straight in my head, i keep forgetting when which gates open :/ does anybody know how to remember something so long and complex?

You need to take notes, read them, cover them up, rewrite. Keep doing this until you make no mistakes.

Its the only way i can revise long winded chunks of Biology like that.

Reply 1750

Nadine2010

Why is atpase required in muscles? If it for the myosin head to return to it's original position andd to detach the cross bridges or is 'atp' used for that as an energy source?!?!?!

Reply 1751

Stirlo

Original post by Nadine2010

Why is atpase required in muscles? If it for the myosin head to return to it's original position andd to detach the cross bridges or is 'atp' used for that as an energy source?!?!?!

ATP is used for both providing energy for the 'rowing action' to occur and for the breaking of the acting-myosin cross bridges. SOrry posted too soon. ATPase is used as the enzyme which causes the breakdown of the ATP into ADP and Pi

(edited 12 years ago)

Reply 1752

Tericon

Original post by Nadine2010

Why is atpase required in muscles? If it for the myosin head to return to it's original position andd to detach the cross bridges or is 'atp' used for that as an energy source?!?!?!

ATPase is an enzyme that catalyses the breakdown of ATP into ADP and inorganic phosphate, this reaction produces the energy (from atp) which is used to break the cross bridges, move the myosin head and to actively transport calcium ions back into the sarcoplasmic reticulum once muscle is no longer being stimulated by neurone.

Without ATPase, ATP cannot be broken down and so does not act as an energy source.

Reply 1753

jamesl1

hey, just to check, in muscles there is actin in the I bands, actin and myosin overlapping in the a bands and just myosin in the h zone?

Reply 1754

yellowpurpleyellow

Original post by Tericon

You need to take notes, read them, cover them up, rewrite. Keep doing this until you make no mistakes.

Its the only way i can revise long winded chunks of Biology like that.

Ooo i'll have to keep at it i guess... It's just so frustrating!!!

Thanks :smile:

Reply 1755

Ineluctable

Are you guys revising Unit 5 stuff or synoptic atm?

Reply 1756

Stirlo

Original post by jamesl1

hey, just to check, in muscles there is actin in the I bands, actin and myosin overlapping in the a bands and just myosin in the h zone?

The A band consists of the entire area where myosin filaments are present not just actin and myosin. WHich is why upon contraction the A band width stays the same as the myosin filaments don't contract. You're right with the other 2 though

Reply 1757

Tericon

Original post by jamesl1

hey, just to check, in muscles there is actin in the I bands, actin and myosin overlapping in the a bands and just myosin in the h zone?

Yes

Two others:

M-line = middle of H zone, so just myosin

Z-line = marks boundaries of sarcomere

I remember AIH

A bands stay same length during contraction, I bands get shorter, H zone gets shorter. As does sarcomere.