A2 Biology OCR June 2015 Revision Thread

Could anyone explain the difference between endocrine and exocrine please? Thank you

Also, are we allowed to write in bullet points for questions other than the QWC ones?

Endocrine secrete hormones directly into the blood
Exocrine secrete them into a duct to be transported wherever they're needed

Endocrine glands release hormones directly into the bloodstream. Exocrine glands release mostly enzymes into cavities or onto the skin via ducts

You can write in bullet points in any question, and even some QWC questions. If the QWC says 'use appropriate terminology spelt correctly' then the QWC mark is for knowing long words, so go ahead and bullet point. If you do use bullet points in QWC questions though, try to make each 'point' a complete and coherent sentence rather than fragments of knowledge, eg;probably isn't great for a QWC on insulin.

If the QWC mark is to present your points in a coherent and logical order, then bullet points may even be better than continuous prose.

any predictions of what might come up???

This is the right pic sorry

thank you so much!
inshaAllah will smash this exam

Im getting super confused about Non-cyclic phosphorylation.
What do the electrons that get excited and move to a higher energy level have to do with the pigments?
Are they the electrons of the pigments?
Cheers

Im getting super confused about Non-cyclic phosphorylation.
What do the electrons that get excited and move to a higher energy level have to do with the pigments?
Are they the electrons of the pigments?
Cheers

is chlorophyll a always the primary pigment at reaction centre of the photo systems ?

Thank you so much! So would what you've written for insulin be fine for a non-QWC question?

How much evidence for chemiosmosis do we need to know? will we be given it like that past exam question or could they say 'evaluate the evidence for chemiosmosis(5)' with no information given

is chlorophyll a always the primary pigment at reaction centre of the photo systems ?

TEST: How are photosystems structured to maximise efficiency?

If we have to give the products of the link reaction and the krebs cycle, do you double the values because two pyruvate molecules are produced? So each cycle has to happen twice?
In my textbook it doubles the products of the link reaction but not the krebs cycle?
Help pls

Because there are two pyruvate molecules which are produced by one molecule of glucose, you would state there are two turns of the Krebs cycle per glucose molecule? Hope that makes sense. You would also state that link rections happen twice per glucose molecule as the same applies.
So I suppose you would double the products if it says per glucose definitely for link reaction, as it occurs twice and is not regenerated however as Krebs cycle is regenerated double products only if stated per glucose molecule. Because the products are per cycle.

Thank you!