AQA BIOL2~3rd June 2013~AS Biology (Now Closed)

Original post by elliewoodheadx

I do chem bio and psychology too! I'm on my second year of A levels, but just re-sitting this for an A for uni haha

Ahh haha yeah I'm in AS :frown:

How is psychology A2, not sure if I'm going to take it but looks interesting

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Original post by dooobie_

Haha same! Bio and psychology to go

Posted from TSR Mobile

Same!

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Tinuviel

9

Original post by hassanakhtaruk

If a six marker came up on trancheoles in insects, what would you write? I'm stressing because I just don't know what to expect...btw in past papers I'm doing really well in timing...does anyone else thinks that timing is good in this exam? I always finish in an hour!

Absolutely, same here. But it gives me time to correct myself if need be.

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PR11NCE

Original post by hassanakhtaruk

What do we actually need to know about cellular differentiation? I dont get it. :frown:

..what kind of questions can they ask? Oh and about haemolobin, is it high affinity in the lungs where there is lots of oxygen and less co2? Or the other way round?

That all it is, is the process that cells go through to adapt them to a specific function. You need to know about the organelles in a cell, for example, mitochondria is the site of aerobic respiration and HOW those organelles help that cells function! Look in the CGP revision guide, there's a fantastic double page spread on it and it is more common sense than anything else. If you don't have it, let me know and when I get out of bed il scan and send you it.
HAEMOGLOBIN has a high affinity for oxygen and loads (in the lungs) where the partial pressure of oxygen is high. Oxygen unloading is linked to a higher carbon dioxide concentration (known as the Bohr effect)
Hope this helps

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Original post by PR11NCE

That all it is, is the process that cells go through to adapt them to a specific function. You need to know about the organelles in a cell, for example, mitochondria is the site of aerobic respiration and HOW those organelles help that cells function! Look in the CGP revision guide, there's a fantastic double page spread on it and it is more common sense than anything else. If you don't have it, let me know and when I get out of bed il scan and send you it.
HAEMOGLOBIN has a high affinity for oxygen and loads (in the lungs) where the partial pressure of oxygen is high. Oxygen unloading is linked to a higher carbon dioxide concentration (known as the Bohr effect)
Hope this helps

Whaaaat?! We have to know about the organelles for this unit?? Uhhhhhh

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What's everyone doing revision wise. Are people just learning notes or rewriting them now?

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Original post by hassanakhtaruk

If a six marker came up on trancheoles in insects, what would you write? I'm stressing because I just don't know what to expect...btw in past papers I'm doing really well in timing...does anyone else thinks that timing is good in this exam? I always finish in an hour!

I think you'd write about the tracheoles and trachea system, the spiracles allow oxygen to enter, there are concentration differences between tracheloes and the watery fluid at the end so it travels down a concentration gradient. You could also talk about how muscles help ventilation, there's quite a bit to say look in the textbook :smile:

sorry if my answer was a bit retarded haah

Yeah i love the timing on this exam woo!

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Original post by Suzanna5678

Whaaaat?! We have to know about the organelles for this unit?? Uhhhhhh

We need to know chloroplasts, and then like adaptations of root hair cells and xylem tissue and stuff, everything that's in the textbook.

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Got a feeling the 6 marker will be .. 'Explain how water enters a plant root from the soil and travels through to the endodermis' would cry with happiness if it came up

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HebeDyson

Haemoglobin - Just about whether its the Bohr effect or whether the haemoglobin of a particular animal has high or low affinity and whether because of this has trouble becoming desaturated :P How the haemoglobin in adapted to living in certain conditions, eg a Lugworm in low partial pressures of oxygen has haemoglobin with very high affinity. Means gets 100% saturated at very low partial pressures however means can only dissociate when partial pressure of oxygen in the muscle cells is extremely low, which is a bad thing.

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Original post by maryamnc

We need to know chloroplasts, and then like adaptations of root hair cells and xylem tissue and stuff, everything that's in the textbook.

Adaptions for xylem tissue?! Swear I don't have that in my book

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PR11NCE

Original post by Suzanna5678

Whaaaat?! We have to know about the organelles for this unit?? Uhhhhhh

Read the revision guide page on cell differentiation it's not difficult I assure you:
Human cells
Dna genetic material controls cell etc
Cytoplasm site of chemical reactions
Ribosomes site of protein synthesis
Mitochondria site of aerobic respiration
Etc etc, you will probably have to apply it to a case. They'll say, oh this is a muscle cell, what makes it well adapted for its role and you have to say stuff like, well it's mitochondria for aerobic respiration produces energy for muscle contraction... Etc. They don't require as much detail as oxidative phosphorylation so it's not too bad! Best of luck

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