AQA A2 Biology BIOL5 - 17th June 2015

Sent a message to our exam officer and he said the papers had been rewritten and they got them this morning

who stole the paper?

can anyone tell me about oestrogen acting as a transcriptional factor? in my book it says it can act as a repressor or activator but in the 2010 paper i think it was it just has the answer for activator and the question didnt suggest this either... help!

Hey how long are we meant to spend on the essay?

Hey how long are we meant to spend on the essay?

I just answered this question in the 2010 paper! I wrote a detailed answer about how it can act as either an activator or a repressor, then checked the mark scheme and as you said, the marks were describing its action as an activator only (helping RNA polymerase to bind, etc).

Really hoping it doesn't come up now because I wouldn't be sure what to write. :/

Also, if kinesis comes up...

In favourable conditions, are you going to put that the organism INCREASES or DECREASES its rate of turning? I think increasing the turning makes more sense but every textbook I look in seems to say something different...

About 35-40 minutes inc planning

Considering it's 25 marks around 25 minutes is a good guideline.

Pretty sure Kinesis will mean that if an organism is in an unfavourable environment it is increase its movement, in no certain direction, so on the page it could be shown as loads of squiggly lines, its designed to bring the organism back into favourable conditions, so it happens when the stimulus is less directional, so the organism won't travel is an particular direction, hope that makes sense??

Which may mean that kinesis is more likely to come up on our exam... :/
But how are we supposed to answer a question on it if there is no solid definition of kinesis?

How is everyone preparing for the essay? Have done lots of practice plans but haven't written any essays yet- should i?! My teacher said not to, so what has everyone else done?

The thing that doesn't make sense to me is that if it turned more often, wouldn't it just end up back where it came from? :/ If it just moved in ONE direction, eventually it would get out of the unfavourable environment, rather than doubling back on itself.

Some textbooks say this, and some say the opposite which is what is confusing me...

I'd say do at least a couple of practise essays so you can get your head around the timing! It's easy to overestimate how much you can write in a certain period of time until you try it... That's what I found out when I practised writing the essay anyway. :P

The thing that doesn't make sense to me is that if it turned more often, wouldn't it just end up back where it came from? :/ If it just moved in ONE direction, eventually it would get out of the unfavourable environment, rather than doubling back on itself.

Some textbooks say this, and some say the opposite which is what is confusing me...

hii guys
can someone answer my questions im slightly confused..

during Translation the tRNA has an Amino Acid at the extending part of its chain where does it get this amino acid from?? is it like already there or something :?

does the anitcodon on the tRNA code for the amino acid that is attached to it at the extending end ?

Thank You!

the tRNA molecule gets the amino acid from the amino acid pool in the cytoplasm, they explain it in pretty simple terms in the textbook, and yeah the anticodon codes for the amino acid that is attached, the anticodon is complementary to a codon on the mRNA template

Yeah hmm, I think the AQA want to distinguish that there are two type of responses to stimuli, taxis and kinesis, and the factor that separates them from each other would be that taxis is a directional movement, so travels in straight line away from an unfavourable stimulus or towards a favourable stimulus and kineses is another form of response, where the organism doesn't directly move away from a stimulus but will move more rapidly and change direction in order to bring the organism back into favourable conditions, and this is when the stimulus is less directional, so there isn't necessary light or dark, it will for example move from a warm area to a cold area which will be harder to distinguish from each other, hope this helps!