2009 Biology Unit 3 Exam Suggested Solutions

[hard]

my hpthesis was that Wasps are attracted to the jasmonic acid released by plants eaten by beet ceterpillars.

[Greggler]

my hpthesis was that Wasps are attracted to the jasmonic acid released by plants eaten by beet ceterpillars.

this...
thus i figured that it was all interconnected

but i dunno - coz some of you are saying that this experiment was setup in order to determine whether the wasps go for the acid or the caterpillars
which means my experiment is farrkkeeddd

[shinny]

Well yeh, the hypothesis you were testing was "Some scientists have suggested that these odours (referring to jasmonic acid) attract wasps to the caterpillar-affected plants", and hence, testing whether it was jasmonic acid itself and not anything else. You've added caterpillars in your experiment and haven't taken them away, so if they do go to those plants, it could be either due to the jasmonic acid or the caterpillars themselves. Doesn't necessarily mean you guys have got it wrong though as I'm not sure whether VCAA will pick up on this distinction.

[simpak]

Can you just draw diagrams if they don't say "you may use a diagram?"
I have always wanted to know.

[Greggler]

probs
considering you can do dot points and stuff
i guess if you really require it in order to get a point across - and if its interpretable then its prbably ok

[Kellie Sewell]

with 5b in the past with Negative feedback VCAA want you to put that a change in a variable is detected and then put the part about the response reversing the change or counteracting the change back to normal levels. 

3d  I would say that it would have to shed its leaves.  By May it does not have a lot of Chlorophyll a or b.  When trees start preparing to loose their leaves they slow the production/replacement of chlorophyll in the leaves (some books say start breaking down chlorophyll) and therefore the level of chlorophyll drops (and thus the leaf changes colour).

The blinking question perplexes me on the location of the cell body of the sensory neuron.  I think this diagram is meant to show a monosynpatic reflex where there is a sensory neuron going directly to a motor neurone.  It has always been my understanding on this that the cell body of the sensory neurone would be outside the brain.  Diagram confusing I agree, but I think they would want sensory neurone for the answer.

I hope this helps.

[shinny]

Thanks Kellie! Nice to have some authoritative input on this :]

Also, regarding

It has always been my understanding on this that the cell body of the sensory neurone would be outside the brain.

Now that you bring that up, yes that's true. Cell bodies for sensory/motor neurons are located immediately off the side of the spinal cord. This just complicates the ambiguity of the diagram more now =S

[Greggler]

Rawwwrrrrrrrr
I hate vcaa - with thee stupid ambiguous diagrAms

[mandy]

Seeing as the diagrams were so ambiguous, do you think they will accept more than one answer ?

[physics]

Yeah jasmonic acid will do both actually: attract wasps and result in less caterpillars on the plant. So it would be very hard to just test the one variable :S.. ?? Suggestions on how to answer it properly? Otherwise I'm feeling as content and happy as George Clooney with his piggy possessions.. (Apparently one of George's mates killed his pig by driving into it whilst visiting the Great Man)

there is HOPE for meeeee

[eregos]

yeah, there is hope, as my teacher said she has never heard of anyone that has gotten full marks b4, every one makes at least a couple of mistakes

[rasangi]

what percentage do u think will be needed to get an A+..?

[physics]

what percentage do u think will be needed to get an A+..?

i hope it's pretty low this year

[NE2000]

what percentage do u think will be needed to get an A+..?

i hope it's pretty low this year

It's always pretty low in bio. I haven't read through this thread, from what I've heard 60/75 or so might be around right for A+.

EDIT: 500th post

[simpak]

Oh yeah, there was a little argument in this thread a while ago about whether NADPH+ is an acceptable answer when it's NADPH generally, and I wrote NADPH+ and got the marks.
So, yep.