2009 Biology Unit 3 Exam Suggested Solutions

[shinny]

q 7 in the MC..
why cant it be D
testube one may form all the glucose possible less than 10 minutes
testube 2 may form all the glucose possible a little after testtube one , but less than 10 min  (as it was kept at lower temp)

btw, Memory B lymphocyte is the same as Memory B cell right??
       and Plasma b lymphocyte is the same as Plasma B cell right??
( i didnt put the 'cell' down, but i put the lymphocyte)

Regarding Q7, I didn't actually think of that, but what you said is true. However, I think D is still wrong as the actual 'explanation' part (following the 'as') of D isn't really directly correct. As for lymphocyte/cell, either's fine.

[fridge44]

hey shinny, i do not disagree with your answers..

but technically for question 2C.i. shouldn't tRNA be found in the cytosol? not the cytoplasm?

just because cytoplasm in implying that the organelles are included?

just wondering coz i wrote cytosol and wondering if i was right..

[shinny]

Both are acceptable I guess. Cytosol is actually probably more correct in many ways.

[qshyrn]

just with q 5 in MC,
it was obviously Nucleus first , so that narrows it down to C and D, however, they both seem wrong

C. Nuclei, Mitochondria, Endoplasmic reticulum, ribosomes - Surely mitochondria is not bigger than ER
D. Nuclei, endoplasmic reticulum, ribosomes, mitochondria  - I thought ribosomes were smaller than mitochondria , but not 100% sure (this is what i put down)

Could it be that no answer is correct and the VCAA can award anyone who put an answer down with 1 mark?

[shinny]

just with q 5 in MC,
it was obviously Nucleus first , so that narrows it down to C and D, however, they both seem wrong

C. Nuclei, Mitochondria, Endoplasmic reticulum, ribosomes - Surely mitochondria is not bigger than ER
D. Nuclei, endoplasmic reticulum, ribosomes, mitochondria  - I thought ribosomes were smaller than mitochondria , but not 100% sure (this is what i put down)

Could it be that no answer is correct and the VCAA can award anyone who put an answer down with 1 mark?

I'm not actually too sure about C. D is out by elimination as ribosomes are definitely the smallest; they're just made from 2 protein/DNA complexes. On the other hand, the ER MIGHT be lighter than the mitochondria because it's just made from loose networks of phospholipids, and isn't actually that dense. Whilst it's definitely bigger in size, by weight, it might not be, especially when you consider that it's talking about ALL of the mitochondria (not just one).

[qshyrn]

urgh ok, although in the question they only said size was the issue, not density/weight

i wonder if there is a service where u can complain to vcaa about unclear qs (like that eye one)

[shinny]

urgh ok, although in the question they only said size was the issue, not density/weight

Yeh I know. It was a pretty shocking exam IMO really...quite a lot of ambiguity in the questions =\

[qshyrn]

o well i think were gonna have to wait for the assessment report to be sure of the answers.
i notice that last year (or was it the yr b4)  that there was some multiple choice that was ambiguous and vcaa decided to give people a mark if the put an answer down

[Greggler]

yeah, deff seems as tho a few of the MC could have had multiple answers
also some 2 makers on the SA, it seems as though as long as you justified/explained your answer you could proably pick up some marks

honestly, VCAA pulled out some real crazy shit - like tRNA is that even in unit 3 in depth (i thought more unit4/protein synth)
it seems like the last few exams, 06,7,8 consisted of similar questions - more concept based etc.
whilst this years had a few ambiguous ones - i guess to just try and mix things up a little...

[scocliffe09]

for 8c) if I wrote that chemical 4's different shape would allow it more flexibility and therefore a greater ability to bind with its substrate (bcl2) and therefore it would work better than the other drugs, would that get a mark?
also for the last part of the chlorophyll question - the plant loses its leaves because:
chlorophyll of both types is found in the leaves
amount of chlorophyll is decreasing in autumn
this implies number of leaves is decreasing over autumn
this implies that the plant is losing its leaves in preparation for winter

I think that works?

[shinny]

for 8c) if I wrote that chemical 4's different shape would allow it more flexibility and therefore a greater ability to bind with its substrate (bcl2) and therefore it would work better than the other drugs, would that get a mark?
also for the last part of the chlorophyll question - the plant loses its leaves because:
chlorophyll of both types is found in the leaves
amount of chlorophyll is decreasing in autumn
this implies number of leaves is decreasing over autumn
this implies that the plant is losing its leaves in preparation for winter

I think that works?

For 8c, I'm pretty sure that's acceptable. As for the leaves one, the amount of chlorophyll decreasing doesn't imply that the number of leaves is decreasing. Instead, what's happening is that each leaf just has less chlorophyll in it, and hence why leaves are brown due to their predominately carotene composition during Autumn. I'm just wondering on how to word the answer to explain this since what I THINK is happening is that the tree gradually slows down chlorophyll production until the point that the leaves die, which results in the Autumn shedding. However that's just my guess and I really can't be bothered confirming it.

[simpak]

I'm a little confused about MC 5.
It's the only one I got wrong...
I think I am entirely misinterpreting the question.  It says that larger components will form a pellet and separate at a relatively slow speed, yes?
And then tube one takes 10 minutes to form a pellet, yes?
So since that is the fastest speed, should tube one not contain the smallest organelle?  And isn't that the ribosome?
Wouldn't the answer then, be A or B, not C?
Questions like this thoroughly confuse me...

[hard]

i said that for 8c that drug 4 is more specific to the bcl2 while not affecting surrounding cells but expanded a bit more. is that alright?

[shinny]

i said that for 8c that drug 4 is more specific to the bcl2 while not affecting surrounding cells but expanded a bit more. is that alright?

AKA less side effects, so it's basically the answer I had. So yes.

[Greggler]

it states largest sediment form at low speed
the first tube is at the lowest speed - thus must contain largest sediment aka nucleus

you just have to understand, that the larger the organelle is, the slower speed test tube it was

thus it had to be C or D
however mitochondria anre invariably larger than ribosomes so it must be C