VCE Biology Question Thread

[vox nihili]

Yay
But can someone pick the best meiosis diagram just in case to draw for like a sac or the end of year exam if they asked to "Draw the whole process of meosis".
Thanks

None of them. You wouldn't try to replicate any of these. You just want to show the basic processes. Trying to replicate one of these diagrams would take waaaay too long

[blacksanta62]

Dude, trust yourself a bit more.

Your reasoning was perfect, that's why you smashed it. If you can reason that there's no lagging/leading strand like that, why do you need someone to tell you there's no lagging/leading strand in PCR? You nailed it!

That's the problem, I didn't use that reasoning in the SAC and I wrote it anyway (But I'll take it as a lesson for the exam, trust my reasoning more!
Thank you

[sweetcheeks]

Why is mitochondrial DNA useful in evolution analysis?

I understand that it doesn't undergo crossing over, but why is that important? Is it because mutations can be analysed easier?

Or is it that it mutates at a relatively constant rate and the time of mutation can be easily determined?

[Gogo14]

Why is mitochondrial DNA useful in evolution analysis?

I understand that it doesn't undergo crossing over, but why is that important? Is it because mutations can be analysed easier?

Or is it that it mutates at a relatively constant rate and the time of mutation can be easily determined?

We can use it to track materal heritage. When a sperm and an egg join to form a zygote, the cytoplasm of the zygote is inherited by the mother. Hence the mitochondrial DNA will be passed on from mother to mother and we can use this to track evolutionary lines.

[solution]

Do we have to learn about rational drug design? I've never heard of it before until I read the study design...

[Sine]

Do we have to learn about rational drug design? I've never heard of it before until I read the study design...

yes if it's on the study design it can be accessed.  Maximum 1 or 2 marks on the exam though and its really something that most people just rote-learn.

[Mooshkat]

Hi, I don't exactly know where to post this, but here goes nothing.
I'm averaging a smack bang in the middle A for all my sacs
It was at an A+ until the immunity sac literally destroyed me.
Do I still have a chance of getting a 45+?
I go to a school that does moderately well and I'd say I'm at the upper end of the class in terms of performance. If nothing else can someone give me their sac stories and what they got because I could use the support right now.

[Sine]

Hi, I don't exactly know where to post this, but here goes nothing.
I'm averaging a smack bang in the middle A for all my sacs
It was at an A+ until the immunity sac literally destroyed me.
Do I still have a chance of getting a 45+?
I go to a school that does moderately well and I'd say I'm at the upper end of the class in terms of performance. If nothing else can someone give me their sac stories and what they got because I could use the support right now.

If your at the upper end of your class it doesn't matter whether your averaging an A+, A, B or E. (your raw scores mean virtually nothing only your position in the cohort).
Chance of 45? Nobody can tell you for sure as it will ultimately be dependent on how well you prepare for the exam along with your actual exam performance but it's still an open possibility.

[vox nihili]

Do we have to learn about rational drug design? I've never heard of it before until I read the study design...

Rational drug design: finding out the shape of a receptor. Making a drug that will fit into that shape. Drug can block receptor.


Voilà, that's it

[gameboy99]

Hi I found this question in one of the company papers and I cannot find the answers to it. Could someone kindly mark this answer. 

Is it possible for the parents of albino plants to also be albino? Explain.

The parents of the albino plants have to albino carriers but cannot be albino plants themselves as they cannot survive to pass on their albino genes to the next generation. They cannot survive as their allele combination does not code for the production of chlorophyll. Therefore, no light can be trapped and photosynthesis cannot occur. Once all the resources of the plant is depleted, the plant relies on photosynthesis to produce glucose, however as in albino plant this cannot occur, the albino pants will die.

[vox nihili]

Hi I found this question in one of the company papers and I cannot find the answers to it. Could someone kindly mark this answer. 

Is it possible for the parents of albino plants to also be albino? Explain.

The parents of the albino plants have to albino carriers but cannot be albino plants themselves as they cannot survive to pass on their albino genes to the next generation. They cannot survive as their allele combination does not code for the production of chlorophyll. Therefore, no light can be trapped and photosynthesis cannot occur. Once all the resources of the plant is depleted, the plant relies on photosynthesis to produce glucose, however as in albino plant this cannot occur, the albino pants will die.

The answer could be a little more succinct (it rambles a little bit), but absolutely nailed it on the details so it would get full marks (Y)

[gameboy99]

Thanks!
One more question. This is related to a prac I did.... Why is the predicted ratio not always the same as the observed ratio?
Counting error
Smaller sample size – Increasing the sample size increases the probability of the observed ratio adhering closer to the predicted ratio

This is all I have got.I feel that there is more to explain on the dot points mentioned above on how they skew the results. Could someone answer why...I am a bit stuck here.

[vox nihili]

Thanks!
One more question. This is related to a prac I did.... Why is the predicted ratio not always the same as the observed ratio?
Counting error
Smaller sample size – Increasing the sample size increases the probability of the observed ratio adhering closer to the predicted ratio

This is all I have got.I feel that there is more to explain on the dot points mentioned above on how they skew the results. Could someone answer why...I am a bit stuck here.

Bring it back to basics.

Just because there's a 50% chance a kid will have red hair, and a 50% chance the kid will have blond hair, doesn't make it bizarre if the parents have three blond kids.

[solution]

Why is the answer b) and not c)? Doesn't c) have two types of antibody binding sites that are complementary to the antigens on the bacterium, while b) only has one type? Or am I interpreting the question incorrectly?

[vox nihili]

Why is the answer b) and not c)? Doesn't c) have two types of antibody binding sites that are complementary to the antigens on the bacterium, while b) only has one type? Or am I interpreting the question incorrectly?

Antibodies only have one antigen specificity. In less wanky terms, they can only ever bind to the one thing—you won't have two different binding sites