VCE Biology Question Thread

[Gogo14]

That's correct (for the VCE course anyway )

DNA polymerase can only extend strands, so it needs to be primed. Whereas RNA polymerase can make new strands from scratch.

If you think about what a primer actually is, you might recognise that primase is actually a type of RNA polymerase

Thanks!
Also in mitosis and meiosis, the centrioles replicated, but aren't they just microtubules? So is another centriole synthesized or does it actually replicate by some biochemical process?

[vox nihili]

Thanks!
Also in mitosis and meiosis, the centrioles replicated, but aren't they just microtubules? So is another centriole synthesized or does it actually replicate by some biochemical process?

I'm not 100% sure of the exact details of how, but suffice to say you don't really need to know how that happens in VCE.

Though they're composed of microtubules, they aren't "just" microtubules. They're an organising centre for microtubule growth and also serve as an anchor against which the chromosomes can be pulled.         

[Gogo14]

when questions talk about cell division, do we have to talk about cytokinesis too or is it implied (i.e. just talk about mitosis and meiosis instead of  mitosis and meiosis and cytokinesis)?

[Gogo14]

If a question asked you to describe the stages of mitosis, would you include interphase?
thanks

[Sine]

If a question asked you to describe the stages of mitosis, would you include interphase?
thanks

Interphase isn't strictly a part of mitosis, it is a phase where the cell prepares itself for cell division - I would use this thought for the exam. Do whatever our teacher says for the sac.

[geminii]

I was trying to do this question on pedigrees. The answers say it is autosomal dominant but I was wondering why couldn't it be sex-linked dominant as well? (I've attached the photo)


I'm just confused on the steps you should use in order to deduce what type of pedigree it is, not just in this example but in others as well (sex linked dominant, sex linked recessive, autosomal dominant & autosomal recessive). AKA what questions should I ask myself and what can I write down in my SAC that shows the teacher my reasons for coming to a particular conclusion on what the pedigree is? Thanks.

[vox nihili]

I was trying to do this question on pedigrees. The answers say it is autosomal dominant but I was wondering why couldn't it be sex-linked dominant as well? (I've attached the photo)


I'm just confused on the steps you should use in order to deduce what type of pedigree it is, not just in this example but in others as well (sex linked dominant, sex linked recessive, autosomal dominant & autosomal recessive). AKA what questions should I ask myself and what can I write down in my SAC that shows the teacher my reasons for coming to a particular conclusion on what the pedigree is? Thanks.

This could be X-linked, unless I'm missing something too?


Typically when answering pedigree questions, I try to write in what genotypes we definitely can work out, then work back from that. If they're asking the inheritance type specifically, I usually work out whether it's dominant or recessive (only recessive can skip generations for e.g.), then write in genotypes and see if they work.

[plsbegentle]

I was trying to do this question on pedigrees. The answers say it is autosomal dominant but I was wondering why couldn't it be sex-linked dominant as well? (I've attached the photo)


I'm just confused on the steps you should use in order to deduce what type of pedigree it is, not just in this example but in others as well (sex linked dominant, sex linked recessive, autosomal dominant & autosomal recessive). AKA what questions should I ask myself and what can I write down in my SAC that shows the teacher my reasons for coming to a particular conclusion on what the pedigree is? Thanks.

Is it just me or am i interpreting this terribly wrong. How is this a autosomal or X-linked dominant?Have a look at generation 2 parents 1 and 2. Both parents have the trait and if this trait is dominant, shouldn't all the children have it as well??

[solution]

Is it just me or am i interpreting this terribly wrong. How is this a autosomal or X-linked dominant?Have a look at generation 2 parents 1 and 2. Both parents have the trait and if this trait is dominant, shouldn't all the children have it as well??

Nope, the parents can be carriers (hetrozygous)

[plsbegentle]

Nope, the parents can be carriers (hetrozygous)

hmmm true, i must be muddling up with recessive and dominant patterns then.

[Sine]

I was trying to do this question on pedigrees. The answers say it is autosomal dominant but I was wondering why couldn't it be sex-linked dominant as well? (I've attached the photo)


I'm just confused on the steps you should use in order to deduce what type of pedigree it is, not just in this example but in others as well (sex linked dominant, sex linked recessive, autosomal dominant & autosomal recessive). AKA what questions should I ask myself and what can I write down in my SAC that shows the teacher my reasons for coming to a particular conclusion on what the pedigree is? Thanks.

It can be both  X - linked Dominant and autosomal dominant

For other questions look at whether the trait occurs in every generation, if it does it has a large change of being dominant if it doesn't occur in every generation but goes away and reappears it is most definitely recessive.

Look at the number of males/females with the trait if the numbers are one-sided it's more likely to be x-linked.

In general the way in finding out what mode of inheritance it is just try to disprove all the other types of inheritance.

Is it just me or am i interpreting this terribly wrong. How is this a autosomal or X-linked dominant?Have a look at generation 2 parents 1 and 2. Both parents have the trait and if this trait is dominant, shouldn't all the children have it as well??

both parents may be hetrozygous dominant therefore possible for a child to have two recessive alleles and hence the recessive trait.

[Gogo14]

Is prometaphase a separate phase of mitosis or just the period thats kinda inbetween prophase and metaphase?

[vox nihili]

Is prometaphase a separate phase of mitosis or just the period thats kinda inbetween prophase and metaphase?

Late prophase, early metaphase really. Wouldn't worry about it though

[solution]

As a result of DNA sequencing, an electropherogram is produced. Is this sequence of the template strand (the strand being sequenced) or is it a sequence that is complementary to the template strand?

[neurons]

Hello Would anyone be able to help me with this? Thank you so much!

The magpie moth, Abraxas grossulariata, can have either pale wings (p) or dark wings (P). Scientists experimenting with these flies accidentally broke vials containing the F1 generation. Some of the captured moths had black phenotypes that the scientists needed to establish the parental genotypes of.

Using a cross how could you successfully determine the parental genotype of these black F1 moths? (Show all working)