VCE Biology Question Thread

[The Peasant]

same, what was your explanation?

For the explanation, I wrote about the expected phenotypes of the offspring. So indicated hypothetical genotypes, 1. Female: br/br
2. Male (the second one)

and said that the expected phenotypes of this cross would be 50% "" and 50% "". (cant remeber specifics) and hence as the majority of the offspring are 50% "" and 50% "" the father's genotype is ""(the second one). 

[Biology24123]

I don't remember exactly but it's kinda embarrassing...
I said something about how since it had the same phenotype as the other male in the first part of the question it would need to have that genotype.... :/

No it was a different cross than the first part

[tashhhaaa]

No it was a different cross than the first part

yeah I know but I had no idea how to answer it and I didn't want to leave it blank

oh well it's over

[The Peasant]

yeah I know but I had no idea how to answer it and I didn't want to leave it blank

oh well it's over

It's over, literally, but theres still that period of time where you grieve over what you could have done lol.

[sushibun]

I just cant believe i did not get the gamete/genotype question right... I got literally 4 out of 8 of the genotypes, I just am in shock because it was a simple question... Any marks for this? (2 mark question)

How do you get 8 genotypes? I also got only 4

[TheAspiringDoc]

Wakey wakey biologists

I'm a little confused as I feel like I've heard fom different sources some varying facts on this topic.. I have written in my notes

"Uncharged molecules such as carbon dioxide and oxygen are allowed to diffuse across the cell membrane (also because they are small). Because water is charged, it cannot pass through via diffusion"

But then connect eduaction and this VCE podcast that I listen to have said that water can diffuse across and didn't mention oxygen..

Can someone clarify?

Thank you!!

[grannysmith]

Water can diffuse through the process of osmosis since they're small enough. However, aquaporins (a type of protein channel) are responsible for a significant amount of the water that diffuses, although this is not required knowledge for VCE. Oxygen can diffuse.

[TheAspiringDoc]

Thank you grannysmith!!

Another question:

I get that ATP has phosphate groups, a pentose sugar, and a nitrogenous base and that this makes it a nucleotide.

What I don't get is that ATP is often referred to as a nucleic acid polymer (which of course is made of the nucleic acid monomers). So, how is ATP a nucleic acid? It seems more a like a monomer of one, although maybe not even that as it doesn't even act as a building block of anything..?

[heids]

Thank you grannysmith!!

Another question:

I get that ATP has phosphate groups, a pentose sugar, and a nitrogenous base and that this makes it a nucleotide.

What I don't get is that ATP is often referred to as a nucleic acid polymer (which of course is made of the nucleic acid monomers). So, how is ATP a nucleic acid? It seems more a like a monomer of one, although maybe not even that as it doesn't even act as a building block of anything..?

ATP in itself isn't a nucleotide or a monomer for DNA/RNA (it has 3 phosphates), but I'm pretty sure that cells can use it to synthesise monomers (chop off two of those phosphates and do a couple of other tweaks, which turns it into an adenine deoxyribonucleotide/ribonucleotide).

Where have you seen it called a nucleic acid polymer ?  It definitely isn't that.

[TheAspiringDoc]

ATP in itself isn't a nucleotide or a monomer for DNA/RNA (it has 3 phosphates), but I'm pretty sure that cells can use it to synthesise monomers (chop off two of those phosphates and do a couple of other tweaks, which turns it into an adenine deoxyribonucleotide/ribonucleotide).

Where have you seen it called a nucleic acid polymer ?  It definitely isn't that.

Okay, thanks bangali 

One of the tables in "BIOLOGY a guide by Alon Douek"..

[heids]

One of the tables in "BIOLOGY a guide by Alon Douek"..

Well, I'm guessing that's a slip, since a polymer is made up of repeating units, which ATP definitely isn't.  Though you could make ATP basically by getting an adenine ribonucleotide and building a couple of phosphates on - maybe that's where the idea came from, but it's not a polymer.

[Apink!]

Hi guys

Can anyone explain to me how alpha-glucose and beta-glucose molecules are optical isomers of each other?

I can't see the "mirror". This is really confusing me. When you refer to optical isomers, do you mean two molecules having to be mirror images of each other or atoms bonded to a carbon being mirror images?

Please help

[grannysmith]

Hi guys

Can anyone explain to me how alpha-glucose and beta-glucose molecules are optical isomers of each other?

I can't see the "mirror". This is really confusing me. When you refer to optical isomers, do you mean two molecules having to be mirror images of each other or atoms bonded to a carbon being mirror images?

Please help

This is university level stuff - most definitely not in VCE.

[cosine]

Hi guys

Can anyone explain to me how alpha-glucose and beta-glucose molecules are optical isomers of each other?

I can't see the "mirror". This is really confusing me. When you refer to optical isomers, do you mean two molecules having to be mirror images of each other or atoms bonded to a carbon being mirror images?

Please help

Optical mirrors basically means they have the same molecular formula  () but their structural formula may vary, meaning when you draw the structural composition of the glucose molecules, the placement of a specific OH (hydroxyl) group will differ between the two. You don't need to know anything more, in fact, you don't even need to know difference between alpha and beta glucose in Biology 3/4, but now you do xD

[Apink!]

Thanks!

I was sweating about it because it was in the biozone

Could I ask another question?

Using examples, distinguish between inorganic and organic molecules and their general roles in cells

I know that inorganic molecules don't have carbons in them and organic molecules do. But that's just about what I know. Is there a big difference in the role of inorganic vs. organic molecules within cells?

Thanks so much in advance