VCE Biology Question Thread

[StupidProdigy]

Thankyou to both!

Another q. With a genotype like AaBb, are the first and third letters the alleles from the parent 1 and the second and fourth from the parent 2? Ta! 

[heids]

Thankyou to both!

Another q. With a genotype like AaBb, are the first and third letters the alleles from the parent 1 and the second and fourth from the parent 2? Ta! 

I don't think it's specific, which is why when we get to linked genes, we sometimes use different notation (AB/ab, or Ab/aB), to show which combination of alleles comes from each parent (given that this impacts on recombinant vs. parental gametes).

[vox nihili]

Thanks

> States X.
> Does research.
> Finds that, above VCE level, X is actually quite often wrong and it should be Q.
> Next time, scared to state Y.

This has perfectly summarised my experience with VCE Biol. Wow.

[Maca 13]

Hey everyone!
How much detail do we need for the light independent and light dependent reactions because the study design just says "requirements for photosynthesis – excluding differences between CAM, C3 and C4 plants – including: the structure and function of the chloroplast; the main inputs and outputs of the light dependent and light independent stages"?
So do we need to know all the steps for each? And if so, in how much detail?
Thanks! 

[vox nihili]

Hey everyone!
How much detail do we need for the light independent and light dependent reactions because the study design just says "requirements for photosynthesis – excluding differences between CAM, C3 and C4 plants – including: the structure and function of the chloroplast; the main inputs and outputs of the light dependent and light independent stages"?
So do we need to know all the steps for each? And if so, in how much detail?
Thanks! 

You need to know what it says: what the inputs and outputs are, and where they occur basically.

[Maca 13]

You need to know what it says: what the inputs and outputs are, and where they occur basically.

Ahh OK, thanks!

[cosine]

In terms of gene therapy, is the deliverance of the healthy gene done via viruses? For example, if we agglutinate viruses and insert the desired gene instead of the viral DNA, then would this virus vector inject that desired gene in the affected cells? If not, what vector is used? Drugs?

[StupidProdigy]

Why x2? I try to find out the reason usually but I've got no idea for these two questions (attached). Thanks people!

[BakedDwarf]

Why x2? I try to find out the reason usually but I've got no idea for these two questions (attached). Thanks people!

For the first picture, the rate substrate Q moves across the plasma membrane increases and then becomes constant when all the protein channels are occupied. Hence, the protein channels are saturated by solute Q.

For the second picture, i think the answer is A (competition for light) because the juvenile leaf shapes are large and broad so that more surface area is exposed to the sunlight.

[StupidProdigy]

For the first picture, the rate substrate Q moves across the plasma membrane increases and then becomes constant when all the protein channels are occupied. Hence, the protein channels are saturated by solute Q.

For the second picture, i think the answer is A (competition for light) because the juvenile leaf shapes are large and broad so that more surface area is exposed to the sunlight.

Thanks mate. The bit I don't understand is why it becomes saturated, because wouldn't it be a protein moving through the protein channel and they aren't saturated right?
and with the second (yep that's the right answer  ) I thought that if they had competition for light then that would result in the adult leaf shape being large too?
Sorry these seem like pretty basic misconceptions I have but they're annoying me haha! Thanks!

[Fusuy]

Thanks mate. The bit I don't understand is why it becomes saturated, because wouldn't it be a protein moving through the protein channel and they aren't saturated right?
and with the second (yep that's the right answer  ) I thought that if they had competition for light then that would result in the adult leaf shape being large too?
Sorry these seem like pretty basic misconceptions I have but they're annoying me haha! Thanks!

For the first question, you've gotta break in down into the two axises (if that's even a word). The y -axis shows us rate of movement. So for R it's gradually increasing its rate of movement. Whereas, Q is starts off increasing rate of movement very quickly, but then the rate becomes constant at a pretty high rate. This means Q can't be transported any faster. And I know a protein channels may just sound like tunnels of transport and hence you think how can they get transported.But it could be proteins carriers that transport specific individual substances across the membrane, or the protein channel itself can only let so many particles pass through it at one moment. Hence it becomes saturated. Hope that clears it up? If all else fails, the process of elimination should also get you to the right answer.

[Fusuy]

How can they be saturated*^^

[cosine]

Thanks mate. The bit I don't understand is why it becomes saturated, because wouldn't it be a protein moving through the protein channel and they aren't saturated right?
and with the second (yep that's the right answer  ) I thought that if they had competition for light then that would result in the adult leaf shape being large too?
Sorry these seem like pretty basic misconceptions I have but they're annoying me haha! Thanks!

Looking at both axes of the graph, we see that the gradient for the slope of solute Q increases and reaches a plateau, at a certain concentration outside the cell. This means, when a certain high level of solute is reached, the speed of the solute entering the cell is decreased, it still occurs, but it is decreased as seen on the graph. So this means that all the protein channels that were facilitating these solute particles have been occupied, so the solute particles must wait in line and wait their turn, another words for this is saturation, or being saturated. Fusuy explains it wonderfully, but thought I'd chip in since I have not in ages. xD

Oh and you can also go through elimination:

A. Solute Q is lipid soluble. If this was true, then solute Q would not require protein channels to aid it's movement through the membrane. Also, only hydrophilic substances can go through protein channels. So A is incorrect
C. Nothing really suggests anything about temperature, so we cannot just assume this, so most likely incorrect. But if you really want to be specific, solute R actually diffuses through the membrane, so when temperature decreases, the permeability of the membrane also decreases slightly, and hence the movement of solute R would decrease and not increase.
D. Just nah..

[StupidProdigy]

Thanks everyone. I didn't know what the word "saturated" meant in terms of a biology definition, but you all cleared that up, thanks.

Another question attached...why not c?

edit: thanks mr t-rav. also realised that another reason is because it's a linear chromosome, dammit..

[vox nihili]

Thanks everyone. I didn't know what the word "saturated" meant in terms of a biology definition, but you all cleared that up, thanks.

Another question attached...why not c?

Bacterial don't have centromeres.