VCE Biology Question Thread

[Reus]

The definition of homeostasis is the maintenance of a relatively constant INTERNAL environment blah blah blah, so changing colour to prevent predators probably not homeostasis.

Thanks for that

If alcohol is polar, then why does it dissolve in lipids?

Or is it because it contains both polar and non polar regions - amphipathic?

Yup pretty much because there are polar regions. (dissolving in water)
In the case of lipids it is because of the like non-polar regions found in both.

[katiesaliba]

Can someone please check to see if my summary of the innate immune system's cells is correct? Thanks 

[nerdmmb]

Can someone please check to see if my summary of the innate immune system's cells is correct? Thanks 

I'm pretty sure natural killer cells are agranulocytes because they don't have any granules. (If I'm not mistaken)

[katiesaliba]

I'm pretty sure natural killer cells are agranulocytes because they don't have any granules. (If I'm not mistaken)

Ah yes, you're right! Thanks

[nhmn0301]

If alcohol is polar, then why does it dissolve in lipids?

Or is it because it contains both polar and non polar regions - amphipathic?

Just adding up to what Reus has previously said, here's a bit of Chem 3/4 if you don't mind. So alcohol has the -OH (hydroxyl) group on its chain and this group is polar. However, if you google the structure of an alcohol, you can see that it also contains the C-H group too, due to the little differences in electronegativities value, the C-H group is considered as non-polar. Normally, if the C-H chain is too long in an alcohol, let's say 10 Carbon in its backbone or something, then the effect of OH will be masked by the large amount of C-H, now, it becomes non-polar.
In brief, long chain -> insoluble in water, but soluble in lipids
Short chain -> soluble in water

[davomac]

What is the importance of plants regulating the cell cycle???
Cheers, 

[katiesaliba]

What's an enzyme activation model? Lock and key, induced fit?

[Rishi97]

What's an enzyme activation model? Lock and key, induced fit?

I'm not 100% sure but I'll give it a go. I believe the enzyme activation is basically a graph that shows the amount of activation energy required to begin the reaction. Don't quote me on this. Could someone else please confirm my answer?

[MM1]

What is the importance of plants regulating the cell cycle???
Cheers, 

I'm going to take a guess here and say that plants need to regulate the cell cycle in order to conserve energy and respond appropriately to environmental stimuli. Think of positive phototropism. Also, in the instance where a virus infects a plant cell; that particular infected cell wouldn't replicate itself, this would be done to impede the spread of the viral DNA. So in these instances cell cycle regulation saves the plants energy.
I hope this makes sense. Not sure if it's correct, but if so, could someone articulate it it better please? Thanks.

[katiesaliba]

where would you expect to find the stomata in aquatic plants, and why?

is this stuff about stomata even on the current study design?

[vox nihili]

What's an enzyme activation model? Lock and key, induced fit?

I'd say that lock and fit/induced fit is right here. Bit of an odd terminology.

[Micheal Jackson]

where would you expect to find the stomata in aquatic plants, and why?

is this stuff about stomata even on the current study design?

No..I don't remember learning about it last year. I think it is more unit 1 and 2.

[Rishi97]

Has anyone had their mitosis and meiosis sac yet? Did anyone do it on looking at garlic cells under the microscope?

[Reus]

Has anyone had their mitosis and meiosis sac yet? Did anyone do it on looking at garlic cells under the microscope?

Yup! I did 

[DJA]

In Meisosis, at what stage does Independent Assortment and Segregation occur at? As in at which stage of Prophase 1, Meta 1, Ana 1, Telo 1, Prophase 2, Meta 2, Ana 2, Telo 2?

Also could someone provide good definitions for both those terms?