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March 29, 2024, 09:42:41 am

Author Topic: VCE Biology Question Thread  (Read 3571030 times)  Share 

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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #9375 on: October 04, 2017, 09:36:47 pm »
+1
1. I don't know that pH has an effect? All I have learned about it is that at extremes it can denature proteins.
2. As for alcohol it simply passes through the membrane, that is why it is easy to get drunk very fast.

I don't think information about either would be needed for VCE (correct me if i'm wrong)
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Sam M

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Re: VCE Biology Question Thread
« Reply #9376 on: October 04, 2017, 09:43:05 pm »
+2
I can't seem to find clear answers to these anywhere, help is very much appreciated :)

1. What effect does pH have on plasma membranes, and why?

2. Why doesn't alcohol have any effect on the plasma membrane?



Hi, I don't think that we have to specifically know the affect of pH on plasma membranes, but my class did an experiment involving beetroot and an acid we added (which then caused the beetroot to 'leak' because the Plasma membrane was disrupted).
So I guess you could say that a pH which is too acidic/basic can disrupt the plasma membrane?

No idea about the alcohol though; not too sure you specifically have to know that, although I suppose vcaa could set up a hypothetical experiment on the exam (on which case they would probably give you the necessary info to answer).
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lexellcomet

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Re: VCE Biology Question Thread
« Reply #9377 on: October 05, 2017, 02:58:02 pm »
0

are new world porcupines the most closely related to guinea pigs, or are chinchillas most closely related to guinea pigs? and, did new world porcupines emerge approx 70 mil years ago? pls help

ImmaculateJeff

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Re: VCE Biology Question Thread
« Reply #9378 on: October 05, 2017, 03:03:52 pm »
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Hi, can anyone send me the lecture notes from the Monash revision lectures for bio , chem and methods pleaseee! thanks!! :)

Sine

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Re: VCE Biology Question Thread
« Reply #9379 on: October 05, 2017, 03:04:52 pm »
+2
(Image removed from quote.)
are new world porcupines the most closely related to guinea pigs, or are chinchillas most closely related to guinea pigs? and, did new world porcupines emerge approx 70 mil years ago? pls help
chinchillas are most closely related to the guinea pigs. Since they most recently diverged from each other.
yes it appears New world porcupines emerged approx 70 million years ago.

vox nihili

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Re: VCE Biology Question Thread
« Reply #9380 on: October 05, 2017, 03:34:57 pm »
+3

I can't seem to find clear answers to these anywhere, help is very much appreciated :)

1. What effect does pH have on plasma membranes, and why?

2. Why doesn't alcohol have any effect on the plasma membrane?

Sam M gets closest to the mark on here. Probably outside of the course, though some of you will have done an experiment on it.


Extremes of pH will denature protein in the membrane,  thereby allowing stuff to pass freely though.
Likewise, alcohol acts as a detergent (kind of), and completely disrupts the membrane.
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ardria

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Re: VCE Biology Question Thread
« Reply #9381 on: October 06, 2017, 12:59:43 am »
0
Regarding this study design dot point:

"major trends in hominin evolution from the genus Australopithecus to the genus Homo including structural, functional and cognitive changes and the consequences for cultural evolution"

What are examples of "functional change"? Again, can't find this information anywhere!

LifeisaConstantStruggle

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Re: VCE Biology Question Thread
« Reply #9382 on: October 06, 2017, 01:28:03 am »
+1
Good evening,
I'm not sure if I'm completely right about this one, but structural evolution typically refers to any change in the morphology of the body over time (without considering its implications and consequences). Functional trends would probably be things like the precision grip, bipedalism, having a wide ribcage to compensate for a diet with high fibrous matter, all the implications of structural, cognitive and cultural evolution (to a lesser extent). Hope that cleared some confusion. :)
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ezferns

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Re: VCE Biology Question Thread
« Reply #9383 on: October 06, 2017, 09:07:09 am »
0
Hey again
How do we know if a question is talking about divergent or convergent evolution? Don't all species have a common ancestor if you go back far enough?
I came across a q that said the most recent common ancestor of two species was 100mya and they lived in different areas with similar environments and both had no eyes. It then asked if this was convergent or divergent evolution and apparently it was divergent even though they didn't say whether the no eyes trait was inherited from ancestors or developed due to similar environments.

Also what is the interaction between cultural, technological and biological evolution?

Bri MT

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Re: VCE Biology Question Thread
« Reply #9384 on: October 06, 2017, 09:34:00 am »
+2
Hey again
How do we know if a question is talking about divergent or convergent evolution? Don't all species have a common ancestor if you go back far enough?
I came across a q that said the most recent common ancestor of two species was 100mya and they lived in different areas with similar environments and both had no eyes. It then asked if this was convergent or divergent evolution and apparently it was divergent even though they didn't say whether the no eyes trait was inherited from ancestors or developed due to similar environments.

Also what is the interaction between cultural, technological and biological evolution?

Yes, all species have a common ancestor if you go back far enough. You need to make an assessment of whether the environment or recent ancestory is most responsible for the traits of the species.  In this question, I suspect they thought of it as 100 mya not being *that* long in the scheme of thing with evolution, especially in regards to something as significant as eyes. Having eyes in an environment where they aren't really useful isn't really something that's likely to be quickly selected against, some marine creatures that live where eyes aren't useful still have them despite them being non-functional. 

There's multiple ways that these things interact.
Eg. Hominins developing complex social structures (cultural evolution)   links with  the sclera (part of the eye) becoming white (biological evolution)
Opposable thumb (biological) -> use and development of tools (technological)
Fire being used to prepare food (tech)    links with    proportionally larger brain size (bio)
Bipedalism    encourages   use of tools   (It would be hard to carry a spear while running if all limbs were used for transport)

ezferns

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Re: VCE Biology Question Thread
« Reply #9385 on: October 06, 2017, 02:26:39 pm »
0
Thanks for your answer!
How do the social structures link to the sclera?

Bri MT

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Re: VCE Biology Question Thread
« Reply #9386 on: October 06, 2017, 05:11:04 pm »
+1
Thanks for your answer!
How do the social structures link to the sclera?

Having a white sclera makes it easier to see the pupil clearly, and eye movements & pupil dilation provide social information

ImmaculateJeff

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Re: VCE Biology Question Thread
« Reply #9387 on: October 06, 2017, 05:31:14 pm »
+3
Carrier proteins in facilitated diffusion are passive, carrier proteins in active transport require energy

Also to add to that in faciliatated the carrier proteins take molecules from a region of High concentration to a region of Low while in Active theyre going against the concentration gradient which is why it needs energy to accomplish such a task.

simrat99

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Re: VCE Biology Question Thread
« Reply #9388 on: October 06, 2017, 08:44:09 pm »
0
Hi all,
Can somebody please explain how Tc cells are activated? Do they require Helper T cells at all?
Thanks in advance :)

Eric11267

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Re: VCE Biology Question Thread
« Reply #9389 on: October 06, 2017, 09:11:59 pm »
+1
Hi all,
Can somebody please explain how Tc cells are activated? Do they require Helper T cells at all?
Thanks in advance :)
My understanding is that Helper T cells bind to infected cells and release cytokines which attract Tc cells. Then the Tc cells bind to the virus-infected cell and secrete perforins, inducing lysis.