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March 29, 2024, 02:20:03 am

Author Topic: VCE Biology Question Thread  (Read 3570636 times)  Share 

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caffinatedloz

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Re: VCE Biology Question Thread
« Reply #11745 on: June 11, 2019, 02:50:47 pm »
+4
similarities between photosynthetic autotrophs, chemosynthetic autotrophs?

Both are producers and able to create organic substances (glucose) out of inorganic substances. However, they differ as photosynthetic autotrophs produce glucose in the presence of sunlight while chemosynthetic autotrophs are powered by chemical reactions (generally deep sea creatures with no access to light).

caffinatedloz

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Re: VCE Biology Question Thread
« Reply #11746 on: June 11, 2019, 02:53:01 pm »
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Hey guys!
Wondering if anyone has a list of what organelles are visible under a light microscope and which require an electron microscope.

Thanks!!

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #11747 on: June 12, 2019, 09:54:55 am »
+2
Hey guys!
Wondering if anyone has a list of what organelles are visible under a light microscope and which require an electron microscope.

Thanks!!
All you can really see under a light microscope is the nucleus, chloroplasts, sometimes mitochondria, cell membrane, and cell wall.
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forsande

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Re: VCE Biology Question Thread
« Reply #11748 on: June 12, 2019, 05:43:16 pm »
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Does anyone know if hypersensitivity is in the study design for unit 3? It's in the textbook but I'm skeptical (I've noticed that half of the textbook content you don't even need for VCE level...)


PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #11749 on: June 12, 2019, 05:57:16 pm »
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Does anyone know if hypersensitivity is in the study design for unit 3? It's in the textbook but I'm skeptical (I've noticed that half of the textbook content you don't even need for VCE level...)
It's not, but you need to know about allergic and autoimmune responses which are types of hypersensitivity.
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caffinatedloz

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Re: VCE Biology Question Thread
« Reply #11750 on: June 12, 2019, 07:17:49 pm »
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All you can really see under a light microscope is the nucleus, chloroplasts, sometimes mitochondria, cell membrane, and cell wall.

Thank you!

GodNifty

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Re: VCE Biology Question Thread
« Reply #11751 on: June 13, 2019, 04:49:26 pm »
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Since the introduction of the chicken pox vaccine to the immunisation schedule in 2005, there has been an increase in the incidence of chickenpox in adults. Why?
My answer is that if they used a live attenuated vaccine for adults, then the viral genetic strains could mutate, hence, an increase in incidence of chickenpox for adults.

I'm probably going to be asking a lot of questions.
Thank you, Matt and DBA for answering my previous questions <3

DBA-144

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Re: VCE Biology Question Thread
« Reply #11752 on: June 13, 2019, 05:02:42 pm »
+1
Since the introduction of the chicken pox vaccine to the immunisation schedule in 2005, there has been an increase in the incidence of chickenpox in adults. Why?
My answer is that if they used a live attenuated vaccine for adults, then the viral genetic strains could mutate, hence, an increase in incidence of chickenpox for adults.

I'm probably going to be asking a lot of questions.
Thank you, Matt and DBA for answering my previous questions <3

 Need more info to answer it properly. Is there a question stem? Provide some other info present in the question, if there is any, so we can answer it better. Your answer may suffice, but it depends on other info given tbh.

I would just say that there would be a reduction in chicken pox incidence a short time after the introduction of the chickenpox vaccine to the immunisation schedule, there are some people who don't get the vaccine and these adults get chicken pox.

If there is a graph of some sorts, can you please post that too? I think that what the question is trying to say is that maybe the children are getting vaccinated via the schedule, but not adults and hence there must be some other factor eg. mutation in chicken pox virus, or depletion/low levels of specific memory cells in individuals already immunised to the virus that leads to more adults getting infected.
PM me for Methods (raw 46) and Chemistry (raw 48) resources (notes, practice SACs, etc.)

I also offer tutoring for these subjects, units 1-4 :)

GodNifty

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Re: VCE Biology Question Thread
« Reply #11753 on: June 13, 2019, 05:08:51 pm »
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Nope, there's literally no other information in the question. Question is a bit ambiguous imo.

I would just say that there would be a reduction in chicken pox incidence a short time after the introduction of the chickenpox vaccine to the immunisation schedule, there are some people who don't get the vaccine and these adults get chicken pox.
Ok your answer might work, but if more children get vaccinated from chickenpox (hence more children are immune), then how can adults get chicken pox after the children received their shots? It wouldn't make sense for more adults to get chickenpox than before the children were immunised.

vox nihili

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Re: VCE Biology Question Thread
« Reply #11754 on: June 13, 2019, 05:51:46 pm »
+2
Nope, there's literally no other information in the question. Question is a bit ambiguous imo.
Ok your answer might work, but if more children get vaccinated from chickenpox (hence more children are immune), then how can adults get chicken pox after the children received their shots? It wouldn't make sense for more adults to get chickenpox than before the children were immunised.

An unreasonably tricky question tbh so I wouldn't worry about it.

It happens though because immunity wanes over time. Kids not getting chicken pox anymore because they're vaccinated means that their parents aren't being exposed and having their immunity boosted naturally. So now it's able to decline to a point where they might get chickenpox again.
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GodNifty

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Re: VCE Biology Question Thread
« Reply #11755 on: June 15, 2019, 08:54:36 pm »
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Is clonal expansion only for B lymphocytes or is it appropriate to say that T lymphocytes undergo clonal expansion?
Thx

Erutepa

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Re: VCE Biology Question Thread
« Reply #11756 on: June 15, 2019, 09:08:17 pm »
+6
Is clonal expansion only for B lymphocytes or is it appropriate to say that T lymphocytes undergo clonal expansion?
Thx
It is correct to say both.  :)
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Evolio

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Re: VCE Biology Question Thread
« Reply #11757 on: June 16, 2019, 10:09:15 am »
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Hi guys!  :)
I just had a few questions to ask.

Are pathogens recognised as foreign by the absence of self markers or by the presence of non-self markers?

Also, is it correct to say that virions are non-cellular pathogens?

Just to confirm, are antigens molecules that are recognised as foreign by the immune cells? Are antigens non-self markers?

When describing the steps of the immune response, what the main points we should include because in some sources there is more detail while in other details they don't say that a fever is caused when macrophages secrete interleukins for example?

Thank you for your help.



PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #11758 on: June 16, 2019, 11:27:40 am »
+6
Hi guys!  :)
I just had a few questions to ask.

Are pathogens recognised as foreign by the absence of self markers or by the presence of non-self markers?
Presence of non self markers - antigens. However the absence of a self marker (such as MHC) can also cause an immune response against that cell.

Also, is it correct to say that virions are non-cellular pathogens?
Yep.

Just to confirm, are antigens molecules that are recognised as foreign by the immune cells? Are antigens non-self markers?
Sort of. Antigens are molceules that trigger the production of antibodies - this should mean that they're all non-self, but in the case of things like an auto-immune response, an antigen can be a self molecule.

When describing the steps of the immune response, what the main points we should include because in some sources there is more detail while in other details they don't say that a fever is caused when macrophages secrete interleukins for example?

Thank you for your help.
It depends what part of the immune response you're talking about - you can have a flick through past exam answers and see what they've considered important.

Humoral:
- Naive B cell binds to free antigen
- T helper cell binds to identical antigen presented on MHC2
- T helper cell releases cytokines that cause proliferation and differentiation of both B and Th cells.
- Memory cells stick around, B plasma cells produce heaps of antibodies complementary to the antigen.

Cell-mediated:
- Cytotoxic T cell binds to antigen presented on MHC1.
- Releases granzymes and perforins that kill the cell
- Divides and differentiates and goes around killing other cells presenting identical antigen fragments.
- Maybe mention that cytokines released from T helper cells help with the Tc cell proliferating and differentiating, but also might not need to mention that.

^They're just the rough points, you should write out the ideas properly, but that's the important bits.
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Evolio

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Re: VCE Biology Question Thread
« Reply #11759 on: June 16, 2019, 11:36:11 am »
0
Thank you, PhoenixxFire!
 ;D