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October 17, 2018, 09:34:09 am

Author Topic: VCE Biology Question Thread  (Read 932607 times)  Share 

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tm11

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Re: VCE Biology Question Thread
« Reply #10575 on: July 31, 2018, 06:19:26 pm »
0
How does bacteria become resistant against antibiotics when people overuse or misuse them?

samebz

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Re: VCE Biology Question Thread
« Reply #10576 on: July 31, 2018, 06:26:59 pm »
+1
Overuse and misuse of antibiotics allows the development of antibiotic-resistant bacteria, hence every time a person takes antibiotics, sensitive bacteria (bacteria that antibiotics can still attack) are killed, but resistant bacteria are left to grow and multiply. Resistance bacteria exists due to random mutation; hence some bacteria may contain a resistant gene. This is how repeated use of antibiotics can increase the number of drug-resistant bacteria.

darkdzn

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Re: VCE Biology Question Thread
« Reply #10577 on: July 31, 2018, 06:28:31 pm »
+4
How does bacteria become resistant against antibiotics when people overuse or misuse them?

In your question, we can apply Darwin's theory of evolution and natural selection. So in the population of bacteria, there will already be variation in the population. Therefore, there may exist certain bacteria which are somehow different and are resistant to the antibiotics (due to a random mutation). Then when a person uses antibiotics, it acts as a selective pressure. All of the bacteria without the resistance will die while a small amount of bacteria resistant ones will remain (they have a selective advantage). So when you overuse the antibiotics, you will kill all of the non-resistant ones leaving the resistant ones to breed with each other and they will increase in numbers slowly and then eventually when you try to cure the same infection with the antibiotics, most of the bacteria will be resistant
2018: Biology, Mathematical Methods

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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10578 on: July 31, 2018, 06:45:30 pm »
+2
As well as natural selection, antibiotic resistance can be spread between bacteria. Genes for antibiotic resistance are commonly found on plasmids. Plasmids can be transferred between bacterial species, effectively giving more and more bacteria the resistant gene.
2016: Psychology [37]
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adeena33

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Re: VCE Biology Question Thread
« Reply #10579 on: July 31, 2018, 10:28:25 pm »
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Hey,
Just wanted to know what are the main concepts covered in Biology unit 1 and 2.
Just wanted to have an overview type.
Thanks
Adeena

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10580 on: July 31, 2018, 10:37:06 pm »
+3
Hey,
Welcome to AN ;D

You can read everything you'll cover here.

Basically:
-How cells work
-How things move between cells
-Photosynthesis & Cellular respiration
-How body systems work
-How we classify species
-How species interact with each other
-The cell cycle
-How organisms reproduce
-What genes and chromosomes are and what they do
-What genotypes and phenotypes are and what they're used for
-Pedigree charts and predicting offspring's genotype and phenotype
2016: Psychology [37]
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$noopDodd

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Re: VCE Biology Question Thread
« Reply #10581 on: August 05, 2018, 05:06:33 pm »
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What's the difference between divergent evolution and allopatric speciation?
I've asked my teacher and he said that allopatric speciation is just one source of divergent evolution, but I still don't really understand it - if so, what are the other sources of divergent evolution?
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darkdzn

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Re: VCE Biology Question Thread
« Reply #10582 on: August 05, 2018, 05:10:33 pm »
+4
What's the difference between divergent evolution and allopatric speciation?
I've asked my teacher and he said that allopatric speciation is just one source of divergent evolution, but I still don't really understand it - if so, what are the other sources of divergent evolution?

Well divergent evolution describes the pattern in which evolution occurs and is effectively the creation of a new species from an original population e.g. single population of one species becomes two distinct species or possibly more. Therefore, any form of speciation would be considered a source of divergent evolution - there are a few more types of speciation like peripatric, parapatric, and sympatric - but for VCE, you only need to know allopatric speciation
« Last Edit: August 05, 2018, 05:14:47 pm by darkdzn »
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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10583 on: August 05, 2018, 05:15:16 pm »
+3
What's the difference between divergent evolution and allopatric speciation?
I've asked my teacher and he said that allopatric speciation is just one source of divergent evolution, but I still don't really understand it - if so, what are the other sources of divergent evolution?
Divergent evolution is the accumulation of differences. Once there are enough differences between two populations they are unable to breed and are therefore different species.

Allopatric speciation occurs when populations are separated by a geographical barrier and accumulate enough differences that they are unable to breed and are therefore different species.

Therefore when a population undergoes allopatric speciation it is evolving divergently.

There are other types of speciation but you do not need to know about them for VCE.

Edit: Beaten by darkdzn but Iíll post it anyway
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peachxmh

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Re: VCE Biology Question Thread
« Reply #10584 on: August 11, 2018, 11:42:54 am »
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Does anyone have any tips for memorising the characteristics of the species in the Homo genus, primates, hominins, etc.? I'm finding it quite hard atm as there are lots of things I could memorise for each :( thx!
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juntyhee

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Re: VCE Biology Question Thread
« Reply #10585 on: August 11, 2018, 11:46:01 am »
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An image of a phylogenetic tree is attached below. Which organism is most closely related with the 'Rhea'? An explanation as to WHY will be great.

Scribe

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Re: VCE Biology Question Thread
« Reply #10586 on: August 11, 2018, 12:33:20 pm »
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Hey all,
From what I understand (which may be incorrect), the immune system distinguishes self cells from non-self cells depending on their particular antigens.

What do pattern recognition receptors (PRRS) on phagocytic cells do? Do they just enable cells of the innate immune system to identify extracellular pathogens by recognising and binding to pathogen-associated molecular patterns (PAMPs)? If so, I'm not sure how this is different from antigens. Also, are we actually required to know about PRRs and PAMPs?

Thanks!
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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10587 on: August 11, 2018, 05:06:19 pm »
+3
Does anyone have any tips for memorising the characteristics of the species in the Homo genus, primates, hominins, etc.? I'm finding it quite hard atm as there are lots of things I could memorise for each :( thx!
Donít worry about memorising exact details - you just need to know general trends. Try and remember one or two features of each genus (eg. Australopithecus, Paranthropus, etc.) but donít worry about memorising the differences between each species. (Except you may need to know more for your SAC)

For primates/hominids/hominins just remember the key features of primates (a lot of them are things people know anyway) and then just remember a couple of things that makes a primate a hominid and then a couple that makes a hominid a hominin. You donít need to memorise entire lists of features.

An image of a phylogenetic tree is attached below. Which organism is most closely related with the 'Rhea'? An explanation as to WHY will be great.
Unless Iím missing something, the best you can tell from that tree is that everything below the Rhea is closer related to it than the ostrich. The vertical lines indicate a common ancestor. Species with the most recent common answer are the most closely related. As everything below the Rhea shares a common ancestor with the rhea at the same point, you canít distinguish which of them is more closely related.

Hey all,
From what I understand (which may be incorrect), the adaptiveimmune system distinguishes self cells from non-self cells depending on their particular antigens.

What do pattern recognition receptors (PRRS) on phagocytic cells do? Do they just enable cells of the innate immune system to identify extracellular pathogens by recognising and binding to pathogen-associated molecular patterns (PAMPs)? If so, I'm not sure how this is different from antigens. Also, are we actually required to know about PRRs and PAMPs?

Thanks!
Iím not sure if you need to know about them. I never learnt anything about them, and I havenít seen anything about them on the study design but I know some people have talked about them on here previously, so Iíll leave that for someone else to answer.
2016: Psychology [37]
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Azim.m

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VCE Biology Question Thread
« Reply #10588 on: August 12, 2018, 08:17:27 am »
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The answer is D, but couldnít it also be C?
« Last Edit: August 12, 2018, 08:19:53 am by Azim.m »

darkdzn

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Re: VCE Biology Question Thread
« Reply #10589 on: August 12, 2018, 09:04:55 am »
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The answer is D, but couldnít it also be C?

I suppose that it's D because the question asks for a method which is present in all 3 - eye, airway and mouth - so that'd be lysozyme
2018: Biology, Mathematical Methods

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