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March 28, 2024, 10:28:16 pm

Author Topic: VCE Biology Question Thread  (Read 3570436 times)  Share 

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-Lilac-

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Re: VCE Biology Question Thread
« Reply #12945 on: September 13, 2020, 09:26:19 pm »
+4
I had a few questions:

1. To what level of detail do we need to know about how neurotransmitters work? Because the study design mentions the "sources and mode of transmission of various signalling molecules, including... neurotransmitters". Do we need to know about how the action potential is fired and moves through the neuron? (Sodium-Potassium pump)

2. In some of past study design exams: MC says that the greater the stimulus, the size of the nerve impulse does not change. Can you please explain this and how the action potential/nerve impulse works.


Coolgalbornin03Lo's answer was great but I thought I could just add some comments regarding the second question.

There is some extra info here to help you understand this 'all or nothing principle.' In short, the amplitude (size) of an AP never changes as once you have reached the required threshold, it is fired and it does not matter if there is more stimulus than needed to reach it. 

The reason for this is that an AP is triggered by the opening of voltage-gated sodium channels when the cell reaches a membrane potential of around -55mV. When the sodium channel senses -55mV, it opens and sodium rushes into the cell (positive charge/depolarisation) until the cell reaches a new membrane potential of around +30mV. The voltage-gated potassium channels are then open and K+ leaves the cell which returns the cell to the normal resting potential of -70mV (repolarisation) before they close as well. You have probably seen a graph of an AP which may help contextualize what I have written.

Now you don't need to understand this detail, but once a stimulus enables the cell to reach -55mV, the AP is the same every time and can't get 'bigger'. The AP size is set by the opening/closing of the sodium and potassium channels and that is the same all the time.  However, a stronger stimulus will allow the cell to reach the -55mV threshold more often and therefore increase the frequency of firing. 

Hope that didn't confuse you. But all you really need to take away from this is that a stronger stimulus cannot increase AP size, only frequency.

Also, the sodium-potassium pump is involved in maintaining the resting membrane potential of -70mV (along with leak channels) and not the actual firing of the action potential. They are still very important though.
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12946 on: September 14, 2020, 07:11:17 pm »
0
what are the advantages and disadvantages of a parasitic lifestyle

homeworkisapotato

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Re: VCE Biology Question Thread
« Reply #12947 on: September 14, 2020, 07:48:32 pm »
+3
Advantages are that you have shelter and free food
Disadvantages are that you are dependent on another organism. If the organism dies you lose your source of food and shelter. You are also competing with other organisms for survival on the organism. Lice are competing with other lice for habitat.
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homeworkisapotato

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Re: VCE Biology Question Thread
« Reply #12948 on: September 17, 2020, 03:13:01 pm »
0
Hello! I was doing a Company exam and I came across this question:

In which of the following populations would you expect to find the most genetic variation?
a) asexually reproducing organisms in a stable environment
b) sexually reproducing organisms in a variable environment
c) sexually reproducing organisms in a stable environment
d) asexually reproducing organisms in a variable environment

As this is Unit 1 content, it's highly unlikely that this question will come in the exam right?

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Bri MT

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Re: VCE Biology Question Thread
« Reply #12949 on: September 17, 2020, 04:06:34 pm »
+6
Hello! I was doing a Company exam and I came across this question:

In which of the following populations would you expect to find the most genetic variation?
a) asexually reproducing organisms in a stable environment
b) sexually reproducing organisms in a variable environment
c) sexually reproducing organisms in a stable environment
d) asexually reproducing organisms in a variable environment

As this is Unit 1 content, it's highly unlikely that this question will come in the exam right?



Hey!

This question is a bit weird. The right answer is meant to be sexually reproducing organisms in a variable environment but you're correct that bio 1/2 content isn't assessed in the bio 3/4 exam.

s110820

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Re: VCE Biology Question Thread
« Reply #12950 on: September 17, 2020, 04:30:06 pm »
0
Hey!

This question is a bit weird. The right answer is meant to be sexually reproducing organisms in a variable environment but you're correct that bio 1/2 content isn't assessed in the bio 3/4 exam.

Hey Bri,

I'm sorry to say this but I have to disagree with you, to an extent. I mean, since I'm a QCE student, this may or may not correspond with the VCE curriculum, but when we do our Unit 3&4 exams, my teachers have constantly reminded us about the assumed knowledge (usually Unit 1&2 content) that we may need to know for our papers.

For example, in my Unit 3&4 General Mathematics mock exam last week, a question popped up about multiplying and adding matrices which is what I essentially learnt about in Unit 1&2. However, I'm not sure if this also applies to science subjects, but it could which is why we should be prepared for the worst-case scenairo.

But to whoever are in the process of studying for their Unit 3&4 exams, please note that you shouldn't stress about assumed knowledge too much as it may appear only once in your paper or not at all, and the main focus of your upcoming exams are actually about Unit 3&4 so please prioritise this content over assumed knowledge.

Hopefully, this helps to clarify anything :)

Have a great week and kind regards,

Darcy Dillon.

QUT 2021 - Bachelor of Education (Primary).

Sine

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Re: VCE Biology Question Thread
« Reply #12951 on: September 17, 2020, 05:05:16 pm »
+6
VCE Biology is a subject where the units 1 and 2 content can be very different from what is taught in units 3 and 4. Outside of broad biological concepts that would be reiterated for units 3 and 4 you don't need to know the specifics from units 1 and 2 and you will get tested on content from units 3 and 4.

s110820

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Re: VCE Biology Question Thread
« Reply #12952 on: September 17, 2020, 05:07:47 pm »
+1
VCE Biology is a subject where the units 1 and 2 content can be very different from what is taught in units 3 and 4. Outside of broad biological concepts that would be reiterated for units 3 and 4 you don't need to know the specifics from units 1 and 2 and you will get tested on content from units 3 and 4.

Yeah, that's what I thought - but thanks though :)
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rukayabal

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Re: VCE Biology Question Thread
« Reply #12953 on: September 18, 2020, 07:32:01 am »
0
Hey all,
would anyone know what a specific definition of DNA/RNA be?

SmartWorker

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Re: VCE Biology Question Thread
« Reply #12954 on: September 18, 2020, 02:05:21 pm »
+5
Hey all,
would anyone know what a specific definition of DNA/RNA be?

Both are macromolecules that contain genetic information, known as nucleic acids. You will need to know the differences between DNA and RNA (in terms of structure and function). DNA is deoxyribonucleic acid whereas RNA is ribonucleic acid.
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rukayabal

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Re: VCE Biology Question Thread
« Reply #12955 on: September 18, 2020, 03:38:19 pm »
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Both are macromolecules that contain genetic information, known as nucleic acids. You will need to know the differences between DNA and RNA (in terms of structure and function). DNA is deoxyribonucleic acid whereas RNA is ribonucleic acid.

Thanks

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12956 on: September 18, 2020, 04:21:26 pm »
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My teacher said Parallel evolution and convergent is the same thing and now I am confused

rukayabal

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Re: VCE Biology Question Thread
« Reply #12957 on: September 18, 2020, 04:31:57 pm »
+2
My teacher said Parallel evolution and convergent is the same thing and now I am confused

They are. These are definitions that i copied off the web:

Parallel evolution is the similar development of a trait in distinct species that are not closely related, but share a similar original trait in response to similar evolutionary pressure.
 
Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups due to similar selection pressures.

As you can see, they are the same thing as they involve the evolution of analagous structures due to similar selection pressures.
 However, this is irrelevant to the 2020 study design.

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Re: VCE Biology Question Thread
« Reply #12958 on: September 18, 2020, 10:59:34 pm »
+2
Hey Bri,

I'm sorry to say this but I have to disagree with you, to an extent. I mean, since I'm a QCE student, this may or may not correspond with the VCE curriculum, but when we do our Unit 3&4 exams, my teachers have constantly reminded us about the assumed knowledge (usually Unit 1&2 content) that we may need to know for our papers.

For example, in my Unit 3&4 General Mathematics mock exam last week, a question popped up about multiplying and adding matrices which is what I essentially learnt about in Unit 1&2. However, I'm not sure if this also applies to science subjects, but it could which is why we should be prepared for the worst-case scenairo.

But to whoever are in the process of studying for their Unit 3&4 exams, please note that you shouldn't stress about assumed knowledge too much as it may appear only once in your paper or not at all, and the main focus of your upcoming exams are actually about Unit 3&4 so please prioritise this content over assumed knowledge.

Hopefully, this helps to clarify anything :)

Have a great week and kind regards,

Darcy Dillon.



Hey Darcy,

Yeah absolutely for QCE 1&2 is assumed knowledge (although not likely to be the active focus of testing, you may still need it); for VCE biology students don't need to worry about things that are units 1&2 specific (not even as a "to be safe" thing).

I'm not really adding substantial to Sine's reply but I thought I'd give you some context for why VCE content can be treated a bit differently.

VCE students have the advantage of dozens of past exam papers which aren't all relevant anymore but still aid understanding of assessment which unfortunately QCE doesn't have yet, this + different directions in VCE study designs vs QCE syllabuses help us be able to speak confidently on some VCE things where in QCE playing it safer is the smarter move.


Good to see you around again btw

homeworkisapotato

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Re: VCE Biology Question Thread
« Reply #12959 on: September 19, 2020, 07:18:19 pm »
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Hi!! I got this mc question and I was wondering if this is assessable this year?
Two fossils had limb-like appendages and so scientists determined that they are analogous structures. As they are analogous structures, they must have shared similar
A. selection pressures
B. DNA sequences
C. RNA sequences
D. environments
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