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September 27, 2020, 03:15:18 am

Author Topic: VCE Biology Question Thread  (Read 1810700 times)  Share 

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1729

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Re: VCE Biology Question Thread
« Reply #12825 on: August 05, 2020, 12:32:54 pm »
+5
Could someone please explain the Gel electrophoresis to me? I watched the edrolo video but I still don't get it , thanks
This picture might help. So basically, you put your DNA mixture into the wells. The blue stuff is the gel. You turn on the power, and since DNA is negatively charged, the DNA will move towards the positive end. The smaller fragments will travel farther in the gel than the longer fragments, so they get sperated by size.

DNA is overall negatively charged so it moves away from the + from the electrical source. Since all DNA isn't the same size, their ability to pass between the tiny holes in the gel varies. Basically, the small fragments have an easier time to go through the holes than the larger ones, the smaller ones will travel farther down the gel than the longer ones. When fragments stop moving, they cause lines due to the dye, which is what you see in the final gel sample.

If you have any questions don't hesitate to ask! :)

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Re: VCE Biology Question Thread
« Reply #12826 on: August 05, 2020, 04:08:17 pm »
+4
DNA is overall negatively charged so it moves away from the + from the electrical source.

I think you mean away from the negative / towards the +, like you had earlier in your post

It's kind of implicit but the distance stuff is based on the amount of time you have it running for in addition to how fast the DNA fragments travel (which has been correctly pointed out is based on size). This is why you put fragments of known length in to act as a molecular ruler - since the distance will be based on size + the gel + how long the voltage is applied, you need that comparison if you want to know how long your fragments are.

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12827 on: August 05, 2020, 04:54:20 pm »
0
Hello
I was having trouble with this question if someone could help me
You are given the task to develop an antiretroviral drug to combat the recently discovered infectious agent know as HIV. You decide to develop a drug that targets an aspect of the HIV life cycle. Which aspect of the HIV cycle would you target and why

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Re: VCE Biology Question Thread
« Reply #12828 on: August 05, 2020, 05:32:04 pm »
+5
Hello
I was having trouble with this question if someone could help me
You are given the task to develop an antiretroviral drug to combat the recently discovered infectious agent know as HIV. You decide to develop a drug that targets an aspect of the HIV life cycle. Which aspect of the HIV cycle would you target and why

I am not sure if in VCE you go into detail regarding retroviral life cycles (& tbh HIV gets pretty complicated!) so I am going to give some general advice. But let me know if you feel you need more HIV specific advice.

First of all, think about a simple viral lifecycle. The virus gains entry into the cell, replicates inside the cell to high numbers and then viral particles are released to go and infect new host cells. By inhibiting any of those steps you would render that virus unable to complete this life cycle and therefore limiting disease. Could a drug block entry of HIV to the CD4 T cells? Could a drug inhibit viral replication?

Furthermore, you would want to target a part of the viral lifecycle that would not interfere with normal host cell processes. For example, viruses use the host cell ribosome to synthesize critical viral proteins, however,  targeting the ribosome would not be good for the host.
BSc (Biochemistry and Immunology)

Owlbird83

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Re: VCE Biology Question Thread
« Reply #12829 on: August 05, 2020, 05:34:57 pm »
+4
Hello
I was having trouble with this question if someone could help me
You are given the task to develop an antiretroviral drug to combat the recently discovered infectious agent know as HIV. You decide to develop a drug that targets an aspect of the HIV life cycle. Which aspect of the HIV cycle would you target and why
Hey, I reckon with this question there are likely a few ways you could answer depending on which step of the life cycle you pick to target. I would say target the binding stage with a drug to block the receptors or proteins, which would prevent the virus from being able to enter the cell and hijack it.

Edit: haha Lilac beat me
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tiredandstressed

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Re: VCE Biology Question Thread
« Reply #12830 on: August 05, 2020, 05:39:52 pm »
+5
Hello
I was having trouble with this question if someone could help me
You are given the task to develop an antiretroviral drug to combat the recently discovered infectious agent know as HIV. You decide to develop a drug that targets an aspect of the HIV life cycle. Which aspect of the HIV cycle would you target and why
You may need to consider the principle of Relenza as a drug for Influenza
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whys

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Re: VCE Biology Question Thread
« Reply #12831 on: August 05, 2020, 05:59:29 pm »
+5
Hello
I was having trouble with this question if someone could help me
You are given the task to develop an antiretroviral drug to combat the recently discovered infectious agent know as HIV. You decide to develop a drug that targets an aspect of the HIV life cycle. Which aspect of the HIV cycle would you target and why
For this question, I would say the administration of a drug that inhibits the action of reverse transcriptase, an enzyme used to back-copy RNA to DNA (reverse transcription) in retroviruses such as HIV. By blocking the action of this enzyme, the virus will not be able to successfully insert its genetic material into a cell and infect it. There are probably other viable options, but this is the answer I would put for the sake of sticking to the study design. Hope it helps!

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12832 on: August 05, 2020, 06:07:16 pm »
0
Thanks guys!

homeworkisapotato

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Re: VCE Biology Question Thread
« Reply #12833 on: August 05, 2020, 07:03:19 pm »
0
Hey! Rational drug design has been taken off the study design this year  :)
Edit: Is it still possible to get this kind of question in an exam?
« Last Edit: August 05, 2020, 07:45:19 pm by homeworkisapotato »
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eemmaa

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Re: VCE Biology Question Thread
« Reply #12834 on: August 09, 2020, 06:38:17 pm »
0
What's the difference between a mould and cast fossil?
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homeworkisapotato

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Re: VCE Biology Question Thread
« Reply #12835 on: August 09, 2020, 06:43:33 pm »
+4
What's the difference between a mould and cast fossil?
Mould fossils show the impression the body of an organism leaves with no soft tissues. For example, the print of a leaf.
Cast fossils are similar but the soft tissues are replaced by other minerals in the area which seep in. For example, the shell of some ancient snail filled with opal stone inside near an opal mine.
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whys

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Re: VCE Biology Question Thread
« Reply #12836 on: August 09, 2020, 06:45:33 pm »
+4
Hey! Rational drug design has been taken off the study design this year  :)
Edit: Is it still possible to get this kind of question in an exam?
Questions specifically on rational drug design will not be on the exam. However, the question posted by chocolatepistachio does not require knowledge about rational drug design to answer (although it may be helpful) - you just need to have an understanding of viruses and you should be able to come up with a reasonable answer.

What's the difference between a mould and cast fossil?
A mould fossil is an impression or imprint, whereas a cast fossil is the mineral sediment that fills a mould/imprinted shape. I have not done this topic yet, so might want to clarify with someone else. :)
EDIT: (homeworkisapotato bet me to it)
« Last Edit: August 09, 2020, 06:53:03 pm by whys »

homeworkisapotato

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Re: VCE Biology Question Thread
« Reply #12837 on: August 10, 2020, 09:06:04 am »
0
Questions specifically on rational drug design will not be on the exam. However, the question posted by chocolatepistachio does not require knowledge about rational drug design to answer (although it may be helpful) - you just need to have an understanding of viruses and you should be able to come up with a reasonable answer.
A mould fossil is an impression or imprint, whereas a cast fossil is the mineral sediment that fills a mould/imprinted shape. I have not done this topic yet, so might want to clarify with someone else. :)
EDIT: (homeworkisapotato bet me to it)
Thank you for answering my rational drug design question!

I was wondering for unit 4 aos 1, how much do we have to know about all the different hominin species? Specifically Homo heidelbergensis, homo erectus, and homo habilis? I understand that Australopithecus and homo neanderthalensis are important, but my textbook and other resources go specifically into the other three sometimes. Also with the structural changes of hominins, my textbook gives specific measurements for changes in cranial capacity (like 460 cubic centimetres to 1350cc). Do I need to memorise that?
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Owlbird83

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Re: VCE Biology Question Thread
« Reply #12838 on: August 10, 2020, 10:42:18 am »
+4
Thank you for answering my rational drug design question!

I was wondering for unit 4 aos 1, how much do we have to know about all the different hominin species? Specifically Homo heidelbergensis, homo erectus, and homo habilis? I understand that Australopithecus and homo neanderthalensis are important, but my textbook and other resources go specifically into the other three sometimes. Also with the structural changes of hominins, my textbook gives specific measurements for changes in cranial capacity (like 460 cubic centimetres to 1350cc). Do I need to memorise that?

Definitely don't need to memorise that stuff. The textbook has way too much detail you don't need to know in this topic particularly I think. In VCAA FAQs they say that you don't need to know specific traits of each species, just the general trends in evolution of them. For example how overtime the cranial capacity to body size increases through the species.
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12839 on: August 10, 2020, 07:05:31 pm »
0
For this question
Why is genetic variation important?
Genetic variation is important because is there is a change in the environment some individuals will be able to survive and reproduce therefore maintaining the survival of the population.
Would this answer be fine

Also
How can genetic drift be slowed by gene flow