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March 29, 2024, 10:18:44 am

Author Topic: VCE Biology Question Thread  (Read 3571049 times)  Share 

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lm21074

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Re: VCE Biology Question Thread
« Reply #13695 on: September 08, 2021, 04:32:58 pm »
+7
can someone explain the difference between a chromosome mutation and a block mutation?
My understanding is that block mutations are gene mutations that result in large sections of a chromosome changing whereas chromosomal mutations affect entire chromosomes - for instance, aneuploidy (too many or too few individual chromosomes) or polyploidy (extra set of chromosomes).

Edited to add this:
is there a difference between gene cloning and therapy?
Gene cloning is making exact copies of a specific gene whilst gene therapy is an application of cloning that involves inserting a functional gene into cells that have a missing or faulty gene. There are differences in the ways the processes work.

Gene therapy uses a vector to carry the normal gene, which is either injected into the patient (in vivo) or cells, such as bone marrow stem cells, are removed from the patient and a vector containing the normal gene is added to the cells in a laboratory (in vitro method).

Gene cloning involves extracting the gene of interest using restriction enzymes (you can also make DNA using reverse transcriptase from mRNA), copying the DNA (using PCR), making a recombinant plasmid (gene of interest is inserted into plasmid) and bacterial transformation occurs (basically a plasmid is inserted into bacterium).



Please correct me if I'm wrong here!
« Last Edit: September 08, 2021, 07:57:02 pm by lm21074 »
2021: VCE
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wingdings2791

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Re: VCE Biology Question Thread
« Reply #13696 on: September 14, 2021, 10:09:32 pm »
+5
Hey, could someone help me with this question. Would it be that histones wrap around DNA. But I'm not sure exactly why they do it and why needed.

How do histones proteins help in the coiling of DNA?

Thanks

Hi biology1234,
You're on the right track, but it's actually the other way around- DNA wraps around histones.
What they are: Histones are small proteins that DNA wraps around in order compact the DNA into a smaller space, somewhat like sewing thread on a spool.
Why and how: There is a massive amount of genetic information to be stored in a not very large nucleus, so it's a matter of efficient storage. The histone proteins are positively charged, so they form ionic attractions to the negatively charged DNA phosphate backbone and hence, strong bonds are formed between histones and DNA.

Hope this helps!
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Acegtr

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Re: VCE Biology Question Thread
« Reply #13697 on: September 20, 2021, 04:28:10 pm »
0
Are there any benefits that In Vivo gene therapy has over Ex vivo? Or what's the purpose of In Vivo gene therapy if Ex vivo is safer? Thanks in advance!

letde

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Re: VCE Biology Question Thread
« Reply #13698 on: September 21, 2021, 12:58:12 pm »
0
Hey could someone please help me out with this question. For the bio exam would you recommend briefly studying about the Homo naledi case study or in detail? This is related to how biologists can often disagree when interpreting the human fossil records.
I've seen quite a few questions regarding Homo naledi in the practice exams.

Thanks :)

valjaybj

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Re: VCE Biology Question Thread
« Reply #13699 on: September 21, 2021, 04:28:57 pm »
+3
Hey could someone please help me out with this question. For the bio exam would you recommend briefly studying about the Homo naledi case study or in detail? This is related to how biologists can often disagree when interpreting the human fossil records.
I've seen quite a few questions regarding Homo naledi in the practice exams.

Thanks :)

Hi! I think it's definitely important to understand that the human fossil record is a classification scheme that is open to interpretations (this is explicitly mentioned in the study design), but a brief study of Homo naledi should be enough. If there's a question about H. naledi they will provide you with context. In saying that, if you feel more confident by having a look in more detail then go for it! But I don't think it's a necessity. Hope this helps! :)

Acegtr

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Re: VCE Biology Question Thread
« Reply #13700 on: September 25, 2021, 04:14:18 pm »
0
Hi,
When comparing DNA sequences, especially mtDNA, why is a higher mutation rate better? My thinking is that if there are more differences over time, how would it make mtDNA better than normal DNA if it has a higher mutation rate? I get that it's only passed down maternally, and this could help in tracing, but wouldn't a higher mutation rate still make it harder to relate individuals?

Thanks in advance!

specimen

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Re: VCE Biology Question Thread
« Reply #13701 on: September 25, 2021, 06:11:04 pm »
+5
Hi,
When comparing DNA sequences, especially mtDNA, why is a higher mutation rate better? My thinking is that if there are more differences over time, how would it make mtDNA better than normal DNA if it has a higher mutation rate? I get that it's only passed down maternally, and this could help in tracing, but wouldn't a higher mutation rate still make it harder to relate individuals?

Thanks in advance!

A higher mutation rate can be used to find the relationship between closer related species. For example if two species have recently diverged then looking at the differences in their nuclear DNA may not be useful as there may have not been enough mutations accumulated over the short time period, whereas there will be more mutations accumulated in their mtDNA which can give the scientists a better understanding of their relationship and when exactly they diverged.

For species which have diverged much earlier, using nuclear DNA more useful.


hamnafahmi

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Re: VCE Biology Question Thread
« Reply #13702 on: September 29, 2021, 10:49:42 am »
0
Does anyone know when the new study design is releasing for 3/4 Biology? I just want to familiarise myself with the topics before the next year starts.

hamnafahmi

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Re: VCE Biology Question Thread
« Reply #13703 on: September 29, 2021, 11:35:23 am »
0
In what part of atps structure is the readily usable energy stored?
Is it only in the last phosphate bond

Energy is stored in its three phosphate bonds. However, a large amount of energy is released when the last phosphate group is broken from the rest of the ATP molecule.

biology1234

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Re: VCE Biology Question Thread
« Reply #13704 on: September 29, 2021, 03:07:31 pm »
0
hey all,
I had an important question. As the study design for next year has changed. Are the old exams that are from the 2016-2021 study design still relevant and good to use. Is this a disadvantage and are their any tips as I am really nervous. Are their any other resources that would help.
thankss

Sine

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Re: VCE Biology Question Thread
« Reply #13705 on: September 29, 2021, 04:04:56 pm »
+3
hey all,
I had an important question. As the study design for next year has changed. Are the old exams that are from the 2016-2021 study design still relevant and good to use. Is this a disadvantage and are their any tips as I am really nervous. Are their any other resources that would help.
thankss

You can still use the relevant questions in old exams. Depending on how much the study design has changed you may or may not be able to use them as full exams but you could remove the irrelevant questions and reduce the amount of time you have accordingly to try to replicate what a real exam would feel like. When I did biology I did past exams from about 15 years prior and they were still useful.

Other resources that would be useful would be commercial company examinations but as always VCAA is the gold standard since they make your exam.

biology1234

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Re: VCE Biology Question Thread
« Reply #13706 on: September 29, 2021, 05:19:39 pm »
0
Hi everyone, could someone help me explain this graph. Is it like the more carbon dixoxide present the more effect on light intensity. If someone could explain it would help. thanks

biology1234

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Re: VCE Biology Question Thread
« Reply #13707 on: September 29, 2021, 05:22:41 pm »
0
You can still use the relevant questions in old exams. Depending on how much the study design has changed you may or may not be able to use them as full exams but you could remove the irrelevant questions and reduce the amount of time you have accordingly to try to replicate what a real exam would feel like. When I did biology I did past exams from about 15 years prior and they were still useful.

Other resources that would be useful would be commercial company examinations but as always VCAA is the gold standard since they make your exam.


Thank you for that. Do you think that the new study design will mean the exam is more difficult. I know from 2016 to 2017 their was a jump, so I am wondering. What do you think?

chhhliii

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Re: VCE Biology Question Thread
« Reply #13708 on: September 29, 2021, 05:41:36 pm »
0
Hii! Can radiometric dating only be used on igneous rocks? I did a practise exam question (from external company), and the question was "what dating method would you use," and the scenario information said that the fossil was found in sedimentary rock, and the age was approximately 110 million years old. I said uranium-lead dating, but the answer was stratigraphy. So now I'm confused.
And can radiocarbon dating be used on sedimentary rock? Or all of them can't?
Thank you!

Lymphhh

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Re: VCE Biology Question Thread
« Reply #13709 on: September 29, 2021, 08:28:47 pm »
+4
Hii! Can radiometric dating only be used on igneous rocks?
And can radiocarbon dating be used on sedimentary rock? Or all of them can't?
Thank you!

Can radiometric dating be used on sedimentary rock?”

From my understanding we do not date sedimentary rock but rather we date the fossils. The sedimentary layer is composed of sediments that came from areas like mountains, etc. So by dating the sedimentary layer, you are essentially estimating the age of the rocks in their initial placement, not the age of when the particular stratum was formed. So we can’t date the sedimentary rock layer to find the age of the fossil.

Can radiometric dating only be used on igneous rocks? “

No. Radiometric dating can involve many different types of radioisotopes. Depending on the radioisotope that we use, the substances we can date will vary. For instance, radiocarbon dating is used for dating fossils younger than 50,000 years or so, while potassium-argon dating is used to determine the age of igneous rock. We cannot use potassium-argon dating directly on fossils. (potassium 40 decays into argon which is a noble gas. Therefore, potassium - argon dating can only be done in substances that trap argon. This is generally, igneous rocks formed from volcanic eruptions.)

Although we can’t directly date a fossil using potassium-Argon dating, we can still use it to date fossils:

-> If the fossil is found in between two dateable igneous rock layers, we can obtain the date of formation of the igneous rocks. Then we can infer that the age of the fossil is between the ages of the two igneous rocks by using the law of superposition.

-> if the fossil is found in a dateable igneous rock, then we can date the igneous rock. The absolute age of the igneous rock would be around the same age as the fossil.

I hope that helps. This is my understanding. It could be wrong idk.
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