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Author Topic: VCE Biology Question Thread  (Read 3571317 times)  Share 

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Owlbird83

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Re: VCE Biology Question Thread
« Reply #11145 on: October 30, 2018, 03:05:42 pm »
+1
Do we need to know about continuous and discontinuous variation?


Do we also need to know DNA replication? Like drawing it, identifying all stages and about Okazaki fragments?

No I don't think so, they are part of the old study design.
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EllingtonFeint

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Re: VCE Biology Question Thread
« Reply #11146 on: October 30, 2018, 03:14:54 pm »
0
In the 2012 exam there’s a phylogenetic tree.
In the examiners report, it says that it is incorrect to say that the species which most recently diverged “are more closely related”. Why...?



Also are index fossils a relative form of dating?
« Last Edit: October 30, 2018, 03:45:15 pm by Angelica2001 »
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Erutepa

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Re: VCE Biology Question Thread
« Reply #11147 on: October 30, 2018, 03:32:57 pm »
+3
Here are a few Qns I have

1. Is chlorophyll a pigment containing enzymes or a protein embedded in the thylakoid membrane?

2. With the peptide bond, is it the bond between the Carbon of one amino acid and Nitrogen of the next amino acid?
A solution to an exam paper circled the Carbon double bonded to Oxygen along with the Carbon bonded to Nitrogen as being the peptide bond.

3. For a particular qn, it asked for the impact of using a large sample size.

The answer was that Increasing sample size increases the validity of results, but I thought a large sample size increases reliability.

  4. When the Lac repressor is bound to the operator, is it true that RNA polymerase cannot bind to the promoter or can it bind but not move forward and transcribe the structural genes due to the repressor protein?
Thanks

1. chlorophyll is a pigment which is housed in protein complexes embedded in the thylakoid membrane (although I don't think you need to know this). Just simply know that absorbs light energy which is then used to split water.

2. a peptide bond forms between the carbon of one amino acid's carboxyl group and the nitrogen of another amino acid amine group.

3. I would say that it does increase the 'reliability' of the results in how the average results would likely be more accurate as a large sample size can decrease the impact of erroneous results. That being said, validity would be my first pick.

4.most sources say that the binding of the operator will prevent the RNA polymerase from correctly binding; not blocking it after binding. Of course, as a result of RNA polymerase not being able to bind to the promoter, no transcription will occur.

Does anyone have a list of all the possible techniques used to determine relatedness between species? Eg. gel electrophoresis

I will try my best to get as many as is relevant:
Molecular Homology
 - looking at similarities between molecules, most commonly with comparing DNA sequences or the amino acid sequences of proteins
DNA hybridization
 - this will indicate similarities in the nucleotide base sequence of DNA
Structural morphology
 - comparing the structure of animals. different structures like analogous, homologous and vestigial structures all indicate relationships of some sort.
Molecular clock
 - comparing DNA sequences (usually mRNA sequences) and using known mutation rates to establish timelines of evolution

I don't think I would say a gel electrophoresis is a tool for determining relatedness, but rather a tool for separating DNA by base-pair length. Of course, this can be used in creating DNA profiles for comparison, in which case I would call it molecular homology perhaps. (not sure though)

Mod edit (PF): Merged double post
« Last Edit: October 30, 2018, 10:08:01 pm by PhoenixxFire »
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Owlbird83

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Re: VCE Biology Question Thread
« Reply #11148 on: October 30, 2018, 03:53:58 pm »
+1


Also are index fossils a relative form of dating?

Yes
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Erutepa

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Re: VCE Biology Question Thread
« Reply #11149 on: October 30, 2018, 03:59:15 pm »
+3
Do we need to know about continuous and discontinuous variation?


Do we also need to know DNA replication? Like drawing it, identifying all stages and about Okazaki fragments?

It wouldn't hurt to know about continuous and discontinuous variation.
Discontinuous variation refers to traits for which there are a finite number of polymorphisms/variants (e.g. blood groups). These traits are usually controlled by 1 (if not a very few) gene loci
Continuous variation refers to traits for which there is an infinite spectrum of polymorphisms/variants between two extremes (e.g. height). These are controlled by many gene loci

You don't need to know in detail about DNA replication, but it is useful as many elements such as the action of DNA polymerase and primers are relevant to describing PCR. That being said, knowledge of Okazaki fragments is not needed and I wouldn't think you would need to draw DNA replication.
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AISHAB

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Re: VCE Biology Question Thread
« Reply #11150 on: October 30, 2018, 04:07:52 pm »
0
Hi,

When looking at a Primary and Secondary Immune response graph. What is the reason for the decline in antibodies, in the primary response?

Thanks

Erutepa

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Re: VCE Biology Question Thread
« Reply #11151 on: October 30, 2018, 04:08:09 pm »
+3
In the 2012 exam there’s a phylogenetic tree.
In the examiners report, it says that it is incorrect to say that the species which most recently diverged “are more closely related”. Why...?



Also are index fossils a relative form of dating?
I have tried to find the question you are talking about, but I have not had any luck. Can you possibly recall what question this is and in which 2012 exam.


Index fossils are used for relative dating along with stratigraphy.

Hi,

When looking at a Primary and Secondary Immune response graph. What is the reason for the decline in antibodies, in the primary response?

Thanks

Antibodies have a half-life much as radioactive isotopes do. As time goes on antibodies will decline as they degrade. Each of the different subclasses (IgM, IgD, IgA, IgG, and IgE) all have differing half-lives which have to do with the length of the constant/Fc region of the antibody.
Also note that this decline in antibody levels (usually in the serum it measured) is not exclusive to primary responses and will occur in secondary responses, only that antibodies in secondary responses are produced in much greater quantities.

Mod edit (PF): Merged double post
« Last Edit: October 30, 2018, 10:09:59 pm by PhoenixxFire »
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Maultima

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Re: VCE Biology Question Thread
« Reply #11152 on: October 30, 2018, 04:20:22 pm »
0
I just have a few questions to clear up.

1) Is polymorphism/ monomorphism important and if so what are they, as all the definition I have read vary significantly.

2) What is biogeography and how does it support the theory of evolution?

3) What is ELISA and why is it used?

4) How Electron Spin Resonance functions as an absolute dating method

5) Also for expiremental question, I seem to be stuggling with:
- comparisons when they give a graph with effect of different concentrations of variables, what should I include on these and are there any important phrases to implement such as ‘positive correlation’
- general ways experiments could be improved, I have increase sample size, repeat experiment btu are there anymore?
- structure for hypothesis. In every exam whether it be VCAA or private papers the way they begin or end hypothesis varies and I’m afraid I won’t correctly phrase my hypothesis on Friday.
- what should be included in a conclusion.

Thanks guys and girls :)
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randy123

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Re: VCE Biology Question Thread
« Reply #11153 on: October 30, 2018, 04:24:05 pm »
0
Hi,

Can someone explain how monoclonal antibodies work... is it a form of rational drug design?

Thanks,
« Last Edit: October 30, 2018, 04:28:15 pm by randy123 »

Maultima

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Re: VCE Biology Question Thread
« Reply #11154 on: October 30, 2018, 04:35:26 pm »
+4
Can someone explain how monoclonal antibodies work... is it a form of rational drug design?

Rational drug describes how a drug is synthesised against a particular disease/disorder to target a biomolecule, vital in the development of the disease/disorder. (The best example is drug which binds to an enzyme that produces a molecule necessary for the ongoing duration of the disease and inhibits it’s action).

Monoclonal antibodies are artificially synthesised antibodies which complementarily bind to a specific antigen, especially those on cancer cells. It does this by inducing apoptosis on the cell/ flag cells for recognition by other immune cells for destruction/ block binding site.

Although I am unsure whether a monoclonal antibody is a rational drug, I would conclude it isn’t. It is synthesised artificially the same way and do both inhibit the actions of a biomolecule necessary for the development of the disease, however, I would not regard monoclonal antibodies as “drugs” but yet again mocolonal antibodies can deliver radiation or chemotherapy treatment as per NHT VCAA Biology 2018 Paper. I may be wrong so please correct me!
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galaxy21

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Re: VCE Biology Question Thread
« Reply #11155 on: October 30, 2018, 04:39:01 pm »
+4
3) What is ELISA and why is it used?
Not 100% sure on the other ones, so I will leave them for someone else, but for ELISA...
ELISA (Enzyme-Linked Immunosorbent Assay) is a technique that uses an antibody-enzyme complex. The antibody section of the complex binds with the pathogen antigen. The enzyme ‘s usual substrate is then added and reacts with the enzyme, producing a colour change that can be detected.
The process is as follows:
1.   Antibodies for the suspected antigen (of the pathogen) are added to the bottom of a well
2.   The blocking agent is added to fill any areas not bound by the antibody.
3.   Swabs from a patient’s sample are added. If the antigen is present in the sample, it attaches to the antibody. If the antigen is not present in the sample, it does not attach to the antibody.
4.   An antibody with an enzyme attached is added. If the antigen has attached to the antibody, this second antibody attaches to the other end of the antigen. If the antigen has not attached, this second antibody does not attach either.
5.   The plate is treated is that the solutions in the wells turn a particular colour only in the presence of the antigen-antibody complex.
Note: between each of the above steps, a washing step occurs to remove any loose particles.
The strength of the colour indicates the quantity of antigens present. The darker the colour, the more antigens are present, and therefore the more infectious the person is.
(Sorry... just copied it directly from my notes so hopefully it makes some sense :o )

Hi,

Can someone explain how monoclonal antibodies work... is it a form of rational drug design?

Thanks,

Monoclonal antibodies are antibodies that are produced from a single plasma B cell. Basically, the process is:
   1. An antigen (for which antibodies are required) is injected into the cell of an animal (e.g. a mouse). The animal produces plasma B cells that are specific to the antigen.
   2. The plasma B cells are removed and fused with a tumor cell (called hybridisation) because tumor cells replicate rapidly and uncontrollably, and therefore are very effective to produce high numbers of the plasma cell.
   3. The result is called a hybridoma cell, and it is capable of synthesising large amounds of the monoclonal antibody. They can be extracted and used for theraputic purposes, such as diagnostic tests such as pregnancy tests, neutralising toxins in poisons that are produced by endotoxins in the blood, or to target cancer cells if the body does not do this itself.
I am pretty sure that monoclonal antibodies are not a rational drug, but someone else might have to clarify this.

Hope all of this kind of makes sense...sorry if it doesnt!
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Robot10

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Re: VCE Biology Question Thread
« Reply #11156 on: October 30, 2018, 04:39:50 pm »
+2
1. chlorophyll is a pigment which is housed in protein complexes embedded in the thylakoid membrane (although I don't think you need to know this). Just simply know that absorbs light energy which is then used to split water.

2. a peptide bond forms between the carbon of one amino acid's carboxyl group and the nitrogen of another amino acid amine group.

3. I would say that it does increase the 'reliability' of the results in how the average results would likely be more accurate as a large sample size can decrease the impact of erroneous results. That being said, validity would be my first pick.

4.most sources say that the binding of the operator will prevent the RNA polymerase from correctly binding; not blocking it after binding. Of course, as a result of RNA polymerase not being able to bind to the promoter, no transcription will occur.

Thanks

I was just wondering how a large sample size increases validity


AngelWings

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Re: VCE Biology Question Thread
« Reply #11157 on: October 30, 2018, 04:41:43 pm »
+5
Please be wary that my answer may not be up to VCE standard as I never did VCE Bio.
1) Is polymorphism/ monomorphism important and if so what are they, as all the definition I have read vary significantly.
A polymorphism is essentially stating that there are multiple forms of an allele. Monomorphism is that there's just one form. I don't know if that's important to the VCE Bio course.
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randy123

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Re: VCE Biology Question Thread
« Reply #11158 on: October 30, 2018, 04:44:21 pm »
+5
Here are a few Qns I have

1. Is chlorophyll a pigment containing enzymes or a protein embedded in the thylakoid membrane?

2. With the peptide bond, is it the bond between the Carbon of one amino acid and Nitrogen of the next amino acid?
A solution to an exam paper circled the Carbon double bonded to Oxygen along with the Carbon bonded to Nitrogen as being the peptide bond.

3. For a particular qn, it asked for the impact of using a large sample size.

The answer was that Increasing sample size increases validity of results, but I thought a large sample size increases reliability.

  4. When the Lac repressor is bound to the operator, is it true that RNA polymerase cannot bind to the promoter or can it bind but not move forward and transcribe the structural genes due to the repressor protein?
Thanks


1. chlorophyll doesnt contain proteins as it is a pigment, it is a much smaller molecule

2. Yeah its between carbon and nitrogen: when the peptide bond is formed, one hydrogen from the nitrogen side detaches and the oxygen and hydrogen detach from the carbon side. then a bond is formed between the carbon and nitrogen and a biproduct of water (from the hydrogens and oxygen form bonds together) is produced.

3. I think youre right, i think that saying increased validity is wrong, but the thing is yeah the term is kinda thrown around.

4. RNA polymerase can bind to the promotor region but cant continue, this is coz the repressor protein is further downstream to the promotor region, the RNA polymer binds to promotor region and moves down but is stopped when it reaches the repressor protein region (regulatory region).

hope that helps.

galaxy21

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Re: VCE Biology Question Thread
« Reply #11159 on: October 30, 2018, 04:48:26 pm »
+3
Thanks

I was just wondering how a large sample size increases validity

Larger sample size increases validity as it reduces the effect of random errors that may be present. It's basically just averaging data - if you measured, for example, how fast people could run 100m (completely unrelated to bio but still), and 99 people took between 20-25 seconds, and one person took 45 seconds because they tripped over half way through (a (pretty terrible) example of an error), the effect that this person would be reduced, as so many of the other runners were within a small range. If the test was out of 5 people, and one person took significantly longer, then the results would be more greatly influenced by this. It's the same for an experiment - if there is an outlier in the results, its effect on the general data is greatly reduced if we have a sample size of 100 rather than 3.
It means that the data can be generalised more as well, as it is more reliable.
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