VCE Biology Question Thread

[Calebark]

i need badly help with this question please guys help me out

"describe how vaccination for meningococcal triggers the immune response and prevents the spread of disease" 5 marks
"explain how gamete formation and sexual reproduction introduce variation in offspring" - 5marks
"explain why both passive and active process are required in the nephron to regulate body fluid composition" -2marks

Hey, welcome to AN what are your thoughts on these questions so far? That way we can better help you

[AngelWings]

"explain how gamete formation and sexual reproduction introduce variation in offspring" - 5marks

This touches on my Honours project. Won't give you the answer, like Calebark, but think carefully as to how sexual reproduction occurs and at what stage(s) potential variation can be introduced.

[LifeisaConstantStruggle]

i need badly help with this question please guys help me out

"describe how vaccination for meningococcal triggers the immune response and prevents the spread of disease" 5 marks
"explain how gamete formation and sexual reproduction introduce variation in offspring" - 5marks
"explain why both passive and active process are required in the nephron to regulate body fluid composition" -2marks

To answer long questions like these it is often easier if you were to split up the question into manageable bits, and start crunching the question from there.
1) "describe how vaccination for meningococcal triggers the immune response and prevents the spread of disease"
- vaccination: What does a vaccine consist of? Dead/attenuated forms of a pathogen, commonly a virus. Which category of immunity does a vaccine belong to? Artificial active immunity.
- triggers the immune response: So we know what a vaccine does (and which category of immunity it belongs to), so from here we just need to elaborate the humoral response (since vaccines trigger the humoral response) and its steps, which subsequently creates memory cells against a specific disease in case if a pathogenic attack does occur.
- people usually stop here, and that's fine (if I remember correctly, you can gain full marks already, but we can go further) how does a vaccine prevent the spread of a disease? you can talk about a population of human beings, and how herd immunity can benefit those who are not immunised as well.

Please attempt the other questions on your own, remember to just separate the question into smaller, manageable chunks, and it will help you heaps. best of luck!

[Azim.m]

Does anyone know a website that specifically outlines which past vcaa exam questions are relevant to the new study design?
Thanks

[Sine]

Does anyone know a website that specifically outlines which past vcaa exam questions are relevant to the new study design?
Thanks

you should be able to work out which one's are relevant as they would be the ones that you can actually answer (given you've learnt the whole study design) otherwise you can always check by asking AN/teacher or checking the study design to see whether they match up to any dot points.

[MAGGOT]

Why is fermentation important for yeast cells?

[Azim.m]

Would a question like this still be applicable in the study design?

[napkin101]

This is a question relating to activity 4 of Biozone. (RBCs are placed in 0.3 mol solution of glucose, sucrose, urea and glycerol (one by one))

Why does solute move into RBCs to form an isotonic solution as well as water into the RBCs? Doesn't osmosis occur from low solute concentration to high concentration to reach an isotonic solution? Because wouldn't solute moving in and water moving in have opposite affects, therefore there is no change in concentrations? I'm not sure if I'm being stupid but any help would be appreciated.

EDIT: I think I got it. Can someone please confirm if this is right? So basically what I understand is that the solute moves in along its concentration gradient to balance the concentration, and then because the RBC solute concentration has risen, water moves in to balance again and this causes the RBC to burst. Thanks!

[FabAsianZung]

Hey guys, can anyone with past experiences help me out a bit?

Tomorrow I will be going to Melb Uni to conduct my Unit 4 AOS 2 SAC. Which will probably only be about DNA manipulation techniques. Can anyone tell me what the SAC actually is? I heard we get a booklet, which we have to fill in answers, as we conducts the practical/experiments. Can anyone tell me what else will I need to know or prepare before the SAC tomorrow? 

[sumaiya.haque]

i got my trial next week help me OUTTTTTTTT guys....

"describe the main steps in the first stage of the process of gene expression?" 3marks

[napkin101]

i got my trial next week help me OUTTTTTTTT guys....

"describe the main steps in the first stage of the process of gene expression?" 3marks

What are the basics that you know about first stage of gene expression? It would be good, as you probably have seen from earlier posts, that giving you the answer isn't going to do too much good for you. So it'd be good if you could tell us what you know so we can clarify any confusing points.

[FabAsianZung]

Google: In biology, a mutation is the permanent alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements.

So does that mean genetic engineering is a form of mutation?

[FabAsianZung]

Another question. Say, if a dog that has some type of disease, which got the bacteria in its mouth infected as well and the dog bit a human. But when inside the human body, the human discovered the presence of this infectious bacteria and took antibiotics. But then the bacteria mutated and become antibiotic resistant. (This is all hypothetical)

What happens then? And how does the bacteria mutate, to become antibiotic resistant?

[darkz]

Would a question like this still be applicable in the study design?

Hey,
I doubt that question would still be in the study design, simply because the nervous system has been downplayed a lot since the past study designs

Google: In biology, a mutation is the permanent alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements.

So does that mean genetic engineering is a form of mutation?

No, genetic engineering is not a form of mutation. Mutations occur either spontaneous via random errors in DNA replication or induced via mutagens (e.g. radiation) when DNA fails to repair itself when a fault occurs in the nucleotide sequence (DNA constantly undergoes changes and errors, however most of these are repaired and in the rate circumstance that they aren't, they form mutations) => Mutations are indeed a permanent alteration in the nucleotide sequence, however they result from the failure of DNA repair

Another question. Say, if a dog that has some type of disease, which got the bacteria in its mouth infected as well and the dog bit a human. But when inside the human body, the human discovered the presence of this infectious bacteria and took antibiotics. But then the bacteria mutated and become antibiotic resistant. (This is all hypothetical)

What happens then? And how does the bacteria mutate, to become antibiotic resistant?

Well firstly, not everything is about mutations - applying the theory of natural selection here would be more appropriate in my opinion

Here's some info from https://www.rxlist.com/antibiotic_resistance/drugs-condition.htm on antibiotic resistance if you want to read more about it

"Antibiotic resistance occurs when bacteria change in some way that reduces or eliminates the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The bacteria survive and continue to multiply causing more harm. Bacteria can do this through several mechanisms. Some bacteria develop the ability to neutralize the antibiotic before it can do harm, others can rapidly pump the antibiotic out, and still others can change the antibiotic attack site so it cannot affect the function of the bacteria.

Antibiotics kill or inhibit the growth of susceptible bacteria. Sometimes one of the bacteria survives because it has the ability to neutralize or escape the effect of the antibiotic; that one bacterium can then multiply and replace all the bacteria that were killed off. Exposure to antibiotics therefore provides selective pressure, which makes the surviving bacteria more likely to be resistant. In addition, bacteria that were at one time susceptible to an antibiotic can acquire resistance through mutation of their genetic material or by acquiring pieces of DNA that code for the resistance properties from other bacteria. The DNA that codes for resistance can be grouped in a single easily transferable package. This means that bacteria can become resistant to many antimicrobial agents because of the transfer of one piece of DNA."

[Scribe]

Hey guys,

What's the difference between phylogenetic trees and a cladogram? I'm stuck trying to wrap my head around these two.