VCE Biology Exam - 01/11/19 - Discussion/Questions/Solutions

[dev_xy]

Based on most people saying that the exam was relatively straightforward I am guessing the will be probably the usual strictness or maybe a bit more strict (although this will always be question/assesor dependent).

if bio scales down this year because of this X_X

[Sine]

if bio scales down this year because of this X_X

If bio does scale down (which is unlikely) the difficult of exam/marking of the exam won't be the reason for this.

Scaling depends on the strength of the cohort which is measured as how well biology students do in all of their other subjects.

[holly.morrison]

How can a vaccine for an allergen be produced? in relation to question 4.. We don't get vaccinated for a peanut allergy, so why is any other allergen different? So confused

[malt.eser2002]

Hi guys
couple of quesions
Could you say desensitisation for 4b as a method of dealing with thunderstorm astham
-Did u have too specific the anitbody as Ige for 4A
-Did you have too say both Homo heidelbergisis and Homo Saipen for 10c
-Could you say that the fossil evidence found was not distinctive of a unique hominin group morphologicaly therefore was not sufficient by itself to suggest another hominin group for 10A
-Could you say the Nuclear DNA is better than mtDNA for this comparison as it provides mor genetic information for comparions compared too mtDNA
-Could you say the type of gel in use for 8c would vary the seperation of DNA fragments
SORRY FOR THE CRAP TON OF QUESTIONS highkey pissing myself rn
Thanks

[Sine]

How can a vaccine for an allergen be produced? in relation to question 4.. We don't get vaccinated for a peanut allergy, so why is any other allergen different? So confused

not everyone will be susceptible to produce an allergic response towards peanuts thus no need for vaccination for everyone (the body does not detect it as something they need to produce an immune response against).

so for someone with a peanut allergy, that type of vaccination could actually be useful -> there are a few ongoing clinical trials I believe so could be available in the future (if not already)

[PhoenixxFire]

How can a vaccine for an allergen be produced? in relation to question 4.. We don't get vaccinated for a peanut allergy, so why is any other allergen different? So confused

There was actually vaccine trials last year (and i believe they continued this year) for a vaccine against grass pollen.
There's also other "vaccines" that aren't vaccines in the sense that you'd think of them against other allergens (including peanuts), but what they do you aren't taught in vce.

The explanation I wrote for that question is one that it'd be reasonable for you to make in vce - you could trigger an immune reaction using pollen fragments which would mean that then when thunderstorm asthma occurred, you'd get B memory cells making antibodies that bind to the pollen which prevents them from crosslinking the IgE antibodies on mast cells instead - sort of like how anitbodies can cause agglutination of snake venom.

It's possible that vcaa would also accept you saying that it's not possible to make a vaccine along with a reasonable justification, but it definitely seemed like they were wanting you to apply your immunity knowledge to a theoretical scenario.

Hi guys
couple of quesions
Could you say desensitisation for 4b as a method of dealing with thunderstorm astham
-Did u have too specific the anitbody as Ige for 4A
-Did you have too say both Homo heidelbergisis and Homo Saipen for 10c
-Could you say that the fossil evidence found was not distinctive of a unique hominin group morphologicaly therefore was not sufficient by itself to suggest another hominin group for 10A
-Could you say the Nuclear DNA is better than mtDNA for this comparison as it provides mor genetic information for comparions compared too mtDNA
-Could you say the type of gel in use for 8c would vary the seperation of DNA fragments
SORRY FOR THE CRAP TON OF QUESTIONS highkey pissing myself rn
Thanks

-Maybe. Depends how strict the examiners are being, it says actions "a person can take" - desensitisation requires medical supervision generally.
- Most likely yes
- No. I put both because you could make a case for either (according to the article they were both there over the time period specified).
- Maybe. The question says "based on the article" and there's no reference to morphological similarity/dissimilarity in the article so it isn't a great justification.
- Maybe. It does have a larger genome so more loci to compare, but I'm not really sure what the examiners will accept.
- Probably not. Agarose gel is a specific type of gel.

[Amnilauv]

The explanation I wrote for that question is one that it'd be reasonable for you to make in vce - you could trigger an immune reaction using pollen fragments which would mean that then when thunderstorm asthma occurred, you'd get B memory cells making antibodies that bind to the pollen which prevents them from crosslinking the IgE antibodies on mast cells instead - sort of like how anitbodies can cause agglutination of snake venom.

I still can't see how it can be possible to create a vaccine for an allergen, because the allergen from the vaccine would still create IGE antibodies, which are already bound to mast cells, so if a vaccine containing and allergen is introduced, then wouldn't the body just be making more IgE antibodies (which actually does the complete opposite of what vaccines are supposed to do)? Or am I thinking of it wrongly?

[PhoenixxFire]

I still can't see how it can be possible to create a vaccine for an allergen, because the allergen from the vaccine would still create IGE antibodies, which are already bound to mast cells, so if a vaccine containing and allergen is introduced, then wouldn't the body just be making more IgE antibodies (which actually does the complete opposite of what vaccines are supposed to do)? Or am I thinking of it wrongly?

They're altered like how other pathogens are altered, except in this case it's so that they can't crosslink (or at least that's what they're doing for the grass pollen vaccine).

[hearteyes4u]

for question 2ai could u hv written NADPH and ATP

[PhoenixxFire]

for question 2ai could u hv written NADPH and ATP

They get used and reused in photosynthesis - there's no need for them to be diffusing into the chloroplast.

[malt.eser2002]

Do you have any idea what would be a good exam score for 45 plus this year with high sac scores

[cookielife]

- For the last question(limitations), can you say that a limitation was that the three students didn't do it in the same time of day?
- And I still don't understand the thunderstorm asthma vaccine question? Vaccines are used to trigger an immune response, but with this scenario, an immune response is already occurring?
- For question 1b, can you say that there are over 300 monomers because of how one amino acid is coded for by 3 monomers, therefore 10x3=300 and 6 monomers for START and STOP codons?
- For 3a, can you say entry via mouth or nose if pathogen has airborne or droplet transmission?
- For 3d, did you have to specify MHC Class II receptors?
- For 5c, did you have to specify advantageous phenotypes-natural selection,etc.?
- For 6aii, can you say chromosomes in WBC?
- For 8c, can you have said the time that the gel was left on for? Cos if the gel is left on for too long, then all the fragments will settle at the bottom?
- For 9a, can you say the use of public toilets as a social/economic factor?
- For 10b, can you say nuclear DNA can be used for DNA hybridisation, wherease mtDNA cannot?

I'm so sorry for so many questions! Don't really think I did too well, after looking at the answers

[sw4gm0n3y]

nah I’m pretty sure it stated that the human gene for insulin production was inserted, or at least it mentioned the word “human”, so it was transgenic organism

[IThinkIFailed]

They're altered like how other pathogens are altered, except in this case it's so that they can't crosslink (or at least that's what they're doing for the grass pollen vaccine).

I’ve also seen this explanation online about allergen vaccines, and it is what I used in the exam. Do you think it could work, even though it’s not explained as much at the cellular level like you did?

I said that vaccines can be made by exposing allergy sufferers to small amounts of the pollen antigen, in a bid to slowly desentise the body the allergen by basically making them more tolerant the substance so the immune system recognises it as a harmless substance.

[-Lilac-]

- And I still don't understand the thunderstorm asthma vaccine question? Vaccines are used to trigger an immune response, but with this scenario, an immune response is already occurring?

I haven’t seen the question but regarding how a vaccine against a allergen could work.
The pollen would be attenuated so it had low reactivity with IgE antibodies (they wouldn’t be able to bind = no mast cell degranulation). However, our immune response would still build up non-IgE antibodies to the pollen antigen. Therefore, when the individual is exposed to the real pollen the pollen specific memory B cells would be able to very quickly produce antibody and sort of neutralise the pollen, preventing any IgE antibodies that are produced from binding as the IgG antibodies have already bound. Much like how you can neutralise a virus by binding antibody and preventing it from interacting with host cells.

I’d doubt they would expect you to describe such detail but I thought I’d share for interest.