VCE Biology Question Thread

[melons]

You would give this person antihistamines which, is a drug that inhibits the action of histamine by blocking its attachment to histamine receptors, thus reducing the allergic response. I think this is how you would go about this.

Thank you.
Could you explain how they do it through allergen treatment ( or whatever it's called) ?

[katiesaliba]

Could someone please explain how you'd desensitize someone to an allergen?

Desensitise by regularly exposing an individual to small amounts of the allergen. Antihistamines suppress the immune response rather than desensitise.

How was this evident in this question?

You can tell because the chromosomes fail to separate into sister chromatids. Also, the question itself refers to another 'kind of error'. So it's reasonable to assume non-disjunction in meiosis II! I hated this question, because the letters confused me ahah.

[melons]

Desensitise by regularly exposing an individual to small amounts of the allergen. Antihistamines suppress the immune response rather than desensitise.

Thanks. So do the doses of allergens stop the production of antibodies or...?

[AllG_]

Thanks for response you guys!
Another question: how is a compact pelvis evidence of bipedalism? Is it to provide superior stability and weight support? I remember in the 2013 VCAA exam it said something along the lines of "a wider pelvis (as opposed to compact) tips the centre of gravity" Could anybody explain the centre of gravity bit?
Thankyouuu

[katiesaliba]

Thanks. So do the doses of allergens stop the production of antibodies or...?

The allergen cross linking between IgE makes less IgE available for future reactions, thus reducing the severity of allergic reactions.

[melons]

The allergen cross linking between IgE makes less IgE available for future reactions, thus reducing the severity of allergic reactions.

Thank you.

[RazzMeTazz]

For this question (Attached below) the answer is: " The transcription of all genes is stopped or suppressed."

But I don;t understand how? Doesn't regulation pathway X only involve tryptophan acting as a repressor and preventing gene three from being transcribed? How does it affect all the genes?

[doomdestroyer]

For this question (Attached below) the answer is: " The transcription of all genes is stopped or suppressed."

But I don;t understand how? Doesn't regulation pathway X only involve tryptophan acting as a repressor and preventing gene three from being transcribed? How does it affect all the genes?

The arrow from tryptophan is pointing to a group of arrows which point to each gene, it looks like it's pointing to just gene 3 but when you look more closely it's actually all genes that tryptophan acts on.

[grannysmith]

Also, how you would treat an autoimmune disease by injecting antibodies? What do these antibodies attack?

I'd presume that the injected antibodies attack the autoantibodies, thus preventing destruction of self cells.

[dankfrank420]

For this question (Attached below) the answer is: " The transcription of all genes is stopped or suppressed."

But I don;t understand how? Doesn't regulation pathway X only involve tryptophan acting as a repressor and preventing gene three from being transcribed? How does it affect all the genes?

Pretty sure this sort of shit isn't in the SD anymore

[Rishi97]

what is the difference between pathogens and antigens?

[soNasty]

what is the difference between pathogens and antigens?

Pathogen is any substance capable of causing an immune response.
An antigen is a substance found on the external surface of cells that our bodies recognise as foreign, stimulating an immune response, producing antibodies specific for that antigen

[chekside]

On the VCAA Unit 4 Exam 2011 for question 11 in MC, the answer they provide is C, however I thought it was D. Furthermore, the explanation they give indicates that the correct answer is D so which one is right?

[dankfrank420]

On the VCAA Unit 4 Exam 2011 for question 11 in MC, the answer they provide is C, however I thought it was D. Furthermore, the explanation they give indicates that the correct answer is D so which one is right?

The answer supports C?

[nerdmmb]

Can someone please help me with this question? It's from the sample exam from VCAA but the answers have not been provided.

Thanks!