VCE Biology Question Thread

[ravi2]

For the current biology design, do we have to know about primary/ secondary hosts? Also, do we have to know the nitty gritty about all the individual types of pathogens or will just an overview of each suffice? And lastly, are all the action potential and the repolorisation/depolarisation material examinable?

Thanks hepas

[katiesaliba]

Is there a specific reason as to why the origin occurs in the middle of a replication bubble rather than at replication forks? Just seems a bit random ahah 

[vox nihili]

Is there a specific reason as to why the origin occurs in the middle of a replication bubble rather than at replication forks? Just seems a bit random ahah 

The replication fork moves though... So it can't be an origin because it's not fixed. A replication bubble is created because helicase is unwinding the DNA in both directions.

[nhmn0301]

Hi, can someone explain to me what does "mRNA hybridising" mean? Thanks!

[ravi2]

Hey I'm sorry to ask a simple question but one of the questions which I came across in a STAV pass paper asked:
"name the class of chemicals to which this biomacromolecule belongs." The answers said carbohydrate or cellulose, but I said polysaccharide. Does anyone know why polysaccaride is wrong in the context of this question?

Thanks heaps:)

[alchemy]

Hey I'm sorry to ask a simple question but one of the questions which I came across in a STAV pass paper asked:
"name the class of chemicals to which this biomacromolecule belongs." The answers said carbohydrate or cellulose, but I said polysaccharide. Does anyone know why polysaccaride is wrong in the context of this question?

Thanks heaps:)

Polysaccharide is an example of a carbohydrate. They're rather looking for the category (which they term 'class of chemicals') that a biomacromolecule belongs to. So therefore, the answer can be simply 'carbohydrate' as a biomacromolecule can indeed a carbohydrate. It also depends on the question since you haven't showed us what "this" biomacromoleule is...I assume there might've been a diagram of some sort for this question.

[ravi2]

Polysaccharide is an example of a carbohydrate. They're rather looking for the category (which they term 'class of chemicals') that a biomacromolecule belongs to. So therefore, the answer can be simply 'carbohydrate' as a biomacromolecule can indeed a carbohydrate. It also depends on the question since you haven't showed us what "this" biomacromoleule is...I assume there might've been a diagram of some sort for this question.

thanks for your help! sorry for not specifying the "this" which was a diagram of cellulose

[nhmn0301]

In a practice exam,
Lyme disease is transmitted to humans through the bite of infected ticks.
The western fence lizards have been found to affect the occurrence of Lyme disease by reducing it when the lizards are found in an area.
What might be a possible explanation?

My answer: western fence lizards eat the ticks and have special immunity that humans don't have to the pathogen that causes Lyme disease. Hence, they are not infected and decrease the number of infected ticks.
Solution: The western fence lizard produces a substance (protein) that kills the bacterium that causes Lyme disease. This is passed on when the ticks bite the western lizard (I still don't get what this solution is trying to say??!! I mean, they produce protein that kills the bacterium, then what? )
My answer is  quite different from the solution but I still want to know if mine would make sense and gain some marks?
Thanks!

[grannysmith]

Perhaps the protein produced are antibodies specific to the bacteria and by biting the lizards, the infected ticks gain (passive) immunity.

[nhmn0301]

Perhaps the protein produced are antibodies specific to the bacteria and by biting the lizards, the infected ticks gain (passive) immunity.

So we can gain immunity by bitting?? Company exams are so douchey . Thanks anw!

[grannysmith]

Haha, I wouldn't recommend it LOL. I'm not too sure though.

[Scooby]

In a practice exam,
Lyme disease is transmitted to humans through the bite of infected ticks.
The western fence lizards have been found to affect the occurrence of Lyme disease by reducing it when the lizards are found in an area.
What might be a possible explanation?

My answer: western fence lizards eat the ticks and have special immunity that humans don't have to the pathogen that causes Lyme disease. Hence, they are not infected and decrease the number of infected ticks.
Solution: The western fence lizard produces a substance (protein) that kills the bacterium that causes Lyme disease. This is passed on when the ticks bite the western lizard (I still don't get what this solution is trying to say??!! I mean, they produce protein that kills the bacterium, then what? )
My answer is  quite different from the solution but I still want to know if mine would make sense and gain some marks?
Thanks!

Dodgy question - you wouldn't be expected to deduce that. Your answer would get marks. I probably wouldn't use the term "special immunity" though - just mention that the western fence lizard is resistant to infection by the bacteria that cause Lyme disease

[The Usual Student]

If something is soluble in water does that make it insoluble in lipids vice versa?
Does that make starch soluble in liupd s

[Rishi97]

If something is soluble in water does that make it insoluble in lipids vice versa?
Does that make starch soluble in liupd s

Yes, if something is water soluble, then it means that it is lipid insoluble. I also do chemistry so I think of it as functional groups. If a molecule has many OH- groups, it only means that is is soluble in water.
Ummm, not quite sure about your other question. I would say no.... but could someone please correct me.
Hope this helps

[lzxnl]

Ethanol is soluble in water and in lipids
Solubility is a spectrum