VCE Biology Question Thread

[vox nihili]

Their answer is also attached, it is the second image along with the percentage of students who answered correctly. xD

Whoops, sorry!

I think your answer would probably pick up the marks, though the answer provided by VCAA is technically wrong.

[cosine]

Whoops, sorry!

I think your answer would probably pick up the marks, though the answer provided by VCAA is technically wrong.

But why is it wrong? Is it just because the receptors on the immune cells recognise the antigens on the MHC markers, and not recognise the markers?

[Biology24123]

What do we need to know regarding human evolution

Characteristics distinguishing hominids from primates
Traits defining primates
Cultural evolution
Anything else

Do we actually need to know names of primates apart fro genus?

[Biology24123]

But why is it wrong? Is it just because the receptors on the immune cells recognise the antigens on the MHC markers, and not recognise the markers?

Yeah, that's why it's wrong

[heids]

What do we need to know regarding human evolution

Characteristics distinguishing hominids from primates
Traits defining primates
Cultural evolution
Anything else

- Definitely the general trends from early homo to homo sapiens - like skull structure and size, changes in hands and feet, etc., but mainly skull changes. 
- General knowledge of the main homo species and their general order (basic ones, like erectus, habilis and neanderthalensis etc.)
- Features that show bipedalism.

With cultural/technological evolution and primate/homonoid features, think that's about it.

Do we actually need to know names of primates apart fro genus?

Do you mean hominins?  With primates, you don't need to know anything, but with hominins, you just need to know their species name. 

(Apologies, I'm really backward in this section of the course because it interests me least, so.  Woops.)

[StupidProdigy]

I'm a bit confused about desensitization to allergens..from vcaa "The injected antigens react with particular antibodies already present in an individual. Removal of these antibodies means they are unavailable for involvement in an allergic reaction should the person come into contact with the allergen again." The first sentence I don't get because if they react then wouldn't this cause the allergic response? and if it's referring to different antibodies (not the IgE's) then why does it react with them instead of the IgE's? cheers

edit: so once an antigen binds to an antibody, does that antibody just stay there and do nothing? Like after an allergic response has occured due to a particular mast cell, will the antibodies on this mast cell that caused the response just stay attached to the mast cell with the old antigen fragments, meaning it's basically useless?

[Sine]

• hominin evolution:
– shared characteristics which define primates, hominoids and hominins
– major trends in hominin evolution from the genus Australopithecus to the genus Homo including
morphological, structural and cognitive development resulting in cultural evolution and the
rise of technologies

Just wanted to clarify some understanding directly from the study design.

– shared characteristics which define primates, hominoids and hominins

Features that are solely for that group of organisms not shown in any other.

– major trends in hominin evolution from the genus Australopithecus to the genus Homo including
morphological, structural and cognitive development resulting in cultural evolution and the
rise of technologies

Change, either increase or decrease of prominence of a feature. e.g decreased prominence of brow ridge/smaller teeth/larger brain capacity
Cognitive development I'm not too sure about this one; increased intellectual capabilities resulting in ceremonies/burials. All in relation from Australopithecus--->Homo
Do we need to know about the specific species of Australopithecus and the differences between them and the differences between various homo species?
Cultural/Technological-Use of symbols, art & language. What exactly do we need to know or understand about technological evolution

[cosine]

Are we required to know certain features of certain Primate ancestors?

[Jay.C]

Is probing the only technique for determining if a gene is present in an organism.

[BakedDwarf]

Are we required to know certain features of certain Primate ancestors?

I think we are required to know some distinguishing features of primates, such as:
- 3D binocular and colour vision
- Nails instead of claws
- Large brain size relative to body size
- Opposable thumbs
- Flexible skeletons and arms that can rotate in their sockets which lead to their arboreal lifestyle

[cosine]

I think we are required to know some distinguishing features of primates, such as:
- 3D binocular and colour vision
- Nails instead of claws
- Large brain size relative to body size
- Opposable thumbs
- Flexible skeletons and arms that can rotate in their sockets which lead to their arboreal lifestyle

Where can I get the information and comparisons? My textbook does not include anything of this.

Also, a question asks:

Suggest why plasmids were not used instead of a retrovirus for gene therapy?
I said because plasmids dont actually incorporate their genes into the DNA of the liver cells, and hence will not be as effective, as viruses actually incorporate their DNA into the DNA of the patient, and this DNA will undergo replication and new cells formed will also possess this genotype and hence phenotype. Would this be true?

[vox nihili]

Where can I get the information and comparisons? My textbook does not include anything of this.

Also, a question asks:

Suggest why plasmids were not used instead of a retrovirus for gene therapy?
I said because plasmids dont actually incorporate their genes into the DNA of the liver cells, and hence will not be as effective, as viruses actually incorporate their DNA into the DNA of the patient, and this DNA will undergo replication and new cells formed will also possess this genotype and hence phenotype. Would this be true?

Not really true but part of me suspects that this is the answer the authors were looking for.

Assuming this is what they wanted, it could be a good idea to think about why it is better to insert the DNA into the genome other than let it float around the cytoplasm. If you're stuck, ask.

[cosine]

Not really true but part of me suspects that this is the answer the authors were looking for.

Assuming this is what they wanted, it could be a good idea to think about why it is better to insert the DNA into the genome other than let it float around the cytoplasm. If you're stuck, ask.

What do you mean not true? How is it not true, are you saying that plasmids incorporate their DNA into the original cell's DNA? (We are talking about humans).

Is it because if the plasmid floats around, it won't really express the genome in the cell, right? As it has no instructions etc..? Like yeh, it has the required DNA segment incorporated into it, but what's the point when it does not express the phenotype of it?

[vox nihili]

What do you mean not true? How is it not true, are you saying that plasmids incorporate their DNA into the original cell's DNA? (We are talking about humans).

Is it because if the plasmid floats around, it won't really express the genome in the cell, right? As it has no instructions etc..? Like yeh, it has the required DNA segment incorporated into it, but what's the point when it does not express the phenotype of it?

I know that we're talking about humans. It is not out of the realm of possibility that plasmid DNA be taken up by the genomic DNA. In fact, it happens quite frequently in bacteria. The issue in humans is that the efficiency of such delivery is very, very low indeed

The issue with the plasmid is that it typically just sticks outside of the nucleus. Retroviruses find ways to get their genome (after being turned into vDNA) into the nucleus so that it can be integrated.

[banaidil]

first time asking a question and it might be a dumb one  but i still don't really understand a proteome, can you please explain it to me. thanks