VCE Biology Question Thread

[Globe]

Do we need to know about phototropism and auxins? Thanks!

[C14M8S]

Should I say that T helper cells have antigens presented to them by macrophages or by dendritic cells? Also, they can encounter free antigens and proliferate based on them, correct?

[PhoenixxFire]

Do we need to know about phototropism and auxins? Thanks!

Nope

Should I say that T helper cells have antigens presented to them by macrophages or by dendritic cells? Also, they can encounter free antigens and proliferate based on them, correct?

I would just say APC but I think either would be fine (macrophages are probably better)
No, they have to be presented with their antigen on MHC, B cells can bind free antigens.

[Scribe]

assuming you mean a chromosomal inversion?

In this case yes as it could potentially decrease the production of viable gametes depending on the location of crossing over in meiosis.
Although I don't think you need to know this much detail.

Thanks! How about chromosomal translocations? My notes say "A person may experience a translocation and be phenotypically normal as the same genetic material is still present within the cell but in a different position." but I want to check.

[vox nihili]

I would just say APC but I think either would be fine (macrophages are probably better)
No, they have to be presented with their antigen on MHC, B cells can bind free antigens.

Might just add here that you should say antigen-presenting cell, not APC.

Would an inversion mutation have any adverse effects on the organism?

Yes, it would usually. An inversion happens when a big chunk of the chromosome gets flipped over. If the flip points are in the middle of a gene, half a gene could be moved to the other end of the chromosome.

Thanks! How about chromosomal translocations? My notes say "A person may experience a translocation and be phenotypically normal as the same genetic material is still present within the cell but in a different position." but I want to check.

Same idea as the inversion above (Sine's answer also perfectly correct too!).

[Sine]

Should I say that T helper cells have antigens presented to them by macrophages or by dendritic cells? Also, they can encounter free antigens and proliferate based on them, correct?

Dendritic since it's the best APC and initiates the adaptive immune response.
EDIT: As others have said just saying antigen presenting cell will probably be sufficient.

Thanks! How about chromosomal translocations? My notes say "A person may experience a translocation and be phenotypically normal as the same genetic material is still present within the cell but in a different position." but I want to check.

yes as long as the chromosome complement is balanced (all the genes are present and there are no duplications nor deletions) and no genes that are vital for life aren't disrupted they are phenotypically fine. However, they have reduced fertility, but still possible to have children.

[Bri MT]

Slightly off topic but please get some sleep PheonixxFire, you've got an exam tomorrow & we all want you to go into that your best self - even if that means other people answering bio questions here.

Please take care of yourself

[Globe]

Sorry for so many last minute questions >.< Anyways - in terms of an allergen coming into contact with a B lymphocyte, does that B lymphocyte have to come into contact with a T-Helper cell first before it undergoes clonal expansion (same as humoral i guess?)

[Hiea]

What would be a good definition for cultural evolution? Would "the transmission of non-genetic information through observation of or* active teaching" be okay, or is that too narrow?

*Oops! Thank you for pointing that out, miniturtle!

Sorry for so many last minute questions >.< Anyways - in terms of an allergen coming into contact with a B lymphocyte, does that B lymphocyte have to come into contact with a T-Helper cell first before it undergoes clonal expansion (same as humoral i guess?)

Yes; B-cells need to be stimulated by cytokines from Th cells before undergoing clonal expansion.

[Bri MT]

What would be a good definition for cultural evolution? Would "the transmission of non-genetic information through observation of active teaching" be okay, or is that too narrow?

Yes; B-cells need to be stimulated by cytokines from Th cells before undergoing clonal expansion.

That should be an "or" rather than "of" but once you've made that change should be good

[vox nihili]

Sorry for so many last minute questions >.< Anyways - in terms of an allergen coming into contact with a B lymphocyte, does that B lymphocyte have to come into contact with a T-Helper cell first before it undergoes clonal expansion (same as humoral i guess?)

Yeah it does. This is right on the edge of beyond VCE though

[PhoenixxFire]

Slightly off topic but please get some sleep PheonixxFire, you've got an exam tomorrow & we all want you to go into that your best self - even if that means other people answering bio questions here.

Please take care of yourself

I will, don't worry <3

I'm going to be so bored after tomorrow (I'm going to have to chase the 1/2 bio ppl and demand questions haha)

Might just add here that you should say antigen-presenting cell, not APC.

That's the second time today someone's pointed out that I'm being lazy with my typing

[AISHAB]

Could anyone briefly define validity,accuracy,precision,etc. From the scientific knowledge dot points. My definitions are all too similar.

[Sine]

Could anyone briefly define validity,accuracy,precision,etc. From the scientific knowledge dot points. My definitions are all too similar.

PF has answered a part of this a few hours ago

Validity: whether the experiment is measuring what it’s supposed to be measuring (ie. if it is actually measuring the effect of the IV on the DV)
Accuracy: how close your measurement is to the actual value of something (whether that be weight or length or whatever)

Precision: how close your experimental measures are from one another (this is important for random errors)

[kaylafvng]

hey! i'm going into bio 3&4 next year and i'm wondering if it's worth it to get the A+ notes? i'm talking about in terms of revision or as some kind of summary. thanks in advance.