VCE Biology Question Thread

[shivaji]

In cell-mediated immunity, where do the T-memory cells come from?
Is it that a Th cell activates a cytotoxic cell to divide, and some also  divide to memorcy cells as well?

[Reus]

yep no neg feedback, no  pos feedback, no homestasis, no blood/glucose, no more weird flowcharts to analyse

My weakness is no longer a weakness. 


Also does anyone know why at an older age (60 years old) does one's thymus gland has a reduced immune response with fewer T cells produced? Thanks heaps.

[kk.08]

I do the same, gibberellins starts with G - so is associated with growth and germination.
cytokinins starts with C - initiates cell reproduction
abscisic acid - 'scis' for 'scissors' - only one that inhibits growth

they sound a little silly but it helps for me!

Haha no way, that's amazingly helpful, thanks heaps!

[melons]

Also does anyone know why at an older age (60 years old) does one's thymus gland has a reduced immune response with fewer T cells produced? Thanks heaps.

T cells mature in the thymus. And the thymus reduces in weight/size as a person ages, so less T cells are able to mature.

[Reus]

T cells mature in the thymus. And the thymus reduces in weight/size as a person ages, so less T cells are able to mature.

So it's just a thing with age? The older you get the lighter your thymus becomes? Thus decreasing the number of The cells as there is less to produce? I'm just confused haha thanks

[RazzMeTazz]

Does the term stratigraphy just collectively refer to the principle of superposition and the principle of correlation?

[Reus]

Does the term stratigraphy just collectively refer to the principle of superposition and the principle of correlation?

Yes it's just a chronological order of age through startas

[vox nihili]

Ah yes, makes sense! Thank you

When was it removed? Also, do I have to know where insulin and glucagon are produced (pancreas)...well I guess this relates back to negative feedback mechanisms. It's just that I went to lectures (TSFX) and this stuff was all covered

Negative feedback was removed from the course in 2013. So when I did VCE Biol it figured quite heavily, but now they just want you to understand homeostasis (what homeostasis exactly is without feedback god only knows).

[Reus]

Are interferons from the second line of defence right?

[dankfrank420]

Are interferons from the second line of defence right?

Yes it is.

But why is this the case? I thought it would be a third-line defence as it is a response to a specific virus?

[vox nihili]

Yes it is.

But why is this the case? I thought it would be a third-line defence as it is a response to a specific virus?

They're not specific to particular viruses, they're general.

[melzwelz]

Is there a difference between "selection pressures" and "selective pressures"?

[flares]

gene expression vs gene regulation? explain please,
thanks

[althepal]

gene expression vs gene regulation? explain please,
thanks

Gene expression is the transcription and translation of genes to form a protein. Gene regulation is the switching on and off of genes to ensure that particular proteins are only produced when they're needed.

[flares]

Gene expression is the transcription and translation of genes to form a protein. Gene regulation is the switching on and off of genes to ensure that particular proteins are only produced when they're needed.

thanks, buddy