VCE Biology Question Thread

[chekside]

For question dii in the attached image, why would the answer be 1/3 and not 2/3? I understand that a 9/18 and a 9 chromosome express a normal phenotype, but why wouldn't a sole 9/18 chromosome also express a normal phenotype-all the genes are still present? Thanks!

Because the question says the same kind of translocation. As the father's translocation was the 9/18 and a 9 chromosome, the sole 9/18 chromosome isn't the same kind of translocation that the father had.

[vox nihili]

Can antibodies attack cells? Because in autoimmune disorders and alike, autoantibodies are produced which attach self-cells such as myelin etc...
If they do, then what's the point of Tc cells?

Autoantibodies attack cells that you don't want to be attacked. They attack self molecules, whereas T_C cells only respond to non-self (expressed on MHC Class I)

[katiesaliba]

Because the question says the same kind of translocation. As the father's translocation was the 9/18 and a 9 chromosome, the sole 9/18 chromosome isn't the same kind of translocation that the father had.

I overthought that way too much ahahaha thank you

[katiesaliba]

Are we required to know about how organisms can alter their surface proteins?

[grannysmith]

Are we required to know about how organisms can alter their surface proteins?

Nah, not how but usually why they do and what it entails.

What's a good definition for a hormone without being specific?
Right now I've got: a chemical messenger produced by a cell, which brings about a specific response in a cell that has specific receptors to which the hormones binds.

I want to take into account the different types of hormone signalling (autocrine, paracrine, endocrine). So I guess the the commonalities between the different types is that a) it's a chemical messenger b) binds to specific receptors c)induces a specific response.
It wouldn't be quite accurate to say that they're released into the extracellular fluid of the cell, right?

[vox nihili]

Are we required to know about how organisms can alter their surface proteins?

Don't even need to know that they do it quite frankly.

[grannysmith]

In experimental design questions, does the control group have to be given a placebo, or is simply not giving them substance X enough?

[psyxwar]

In experimental design questions, does the control group have to be given a placebo, or is simply not giving them substance X enough?

Give them a placebo

[shivaji]

Is the difference between comparative genomics and comparison of DNA sequences that comparative genome compares the whole genome between species whilst comparison of DNA sequences is just the comparison of parts of the genome?

[RazzMeTazz]

When using molecular studies such as comparing amino acid sequences , DNA-DNA hybridisation,  do these show divergence from a common ancestor or simply just close relatedness not necessarily divergence?

[DJA]

Good definition for Independent Assortment?
thanks in advance!

[howlingwisdom]

Good definition for Independent Assortment?
thanks in advance!

I'll give it a crack: The random alignment of homologous pairs of chromosomes during metaphase I

[shivaji]

Good definition for Independent Assortment?
thanks in advance!

The arrangment of a pair of homologous chromosomes during meiosis (metaphase 1) is not influenced by the arrangement of other homologus chromosomes.

[katiesaliba]

I understand that mast cells are involved in innate defence, however does their degranulation during allergic reactions still count as non-specific? After all, a specific antigen is required for the degranulation process to occur...

Do we have to know the functions of the stroma and thylakoid (aside from being the sites of light dependent/independent photosynthesis)?

Are glycoproteins often receptor molecules?

Do we have to know about why plants wilt?

A TSSM exam stated that cell-mediated immunity involves NK cells, but I thought that NK cells were involved only in innate responses (even though they are lymphocytes)? Can someone please clarify?

[Russ]

Mast cells will degranulate in response to many different antigenic stimuli, which makes them nonspecific

Cell mediated immunity is not the same thing as the innate response, they're different things. CMI is just a response generated by cells