VCE Biology Question Thread

[chrisjudd00]

Hi. I was just wondering whether BMP4 regulates length and width of beak size, or if we need to talk about CAM when it comes to finch beak length?

Thanks in advance 

[TheBigC]

Modern day Africans don't have any Neanderthal DNA as the hominin population that remained in Africa and did not migrate, were unable to cross paths with other hominins such as Homo Neanderthalensis and therefore could not interbreed with them. Other races of modern humans would have Neanderthal DNA as the Homo sapiens that did migrate out of Africa had interbred with Homo neanderthalensis.

EDIT: Neanderthal ancestors had left Africa before Homo sapiens evolved according to a STAV paper.
Someone please correct me because I'm not 100 percent certain.

Yeah, the STAV paper is correct. H. neanderthalensis evolved prior to H. sapiens and hence were able to migrate out of Africa (entirely - ALL H. neanderthalensis populations) prior to the evolution of H. sapiens. When H. sapiens had evolved ONLY the populations that left Africa and co-existed in terms of space and time with H. neanderthalensis actually interbred (i.e. European populations etc.)

[rainbowsparkles15]

Which lymphocytes attack the myelin sheath of nerve cells in Multiple Sclerosis?

[Jackie Chan]

Which lymphocytes attack the myelin sheath of nerve cells in Multiple Sclerosis?

Cytotoxic T cells attack the myelin sheath

[Nomi16]

Can anyone please answer this question:
If a child is suspected of having measles, a serum sample is taken and tested for measles-specific IgM and IgG antibodies.
What conclusions could be made if high levels of these antibodies were found and what action would be taken?

[Jackie Chan]

Can anyone please answer this question:
If a child is suspected of having measles, a serum sample is taken and tested for measles-specific IgM and IgG antibodies.
What conclusions could be made if high levels of these antibodies were found and what action would be taken?

If high levels of antibodies were found, it means that the child must have the measles and therefore you would most likely want to isolate them from others to prevent the spread of the disease.

[M-D]

Hi all,

Which types of speciation do we need to know? Allopatric only?

[Apricot]

Can somebody please answer a few of my questions

1) Are paracrine, autocrine, juxtacrine signalling molecules considered hormones, or are hormones only endocrine (some old vcaa exams say that endocrine isnt only type of hormone)
2) In terms of defining autoimmune disorder, should we say self antigens are recognised as non self or self cells are recognised as non self?
3) What do they mean by "types of treatments" in the study design dotpoint, asides from vaccinations, antivirals/antibiotics, what else could this encompass?
4) In the 2015 VCAA exam, q7c asks "how the same genetic sequence could lead to distinct proteins in different cell types" and the answer suggests that it is due to factors expressed by regulatory genes causing this. However, on the previous page, it discusses how the hormone causing this binds upstream to one specific gene (growth hormone gene), so if one gene causes different proteins to be produced, would discussing alternative splicing and exon juggling causing different proteins in each cell suffice as an answer?
5) If we had to discuss the autoimmune response for multiple sclerosis, do we discuss the myelin sheath being destroyed or the oligodendrocytes?

Extremely sorry for the long questions but I would appreciate it if someone could answer. Thank you!

[Apricot]

Hi all,

Which types of speciation do we need to know? Allopatric only?

Study design specifies allopatric only

[TheBigC]

Can anyone please answer this question:
If a child is suspected of having measles, a serum sample is taken and tested for measles-specific IgM and IgG antibodies.
What conclusions could be made if high levels of these antibodies were found and what action would be taken?

Okay... now - by 'child' I am assuming you mean a 'baby'... because it wouldn't really make any sense for a question to be so randomly specific.
Assuming you mean 'baby'... If high IgG antibodies are found, it might signify that the mother had measles (as IgG crosses the placenta) and hence the baby was not affected during the pregnancy, however if high IgM was found (which does NOT cross the placenta), then the baby likely had measles and produced specific antibodies against the measles virus. (which may be an issue if this occurred during pregnancy as it could affect the baby's development)

[vox nihili]

Okay... now - by 'child' I am assuming you mean a 'baby'... because it wouldn't really make any sense for a question to be so randomly specific.
Assuming you mean 'baby'... If high IgG antibodies are found, it might signify that the mother had measles (as IgG crosses the placenta) and hence the baby was not affected during the pregnancy, however if high IgM was found (which does NOT cross the placenta), then the baby likely had measles and produced specific antibodies against the measles virus. (which may be an issue if this occurred during pregnancy as it could affect the baby's development)

It could still be a child....


High IgM means that the infection is recent/active.
IgG could mean that the child was immunised as a baby or had measles in the past.

[lowkeyloco11]

For the study design dot point: •significant changes in life forms and earths geological history including rise of multicellular organisms ect
Do we have to the specific eras, periods, epochs and do we have to know the age of them ect 145 million years ago?

[cookiedream]

Hi. I was just wondering whether BMP4 regulates length and width of beak size, or if we need to talk about CAM when it comes to finch beak length?

Thanks in advance 

CAM is not specified in the study design. BMP4 is definitely mentioned. BMP4 affects the depth/width of the beak (i.e. the greater the BMP4 gene expression, the wider the beak is for Darwin's Finches). For cichlids, higher BMP4 expression confers a shorter jaw with small, close-spaced teeth while reduced expression causes an elongated jaw with larger, widely spaced teeth.

(I copied these from my notes, so I don't think you should memorise the exact effects of the BMP4 gene. Just know its role as a master regulatory gene which affects the expression of multiple genes during embryonic development)

[TheBigC]

Can somebody please answer a few of my questions

1) Are paracrine, autocrine, juxtacrine signalling molecules considered hormones, or are hormones only endocrine (some old vcaa exams say that endocrine isnt only type of hormone)
2) In terms of defining autoimmune disorder, should we say self antigens are recognised as non self or self cells are recognised as non self?
3) What do they mean by "types of treatments" in the study design dotpoint, asides from vaccinations, antivirals/antibiotics, what else could this encompass?
4) In the 2015 VCAA exam, q7c asks "how the same genetic sequence could lead to distinct proteins in different cell types" and the answer suggests that it is due to factors expressed by regulatory genes causing this. However, on the previous page, it discusses how the hormone causing this binds upstream to one specific gene (growth hormone gene), so if one gene causes different proteins to be produced, would discussing alternative splicing and exon juggling causing different proteins in each cell suffice as an answer?
5) If we had to discuss the autoimmune response for multiple sclerosis, do we discuss the myelin sheath being destroyed or the oligodendrocytes?

Extremely sorry for the long questions but I would appreciate it if someone could answer. Thank you!

1. As far as I am aware, the ONLY* type of hormones are endocrine... *EXCEPT, in terms of plant HORMONES (/ plant growth regulators) that do not use endocrine signalling (due to lack of bloodstream). The autocrine, paracrine and juxtacrine/cell-to-cell/contact-dependent signalling all merely involve 'signalling molecules'. Now, a piece of evidence that strengthens what I have just stated is that neurotransmitters are classified under paracrine signalling... which most definitely is NOT a group of hormones....

2. Definitely say ANTIGENS. Immune cells do not recognise other CELLS per se, but rather recognise other cell's antigens. In autoimmunity, these antigens are identified as NON SELF and an immune response is mounted against cells containing these ANTIGENS.

3. This would encompass the types of treatments against pathogens, which I would suspect would involve vaccinations and antibiotics/antivirals as you mentioned.... however, this is one of those vague dot points where I could only guess... maybe: antimycotics, antihelminths... not sure to be honest... maybe even monoclonal antibodies.. I really wouldn't sweat it..

4. Yeah.. I have encountered this question multiple times with different people. I also agree with your answer (an answer that many other people also believe is correct). Their answer is far too vague - I have actually answered this question a few pages back - however, I made the assumption that there was more than one GRE binding site (in an attempt to make logic of the VCAA answer). But I most definitely believe that the BEST answer involves mention of alternative splicing or exon juggling. (By the way - be careful, the question only made mention of the GRE being upstream of the GH gene, not the 'specific' GH gene - a subtle difference).

5. Both would technically be correct answers., however, within the scope of the study design just mention the myelin sheath.

Good luck!

[TheBigC]

It could still be a child....


High IgM means that the infection is recent/active.
IgG could mean that the child was immunised as a baby or had measles in the past.

Thanks for the insight.
In the scope of the study design, however, I doubt VCAA would expect that level of depth, but merely wants students to recognise IgG as signifying crossing placenta, and IgM as active immunity (as opposed to passive).

I could however be wrong.. what do you think?

NOTE: I did a quick google search on the question asked (as I recognised it upon the mention of IgM and IgG from a past VCAA question (which actually instigated me to believe he/she meant 'baby' and not 'child')) and found it in the 2012 Biol Exam 1 - Q18 multiple choice... (it is referring to a baby) (Further NOTE: This may not be the question.. just a coincidence)