VCE Biology Question Thread

[TheBigC]

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?

I have never seen a question requiring background on these dates... VCAA just wants you to be familiar with the geological time scale..
HOWEVER, it is likely handy to just make sure you are aware of the sequence with which life arose... (i.e. prokaryotic --> multicellular --> animal --> angiosperms etc.)

[Apricot]

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!

Thank you for your answers! Just a quick question, how come a few years ago VCAA said that a hormone is "a chemical compound produced in a cell. It either acts within the cell or diffuses or is transported to other cells where it brings about a specific response," this implying paracrine autocrine and endocrine signalling?

[Digi]

What do vcaa like to see w/ total number of ATP created in Aerobic Respiration?I don't want to get Nazi'd

[TheBigC]

Thank you for your answers! Just a quick question, how come a few years ago VCAA said that a hormone is "a chemical compound produced in a cell. It either acts within the cell or diffuses or is transported to other cells where it brings about a specific response," this implying paracrine autocrine and endocrine signalling?

Yeah, I know exactly what definition you are talking about - this could technically - given the vagueness of the definition imply both (i.e. paracrine signalling molecules diffuse between cells and initiate a specific response)... to be honest, if asked for the definition of a hormone - I would simply mention:
- Produced by a cell
- Transported between cells
- Act on specific target cells
- Initiate specific response.

Given that many different resources use the term 'hormone' interchangeably with 'signalling molecule', I wouldn't be too accurate in terms of the defintion (you cannot be sure which resources VCAA are using), hence, if VCAA are going to feed you vague definitions in past exams - I would also feed these similarly 'vague' definitions back... (NOTE: DO NOT try this with other types of questions, for example, in the 2016 VCAA Biology Exam, the level of detailed required for a transcription question increased relative to other years)

Hope this helps...

[smamsmo22]

Hi, a couple more questions!

1. Is the BMP4 protein produced by the BMP4 gene a DNA binding protein (transcription factor) or a signalling molecule which binds to other cells and initiates gene expression? And is it true that the BMP4 master regulatory gene regulates a suite of genes including regulatory and structural genes (or should we just focus on the structural ones)?

2. Does anyone have any tips for writing a hypothesis? Some exams recommend the basic one i.e. 'That an increase in (independent variable) will lead to an increase in (dependent variable)', but then some are more complicated like 'if (---) has an effect on (---), then (----). Sorry if that makes no sense but if anyone has a good general idea of what is required in a hypothesis it would be much appreciated.

Thanks!

[Seno72]

Hi, a couple more questions!

1. Is the BMP4 protein produced by the BMP4 gene a DNA binding protein (transcription factor) or a signalling molecule which binds to other cells and initiates gene expression? And is it true that the BMP4 master regulatory gene regulates a suite of genes including regulatory and structural genes (or should we just focus on the structural ones)?

2. Does anyone have any tips for writing a hypothesis? Some exams recommend the basic one i.e. 'That an increase in (independent variable) will lead to an increase in (dependent variable)', but then some are more complicated like 'if (---) has an effect on (---), then (----). Sorry if that makes no sense but if anyone has a good general idea of what is required in a hypothesis it would be much appreciated.

Thanks!

1) I'm not really sure on this question but I think when we are talking about how BMP4 is a master gene and controls the expression of other genes, we would talk about structural genes as the study design focuses on the beak shape and structure of Dareins finches.

2) For a hypothesis I would say an if....then statement. Sometimes I've seen Bio 3/4 papers asking these type of questions and then their answers are not a hypothesis but more like an aim.

E.g. For example I am monitoring the optimal temperature of an enzyme and I calculate this by the number of substrate produced at 30 mins. I would say: If the optimal temperature was 30 degrees, then a maximum (amount) of substrate is produced.

I'm not sure if this correct but this how I would do it.

[ezferns]

What are some reasons for a cell to induce apoptosis intrinsically?

What about extrinsically?

[PhoenixxFire]

What are some reasons for a cell to induce apoptosis intrinsically?

What about extrinsically?

Intrinsic: DNA damag eg due to UV.
Extrinsic: cell in wrong area eg. Lung cell in your hand.

[rainbowsparkles15]

Do cytotoxic T cells and Natural Killer cells stimulate the extrinsic apoptosis pathway?

[TheBigC]

Do cytotoxic T cells and Natural Killer cells stimulate the extrinsic apoptosis pathway?

Yup.
- T Cytotoxic cells do so through cell-to-cell signalling where a ligand on their surface (FasL) binds to the death receptor (FasR).
- NK cells also do so through cell-to-cell signalling. But, NK cells do so in the case of cells lacking or having an abnormal MHC marker (as far as I am aware)

[ezferns]

Would the case of Tc and NK cells inducing apoptosis through perforin and granzymes be considered intrinsic or extrinsic apoptosis? I'm thinking it leads to damage within the cell therefore it may cause the release of cytochromes which activate caspases therefore may be intrinsic.

[TheBigC]

What are some reasons for a cell to induce apoptosis intrinsically?

What about extrinsically?

Intrinsic:
- DNA Damage (i.e UV light)
- Mitochondrial damage
- Lacks of growth factors
- ER stress
Extrinsic:
- Cell is no longer needed (i.e.certain immune cells after immune response)
- Cell is worn out or damaged (i.e. cells lining intestine)
- Cell is cancerous (i.e. unable to initiate intrinsic pathway)

[M-D]

Do we need to know the different parts/sections of chromosomes such as centromeres, spindle fibers, sister chromatids?

Thanks

[TheBigC]

Do we need to know the different parts/sections of chromosomes such as centromeres, spindle fibers, sister chromatids?

Thanks

No. It is not in the study design...however, I would say it wouldn't hurt to know it as they may use that terminology in the exam to identify aspects of a question (MAYBE).

[vox nihili]

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)

Yeah I agree. I don’t think they’d expect you to know that and should have flagged it in my answer; good pick up