VCE Biology Question Thread

[vox nihili]

All are involved (as you say), but isn't it only mast cells (out of the options) that contribute to inflammation directly? I could be completely wrong, but I thought I may as well ask for my own clarification

Hmmmm gonna let the current VCE students answer this one.




The VCE definition of inflammation vs what is actually inflammation are pretty different unfortunately.

[solution]

During DNA hybridization, is the "melting" of DNA hybrid strands the heat needed to denature them into single strands?

[blacksanta62]

Hey guys, is there anything I should be aware of when reading and constructing phylogenetic trees?
-When dealing with allopatric speciation, is there anything I should be aware of?
I know these are quite broad questions but I've already had three SACs this week, 2 of which are week long, and one (chemistry) which I'll be doing tomorrow morning before my biology SAC.
-Also, is sympatric speciation in the study design?
Thank you

[solution]

Answer is A. I thought male ants, who are haploid (as they developed from a haploid egg) cannot produce sperm from meiosis as meiosis requires a diploid cell?

[plsbegentle]

Answer is A. I thought male ants, who are haploid (as they developed from a haploid egg) cannot produce sperm from meiosis as meiosis requires a diploid cell?

If they are developed from a unfertilised egg doesn't mean they are haploid.It means they reproduced through mitosis which produce genetically identical offspring.
Also all the other answers are completely wrong and u could probably eliminate all of them and get A.

[solution]

When part of a chromosome is translocated, can that segment be transcribed and translated into the same protein? Or does it depend on the gene and chromosome?

[88mimi12345]

To what extent should we know about plant regulation? Are there many questions about plant regulators in the current study design? Because so far I've only revised the functions of some of them. (eg. auxins, gibberellins, cytokinins, abscisic acid etc.) Thanks!

[Sine]

To what extent should we know about plant regulation? Are there many questions about plant regulators in the current study design? Because so far I've only revised the functions of some of them. (eg. auxins, gibberellins, cytokinins, abscisic acid etc.) Thanks!

for the 2013-2016 SD plant hormones is not examinable according to a Frequently asked questions post uploaded by VCAA - however it may still come up on the exam but they will give you the required information.

[88mimi12345]

When part of a chromosome is translocated, can that segment be transcribed and translated into the same protein? Or does it depend on the gene and chromosome?

I'm not 100% sure, please tell me if I'm wrong:
Translocations occur when a section of a chromosome breaks off and attaches to another non-homologous chromosome. When this occurs, normal control over the genes in that segment is lost, thereby disrupting gene function. This gene fusion can give rise to hybrid proteins, rather than the expected protein. So any breaks within a gene may cause alteration of its function, which will transcribe and translate into an abnormal protein, thereby resulting in some cancers, eg. Leukemia.

[88mimi12345]

for the 2013-2016 SD plant hormones is not examinable according to a Frequently asked questions post uploaded by VCAA - however it may still come up on the exam but they will give you the required information.

Thank you so much!!

[anotherworld2b]

Hi I wasn't sure where I should ask this but we were assigned a task to a essay on the controversy of embryonic stem cell research.
We were asked to refrain from being too opinionated and to do it like report but I wasn't sure if my draft attempt follows this requirement.
I've done a rough draft and was hoping if I could get feedback on whether if its not too opinionated for a essay like this.

Spoiler

Introduction:
Stem cells are special types of cells that are capable of differentiation. Embryonic stem cells are pluripotent stem cells that differentiate into all of the specific cell types that make up the human body. The use of embryonic stem cells has been highly-publicized and is controversial due to the fact the harvest of embryonic stem cells destroys the embryo. However, despite this controversy the potential stem cell holds to heal disease and ailments as well repair damaged tissue is evident from its unique properties: 
Being able to replicate to create many more stem cells through subculturing
Being able to grow into different types of cells throughout the body – liver, muscle, bone, nerve, etc when compared to other cells in the body.

The term ‘stem cell’ first appeared in scientific literature in 1868. Other key events in stem cell research include:

1978: Stem cells were discovered in human cord blood
1981: First in vitro stem cell line developed from mice
1988: Embryonic stem cell lines created from a hamster
1995: First embryonic stem cell line derived from a primate
1997: Cloned lamb from stem cells
1997: Leukaemia origin found as haematopoietic stem cell, indicating possible proof of cancer stem cells

One supporting point for embryonic stem cell research is that the production of replacement tissues and organs may save lives and alleviate suffering.Studying these cells would likely cause progress in cancer research. Embryonic stem cells are very similar to cancerous cells, "Gaining a better understanding of the molecular, biochemical and functional characteristics of cancer stem cells may lead to the development of more effective, precisely targeted treatments" (Norris par.7). This could change the lives of countless people around the world. Supporters of embryonic stem cell research argue that due to the special ability of embryonic stem cells there are numerous medical possibilities. These cells are undifferentiated, allowing them to be used in all parts of the body, giving them the potential to cure hundreds of diseases with the use of all of the different cells that can be created from them.

Whereas some people argue that embryonic stem cell research is relatively new meaning that we do not currently have a complete understanding of them. Embryonic stem cells and induced pluripotent stem cells can sometimes divide uncontrollably, forming tumors and growths made of unwanted tissues. In his study, Dr. David A. Prentice said, "Experiments at treating Parkinson's disease in animals gave a slight benefit, but also killed 20% of the animals with brain tumors caused by the embryonic stem cells" (Prentice par.4). This is a serious risk but with more research scientists can get a better understanding about these cells and likely reduce this statistic. This disadvantage is further supported by the fact that after twenty years of research, there are no approved treatments or successful human trials utilizing embryonic stem cells. Their tendency to produce teratomas and malignant carcinomas, cause transplant rejection and form random undirected types of cells are just a few of the hurdles that embryonic stem cell researchers still face. Many nations currently have governmentally-imposed restrictions on either embryonic stem cell research or the production of new embryonic stem cell lines. Because of their combined abilities of unlimited expansion and pluripotency, embryonic stem cells remain a theoretical potential source for regenerative medicine and tissue replacement after injury or disease.

Another supporting point is that adult stem cell research may take many years to produce practical uses.
The effectiveness of embryonic stem cell research is evidently greater than adult stem cell research due to the unique abilities embryonic stem cell possess. This point is further reinforced by the potential embryonic stem cell research can achieve when compared to the limited potential of adult stem cell research.The number of stem cells in an organ is limited; in bone marrow only one in every 10,000 to 15,000 cells is a stem cell.  Whereas, a conflicting point is that stem cell research is potential but may take many years many destroyed embryos. This is evident by fact that a single stem cell treatment will not work on a multitude of unrelated diseases or conditions.

Another advantage of stem cell research is that it uses surplus IVF embryos which would have been destroyed anyway. This is evident due to the fact the controversy of this research has placed restrictions on how embryos are ethically obtained. Embryonic stem cells are generally are taken from aborted fetuses or fertilized eggs that are left over from in vitro fertilization (IVF) that are voluntarily donated to research. These stem cells are useful for medical and research purposes because they can produce cells for almost every tissue in the body. Cells may be obtained by IVF and are often unused by donors.Whereas, a conflicting point is that routine destruction of embryos desensitising of value of human life. This conflicting point is supported by the fact that in most cases embryos used are seen as sources that can be used to experiment on just like any other substance or equipment. This is supported by the statistic that a research process called Somatic Cell Nuclear Transfer [SCNT] allows scientists to produce embryonic stem cells without using sperm to fertilize an egg. The application of this process desensitises the purpose of reproduction and the value of embryos.Some embryonic stem cell lines also come from embryos that a couple has chosen not to implant because they carry genetic mutations like the ones that cause cystic fibrosis or Tay Sachs disease. This could increase sense of playing God in deciding whether an embryo is allowed to live or die.

Embryonic stem cell research is an evident controversial topic which has various advantages and disadvantages. It is dependent on the viewpoint of particular individuals that influence their perception towards embryonic stem cell should be permitted or not.

Stem cells could also be used to gain a better understanding of how genetics work in the early stages of cell development. This can help scientists understand why some cells develop abnormally and lead to medical problems, such as birth defects and cancer. In the future, scientists may be able to prevent some of these diseases such as Parkinson's disease, or even a severed spinal cord which would’ve been untreatable.
Stem cells may also be useful in the testing and development of drugs. Because stem cells can be used to create unlimited amounts of specialized tissue, such as heart tissue, it may be possible to test how medicines react on such tissues before testing the medicines on animals and humans. Medicines could be tested for effectiveness and side effects more rapidly.

[plsbegentle]

Hey! Does anyone have a spare ticket for the bio 3/4 lectures??

[Hydroxyl]

Hey guys! I'm confused about this U3 Question:

The question states:

10)
The following equation represents the overall process of photosynthesis.

6CO2 + 6H2O — — — —> C6H12O6 + 6O2

The function of water in this process is to:


A) Combine with CO2.
B) Absorb Light Energy.
C) Provide O2 for the light independent reaction.
D) Supply High Energy Electrons in the Light-Dependant Reaction.


The model answer is D.

Here is where I am confused + my reasoning:

A) Water does not combine with carbon dioxide because the water is split by light and the oxygen diffuses. The H+ ions are then passed on to the Light Independent Reaction.

B) Water does not absorb light energy - chlorophyll does.

C) Oxygen diffuses at this stage. The oxygen from Carbon Dioxide is the source of oxygen in the Light Independent Reaction.

D) Doesn’t the “High energy electrons” get passed on to the Light Independent Reaction and not the Light Dependant Reaction? ATP and NADH are the only products that are carried into the Light Independent Reaction.

This could possibly be a typo, but I’m not sure.

Thanks Everyone

[vox nihili]

Hey guys! I'm confused about this U3 Question:

The question states:

10)
The following equation represents the overall process of photosynthesis.

6CO2 + 6H2O — — — —> C6H12O6 + 6O2

The function of water in this process is to:


A) Combine with CO2.
B) Absorb Light Energy.
C) Provide O2 for the light independent reaction.
D) Supply High Energy Electrons in the Light-Dependant Reaction.


The model answer is D.

Here is where I am confused + my reasoning:

A) Water does not combine with carbon dioxide because the water is split by light and the oxygen diffuses. The H+ ions are then passed on to the Light Independent Reaction.

B) Water does not absorb light energy - chlorophyll does.

C) Oxygen diffuses at this stage. The oxygen from Carbon Dioxide is the source of oxygen in the Light Independent Reaction.

D) Doesn’t the “High energy electrons” get passed on to the Light Independent Reaction and not the Light Dependant Reaction? ATP and NADH are the only products that are carried into the Light Independent Reaction.

This could possibly be a typo, but I’m not sure.

Thanks Everyone

Good question. This is really tricky stuff.

Also, awesome work for providing your reasoning.




Energy from light is used to split water into hydrogen ions and oxygen, which also liberates some electrons too. These electrons are fed into an electron transport chain (still light-dependent), which is used to make the ATP that is then passed onto the light-independent reaction.

TL;DR: bust water open with light, electrons wizz around to make ATP

[Hydroxyl]

Good question. This is really tricky stuff.

Also, awesome work for providing your reasoning.




Energy from light is used to split water into hydrogen ions and oxygen, which also liberates some electrons too. These electrons are fed into an electron transport chain (still light-dependent), which is used to make the ATP that is then passed onto the light-independent reaction.

TL;DR: bust water open with light, electrons wizz around to make ATP

Thank You! This makes sense

I chose the correct answer but then re-read it and my mind went into a frenzy.

Once again, Thank You!