VCE Biology Question Thread

[FatimaEl]

In VCE bio land, is mitosis regarded as the division of a cell, or replication of a nucleus?

Cellular division

[plsbegentle]

Cellular division

Sorry for correcting u again, but mitosis is actually nuclear division. I remember thushan (atarnotes lecture) said  that mitosis was nuclear division and clearly told us to  never write cell division on the exam

[FatimaEl]

Sorry for correcting u again, but mitosis is actually nuclear division. I remember thushan (atarnotes lecture) said  that mitosis was nuclear division and clearly told us to  never write cell division on the exam

I was  about to write nuclear division but then i checked my textbook and it said cellular division, then again my book is kinda crap, so thanks for letting me know! 

[The Usual Student]

Sorry for correcting u again, but mitosis is actually nuclear division. I remember thushan (atarnotes lecture) said  that mitosis was nuclear division and clearly told us to  never write cell division on the exam

^^^^^ yeah I think you can attribute the actual division of cells to cytokinesis? or is that just the splitting of the membrane?

[plsbegentle]

^^^^^ yeah I think you can attribute the actual division of cells to cytokinesis? or is that just the splitting of the membrane?

yep the actual division of the cell is done by cytokinesis

[vox nihili]

My two bobs: mitosis is technically a nuclear division.

Division of the cell is a separate process called cytokinesis, as above

[Vaike]

Hi everyone,

Was just doing the 2013 exam and got a bit confused by this question. The answer states that boosters are used to produce more memory B cells, which I understood, but then goes on to also say memory B cells are short lived? I was under the impression the B memory cells last for a long time, and because of this they can provide immunity? Thanks

[sweetcheeks]

Hi everyone,

Was just doing the 2013 exam and got a bit confused by this question. The answer states that boosters are used to produce more memory B cells, which I understood, but then goes on to also say memory B cells are short lived? I was under the impression the B memory cells last for a long time, and because of this they can provide immunity? Thanks

Different B memory cells have different life spans. It also has to do with the amount produced during initial vaccination. Some vaccinations may produce less memory cells than others. If there are is a lower amount of B memory cells, they will reach the point where the amount is ineffective quicker than others.

[Sanaz]

Hi everyone,

Was just doing the 2013 exam and got a bit confused by this question. The answer states that boosters are used to produce more memory B cells, which I understood, but then goes on to also say memory B cells are short lived? I was under the impression the B memory cells last for a long time, and because of this they can provide immunity? Thanks

Hey there! I'm not sure if you want my help but I will offer it anyway (best to confirm with a ATARnotes lecturer as I'm a student). You are quite right in the fact that vaccinations stimulate an immune response which produces memory B cells as the antigen of the pathogen is present in the vaccine in a weakened form. The immune response usually lasts forever.

The first time you get the disease your immune response takes a longer time to fight the pathogen and the antibodies produced are lower. With your second exposure, the response is much larger and it takes a shorter time to get better. As you take more boosters, the response gets faster and quicker and larger just like if you were exercising at a sport or (studying for bio) 

The reason that boosters are needed for some vaccines such as (tetanus) is because of how fast the disease progresses once it is in the body. These diseases are quick and can cause fatal symptoms in a short amount of time. One vaccine isn't enough to

Boosters allow the body to keep a good memory of the virus, so the immune response can quickly recognise the invader and fight it off. With slower progressing diseases, the immune response does not have to be as quick because the symptoms won't be too serious for some time. The body can keep the viral memory "in the back of it's mind" because it has the time to search for it, release the correct antibodies, and destroy the virus before symptoms get too bad.

[Gogo14]

Does non dysjunction occur at anaphase 1 or 2 or both?

[Gogo14]

Also, can someone please explain why I got these multiple choices wrong clearly?

1. http://imgur.com/C41aRaB What and how does rearrangement of gene sequences relate to B cells?
2. http://imgur.com/HxkpKNx
3. http://imgur.com/BxcA01I
4. http://imgur.com/gDzaZBI I though the the light independent stage can occur in both light and dark?
5. http://imgur.com/pkMJESB

Sorry for long post

[The Usual Student]

Also, can someone please explain why I got these multiple choices wrong clearly?

1. http://imgur.com/C41aRaB What and how does rearrangement of gene sequences relate to B cells?
2. http://imgur.com/HxkpKNx
3. http://imgur.com/BxcA01I
4. http://imgur.com/gDzaZBI I though the the light independent stage can occur in both light and dark?
5. http://imgur.com/pkMJESB

Sorry for long post

1) Onion ROOT cells wouldn't need chloroplasts since they don't photosynthesis, the are under the ground and they don't recieve light. So chloroplasts are useless. Hence A was the right answer
2) The light independent reaction requires the light dependent reaction to work, the secondary reaction is dependent on the first hence it only works during the day

[FatimaEl]

Also, can someone please explain why I got these multiple choices wrong clearly?

1. http://imgur.com/C41aRaB What and how does rearrangement of gene sequences relate to B cells?
2. http://imgur.com/HxkpKNx
3. http://imgur.com/BxcA01I
4. http://imgur.com/gDzaZBI I though the the light independent stage can occur in both light and dark?
5. http://imgur.com/pkMJESB

Sorry for long post

• (question on pheromones) its a common misconception that pheromones are just for mating, rather they are hormones emitted by specific species that affect the behaviour of another member of the same species.
• (question on signal transduction) Since the two cells X and Y are neurons, as made evident by the info on reflex arc, then the signalling molecules would be neurotransmitters, and signal transduction for neurotransmitters takes place in the synapse between two neurons.

[Gogo14]

1) Onion ROOT cells wouldn't need chloroplasts since they don't photosynthesis, the are under the ground and they don't recieve light. So chloroplasts are useless. Hence A was the right answer
2) The light independent reaction requires the light dependent reaction to work, the secondary reaction is dependent on the first hence it only works during the day

Ok thanks, but I saw another paper saying that light independent occurs in both light and dark, so I'm not sure which oneis right

Thanks FatimaEl, so signal transduction can occur outside of cells?

[sweetcheeks]

Also, can someone please explain why I got these multiple choices wrong clearly?

1. http://imgur.com/C41aRaB What and how does rearrangement of gene sequences relate to B cells?
2. http://imgur.com/HxkpKNx
3. http://imgur.com/BxcA01I
4. http://imgur.com/gDzaZBI I though the the light independent stage can occur in both light and dark?
5. http://imgur.com/pkMJESB

Sorry for long post

To be able to manufacture different antibodies (which are proteins) B cells have the ability to modify their genes, which modifies the protein that will be produced.

The signal transduction pathway in the reflex arc involves a protein signalling molecule. The pathway commences when the molecule binds to the extracellular receptor on neuron, which is located in the synapse. It was asking where does the pathway commence i.e. where does the reception occur.