VCE Biology Question Thread

[Reus]

yes, it would still be correct. 'B lymphocyte' is just the fancier, and more complicated word for 'B cell', just like 'immunoglobulin' is the fancier, more complicated word for 'Antibody'

Thanks!!

What is the difference between MHC markers and antigens?

Did you mean antibody? Since they are quite similar. Nonetheless, MHC markers are proteins that are on a cell which indicates to the organism's immune system that it is a self cell. Examples of cells with MHC markers include macrophages, B cells and dendritic cells. An antigen are also proteins, an agent; pathogen, that 'binds' to an antibody, initiating a immune response.

However MHC markers, in the instance of an organ transplant can go under 'attack' as they are recognised as non-self cells as that organ does not possess the appropriate MHC markers.

[Reus]

do we need to know about desmosomes and tight junctions and all that stuff

I remember my teacher saying that it's not examinable, however may pop up in company-based trial exams.

sweet.
Do protein based hormones trigger a faster response based on the fact that their receptors are located on the surface of the cell? Whereas lipid-soluble hormones have to travel within the cytosol and attach to the appropriate cytoplasmic receptor?

Also.. with blood typing, is Type O considered the universal donor because it possesses both antibody A and B in its plasma, but no antigens on its surface? Whereas AB is the universal recipient, because it possesses both antigens A and B on RBC's surface, with no A and B antibodies in plasma?

What are the functions of the antibodies in plasma though? Wait.. (im thinking while asking this)
Since Blood type A carries antibodies for B blood, and since A blood cannot be donated to someone with B blood... hmmm
So, if a blood type possesses antibodies for another blood type in its plasma, it cant be donated to it?

Confusing lol

Pretty much. Just know that people with blood types A or B can accept blood from a person with type O.

[chekside]

In the VCAA 2013 exam for question 4c the answer says that regular boosters are required because memory cells are short lived, I thought memory cells had a long lifespan, sometimes lasting for life, so can anyone clarify this?

[flares]

Does anyone have a list of definitions and functions for the 5 type of immunoglobulins?
-IgG
-IgA
-IgM
-IgE
-IgD

Thanks

[howlingwisdom]

In the VCAA 2013 exam for question 4c the answer says that regular boosters are required because memory cells are short lived, I thought memory cells had a long lifespan, sometimes lasting for life, so can anyone clarify this?

I think that there are certain memory cells that do last for a while (a few decades) and others that do not last as much.

[shivaji]

Did you mean antibody? Since they are quite similar. Nonetheless, MHC markers are proteins that are on a cell which indicates to the organism's immune system that it is a self cell. Examples of cells with MHC markers include macrophages, B cells and dendritic cells. An antigen are also proteins, an agent; pathogen, that 'binds' to an antibody, initiating a immune response.

So does this mean that all makers which are "self" are MHC markers? So there is only one type of antigen - the foreign antigen which causes an immune response, but you do not refer to the markers on your own cells as antigens?

pls clarify:)

[Reus]

Does anyone have a list of definitions and functions for the 5 type of immunoglobulins?
-IgG
-IgA
-IgM
-IgE
-IgD

Thanks

-IgG - Has a life span of 21 days, mostly circulating antibodies and function in agglutination and complement activation.
-IgA - Has a life span of 6 days, found in external secretions, tears, saliva and milk. Functions as mucosal immunity.
-IgM - Has a life span of 10 days, produced early in infection response and function in agglutination and complement activation.
-IgE - Has a life span of 2 days, produced in allergic reactions and attaches to mast cells.
-IgD - Has a life span of 3 days, located on the surfaces of antibody-producing cells (B lymphocytes)  and are responsible for the development of antibody response.

The SD doesn't explicitly say to know these. However IgD and IgE are two I would make sure I knew.

[vox nihili]

-IgG - Has a life span of 21 days, mostly circulating antibodies and function in agglutination and complement activation.
-IgA - Has a life span of 6 days, found in external secretions, tears, saliva and milk. Functions as mucosal immunity.
-IgM - Has a life span of 10 days, produced early in infection response and function in agglutination and complement activation.
-IgE - Has a life span of 2 days, produced in allergic reactions and attaches to mast cells.
-IgD - Has a life span of 3 days, located on the surfaces of antibody-producing cells (B lymphocytes)  and are responsible for the development of antibody response.

The SD doesn't explicitly say to know these. However IgD and IgE are two I would make sure I knew.

You really don't need to know any. If you're going to know one, know that IgE is found on mast cells. You certainly don't need to know about IgD, because that's the one that we know least about.

[Reus]

You really don't need to know any. If you're going to know one, know that IgE is found on mast cells. You certainly don't need to know about IgD, because that's the one that we know least about.

Thanks for that!

[Reus]

For this question, I presumed that the heterozygous plant would be BbGg, being a normal stalk yellow. However it's normal stalk green. It says that green (g) is recessive to yellow (G).
Does this not mean G, yellow is dominant? Unless there is a typo on the assessors report? Haha

[millie96]

I got the question "Explain the role of the prominent sagittal crest and large zygomatic arches of the gorilla". Do we have to know this detail about hominid evolution? Because i've never seen these structures before

[soNasty]

how the hell is the answer B...
i get that a quarter of the fruit without hair have white flesh........

[flares]

You really don't need to know any. If you're going to know one, know that IgE is found on mast cells. You certainly don't need to know about IgD, because that's the one that we know least about.

I've just come across some of them in the practice VCAA exams..
Thanks for that. I'll take your word for it

[dankfrank420]

(Image removed from quote.)

how the hell is the answer B...
i get that a quarter of the fruit without hair have white flesh........

You're misreading the question.

You are correct when you say a quarter would have no hair/white flesh, but that isn't what B is saying. B is sort of a conditional probability question - it's saying "given the fruit has no hair, what is the probability that it has white flesh".

[Reus]

I got the question "Explain the role of the prominent sagittal crest and large zygomatic arches of the gorilla". Do we have to know this detail about hominid evolution? Because i've never seen these structures before

Straight out the SD...

• hominin evolution:
– shared characteristics which define primates, hominoids and hominins
– major trends in hominin evolution from the genus Australopithecus to the genus Homo including morphological, structural and cognitive development resulting in cultural evolution and the rise of technologies.