HSC Biology Question Thread

[Arvacado]

Hiii! Another question  Analyse the ways in which theories in biology are tested and validated, using the theory of evolution as an example.

[Arvacado]

More questions 
1.How does the kidney function?
2.What is the interaction between T cells and B cells?

[Potatohater]

More questions 
1.How does the kidney function?
2.What is the interaction between T cells and B cells?

1. The kidney functions by filtering the blood in the glomerulis, with all the filtrate entering the bowman's capsule (blood cells stay in the blood) then various substances such as glucose are reabsorbed in the proximal tubule, and water and salts are reabsorbed in the loop of henle and distal tubules. In the collecting duct some water and salts may also be reabsorbed if ADH and aldosterone hormones have been released. So basically it filters blood and reabsorbs what is needed.
2. Pretty sure when presented with an antigen helper T cells stimulate B cells to produce plasma B cells and memory B cells - but I'm a little rusty on this so you might wanna double check

[rainbowsparkles15]

More questions 
1.How does the kidney function?
2.What is the interaction between T cells and B cells?

To answer your second question, when a phagocyte such as a macrophage presents an antigen on its MHCII marker, a specific T Helper cell will recognise it and bind. It will then release cytokines that stimulate the specific B cell with the same receptors to undergo clonal expansion and differentiate into B plasma cells and B memory cells
(I do VCE so sorry if some of this isn't relevant) Hope this helps, good luck!

[Potatohater]

To answer your second question, when a phagocyte such as a macrophage presents an antigen on its MHCII marker, a specific T Helper cell will recognise it and bind. It will then release cytokines that stimulate the specific B cell with the same receptors to undergo clonal expansion and differentiate into B plasma cells and B memory cells
(I do VCE so sorry if some of this isn't relevant) Hope this helps, good luck!

Don't worry, it's all relevant, I think the only part we don't look at for HSC is clonal expansion, but the extra knowledge doesn't hurt

[sidzeman]

1. The kidney functions by filtering the blood in the glomerulis, with all the filtrate entering the bowman's capsule (blood cells stay in the blood) then various substances such as glucose are reabsorbed in the proximal tubule, and water and salts are reabsorbed in the loop of henle and distal tubules. In the collecting duct some water and salts may also be reabsorbed if ADH and aldosterone hormones have been released. So basically it filters blood and reabsorbs what is needed.
2. Pretty sure when presented with an antigen helper T cells stimulate B cells to produce plasma B cells and memory B cells - but I'm a little rusty on this so you might wanna double check

Just a few nitpicky things - ADH is released in the collecting yes - but aldosterone is released in the ascending loop of Henle, and concerns salt reabsorption specifically (although it also causes water reabsorption due to changing the osmotic pressure).
More specifically for the function of the kidney there are 2 main functions -
1) osmoregulation - e.g. reabsorbing water to ensure there are sufficient levels in the body
2) Excretion of nitrogenous wastes e.g. urea (this is what potatohater meant when he said it filters blood)   

[Arvacado]

Hiiii!
What is one of the limitations of Koch's postulates?

[pikachu975]

Hiiii!
What is one of the limitations of Koch's postulates?

Doesn't work for non-infectious diseases because those are not caused by pathogens

OR

Requires a second host to be inoculated with the disease which could be dangerous to their health

Don't worry, it's all relevant, I think the only part we don't look at for HSC is clonal expansion, but the extra knowledge doesn't hurt

Clonal expansion is part of clonal selection theory, formed by Macfarlane Burnet - which can be tested in the HSC as it is one of the dot points in the left hand column of the syllabus.

More questions 
2.What is the interaction between T cells and B cells?

B cells can bind to a specific antigen and present it to a helper T cell via an MHC II molecule or a macrophage can lyse the pathogen through phagocytosis and present the antigen to the helper T cell. The helper T cell then releases interleukin-2 to stimulate B and T cells to rapidly divide and differentiate, also known as clonal selection theory. The helper T cell can also stimulate production of antibodies.

A further interaction can be seen as suppressor T cells can signal B cells to stop producing antibodies once the infection is gone.

Hiii! Another question  Analyse the ways in which theories in biology are tested and validated, using the theory of evolution as an example.

I learnt this from physics but there has to be an observation, problem raised, new hypothesis, experiment, data analysis, and then if the results support the hypothesis it becomes a new theory or law, if not then they come up with a new hypothesis.

I guess for this you could look at that dot point talking about theories of evolution.

You've got Linnaeus who classified humans and apes together. Then Erasmus Darwin who said all life came from a single source. Then Lamarck who talked about use/disuse of body parts which was proved wrong which then led to a new hypothesis by Darwin and Wallace about natural selection and isolation. This was tested and validated through Darwin's 14 finches in the Galapagos and Cocos Islands where he noticed divergent evolution as all the new species had adapted to their respective niches.

[left right gn]

For line/curve of best fits, do we join the dots??

[Potatohater]

For line/curve of best fits, do we join the dots??

No! Don't mean to come off as aggressive with that no, but whatever you do, do not join the dots for a line or curve of best fit
Only join the dots if it is an epidemiological graph, otherwise it is always either a curve or a line of best fit.

[Mathew587]

For line/curve of best fits, do we join the dots??

dont connect the dots
just chuck a line through what seems to be the majority of the dots and make it neat
a mark right there

[sidzeman]

Clonal expansion is part of clonal selection theory, formed by Macfarlane Burnet - which can be tested in the HSC as it is one of the dot points in the left hand column of the syllabus.

Sorry what exactly is the clonal selection theory and clonal expansion? Don't think I've ever come across these terms before. My knowledge of Burnet is also kinda iffy - didn't he identify MCH I or II molecules as being present on cells that identified them as being part of ones own body, and so did not trigger the immune response?

[Opengangs]

Sorry what exactly is the clonal selection theory and clonal expansion? Don't think I've ever come across these terms before. My knowledge of Burnet is also kinda iffy - didn't he identify MCH I or II molecules as being present on cells that identified them as being part of ones own body, and so did not trigger the immune response?

The clonal selection theory explains the process of immunological memory in the form of two lymphocytes. One of these lymphocyte act as the immediate combatant to the infection, while the other remains in the body in the form of memory cells. It is these memory cells that enable an individual to have immunity over these specific antigens. While Burnet was not the one who proposed this idea, he extended the pre-existing theories surrounding these experiments and publicised his findings, naming it 'the clonal selection theory'.

[sidzeman]

The clonal selection theory explains the process of immunological memory in the form of two lymphocytes. One of these lymphocyte act as the immediate combatant to the infection, while the other remains in the body in the form of memory cells. It is these memory cells that enable an individual to have immunity over these specific antigens. While Burnet was not the one who proposed this idea, he extended the pre-existing theories surrounding these experiments and publicised his findings, naming it 'the clonal selection theory'.

Ahhhh I see thank you so much you may have just saved me some easy marks in the hsc!

[Potatohater]

Ahhhh I see thank you so much you may have just saved me some easy marks in the hsc!

Lol, I personally wouldn't have called that easy marks, I'm still confused, I feel like all that just went in one eye and out the other