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March 29, 2024, 06:59:58 am

Author Topic: HSC Biology Question Thread  (Read 341522 times)  Share 

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studybuddy7777

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Re: Biology Question Thread
« Reply #30 on: August 02, 2016, 06:50:41 pm »
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My guess is that you need 2 examples. These include the
Osmoregulators: organisms that avoid changes in their internal environment and have the ability to keep the solutes at an optimal level (‘regulate’ solute concentrations within the body), regardless of the differing external environment. i.e Mussels close their mouths in order to keep the salt levels in their tissues the same as sea water
Osmoconformers: organisms that tolerate the changes in the environment by altering the concentration of their internal solutes to match the external environment. i.e the fiddler crab accumulates salt into its tissues to match seawater and pumps out the excess when exposed to fresh water.

You should also talk what estuaries are and what change in the environment that requires enantiostasis to occur for these organisms to live in their ecosystems

Wow okay thanks for the information! I'll thank you now but read it later as its all going over the top of my head right now (2 trial papers does that to you, especially when one is English Adv paper 2 modules)

Skidous

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Re: Biology Question Thread
« Reply #31 on: August 02, 2016, 06:53:30 pm »
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Them feels man, them feels. English trials are over though so that means only the "easy" subjects are left. Y'know, physics, chemistry, maths, SOR II and Bio
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studybuddy7777

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Re: Biology Question Thread
« Reply #32 on: August 02, 2016, 06:58:42 pm »
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Them feels man, them feels. English trials are over though so that means only the "easy" subjects are left. Y'know, physics, chemistry, maths, SOR II and Bio

You seriously did not just put SOR II and "easy" in the same sentence.. :P
I agree that the sciences are certainly easier than english, math comes down to the mindset and level being assessed but omg i am so screwed for SOR II. Perhaps even more so than english. Section III and IV are not looking fun  :-\ :'(

But its my last exam so i can relax a bit  :D

Skidous

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Re: Biology Question Thread
« Reply #33 on: August 02, 2016, 07:00:26 pm »
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I don't mean to brag but I'll have you know that I came third in SOR II and I barely did study for all 3 assessment tasks
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studybuddy7777

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Re: Biology Question Thread
« Reply #34 on: August 02, 2016, 07:03:36 pm »
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I don't mean to brag but I'll have you know that I came third in SOR II and I barely did study for all 3 assessment tasks

I dont want sympathy but I actually tried in all my assessment tasks and are still ranked 7th (out of 20) for SOR II. Life is not fair lol.

Skidous

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Re: Biology Question Thread
« Reply #35 on: August 02, 2016, 07:10:27 pm »
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It's ok, I'm only ranked 3rd (out of 16) so we're basically the same rank
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Ayyddaan

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Re: Biology Question Thread
« Reply #36 on: August 02, 2016, 07:34:36 pm »
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Could someone please explain the mechanisms that allow interaction between B and T cells?? (INCLUDING MHC molecules?)
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Skidous

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Re: Biology Question Thread
« Reply #37 on: August 02, 2016, 07:37:19 pm »
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Could someone please explain the mechanisms that allow interaction between B and T cells?? (INCLUDING MHC molecules?)


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Skidous

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Re: Biology Question Thread
« Reply #38 on: August 02, 2016, 07:41:00 pm »
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The major histocompatibility complex (MHC) is a set of cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates. so you would refer to them basically as the protein flags which determine whether a cell is self or non-self (and consequently an antigen)
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Ayyddaan

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Re: Biology Question Thread
« Reply #39 on: August 02, 2016, 07:42:08 pm »
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The major histocompatibility complex (MHC) is a set of cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates. so you would refer to them basically as the protein flags which determine whether a cell is self or non-self (and consequently an antigen)

Ohhhhh, thanks dude!!
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Skidous

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Re: Biology Question Thread
« Reply #40 on: August 02, 2016, 07:42:52 pm »
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Ohhhhh, thanks dude!!

No problem man, always happy to help
 
For some extra information there are 2 types of MHC molecules
MHC II can be conditionally expressed by all cell types, but normally occurs only on professional macrophages and B cells, used primarily to assist in antibody mediated immunity (Humoral Immunity)
MHC I occurs on all nucleated cells—in essence all cells but red blood cells—and presents epitopes to killer T cells, also called cytotoxic T lymphocytes. CD8 receptor on Cytotoxic T-cells docks to MHC I molecules, if they fit together it triggers the cell to undergo programmed cell death by apoptosis, hence assisting with Cell Mediated Immunity (addressess intracellular pathogens, such as viruses and some bacteria)
« Last Edit: August 02, 2016, 07:50:23 pm by Skidous »
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Ayyddaan

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Re: Biology Question Thread
« Reply #41 on: August 02, 2016, 11:34:59 pm »
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Can someone please explain the difference between Cell-mediated and antibody-mediated immunity???

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« Last Edit: August 03, 2016, 08:34:19 am by Skidous »
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Skidous

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Re: Biology Question Thread
« Reply #42 on: August 03, 2016, 08:37:09 am »
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Hey Ayyddaan

Cell-Mediated Immunity is the immune response that occurs when T-Cells interact with antigens, resulting in the death of cells through the use of cytotoxins in order to kill the cell and the pathogen.
Antibody Mediated Immunity (AKA Humoral Immunity) is the immune response where antibodies produced by plasma cells (B-cells) attach themselves to a specific antigen to form an antibody-antigen complex, which deactivates the antigen and marks it for destruction by macrophages through phagocytosis.

Hope this helps, Skidous
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vox nihili

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Re: Biology Question Thread
« Reply #43 on: August 03, 2016, 06:35:41 pm »
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No problem man, always happy to help
 
For some extra information there are 2 types of MHC molecules
MHC II can be conditionally expressed by all cell types, but normally occurs only on professional macrophages and B cells, used primarily to assist in antibody mediated immunity (Humoral Immunity)
MHC I occurs on all nucleated cells—in essence all cells but red blood cells—and presents epitopes to killer T cells, also called cytotoxic T lymphocytes. CD8 receptor on Cytotoxic T-cells docks to MHC I molecules, if they fit together it triggers the cell to undergo programmed cell death by apoptosis, hence assisting with Cell Mediated Immunity (addressess intracellular pathogens, such as viruses and some bacteria)

Not sure how much detail you guys go into, but I'd just add that dendritic cells are probably the most important cell that expresses MHC class II. It would also be reasonable to say that only antigen-presenting cells express MHC class II.
Also, it is probably somewhat incorrect to say that MHC class II is directed at humoral immunity and class I to cellular immunity. The role of CD4+ (helper) T-cells in cellular immunity is well-established too.
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Skidous

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Re: Biology Question Thread
« Reply #44 on: August 03, 2016, 06:36:54 pm »
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That's correct I forgot to add that in, didn't know about the dendritic cells however
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