Login

Welcome, Guest. Please login or register.

March 29, 2024, 07:15:42 am

Author Topic: VCE Biology Question Thread  (Read 3570914 times)  Share 

0 Members and 7 Guests are viewing this topic.

darkz

  • Forum Obsessive
  • ***
  • Posts: 413
  • Respect: +154
Re: VCE Biology Question Thread
« Reply #10410 on: June 03, 2018, 06:28:44 pm »
+1
Why are hypersensitivity reactions considered to be apart of the innate immune system? After-all, they are specific to certain allergens e.g. pollen etc?
2018: Biology [50 + Prems]
2019: English [46], Latin [45], Chemistry [41], Mathematical Methods [48], Specialist Mathematics [41]
ATAR: 99.95

2020: BMedSci, M.D. @ Monash Uni

VCE Biology Units 1&2 and 3&4 Tutoring for 2021

PopcornTime

  • Forum Obsessive
  • ***
  • Posts: 264
  • Respect: +10
Re: VCE Biology Question Thread
« Reply #10411 on: June 03, 2018, 08:15:54 pm »
+1
Hey friends, few questions:

1. "...apoptosis is tidy and splits the cell into little parcels that can be taken up and recycled by other cells."
What does it mean by "recycle"? If these "little parcels" are phagocytosed and destroyed, then how can they be ' ???'?

Khan academy... The phagocytes would recycle the contents for energy/nutrients.


2. Can second messengers act as effector molecules? And do they always amplify cellular responses?

I dont think they can act as effector molecules, but they can activate effector molecules. Their purpose is to amplify the signal - so yes.


Also, can you please confirm the following definitions?

Second Messenger: Molecules that relay signals through the cytoplasm after the binding of a signalling molecule, by activating a cascade of events to trigger a specific cell response.

Signal Amplification: The ability of one signalling molecule to cause the activation of many molecules inside the cell, initiating a cascade of events that lead to a faster cell response.


PopcornTime

  • Forum Obsessive
  • ***
  • Posts: 264
  • Respect: +10
Re: VCE Biology Question Thread
« Reply #10412 on: June 05, 2018, 05:23:15 pm »
+1
Why are hypersensitivity reactions considered to be apart of the innate immune system? After-all, they are specific to certain allergens e.g. pollen etc?

Isn't it apart of adaptive immunity?

"Allergies are not normal immune responses to antigens. They are over-reactions – hypersensitivity reactions – that occur in some people for reasons that are poorly understood. If you had to put allergies into either the innate or adaptive category, though, you would consider them part of the adaptive immune system because they involve lymphocytes and antibodies (mast cells and eosinophils are involved too – but those cells are not considered part of routine innate or adaptive immunity)."

Link for above^ https://www.pathologystudent.com/are-allergies-part-of-the-innate-immune-system/

persistent_insomniac

  • Forum Regular
  • **
  • Posts: 88
  • Respect: +1
  • School: -------
  • School Grad Year: 2019
Re: VCE Biology Question Thread
« Reply #10413 on: June 05, 2018, 05:28:12 pm »
0
Hey can someone please explain to me what exactly antigens are I seem to be very confused? Some sources state it is anything that triggers and immune response whilst others say they are protein markers? Are self-antigens MHC markers found on our cells that identify them as belonging to us whilst non-self antigens are things like pathogens?
Thanks so much.

Erutepa

  • VIC MVP - 2019
  • Forum Leader
  • ****
  • Posts: 721
  • evenin'
  • Respect: +775
Re: VCE Biology Question Thread
« Reply #10414 on: June 05, 2018, 06:19:13 pm »
+1
Hey can someone please explain to me what exactly antigens are I seem to be very confused? Some sources state it is anything that triggers and immune response whilst others say they are protein markers? Are self-antigens MHC markers found on our cells that identify them as belonging to us whilst non-self antigens are things like pathogens?
Thanks so much.
An antigen is something that can illicit an immune response. Often times they are protein markers on cell surfaces, but they can also simply be molecules of their own.
In response to your question about MHC markers, our own cells posess many different surface antigens. Howeverm as MHC markers are the most important in temrs of the immune system, we mainly focus on these. MHC proteins have two different classes: class I and class II. Class I MHC markers are expressed by all nucleated cells (things like red blood cells don't have them) and present protein fragments from within the cell. As such, these markers can be used to 'check' if the cell is functioning properly as aberrant cells (ie. virus-infected or cancer cells) would produce certain proteins that may be presented to immune cells on these MHC class I markers. MHC class II markers are expressing in certain immunce cells called antigen presenting cells (APCs). This class of MHC marker allows antigens engulfed by the cell to be presented (after processing) on the cell's surface. The main purpose of this is in allowing for activation of the active immune response.
In reguards to non-self antigens, there are many sources of these. Pathogens are one source, as they present and produce molecules that can trigger an immune response. But there are proteins and molecules  - like those of allergens - which can also illicit an immune response that are not pathogenic.
Hope this helps.
Qualifications
 > Have counted to 227
 > Can draw really good spiders
 > 2 Poet points
 > 6.5 insanipi points
 > 1 Bri MT point

PopcornTime

  • Forum Obsessive
  • ***
  • Posts: 264
  • Respect: +10
Re: VCE Biology Question Thread
« Reply #10415 on: June 05, 2018, 06:20:42 pm »
+1
Hey can someone please explain to me what exactly antigens are I seem to be very confused? Some sources state it is anything that triggers and immune response whilst others say they are protein markers? Are self-antigens MHC markers found on our cells that identify them as belonging to us whilst non-self antigens are things like pathogens?
Thanks so much.

So antigens are pretty much any molecule or parts of a molecule that initiate an immune response (study design). Sources for antigens (where antigens can be located) include bacteria, viruses, toxins (produced by pathogens) or substances like pollen.

MHC's are protein self markers located on cell membranes which gives the ability of the immune system to recognise between self cells and non-self cells. This marker is your "self-antigen". So yes. Also not that MHC 1 markers are unique to each individual.

PopcornTime

  • Forum Obsessive
  • ***
  • Posts: 264
  • Respect: +10
Re: VCE Biology Question Thread
« Reply #10416 on: June 05, 2018, 06:24:03 pm »
0
What types of cell responses can occur from hydrophilic and hydrophobic hormones?

Hydrophobic - gene expression
Hydrophilic - activation of enzymes?

kyubikofang

  • Fresh Poster
  • *
  • Posts: 2
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #10417 on: June 05, 2018, 07:45:03 pm »
0
Hey! Doing some quick revision and i'm curious to know what are the best/main animal hormones to know about in detail as there are loads we can talk about.

darkz

  • Forum Obsessive
  • ***
  • Posts: 413
  • Respect: +154
Re: VCE Biology Question Thread
« Reply #10418 on: June 05, 2018, 07:47:05 pm »
+1
Hey! Doing some quick revision and i'm curious to know what are the best/main animal hormones to know about in detail as there are loads we can talk about.

The best animal hormones to talk about would be insulin/glucagon and thyroxine :)
2018: Biology [50 + Prems]
2019: English [46], Latin [45], Chemistry [41], Mathematical Methods [48], Specialist Mathematics [41]
ATAR: 99.95

2020: BMedSci, M.D. @ Monash Uni

VCE Biology Units 1&2 and 3&4 Tutoring for 2021

Erutepa

  • VIC MVP - 2019
  • Forum Leader
  • ****
  • Posts: 721
  • evenin'
  • Respect: +775
Re: VCE Biology Question Thread
« Reply #10419 on: June 05, 2018, 08:42:38 pm »
+1
What types of cell responses can occur from hydrophilic and hydrophobic hormones?

Hydrophobic - gene expression
Hydrophilic - activation of enzymes?

Yes. This is right.
Although not always the case, generally hydrophobic signaling molecules (binding to a intracellular receptor protein) function to act as a transcription factor or to inhibit the inihition of the expression of a gene, thus in both cases leading to the expression of a gene. As such these signals are usually involved in longer-lasting and slower acting responses, like that of development.
Typically, hydrophilic signalling molecules initiate a signal cascade which results in the activation of a effector protein. This may not neccasarily be a enzyme as it can activate a channel protein to allow the movement of a certain substance. becuase of this, these signals are usually involved in faster-acting and shorter-lasting responses, like the reception of adrenaline. That being said, I have had SAC questions and seen questions in practice exams that shoe hydrophilic extracellular-binding signals initiate gene expression, so it is probably good to know that it can often do both.
Qualifications
 > Have counted to 227
 > Can draw really good spiders
 > 2 Poet points
 > 6.5 insanipi points
 > 1 Bri MT point

vox nihili

  • National Moderator
  • Great Wonder of ATAR Notes
  • *****
  • Posts: 5343
  • Respect: +1447
Re: VCE Biology Question Thread
« Reply #10420 on: June 05, 2018, 09:09:25 pm »
+1
Hey! Doing some quick revision and i'm curious to know what are the best/main animal hormones to know about in detail as there are loads we can talk about.

None to be honest. You don't need to know the details of any. They'll give you all the information you need on the exam, you'll just need to interpret in the context of what you know generally about hormones from VCE.
2013-15: BBiomed (Biochemistry and Molecular Biology), UniMelb
2016-20: MD, UniMelb
2019-20: MPH, UniMelb
2021-: GDipBiostat, USyd

darkz

  • Forum Obsessive
  • ***
  • Posts: 413
  • Respect: +154
Re: VCE Biology Question Thread
« Reply #10421 on: June 05, 2018, 09:15:12 pm »
0
When B cells are selected i.e. when an epitope binds to their receptor, is this process known as clonal selection? And then do they differentiation & proliferate, or do they have to find a corresponding selected T helper cell which would secrete cytokines promoting differentiation & proliferation?
2018: Biology [50 + Prems]
2019: English [46], Latin [45], Chemistry [41], Mathematical Methods [48], Specialist Mathematics [41]
ATAR: 99.95

2020: BMedSci, M.D. @ Monash Uni

VCE Biology Units 1&2 and 3&4 Tutoring for 2021

vox nihili

  • National Moderator
  • Great Wonder of ATAR Notes
  • *****
  • Posts: 5343
  • Respect: +1447
Re: VCE Biology Question Thread
« Reply #10422 on: June 05, 2018, 09:32:06 pm »
0
When B cells are selected i.e. when an epitope binds to their receptor, is this process known as clonal selection? And then do they differentiation & proliferate, or do they have to find a corresponding selected T helper cell which would secrete cytokines promoting differentiation & proliferation?

The answer isn't really relevant to VCE, but a really interesting question nonetheless (and as usual!).

B-cells can't differentiate without T-cell help. They can proliferate, but the degree of proliferation is really limited.
2013-15: BBiomed (Biochemistry and Molecular Biology), UniMelb
2016-20: MD, UniMelb
2019-20: MPH, UniMelb
2021-: GDipBiostat, USyd

Azim.m

  • Forum Regular
  • **
  • Posts: 64
  • Respect: +1
Re: VCE Biology Question Thread
« Reply #10423 on: June 06, 2018, 06:17:47 pm »
0
Do we need to know the different types of monoclonal antibodies and their uses?

PopcornTime

  • Forum Obsessive
  • ***
  • Posts: 264
  • Respect: +10
Re: VCE Biology Question Thread
« Reply #10424 on: June 06, 2018, 08:21:19 pm »
0
What are the steps leading to an autoimmune disease and an immunodeficiency disease?