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March 28, 2024, 11:02:25 pm

Author Topic: VCE Biology Question Thread  (Read 3570460 times)  Share 

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PopcornTime

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Re: VCE Biology Question Thread
« Reply #10500 on: June 24, 2018, 01:51:04 pm »
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Can the immune system produce antibodies against monoclonal antibodies and how would this work? A prac exam says that eventually an individual will produce antibodies against monoclonal antibodies. How would this work if monoclonal antibodies don't have markers on their surface to display them as foreign?

vox nihili

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Re: VCE Biology Question Thread
« Reply #10501 on: June 24, 2018, 02:05:28 pm »
+1
Can the immune system produce antibodies against monoclonal antibodies and how would this work? A prac exam says that eventually an individual will produce antibodies against monoclonal antibodies. How would this work if monoclonal antibodies don't have markers on their surface to display them as foreign?

Some monoclonal antibodies are made out of rat antibodies. The rat antibody is seen as foreign.
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PopcornTime

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Re: VCE Biology Question Thread
« Reply #10502 on: June 24, 2018, 03:16:45 pm »
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I have a couple questions:
Property of globular protein and how it relates to arrangement of its polypeptide chains.

- sensitivity to changes in temperature
- due to folding of polypeptide chains such that protein mainly exhibits weak hydrogen bonding 

Any other thoughts on different properties?

In the 2017 bio exam, the answer for describing a condensation reaction is:
- condensation reaction
- water is an output
- energy is an input

^ would a student receive the 3 marks just for having these 3 dot points or would further explanation be required?

So is this fine for hydrolysis?
- hydrolysis
- energy is an output
- water is an input

Confirmation on following: coenzymes are organic molecules that act as carriers of hydrogen ions (protons) and electrons between biological reactions; cofactors are inorganic substances that bind to enzymes to assist in catalysing specific reactions.

TheBigC

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Re: VCE Biology Question Thread
« Reply #10503 on: June 24, 2018, 03:59:46 pm »
+1
I have a couple questions:
Property of globular protein and how it relates to arrangement of its polypeptide chains.

- sensitivity to changes in temperature
- due to folding of polypeptide chains such that protein mainly exhibits weak hydrogen bonding 

Any other thoughts on different properties?

In the 2017 bio exam, the answer for describing a condensation reaction is:
- condensation reaction
- water is an output
- energy is an input

^ would a student receive the 3 marks just for having these 3 dot points or would further explanation be required?

So is this fine for hydrolysis?
- hydrolysis
- energy is an output
- water is an input

Confirmation on following: coenzymes are organic molecules that act as carriers of hydrogen ions (protons) and electrons between biological reactions; cofactors are inorganic substances that bind to enzymes to assist in catalysing specific reactions.


1. For globular proteins, they are often water soluble due to arrangement of hydrophobic groups (Z or R groups) on the inside and hydrophilic constituents on the outside. Also, as the name suggests, they are spherical in shape.

2. Dot points are fine, however, the amount of detail required from year-to-year often changes, so I would recommend that you write a more detailed answer than the examiner's report displays.

3. Coenzymes are cofactors. When you describe cofactors, you are instead referring to prosthetic groups. Coenzymes do not just transfer H+ ions or electrons, they can also transfer groups of atoms.

PopcornTime

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Re: VCE Biology Question Thread
« Reply #10504 on: June 24, 2018, 07:06:22 pm »
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2009 VCE bio exam, Q3.) c)

What is the purpose of such additional photosynthetic pigments?
VCAA: to absorb different wavelengths of light
My answer: to capture different photons of light

Would I be wrong or right for this? The reports did bold term absorb.

S200

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Re: VCE Biology Question Thread
« Reply #10505 on: June 24, 2018, 07:11:08 pm »
+1
Well isn't Capture a synonym of absorb?

I'd say you'd get full marks, but I am not a VCAA marker....
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TheBigC

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Re: VCE Biology Question Thread
« Reply #10506 on: June 25, 2018, 12:13:00 am »
+1
2009 VCE bio exam, Q3.) c)

What is the purpose of such additional photosynthetic pigments?
VCAA: to absorb different wavelengths of light
My answer: to capture different photons of light

Would I be wrong or right for this? The reports did bold term absorb.

Do what VCAA says. Moreover, my issue not with your use of the diction, "capture", rather it is with your description of alternate pigments absorbing 'different photons of light', although correct, it is not nearly specific enough. Always mention wavelength and if necessary, energy level.

peachxmh

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Re: VCE Biology Question Thread
« Reply #10507 on: June 25, 2018, 05:05:54 pm »
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Hey all, I had a couple questions that surfaced whilst recapping immunity:

1. What are the roles of complement proteins in the inflammatory response? Do dendritic cells play any role?
- I read on Wikipedia that complement proteins attract macrophages and neutrophils, however, I thought cytokines released by the injured cells did this? Can someone please clarify? I also heard they promote inflammation but how does this work? Do they have any other roles?

2. How does the inflammatory response help the adaptive immune response occur?
I had the impression they were distinct as the inflammatory response does not retain immunological memory?

3. Why are antibodies relatively ineffective at fighting intracellular viral infections?
I can somewhat grasp this concept but am not too sure about it - are they ineffective on intracellular viral infections because they can only bind to foreign antigens and the invaded cell would only have its own normal MHC-I markers? But I thought these cells could display antigens of the pathogen on their MHC-I markers? Or is it because the cells cannot phagocytose the viruses and thus get the foreign antigens displayed?

4. Does clonal selection consist of BOTH the proliferation and differentiation of B and T-memory cells? Do T-memory cells work like B-memory cells as in they will differentiate into active cytotoxic-T cells if they encounter the same antigen presented on an MHC-I marker or active helper T-cells if they ____ (what circumstances would they diff. into active helper T-cells?)

Huge appreciation for whoever takes the time to answer as I'm aware this is a large influx of questions (whoops)
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Mr West

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Re: VCE Biology Question Thread
« Reply #10508 on: June 25, 2018, 06:35:58 pm »
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hey guys,

I'm doing a photosynthesis prac and am using a light bulb that produces green light. are only green wavelengths of light emitted or are other colours also produced? (if that makes sense)

thanks

EDIT: also, at what wavelength is photosynthesis operating at the highest rate?
« Last Edit: June 25, 2018, 07:02:22 pm by Mr West »

TheBigC

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Re: VCE Biology Question Thread
« Reply #10509 on: June 25, 2018, 07:43:42 pm »
+1
 
Hey all, I had a couple questions that surfaced whilst recapping immunity:

1. What are the roles of complement proteins in the inflammatory response? Do dendritic cells play any role?
- I read on Wikipedia that complement proteins attract macrophages and neutrophils, however, I thought cytokines released by the injured cells did this? Can someone please clarify? I also heard they promote inflammation but how does this work? Do they have any other roles?

2. How does the inflammatory response help the adaptive immune response occur?
I had the impression they were distinct as the inflammatory response does not retain immunological memory?

3. Why are antibodies relatively ineffective at fighting intracellular viral infections?
I can somewhat grasp this concept but am not too sure about it - are they ineffective on intracellular viral infections because they can only bind to foreign antigens and the invaded cell would only have its own normal MHC-I markers? But I thought these cells could display antigens of the pathogen on their MHC-I markers? Or is it because the cells cannot phagocytose the viruses and thus get the foreign antigens displayed?

4. Does clonal selection consist of BOTH the proliferation and differentiation of B and T-memory cells? Do T-memory cells work like B-memory cells as in they will differentiate into active cytotoxic-T cells if they encounter the same antigen presented on an MHC-I marker or active helper T-cells if they ____ (what circumstances would they diff. into active helper T-cells?)

Huge appreciation for whoever takes the time to answer as I'm aware this is a large influx of questions (whoops)



1.   Complement proteins are involved in opsonisation, MAC deposition and chemotaxis (as far as VCE is concerned). Chemotaxis means chemical (chemo) attraction (taxis: to move in response to stimuli). Therefore, complement attracts immune cells to the site of infection in the inflammatory response. The release of cytokines by injured cells also acts to attract immune cells to the site of infection. Different substances can have the same function. The main role of dendritic cells is to engulf pathogenic agents and present these agents’ antigens to Tc cells.
2.   The inflammatory response is a bridging mechanism between the innate and adaptive immune responses. Specific innate immune cells acquire antigenic fragments and present this to the adaptive immune response’s cells (i.e. Tc cells), this allows for the occurrence of the adaptive immune response.
3.   Antibodies function extracellularly, causing; agglutination, opsonisation, neutralisation and complement activation. As viruses intracellularly attack cells, extracellular antibodies are inefficacious against them. (Note: Plasma B cells secrete antibodies into the bloodstream or lymph).
4. a) Clonal selection consists of neither proliferation or differentiation (hehe – how about that!?), it merely involves the binding of the epitope of an antigen to a specific receptor of a B cell, T cell etc. Clonal expansion, however involves proliferation.
    b) B memory cells differentiate into B plasma cells or more B memory cells. T memory cells differentiate into T helper or T cytotoxic cells. In terms of conditions that are conducive to the differentiation of memory cells into specific cell types, I used to be familiar with the answer, however for now – I cannot seem to recall it. Hopefully someone else can help, though it is definitely outside of the study design.
« Last Edit: June 25, 2018, 07:48:27 pm by TheBigC »

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10510 on: June 25, 2018, 11:39:42 pm »
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hey guys,

I'm doing a photosynthesis prac and am using a light bulb that produces green light. are only green wavelengths of light emitted or are other colours also produced? (if that makes sense)

thanks

EDIT: also, at what wavelength is photosynthesis operating at the highest rate?
It depends on how good the lightbulb is. Yours will be emmitting other wavelengths. The most photosynthesis occurs under red light.
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PopcornTime

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Re: VCE Biology Question Thread
« Reply #10511 on: June 26, 2018, 10:55:11 am »
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Is there a difference between B cell receptors and antibodies?

I assume its just a functional difference; antibodies neutralise antigens, whereas B cell receptors recognise antigens.

PopcornTime

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Re: VCE Biology Question Thread
« Reply #10512 on: June 26, 2018, 12:50:03 pm »
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Describe a chemical method of defence in a plant:

- production of abscisic acid
- infected leaves drop

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #10513 on: June 26, 2018, 03:27:06 pm »
+1
Is there a difference between B cell receptors and antibodies?

I assume its just a functional difference; antibodies neutralise antigens, whereas B cell receptors recognise antigens.
Yeah it’s just functional. B cell receptors are just antibodies that are embedded in membranes. Note that antibodies also recognise antigens though. Better to say that they allow differentiation/proliferation to occur by binding their complimentary antigen or something like that.
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Owlbird83

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Re: VCE Biology Question Thread
« Reply #10514 on: June 26, 2018, 05:03:45 pm »
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I found that on my mid year exam some questions related to experimental design, which is something that I hadn't revised or payed much attention to. Does anyone know how big of a part this is in the study design? Also are there any resources that can help with those questions?
Thanks :)
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