do we need to know about photosystems 1 and 2 in the light dependent stage of photosynthesis? if so could someone please explain.
MCQ 10 in the 2022 vcaa exam involves it but I have never seen any other questions about it ever, nor is it specified in the study design, nor was I taught it by my tutor or at school! just seems like such a random question.
VCE Biology Questions Thread
Omg yes! When I did bio last year, I went way to in depth in this. I think Douchy has a video about it somewhere…. And there was stuff on Khan Academy too…
Simply put, there are two photosystems in the membrane of chloroplasts. 1 and 2
Photosystem 2 is the important one
It is able to oxidise oxygen! Which is really hard to do. Using sunlight it splits water into O2 gas and H+ ions, and sends the electron down the transport chain - which pumps hydrogens across the membrane, making a proton gradient…
Etc… etc
bioho4
Hi
This is a bit late to ask that question especially since the bio exam has already passed.
Anyways,
VCAA does not expect you to know the details of the biochemical pathways of photosynthesis (such as photosystems). They only expect you to know the reactants, products and location of each stage of photosynthesis and and role of RuBisCO.
FYI, photosystems 1/2 split H20 in the light dependent stage of photosynthesis.
Hope this makes sense.
bioho4
i think this is the relevant dp from the bio study design:
- inputs, outputs and locations of the light dependent and light independent stages of photosynthesis in C3 plants (details of biochemical pathway mechanisms are not required)
so i'm pretty sure you don't need to know much about photosystems, etc. although confusing, i think vcaa uses diagrams like those to see whether students can link where the inputs and output come into the overall process? and thus determine what stage it is, potentially? was definitely still a kinda random question tho
- Edited
Hi bioho4!
Most of diagram was irrelevant, and it included everything you needed to answer the question - given that you knew your standard bio content. The two, and only, pieces of information that was needed was that:
- It was in the light-dependent stage -- this could have been inferred through inclusion of the "sunlight" component [in the diagram].
- The arrows and blank boxes [in the diagram].
Allow me to elaborate;
Given that the biochemical pathway represented was the light-dependent stage of photosynthesis this narrows down all possible inputs to be Water, ADP, and NADP+; and all outputs to be Oxygen, ATP, and NADPH.
Looking at the boxes and arrows, we know that the question asks for the identity of one input (W), and two outputs (V and Z).
To summarise those two points, the answer we are looking for must be a combination of one input and two outputs; that must belong to the light-dependent stage of photosynthesis.
...
Ok, now, with that knowledge lets take a look at all four options;
Option A - 'Water, ATP and NADP+' - We have two inputs and one output here, so that doesn't work.
Option B - 'Oxygen, ATP and NADPH' - We have no inputs and three outputs, this does not work either.
Option C - 'Oxygen, ADP and NADPH' - Ah, one input and two outputs, all of the light-dependent stage of photosynthesis 
.
Option D - 'Carbon Dioxide, ADP and NADP+' - Carbon Dioxide is not apart of the light-dependent stage of photosynthesis, so we need not bother with this option at all.
...
So, in conclusion, Option C was the correct answer, and you didn't need detailed knowledge of the light-dependent stage either.
As the maths shill in me would say, Q.E.D.
...
This was a fairly lengthy post for a MCQ, but I think it was an important post to make.
When you do VCE Biology, you can have faith in that no non-SD content will be assessed - you would (and should) expect that much. And honestly, from personal experience, learning non-SD content is basically useless for many areas of the VCE Biology Study Design; I think doing so would be a regrettable decision, especially in Year 12.
Chances that you get tested on it are extremely slim, and if it is truly non-SD I think consequentials would be awarded anyways. And yes, the extra background knowledge helps, but the tradeoff for time on other subjects is not favourable (this one comes from personal experience 
).
...
My Bio journey is finished for now, but hopefully those still in it (or are yet to begin) will have better luck. Happy studying 
.
3 months later
Is it the RNA polymerase or helicase that unzips DNA for transcription?
Helicase - think of helicopter and its blades cutting through the hydrogen bonds of DNA as an analogy
Hello lovelyherring
RNA Polymerase; it has a built-in Helicase-like component. Whereas DNA Helicase is typically present in DNA replication.
Hope this helps 
4 months later
What are ways that you can further a photosynthesis experiment?
Greta Depends what the photosynthesis experiment is. But you could change one of various factors affecting the rate of photosynthesis, such as temperature, pH, carbon dioxide concentration, wavelength of light, intensity of light, water availability, addition of enzyme inhibitors, etc. and measure its effect on the rate of photosynthesis.
Hey guys,
Has anyone done a SAC yet for "analysis & evaluation of a contemporary bioethical issue" yet? If so, how it it formated? What kind of case study will there be? and how should we answer questions to get full marks & best show our understanding?
BTW this is for U3 AOS 1 - DNA manipulation
a month later
Hey guys! just wondering if you could help me out with a few questions:
- do all cells have antigens?
- do all self cells in an organism have the same MHC marker?
- why isn’t the microbiota barrier detected as non-self? do these bacterial cells have the same antigens as our cells?
- do we need to know about allergy treatments like antihistamine meds, epipens and desensitation?
- are mhc 2 makers empty when there is no pathogen engulfed within the apc?
- are mhc 2 markers on activated t cells and b cells too?
- do we need to know the types of protozoa like ciliated etc?
- is the blood-brain barrier considered a physical or chemical barrier?
- Are all WBCs attracted by cytokines?
- how do we know which cell types will respond to certain scenarios and which will not e.g. how do we know when macrophages will act vs dendritic cells?
- do NK cells only react to viral pathogens
- do we need to know about basophils?
- are all phagocytes APCs?
- why are NK cells considered lymphocytes? I thought it was only B and T cells
- - when non-self antigens enter the lymph node in the humoral response, are these on a pathogen, on an APC or just by themselves?
- why do memory B-cells produce a faster reaction upon second infection than just naïve B-cells? don’t the have the same structure?
- do memory B-cells stay in the lymph node?
- are lymphocytes only B cells or T cells? I though all WBC could be called lymphocytes?
- do both b and t cells undergo clonal expansion or just b cells?
- the textbook I have says that inactivated and subunit vaccines require “booster vaccinations to maintain long-term immunity, by increasing the number of memory B and T cells”. So are B cells and T cells in these vaccines? Or are there pathogens / parts of pathogens in these vaccines? Is the adaptive immune response activated at all?
- the textbook only uses the terms emerging and re-emerging diseases when talking about infectious diseases. can you have an emerging non-infectious disease?
- when talking about monoclonal antibodies: is the myeloma tumour cell a cancer cell? can it be a malignant tumour cell? or must it be the target cancer?
- why must the cancer cell that the mAbs come into contact with be a cancer B cell?
- do the loads from the conjugated mAbs kill the cancer cells? or just stop their growth?
- wouldn't the hybridoma produce normal antibodies? not bispecific or conjugated? how does this work?
thank you so so much - I know there are a lot so any help would be gratefully appreciated 
thank youu
I am going to attempt to answer as many as I can:
do all cells have antigens? Yes, but only nucleated cells (all except Red blood cells) have MHC markers
do we need to know about allergy treatments like antihistamine meds, epipens and desensitation? In our school, we didn't even touch on these. I don't think we need to know these. I noticed a trend with exam questions: you don't need to know many examples, because they usually explain it to you in the exam and they expect you to apply the principles you know to these unfamiliar examples.
are mhc 2 markers on activated t cells and b cells too? MHC 2 markers are found on B cells, dendritic cells, and macrophages. I don't think they are on T cells.
do NK cells only react to viral pathogens? NK cells kill virally infected cells
are all phagocytes APCs? neutrophils(type of phagocyte) are not APCs because they don't have MHC 2
do both b and t cells undergo clonal expansion or just b cells? both
the textbook I have says that inactivated and subunit vaccines require “booster vaccinations to maintain long-term immunity, by increasing the number of memory B and T cells”. So are B cells and T cells in these vaccines? Or are there pathogens / parts of pathogens in these vaccines? Is the adaptive immune response activated at all? They have pathogen/ pathogen parts and those trigger the adaptive immune response. The adaptive immune response will produce memory cells that give you long term active immunity.
Hope this helps
Hi everyone, I was wondering if someone could please explain the difference between attenuation and repression.
Both attenuation and repression are forms of gene regulation in the trp operon.
Repression involves supressing the trp operon when there is lots of free tryptophan in the bacteria cell.
Attenuation involves supressing the trp operon when there is lots of tryptophan attached to tRNA in the cell.
That's one of the main differences.
ohh ok thankss