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March 29, 2024, 09:06:33 am

Author Topic: VCE Biology Question Thread  (Read 3570989 times)  Share 

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elfy

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Re: VCE Biology Question Thread
« Reply #13815 on: May 30, 2022, 06:40:35 am »
0
According to the study design:
Photosynthesis as an example of biochemical pathways
· 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)
· the role of Rubisco in photosynthesis, including adaptations of C3, C4 and CAM plants to maximise the efficiency of photosynthesis
· the factors that affect the rate of photosynthesis: light availability, water availability, temperature and carbon dioxide concentration

Cellular respiration as an example of biochemical pathways
· the main inputs, outputs and locations of glycolysis, Krebs Cycle and electron transport chain including ATP yield (details of biochemical pathway mechanisms are not required)
· the location, inputs and the difference in outputs of anaerobic fermentation in animals and yeasts
· the factors that affect the rate of cellular respiration: temperature, glucose availability and oxygen concentration

I am not that familiar with the updated one... but for the old study-design: we had to know that (eg for aerobic respiration) 1 glucose --> 2 ATP + 2 Pyruvate (glycolysis) --> Krebs cycle ....--> ETC ..... and so on.

So I'd say, u should know the inputs/outputs for each stage (ESPECIALLY ATP YIELD). I think Douchy had a good video explaining it. From checking just now, he's uploaded a bunch more that might be more relevant (eg. https://www.youtube.com/watch?v=th2wwzBNQ1I). Would 100% recommend his podcast as well. (Douchy's Biology)

Hope this helps!
 :)

Sorry I may have worded it wrong, I was talking about the exact number of molecules for example in the Light Dependant stage of photosynthesis:
inputs: 12H2O, 12NADP+, 18ADP + Pi
outputs: 6O2, 12NADPH, 18ATP

valjaybj

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Re: VCE Biology Question Thread
« Reply #13816 on: June 07, 2022, 08:40:22 pm »
+2
Sorry I may have worded it wrong, I was talking about the exact number of molecules for example in the Light Dependant stage of photosynthesis:
inputs: 12H2O, 12NADP+, 18ADP + Pi
outputs: 6O2, 12NADPH, 18ATP

It looks like you already know them haha but for VCAA you won't be asked about the exact number of coenzymes. There are some teachers and online resources that will tell you the numbers but don't worry about them. A summary of what you need to know is the following:

In photosynthesis, you don't need to know the exact number of coenzymes (NADPH and ATP), however it's good to know how much water and oxygen (which you have identified correctly as 6 each); the numbers aren't required in explanations but it's good to be aware of them for the balanced chemical equation.

For cellular respiration however, you do need to know the exact number of ATP made in each stage. Don't worry about the other coenzymes (NADH/FADH2). Just know you make 2 ATP in glycolysis, 2 ATP in the Krebs Cycle and 26-28 ATP in the ETC.
Other than that just know that in glycolysis we have 1 glucose which is converted into 2 pyruvates.
Then in the linking reaction 2 pyruvate is converted to 2 acetyl coA. 6CO2 is released here.
In the ETC we have 6O2 coming in and 6H2O leaving.

Hope this helps
« Last Edit: June 07, 2022, 08:45:22 pm by valjaybj »

successismygoal

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Re: VCE Biology Question Thread
« Reply #13817 on: June 18, 2022, 01:17:07 pm »
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Hey guys!

(im not sure if this is the right place to post questions about scientific method, pls redirect me if thats not the case)
I had a question about repeatability and reproducibility, which have replaced reliability from the old study design.

So from my understanding, repeatability is how close measurements are if repeated in the same conditions with the same method and same experimenters and same equipment, and reproducibility is how close measurements are if an experiment is repeated in different conditions, such as different location, experimenters or equipment.

So if we were asked to comment on the repeatability of an experiment, could we basically say that any experiment is repeatable, because if you do the exact same thing as you initially did under the same conditions, then you would get the same results?

What about reproducibility? If you only conducted an experiment once, could you say that the reproducibility cannot yet be determined, as the experiment was not repeated under different conditions?

Thanks!

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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #13818 on: June 18, 2022, 02:28:12 pm »
+1
Repeatability assess precision- comparison of set of results between two or more repeats of the experiment ( same time and same person). Reproducibility assess accuracy. Reproducibility- comparison of set of results between two or more repeats of the experiment (different time frame or person).

so yea if you only did the experiment once the reproducibility cannot be determined and the repeatability you cant really comment on either if you haven't done the experiment 2 or more times to compare results. I don't think you can say any experiment is repeatable
if it was same conditions you still may not get the same results due to error

successismygoal

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Re: VCE Biology Question Thread
« Reply #13819 on: June 18, 2022, 08:10:32 pm »
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Thank you!
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2022: |Biology [43]| |Legal [50]|

elfy

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Re: VCE Biology Question Thread
« Reply #13820 on: June 20, 2022, 04:59:56 pm »
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What are the best companies that release practice papers for bio 3/4?
I am probably going to start doing practice exams near the end of holidays after I go over unit 4 so I want to know which exams will correspond well with the actual biology exam at the end of the year...

biology1234

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Re: VCE Biology Question Thread
« Reply #13821 on: June 27, 2022, 03:39:25 pm »
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do memory cells recognise the antigen or pathogen? which trigger response with antibodies
thanks

Billuminati

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Re: VCE Biology Question Thread
« Reply #13822 on: June 27, 2022, 03:51:53 pm »
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do memory cells recognise the antigen or pathogen? which trigger response with antibodies
thanks

They recognise antigens
VCE 2016-2018

2017: Biology [38], Further Maths [44]

2018: Methods [37], French [38], Chem [40], English [44]

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2019-2021: Bachelor of Biomedical Science at Monash (Scholars), minoring in Chemistry

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biology1234

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Re: VCE Biology Question Thread
« Reply #13823 on: June 30, 2022, 09:07:32 am »
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does anyone know if there are solutions for the 2022 sample written examination. Thanks

Amadas_

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Re: VCE Biology Question Thread
« Reply #13824 on: July 04, 2022, 02:45:37 pm »
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Does anyone know how to describe the role of the coenzymes NADPH and ATP in photosynthesis? ( this is a SA question from the 2019 VCAA paper)

The answer on the examiner's report seems pretty brief and I'm not sure if there is a better way to word it

valjaybj

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Re: VCE Biology Question Thread
« Reply #13825 on: July 05, 2022, 07:06:21 pm »
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Does anyone know how to describe the role of the coenzymes NADPH and ATP in photosynthesis? ( this is a SA question from the 2019 VCAA paper)

The answer on the examiner's report seems pretty brief and I'm not sure if there is a better way to word it

hey! depends how many marks it is. i would just say NADPH transfers protons and electrons between the light dependent and light independent stages of photosynthesis, and ATP provides the energy to drive the process for glucose formation in the light independent stage

valjaybj

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Re: VCE Biology Question Thread
« Reply #13826 on: July 05, 2022, 07:07:56 pm »
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hi! does anyone know whether cancerous antigens on MHC I markers are recognised as self or non-self? from my understanding it's non-self (but i did a google search and it says self so now im confused)

RaspberryTau

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Re: VCE Biology Question Thread
« Reply #13827 on: July 06, 2022, 11:29:06 am »
+1
Hi,
Hope all's well! Logically speaking - if the body recognised it as non-self - it would attack it..... which would probably (hopefully) kill the cancer cell. I think that's why its so hard to treat - as the immune system doesn't recognise it as non-self. The holy grail of cancer research is finding a way to selectively kill only the cancer cell. What they are looking into more recently is "immunotherapy" - which is essentially just marking the cell as foreign, and getting the immune system to kill it. (I think).

So the sort answer - it would be "non-self". Or if it was "self", it would have mechanisms to defeat/escape lymphocytes. But as with anything in bio - there is so much complexity. For VCE level, I think the above explanation is ok.

Having said that, I haven't read the new study design (and my bio is a bit rusty). Idk.
Hope this helps :)
VCE 2021: Methods (42 raw), Biology (46 raw); 2022: Chemistry, English, Spec, Physics

valjaybj

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Re: VCE Biology Question Thread
« Reply #13828 on: July 06, 2022, 12:20:17 pm »
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Hi,
Hope all's well! Logically speaking - if the body recognised it as non-self - it would attack it..... which would probably (hopefully) kill the cancer cell. I think that's why its so hard to treat - as the immune system doesn't recognise it as non-self. The holy grail of cancer research is finding a way to selectively kill only the cancer cell. What they are looking into more recently is "immunotherapy" - which is essentially just marking the cell as foreign, and getting the immune system to kill it. (I think).

So the sort answer - it would be "non-self". Or if it was "self", it would have mechanisms to defeat/escape lymphocytes. But as with anything in bio - there is so much complexity. For VCE level, I think the above explanation is ok.

Having said that, I haven't read the new study design (and my bio is a bit rusty). Idk.
Hope this helps :)

hey, thanks!! yeah im thinking the same, in terms of understanding that it'd be non-self in order to actually get rid of it (but then in reality it's probably recognised as a self-antigen therefore evading the immune system). thanks for clearing that up!

Bri MT

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Re: VCE Biology Question Thread
« Reply #13829 on: July 06, 2022, 07:56:41 pm »
+1
hi! does anyone know whether cancerous antigens on MHC I markers are recognised as self or non-self? from my understanding it's non-self (but i did a google search and it says self so now im confused)

Cancerous cells can display tumor associated antigens or tumor specific antigens, which allow the immune system to recognise them as harmful despite being self cells. Some of them are recognised as foreign, others are not but are still able to be identified as tumour associated because of how they are expressed (e.g. at too high a level).

Hope this helps :)