Login

Welcome, Guest. Please login or register.

March 29, 2024, 09:46:37 am

Author Topic: VCE Biology Question Thread  (Read 3571030 times)  Share 

0 Members and 7 Guests are viewing this topic.

Scribe

  • Forum Regular
  • **
  • Posts: 69
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #10740 on: October 04, 2018, 09:37:07 pm »
+1
Does anyone have some stats or knowledge on the 2017 bio exam? That is, assuming SAC scores are maximised, what exam scores were required for 45/47/50?

I know a student who achieved a 50 with full scaling SACs and low 90s on the 2017 exam if that helps.
Edit: low to mid 90s (I don't remember exactly)
« Last Edit: October 04, 2018, 09:44:37 pm by Scribe »

PhoenixxFire

  • VIC MVP - 2018
  • Honorary Moderator
  • ATAR Notes Legend
  • *******
  • Posts: 3695
  • They/them/theirs
  • Respect: +3102
Re: VCE Biology Question Thread
« Reply #10741 on: October 04, 2018, 09:40:07 pm »
+1
Does anyone have some stats or knowledge on the 2017 bio exam? That is, assuming SAC scores are maximised, what exam scores were required for 45/47/50?
I was rank 2 for U3 (I think), rank 1 for U4 and got about 85% on the exam.

VCAA publishes grad distributions (just google VCE bio grade distribution 2017) which shows how many people got each exam score, combine that with the percentage of people who get each study score and you might be able to figure it out.

Sine would probably have an idea as well.
2019: B. Environment and Sustainability/B. Science @ ANU
2020: Just Vibing
2021: B. Paramedicine/B. Nursing @ ACU Canberra

Scribe

  • Forum Regular
  • **
  • Posts: 69
  • Respect: 0

galaxy21

  • Trendsetter
  • **
  • Posts: 150
  • Respect: +23
Re: VCE Biology Question Thread
« Reply #10743 on: October 05, 2018, 08:50:59 am »
0
Hi again...Sorry to keep bombarding the bio question thread, but just wondering, does the inflammatory response, including histamine release, occur only if a pathogen enters the body (e.g. through broken skin), or in all cases, even if there is no pathogen?
2018 - Biology, Further
2019 - English, Chemistry, Methods, Health and Human Development
2020 - Bachelor of Science (Melbourne Uni)

PhoenixxFire

  • VIC MVP - 2018
  • Honorary Moderator
  • ATAR Notes Legend
  • *******
  • Posts: 3695
  • They/them/theirs
  • Respect: +3102
Re: VCE Biology Question Thread
« Reply #10744 on: October 05, 2018, 09:10:26 am »
+3
Hi again...Sorry to keep bombarding the bio question thread, but just wondering, does the inflammatory response, including histamine release, occur only if a pathogen enters the body (e.g. through broken skin), or in all cases, even if there is no pathogen?
No, it's not only if there's a pathogen. It also occurs when you get a cut even if pathogens don't get in. Whenever mast cells are damaged they release histamine, so something like a sprained ankle can also cause inflammation even though there's no pathogen. There's a few different things that cause mast cells to release histamine, but the most common is them being damaged.

Hi just wondering, with plant hormones, which ones do we need to know about? Do we need to know if they bind to intracellular or extracellular receptors in cells?
Also I missed this earlier. We had a bit of a debate about this last year and couldn't really decide for sure. The old study design had way more on it that we definitely don't need, so don't worry about all the stuff you find on past exams.
The study design doesn't place any extra emphasis on plant hormones than it does on any other type of signalling molecule
Spoiler
•    the sources and mode of transmission of various signalling molecules to their target cell, including plant and
animal hormones, neurotransmitters, cytokines and pheromones
So given you don't need to know about specific types of any of the others we figured we probably wouldn't need to know about any specific types of plant hormones either. We figured that so long as you knew about plant hormones in general then that'd be fine. Some people learnt about the functions of common plant hormones though (gibberelins, auxins, etc) but you probably don't need to know that.
« Last Edit: October 05, 2018, 09:17:00 am by PhoenixxFire »
2019: B. Environment and Sustainability/B. Science @ ANU
2020: Just Vibing
2021: B. Paramedicine/B. Nursing @ ACU Canberra

darkz

  • Forum Obsessive
  • ***
  • Posts: 413
  • Respect: +154
Re: VCE Biology Question Thread
« Reply #10745 on: October 05, 2018, 09:18:59 am »
+4
Hi just wondering, with plant hormones, which ones do we need to know about? Do we need to know if they bind to intracellular or extracellular receptors in cells?

You just need to know the main ones, so auxin, gibberellins, cytokinins, ethylene and absisic acid - pretty sure you just need to know briefly what they do for the new study design e.g. ethylene increases rate of respiration => increasing the rate of ripening. And no, you don't need to know whether they are hydrophilic/ hydrophobic (so whether they bind to intracellular/ extracellular receptors). If the question wants you to discuss the signal transduction pathway of the specific plant hormone, they will generally give you some background information on it.
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

Scribe

  • Forum Regular
  • **
  • Posts: 69
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #10746 on: October 05, 2018, 09:04:15 pm »
0
Does signal transduction refer to the stage in between reception and response or does it refer to the entire process? If not, what is the entire process called (is it stimulus-response model)?

Scribe

  • Forum Regular
  • **
  • Posts: 69
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #10747 on: October 05, 2018, 09:28:58 pm »
0
Sorry guys! I have a second question.
Are B cells activated by both raw antigens and helper T cells?
1) Free antigens makes direct contact with specific B cell which proliferates and differentiates(?) into plasma cells and memory B cells.
2) Antigen-presenting cell presents antigen to Helper T cell which then presents antigen to B cell.

If so, do we discuss both forms of activation? How do we know which one to talk about on an exam question?
« Last Edit: October 05, 2018, 09:31:17 pm by Scribe »

PhoenixxFire

  • VIC MVP - 2018
  • Honorary Moderator
  • ATAR Notes Legend
  • *******
  • Posts: 3695
  • They/them/theirs
  • Respect: +3102
Re: VCE Biology Question Thread
« Reply #10748 on: October 05, 2018, 10:06:00 pm »
+4
Does signal transduction refer to the stage in between reception and response or does it refer to the entire process? If not, what is the entire process called (is it stimulus-response model)?
Both. The process is called signal transduction and the three steps are
1. reception
2. transduction
3. response
just to make it even harder for us haha

Sorry guys! I have a second question.
Are B cells activated by both raw antigens and helper T cells?
1) Free antigens makes direct contact with specific B cell which proliferates and differentiates(?) into plasma cells and memory B cells.
2) Antigen-presenting cell presents antigen to Helper T cell which then presents antigen to B cell.

If so, do we discuss both forms of activation? How do we know which one to talk about on an exam question?
Yeah what you've said is correct. They don't really divide or differentiate until the cytokines have been released from the T helper cell, so avoid saying that in your answer. Initially they're 'selected' when they bind to their free antigen however they won't really divide or differentiate until the cytokines are released.
If it's a 3 or 4 mark immunity question then yes you need to talk about both. I normally just put it as a one line thing 'The activated B cell and Th cell will then find each other and if they have bound the same antigen, the Th cell will release cytokines.' or something like that (and then go on to talk about the cytokines triggering proliferation and differentiation etc.)
2019: B. Environment and Sustainability/B. Science @ ANU
2020: Just Vibing
2021: B. Paramedicine/B. Nursing @ ACU Canberra

rinner

  • Trailblazer
  • *
  • Posts: 27
  • Respect: +12
Re: VCE Biology Question Thread
« Reply #10749 on: October 05, 2018, 10:15:44 pm »
+1
(edit, phoenixxfire answered your questions)
Quote
Does signal transduction refer to the stage in between reception and response or does it refer to the entire process? If not, what is the entire process called (is it stimulus-response model)?
I'm pretty sure signal transduction refers to the entire process; here's a definition from my notes
"The conversion of an extracellular stimulus, by the cell, that results in a functional change or specific cellular response"
Signal transduction is a specific example of stimulus response model which is a much broader term( in which a external/internal event causes a change).
Quote
Are B cells activated by both raw antigens and helper T cells? 1) Free antigens makes direct contact with specific B cell which proliferates and differentiates(?) into plasma cells and memory B cells. 2) Antigen-presenting cell presents antigen to Helper T cell which then presents antigen to B cell. If so, do we discuss both forms of activation? How do we know which one to talk about on an exam question?
Both 1 and 2 are correct, but I omitted 1 from any of my answers, because it makes it so much simpler. It also works well with all the immune responses, eg. cell mediated. I would refrain from both types of activation just because the answering such questions is already long and wordy. The only time I would answer for both, if it specifically asks for it question.
Cheers!
« Last Edit: October 05, 2018, 10:17:59 pm by rinner »

galaxy21

  • Trendsetter
  • **
  • Posts: 150
  • Respect: +23
Re: VCE Biology Question Thread
« Reply #10750 on: October 06, 2018, 08:31:13 am »
0
Hi
Is anybody able to give a clear time of when bipedalism evolved? I was trying to look it up before the SAC a few weeks ago, and couldn't get an exact time period, but I thought I should definitely clarify this before the exam!
2018 - Biology, Further
2019 - English, Chemistry, Methods, Health and Human Development
2020 - Bachelor of Science (Melbourne Uni)

Qwerty1234qwerty

  • Adventurer
  • *
  • Posts: 18
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #10751 on: October 06, 2018, 09:43:37 am »
0
I’ve got a few Qns

Are complement proteins not effective against viruses? If so, why
Why is the immune response faster in a secondary exposure than a primary exposure?
Do autocrine  hormones only affect the cell the cell that secretes them or the same type of cell

sweetcheeks

  • Forum Obsessive
  • ***
  • Posts: 496
  • Respect: +83
  • School: ---
  • School Grad Year: 2016
Re: VCE Biology Question Thread
« Reply #10752 on: October 06, 2018, 09:59:06 am »
0
I’ve got a few Qns

Are complement proteins not effective against viruses? If so, why
Why is the immune response faster in a secondary exposure than a primary exposure?
Do autocrine  hormones only affect the cell the cell that secretes them or the same type of cell


Have a go at these yourself first. It makes for a much better learning experience if you try to answer the questions before someone gives you the answer.

PhoenixxFire

  • VIC MVP - 2018
  • Honorary Moderator
  • ATAR Notes Legend
  • *******
  • Posts: 3695
  • They/them/theirs
  • Respect: +3102
Re: VCE Biology Question Thread
« Reply #10753 on: October 06, 2018, 10:00:50 am »
+3
Hi
Is anybody able to give a clear time of when bipedalism evolved? I was trying to look it up before the SAC a few weeks ago, and couldn't get an exact time period, but I thought I should definitely clarify this before the exam!
There isn't really a clear answer to this. It's very unlikely that you'll have to give a date on the SAC (actually I seem to remember that VCAA said somewhere what source they used for their dates - I'll go see if I can find it). If you get a question on this it'll probably either be multiple choice with only one option being possible, or it'll be a question where you have to identify the correct order that traits evolved in or something like that. I've dumped a bit of info from here below - really it just shows that we don't know the answer to that though (If I find VCAA's source I'll let you know though!)

Quote
In more recent decades, anthropologists have determined that bipedalism has very ancient roots. In 2001, a group of French paleoanthropologists unearthed the seven-million-year-old Sahelanthropus tchadensis in Chad. Known only from a skull and teeth, Sahelanthropus‘ status as an upright walker is based solely on the placement of its foramen magnum, and many anthropologists remain skeptical about the species’ form of locomotion. In 2000, paleoanthropologists working in Kenya found the teeth and two thigh bones of the six-million-year-old Orrorin tugenensis. The shape of the thigh bones confirms Orrorin was bipedal. The earliest hominid with the most extensive evidence for bipedalism is the 4.4-million-year-old Ardipithecus ramidus. In 2009, researchers announced the results of more than 15 years of analysis of the species and introduced the world to a nearly complete skeleton called Ardi.

Although the earliest hominids were capable of upright walking, they probably didn’t get around exactly as we do today. They retained primitive features—such as long, curved fingers and toes as well as longer arms and shorter legs—that indicate they spent time in trees. It’s not until the emergence of H. erectus 1.89 million years ago that hominids grew tall, evolved long legs and became completely terrestrial creatures.

I’ve got a few Qns

1. Are complement proteins not effective against viruses? If so, why
2. Why is the immune response faster in a secondary exposure than a primary exposure?
3. Do autocrine hormones only affect the cell the cell that secretes them or the same type of cell

1.
No they're not really effective against virus'.
The three things they do are:
1. Opsonize pathogens: They stick on the surface of pathogens in the extracellular environment and make it easier for leukocytes to recognise them.
2. Attract phagocytes to the area: They are chemoattractants, phagocytes will be drawn to the source of complement proteins.
3. Create pores in bacterial membranes. Form a Membrane Attack Complex (MAC): They create a hole in the bacteria, causing fluid from the extracellular environment to rush in and rupture the bacteria.
So they're only really effective against extracellular pathogens (especially bacteria).

2.
This is due to memory cells. During a primary exposure there's one naive immune cell that will recognise the antigen. During a secondary immune response there's lots of memory cells floating around that will recognise the antigen. This means that the antigen will be recognised faster and therefore response will be faster and larger.

3.
Only the cell releasing them. It's not only hormones by the way - cytokines can also have autocrine signalling. Also something can be both autocrine and paracrine so it doesn't necessarily just affect it, but only the part where it effects itself is called autocrine.

@sweetcheeks, sorry for answering them anyway but i'd already typed it up before you posted that haha
« Last Edit: October 06, 2018, 10:02:42 am by PhoenixxFire »
2019: B. Environment and Sustainability/B. Science @ ANU
2020: Just Vibing
2021: B. Paramedicine/B. Nursing @ ACU Canberra

peachxmh

  • Forum Regular
  • **
  • Posts: 84
  • ¯\_(ツ)_/¯
  • Respect: 0
Re: VCE Biology Question Thread
« Reply #10754 on: October 06, 2018, 11:01:54 am »
0
For the question below from STAV 2013, why is option A not correct? (I understand that option C is correct). Don't B and T cells differentiate from stem cells in the bone marrow which is a primary lymphoid organ and thus part of the lymphatic system? I did some research online and couldn't find anything saying otherwise..

The lymphatic system:
A. manufactures B and T cells from stem cells.
B. consists of arteries and capillaries but no veins.
C. has lymph nodes that are storage sites for macrophages and lymphocytes.
D. carries all types of blood cells.
« Last Edit: October 06, 2018, 11:03:34 am by peachxmh »
2019: VCE
2020: Med @ Monash