VCE Biology Question Thread

[Hopelesshopefull]

What the threshold voltage in an action potential indicate?

I don't think action potentials are in the VCE study design (pls double check the study design)  but if you wanted to know:
it is the voltage the needs to be surpassed for an action potential to occur. AP have this 'all or none ' nature whereby an AP will not occur if this threshold is not reached, but will occur as soon as the threshold is passed. This is because the voltage gated sodium channels wouldn't open unless this voltage is reached and we need these voltage gated sodium channels to be open for the AP to occur. 
Hope that helps

[eliseeeeee]

Can someone please explain DNA transcription and translation?? We skipped over it in class and I'm struggling to teach it to myself. Thanks 

[Calebark]

I can't seem to improve my scores for each practice exam I do. They are all really similar. Any tips?

I write down everything I did wrong in my exam, then I'll go and learn it as if I'm doing it from the beginning, to make sure I have everything. I'll use textbooks, Edrolo, and vce.bioninja. If I can, I'll also do questions on it.

Can someone please explain DNA transcription and translation?? We skipped over it in class and I'm struggling to teach it to myself. Thanks 

Hi. Rather than write it down myself, I'll redirect you to this really great resource for transcription  and translation respectively. I think the translatin one goes into a bit too much detail in the end, but the summaries and whatnot are great. If you're still having difficulty, feel free to ask again

[gameboy99]

 just asking your advice on just doing short anwer questions under timed-conditions. Also what company papers would you recommend with short answers that need logic and lateral thinking (plz mention around 3 companies)
thanks 

[blacksanta62]

just asking your advice on just doing short anwer questions under timed-conditions. Also what company papers would you recommend with short answers that need logic and lateral thinking (plz mention around 3 companies)
thanks 

Use dot points. I've found that my answers are a lot neater and more concise. Also means I don't have to put down everything I know about the question
Remain calm. Read the question carefully and talk quitely to yourself, what does the question want me to answer. I do this because timed conditions (especially when I see that there's about 40 mins left) make me panic just enough for my mind to become boggled. Doing this helps keep my head clear and ensures I understand it.
Make sure you breathe!

Not to sure about logic and lateral thinking being the main focus of the bio exam (more your ability to apply biological principles to unfamiliar situations e.g. some plant in South America which has specific enzymes which aid in it's digestion or something. Then you'd be asked about things to do with proteins and whatnot)
Companies:
1. VCAA
2. STAV
3. Neap
Just my opinion. Haven't even done many neap papers but they do have quite challenging papers for maths and chemistry. Hopefully it carries over

[gameboy99]

what is estimated/suggested time to complete Section B(short answer) in??

[lasagne]

Hey guys, for the definition of a hormone would you ever mention autocrine or paracrine signalling? Or just endocrine?

[blacksanta62]

what is estimated/suggested time to complete Section B(short answer) in??

No suggested time or expected time really. Depends on the persons speed and practice. You do however want to have some time left at the end.

Hey guys, for the definition of a hormone would you ever mention autocrine or paracrine signalling? Or just endocrine?

For VCAA this definition will do:
A hormone is a chemical messenger produced by endocrine glands which binds to specific receptors and elicits specific responses in target cells

Edit: How do I evaluate the reliability of my information and the opinions expressed in my research SAC?
Thanks

[Gogo14]

Edit: How do I evaluate the reliability of my information and the opinions expressed in my research SAC?
Thanks

I guess analyse the source you got them from? Like a website from a government will be more reliable than one from wikipedia.

Also, I came across this question which really confused me. It says a graph showing and endergonic reaction, but shouldn't the reaction be exergonic as there is point e is lower than b?

Also in the table, it says that c is without an enzyme and d with one. Shouldn't they be the other way around?

http://imgur.com/TmLUHY3
http://imgur.com/BBiCo1z

[Vaike]

I guess analyse the source you got them from? Like a website from a government will be more reliable than one from wikipedia.

Also, I came across this question which really confused me. It says a graph showing and endergonic reaction, but shouldn't the reaction be exergonic as there is point e is lower than b?

Also in the table, it says that c is without an enzyme and d with one. Shouldn't they be the other way around?

http://imgur.com/TmLUHY3
http://imgur.com/BBiCo1z

I remember doing this question too, and I didn't understand it either. My guess is that it's just a poor question, I can't remember which exam its from? But yeah unless someone else can explain otherwise I'm pretty sure it's just a dodgy question so don't worry too much.

[hodang]

Hey All! I'm having a little bit trouble with these questions. If any of you guys would like to help me that would be great thanks! sorry it's lenthy

Exactly how much ATP molecules are produced in the ETC? Which is better to write- 32 ATP molecules or 36-38? I'm super confused

If we do not simplify ratio's when writing the phenotypic or genotypic ratio, will we be deducted?! For eg, if it's • 2 females with white eyes: 2 males with brown eyes or do we have to write 1 female with white eyes: 1 male with brown eyes?

Lactose attaches to repressor proteins which this change its shape causing it to detach from the operator region right?


What are the temperatures that are used in PCR? Every book is telling me different, is it 94•C/93C then 55 or 50C then 72C? Btw is the DNA strands denatured? Can we use the word denatured or dissociated?

Can we say that
ATP is formed when ADP is phosphorylated? Or
ATP is formed when ADP + Pi is phosphorylated?! Which one?

Does light energy split water molecules into hydrogen ions and oxygen?

Is NADPH and NADP considered as molecules? (2015 vcaa paper only included water, oxygen, ATP as molecules?)

Are igE antibodies produced during an allergic reaction? Can we say that when an allergen is encountered, your B cells produce the antibody igE which later bind to mast cells etc?

Are nerves electrical and chemical? Whereas hormones are just chemical?

What are some immune cells? I know mast cells are but what else?

Okay, for fatty acids/lipids, is it attached to a glycerol head? I'm so confused... where does the phosphate head come into place? Is it glycerol or phosphate?

Do we have to draw glycoprotein as a alpha helix shape? BTW is carbohydrate attached to the glycoprotein?

Lastly, can someone please explain to me everything we need to know about booster injections? I actually have no clue

[Gogo14]

Did a trial exam. It said that in glycolysis 2H2O, 2ATP, 2NADH is produced. Wut?
I thought water was produced in ETC only?

Edit: the answer says 2H2O, 2ATP, 2NADH AND 2 pyruvate

[plsbegentle]

Did a trial exam. It said that in glycolysis 2H2O, 2ATP, 2NADH is produced. Wut?
I thought water was produced in ETC only?

pretty sure should of been 2 pyruvate.. must of been typo. And yes ETC produces water only.

EDIT: Yep no water in glycolysis

[Gogo14]

pretty sure should of been 2 pyruvate.. must of been typo. And yes ETC produces water only.

Forgot to include it. Fixed it up in the edit. So definitely no water in glycolysis?

[Gogo14]

Explain the role of lipids in the plasma membrane. List 2 other functions of lipids
   • In the plasma membrane, the membrane itself is made of phospholipids which are orientated in a bilayer to regulate the input/outputs of a cell
          In addition, cholesterol are also lipids in the plasma membrane that maintains structure and fluidity for the membrane
         

           Fat storage and insulation


Would this be an acceptable answer? I actually do not know the real answer for the question