VCE Biology Question Thread

[biology1234]

Hey,
I am going to be doing  a prac report in a week and was wondering if you guys had any tips for the abstract/ introduction and any pointers and ways to get extra marks. Thanks

[Bluebird]

Hi AN,
Why are second messengers required for hydrophilic signalling molecules but not hydrophobic signalling molecules? I thought they were required for both?

[-Lilac-]

For this question wouldn't it be D as it has the most amount of starch hydrolysed

When thinking about activity it’s not so much about the most product of a reaction but how much was hydrolysed in a certain time period. If more is hydrolysed in a shorter time period then the activity must have been higher.

With that in mind, if you look at D it’s been 9 minutes and 0.55 mg has been hydrolysed but if you go back to B, 0.48 mg was already hydrolysed by 1 minute.

With that in mind,  at what point do you think the enzyme had more activity?

Hi AN,
Why are second messengers required for hydrophilic signalling molecules but not hydrophobic signalling molecules? I thought they were required for both?

Second messengers refer to intracellular signalling molecules that are activated in response to extracellular signalling molecules (via a membrane receptor). Hydrophilic signalling molecules can’t cross the plasma membrane and therefore require secondary messengers to translate their signal from outside to inside the cell. Hydrophobic molecules can just travel across the membrane and bind an intracellular receptor.

[biology1234]

Hi Guys,
Do you have any tips for biology prac reports and any tips for extra marks

[Chocolatepistachio]

the enzyme had more activity at point B

[Bluebird]

When thinking about activity it’s not so much about the most product of a reaction but how much was hydrolysed in a certain time period. If more is hydrolysed in a shorter time period then the activity must have been higher.

With that in mind, if you look at D it’s been 9 minutes and 0.55 mg has been hydrolysed but if you go back to B, 0.48 mg was already hydrolysed by 1 minute.

With that in mind,  at what point do you think the enzyme had more activity?

Second messengers refer to intracellular signalling molecules that are activated in response to extracellular signalling molecules (via a membrane receptor). Hydrophilic signalling molecules can’t cross the plasma membrane and therefore require secondary messengers to translate their signal from outside to inside the cell. Hydrophobic molecules can just travel across the membrane and bind an intracellular receptor.

Thank you! That makes a lot more sense now

[Acegtr]

Hi,
What's the purpose of neutrophils if antigen-presenting cells/phagocytes are already there to phagocytose and destroy pathogens and present the non-self antigens on MHC II markers? Since neutrophils don't present MHC II, what's the point of having them? Do they work faster or are there any other benefits of neutrophils? 
Thanks in advance!

[Sine]

Hi,
What's the purpose of neutrophils if antigen-presenting cells/phagocytes are already there to phagocytose and destroy pathogens and present the non-self antigens on MHC II markers? Since neutrophils don't present MHC II, what's the point of having them? Do they work faster or are there any other benefits of neutrophils? 
Thanks in advance!

Neutrophils are the primary cells of the acute inflammatory response and are quick to get to the site of injury/stress. Things like macrophages and lymphocytes which are APCs take a little longer to get started.

[PhoenixxFire]

^Just fyi we can't provide any specific information on what to do for your sac, it's against vcaa rules. I'll try to come back later and post some more general advice when I get a minute but just wanted to pop in and say be careful because they can come after you for breaching academic integrity by collaborating for that.

[zhouzhennan]

do prions change the amino acid sequences or just the secondary structure?

[Chocolatepistachio]

isn't the peptide bond just the N-C=O not the whole thing

[Sine]

isn't the peptide bond just the N-C=O not the whole thing

I have seen the peptide bond represented in both ways, maybe ask you teacher what they prefer.

[Acegtr]

Hi,
In humoral immunity, it starts off with a B cell receptor recognising the foreign antigen that's on a pathogen, with a helper t cell stimulating the B cell and then differentiation occurring. But where does the B cell get this receptor to recognise a specific foreign antigen in the first place? Would it have something to do with the APCs from the second line of defence? If so, how exactly would that be?
Thanks in advance!

[Chocolatepistachio]

Isn’t the pyruvate oxidation that occurs before the Krebs cycle not technically part of the Krebs cycle so you wouldn’t include those in the outputs so from one cycle it would just be 2CO2, 3NADH ,1 FADH2 and 1 atp

[Acegtr]

Yea I think that's right