VCE Biology Question Thread

[TheAspiringDoc]

I am assuming you're talking about RNA transcription, right?
Well, no, in terms of VCE Biology, the non-template strand is not used to code for RNA, but it has to exist - because remember, the original DNA molecule is double stranded, and because RNA is single stranded, then only one strand of the DNA double helix could possibly be used to transcribe the RNA.

Im not sure if this directly answers your question - bit of a vague one haha, 'what use is it' xD

Well what I mean is if only one paticular strand of the DNA helix actually does anything (so it seems), what's the point of having the other one? Is it to seal off the template one and prevent mutations or something like help transcribe further copies of the template strand as the nontemplate strand has the right corresponding nucleotide bases to do so..?

[cosine]

Well what I mean is if only one paticular strand of the DNA helix actually does anything (so it seems), what's the point of having the other one? Is it to seal off the template one and prevent mutations or something like help transcribe further copies of the template strand as the nontemplate strand has the right corresponding nucleotide bases to do so..?

So you're essentially asking why DNA is double stranded? I dont think anyone can give you a direct answer to that... I guess it remains a mystery of the universe? I dont even know...

[sunshine98]

Well what I mean is if only one paticular strand of the DNA helix actually does anything (so it seems), what's the point of having the other one? Is it to seal off the template one and prevent mutations or something like help transcribe further copies of the template strand as the nontemplate strand has the right corresponding nucleotide bases to do so..?

Actually didn't know the answer but asked Google and according to some random site u r on the right track
It talks about how the bases are what hold the information so having them centred and somewhat shielded by the phosphate and sugars means that they are not exposed to local mutagens and hence mutation rates are reduced  This actually makes sense.
Also, the site says that DNA actually has a lower mutation rate than RNA would ( eg. viruses with DNA app have lower mutation rate than those with RNA ). The explanation is that because it is double stranded , due to the presence of the other strand, changes in bases ( Aka mutations)  can be detected and hence fixed
Idk how accurate this is because never been taught it but it makes sense if u think about it

[Scooby]

Heyo

Can someone please outline the purpose of the non-template strand of DNA?
(I mean if it doesn't even code for RNA, what use is it?)

Thanks!

Let's say the two strands of our DNA molecule are strand A and strand B. For a particular gene, the template strand might be strand A, but for another gene in the same DNA molecule, the template strand might be strand B. When we're looking at a whole DNA molecule, there isn't one particular strand (ie. strand A or strand B) that is designated as template - it's specific to whatever gene we're looking at (although for a particular gene, if strand A is the template, it will always be the template).

Neither strand of the whole DNA molecule is redundant

[TheAspiringDoc]

Let's say the two strands of our DNA molecule are strand A and strand B. For a particular gene, the template strand might be strand A, but for another gene in the same DNA molecule, the template strand might be strand B. When we're looking at a whole DNA molecule, there isn't one particular strand (ie. strand A or strand B) that is designated as template - it's specific to whatever gene we're looking at (although for a particular gene, if strand A is the template, it will always be the template).

Neither strand of the whole DNA molecule is redundant

Ahh  - thank you , that really clears it up

[vox nihili]

So you're essentially asking why DNA is double stranded? I dont think anyone can give you a direct answer to that... I guess it remains a mystery of the universe? I dont even know...

Two reasons really.

1. It's more stable than ssDNA
2. Enzymes make complementary strands of DNA, hence the stability of dsDNA

I guess you could then ask the question "why have we evolved to make complementary DNA strands?". I suspect the answer would, once again, return to stability. The more stable the DNA, the less likely it is to be degraded or mutated. As DNA is a molecule that needs to last a very long time in some cells, this is clearly an evolutionary advantage. If the DNA breaks down, the cell will die; therefore, the stability of DNA is extremely critical and anything that could increase it would be an enormous evolutionary advantage.

Actually didn't know the answer but asked Google and according to some random site u r on the right track
It talks about how the bases are what hold the information so having them centred and somewhat shielded by the phosphate and sugars means that they are not exposed to local mutagens and hence mutation rates are reduced  This actually makes sense.
Also, the site says that DNA actually has a lower mutation rate than RNA would ( eg. viruses with DNA app have lower mutation rate than those with RNA ). The explanation is that because it is double stranded , due to the presence of the other strand, changes in bases ( Aka mutations)  can be detected and hence fixed
Idk how accurate this is because never been taught it but it makes sense if u think about it

Not sure I'm really convinced by the RNA thing. The mutation rate of a nucleic acid, for the most part, is determined by the enzymes that synthesise it, not the inherent properties of the nucleic acid. This is not entirely true, but the fidelity of the enzymes are overwhelming the biggest contributor to mutation rate.

[bills]

Can someone verify if these pieces of information are correct?

- Channel proteins allow water-soluble substances to enter/leave the cell by opening up and allowing water (along with the dissolved substances) to pass through. Or do they somehow separate the substance from the water, bringing only the substance and leaving the water behind?

- Glucose moves into a cell both passively and actively with the help of carrier proteins (actively requires ATP).

- Ions move into a cell actively with the help of channel proteins (that use ATP).

[sunshine98]

Can someone verify if these pieces of information are correct?

- Channel proteins allow water-soluble substances to enter/leave the cell by opening up and allowing water (along with the dissolved substances) to pass through. Or do they somehow separate the substance from the water, bringing only the substance and leaving the water behind? I guess it kinda depends.  Some channel proteins are specific to a specific substance (such as sodium channels which would only allow sodium through etc). 

- Glucose moves into a cell both passively and actively with the help of carrier proteins (actively requires ATP). Yep. It undergoes facilitated diffusion because it is a large molecule

- Ions move into a cell actively with the help of channel proteins (that use ATP). Yep. Active transport requires a protein and even if it wasn't active because we are talking about ions and ions are charged it would need to use a protein.

hope this helps

[bills]

hope this helps

So active transport isn't only limited to carrier proteins? It can be used with channel proteins?

[sunshine98]

So active transport isn't only limited to carrier proteins? It can be used with channel proteins?

Only carrier ( as far as I know )

[Biology24123]

So active transport isn't only limited to carrier proteins? It can be used with channel proteins?

As far as I know, you don't need to distinguish between carrier and channel proteins

[vox nihili]

So active transport isn't only limited to carrier proteins? It can be used with channel proteins?

Stick with carriers in VCE





Channel proteins can be involved in active transport, but this is well beyond the purview of the VCE course.

[The Usual Student]

Water is not on the study design, but the textbook goes into a lot of detail, can someone tell me what I need to know about it?
Thanks
also, can someone explain this from the textbook
" Most materials shrink as the temperature falls because movement of molecules within the material decreases, as the temperature of water falls the rate of molecule movement decreases but at 4 Celcuis there is no longer sufficient movement to break hydrogen bonds"

I understand the latter part of that sentence with hydrogen bonds but not the whole "molecular movement" idea :/
as why do the materials shrink?

[Sine]

Water is not on the study design, but the textbook goes into a lot of detail, can someone tell me what I need to know about it?
Thanks
also, can someone explain this from the textbook
" Most materials shrink as the temperature falls because movement of molecules within the material decreases, as the temperature of water falls the rate of molecule movement decreases but at 4 Celcuis there is no longer sufficient movement to break hydrogen bonds"

I understand the latter part of that sentence with hydrogen bonds but not the whole "molecular movement" idea :/
as why do the materials shrink?

for water just understand a few properties that enable life. High heat capacity, High heat latency, transparency, major component of cells etc.etc

lower temp means less kinetic energy thus less movement and more compact
for example for water at low temperatures it becomes ice due to very little kinetic energy molecules of water move more slowly thus able to form a hexagonal lattice.

not sure as why materials would shrink as ice becomes larger than the water it was.

[Syndicate]

Water is not on the study design, but the textbook goes into a lot of detail, can someone tell me what I need to know about it?
Thanks
also, can someone explain this from the textbook
" Most materials shrink as the temperature falls because movement of molecules within the material decreases, as the temperature of water falls the rate of molecule movement decreases but at 4 Celcuis there is no longer sufficient movement to break hydrogen bonds"

I understand the latter part of that sentence with hydrogen bonds but not the whole "molecular movement" idea :/
as why do the materials shrink?

Hey,

So basically, your textbook is trying to say that when the temperature of water decreases (example -12 Celsius), the volume of the water seems to decrease, as the molecules are moving slower (taking up less space) and causing the volume to shrink. However, when the water is heated, the molecules are moving at a much faster rate, and will take up more space causing the material to seem a little more larger.

I have attached a picture at the bottom, hopefully that helps you.