VCE Biology Question Thread

[wobblywobbly]

Are linked genes a big part of the study design

Yes, but not including map units.

How much do we need to know about EcoRI? Would any questions appear on the exam in regards to this restriction enzyme without any background information in the question about it?
Thanks! 

In your SACs, you might be asked a question on it, if you used it in - let's say - an experiment that you did. Otherwise, on the VCAA exam, they would never give you a question that requires a specific knowledge of X enzyme. They will give background information from which you can figure everything out. To not do that would be just silly.

[Maca 13]

Yes, but not including map units.

In your SACs, you might be asked a question on it, if you used it in - let's say - an experiment that you did. Otherwise, on the VCAA exam, they would never give you a question that requires a specific knowledge of X enzyme. They will give background information from which you can figure everything out. To not do that would be just silly.

Oh, OK, thanks!!

[cosine]

Is PCR and recombinant plasmids both called gene cloning? Because PCR clones (makes more) of the same gene on a DNA strand, as well as the recombinant plasmids.

[cosine]

A question rose to my attention:

What is the difference between DNA amplification and gene cloning?

I'll have a go and say that DNA amplification is when a small DNA fragment undergoes a process where two identical copies of the fragment are produced, whereas gene cloning is when a desired gene that is extracted out of an organism is copied, and recombined with a vector, and the gene is acted upon (it is switched on to produce the desired protein or whatever).
Is this correct guys?

What is splicing?
I have a feeling that it is the process in which restriction enzymes cut a specific DNA sequence, is this true?

[TheAspiringDoc]

Hi, I was just wondering if cytokinesis is part of mitosis?

[Jay.C]

Hi, I was just wondering if cytokinesis is part of mitosis?

It is not.

[vox nihili]

A question rose to my attention:

What is the difference between DNA amplification and gene cloning?

I'll have a go and say that DNA amplification is when a small DNA fragment undergoes a process where two identical copies of the fragment are produced, whereas gene cloning is when a desired gene that is extracted out of an organism is copied, and recombined with a vector, and the gene is acted upon (it is switched on to produce the desired protein or whatever).
Is this correct guys?

What is splicing?
I have a feeling that it is the process in which restriction enzymes cut a specific DNA sequence, is this true?

Embarrassingly, I'm not actually entirely sure of the difference between cloning and amplification. I've heard cloning used in a lot of different contexts so part of me thinks it's one of those words that picks up too many meanings.


Genes are transcribed into mRNA transcripts. As it happens though, the pre-mRNA is actually made up of sequence that is expressed called EXONS and bits that aren't aren't expressed, called INTRONS (for intervening). Splicing is a series of reactions that removes the introns and joins up the exons to make up so-called mature mRNA.

[cosine]

Embarrassingly, I'm not actually entirely sure of the difference between cloning and amplification. I've heard cloning used in a lot of different contexts so part of me thinks it's one of those words that picks up too many meanings.


Genes are transcribed into mRNA transcripts. As it happens though, the pre-mRNA is actually made up of sequence that is expressed called EXONS and bits that aren't aren't expressed, called INTRONS (for intervening). Splicing is a series of reactions that removes the introns and joins up the exons to make up so-called mature mRNA.

What does splicing have to do with gene cloning/amplification?

Has anyone done the recombinant SAC already? Any things to look out for?

[BakedDwarf]

What does splicing have to do with gene cloning/amplification?

I'm going to have a guess and say that desired DNA fragments are spliced before they are placed into a plasmid because bacterial DNA (including plasmids and the one long chromosome) do not contain introns. Hence, they do not have the necessary enzymes to remove introns.

Again, this is just a guess so if i'm wrong (which I mostly am), correct me.

[cosine]

Are endergonic reactions the same as anabolic reactions? Do they just describe the reactions when two reactancts form a more single complex product, whereas exergonic and catabolic reactions describe one reactant breaking down into two simpler ones?

Do ALL endergonic reactions require energy?
Do ALL exergonic reactions release energy?

I know that enzymes release activation energy, but how exactly do they do this? Like a substrate will collide with the enzyme's active site, does the enzyme bind with the substrate/s and de-stabilise/form the bonds? An explanation would be great, cheers.

[HighTide]

What does splicing have to do with gene cloning/amplification?

Has anyone done the recombinant SAC already? Any things to look out for?

Sup,
This question seems beyond the study design. Where was the question from, or was it just curiosity? Anyway, I'd agree with BakedDwarf. Despite the similarities to splicing, gene splicing is also the insertion of a gene into another organism i.e. incorporating DNA into a plasmid.

Are endergonic reactions the same as anabolic reactions? Do they just describe the reactions when two reactancts form a more single complex product, whereas exergonic and catabolic reactions describe one reactant breaking down into two simpler ones?

Do ALL endergonic reactions require energy?
Do ALL exergonic reactions release energy?

I know that enzymes release activation energy, but how exactly do they do this? Like a substrate will collide with the enzyme's active site, does the enzyme bind with the substrate/s and de-stabilise/form the bonds? An explanation would be great, cheers.

The words are not identical but are synonymous. Endergonic reactions are associated with anabolism and exergonic reactions with catabolism. All endergonic reactions require energy, all exergonic reactions release energy.
Enzymes lower activation energy. So when the enzyme attaches to its substrate, it interacts with the substrate via the bonds. Decreasing the amount of activation energy required allows more particles to pass the activation energy barrier, and therefore an increased reaction rate.
When particles are moving around, its kinetic energy. Energy is required to collide. By bringing them together, the enzyme increases the chance of successful collision. At the time, the reactants are unstable and will stabilize via the breaking or making of bonds.
Hope this helps.

I'll attach a detailed explanation from a biology book just in case. There's a pretty decent analogy. You definitely don't need to know in that depth, just the idea that the enzymes lower the activation energy and thus speed up the reaction.
Enjoy 

[cosine]

Sup,
This question seems beyond the study design. Where was the question from, or was it just curiosity? Anyway, I'd agree with BakedDwarf. Despite the similarities to splicing, gene splicing is also the insertion of a gene into another organism i.e. incorporating DNA into a plasmid.
The words are not identical but are synonymous. Endergonic reactions are associated with anabolism and exergonic reactions with catabolism. All endergonic reactions require energy, all exergonic reactions release energy.
Enzymes lower activation energy. So when the enzyme attaches to its substrate, it interacts with the substrate via the bonds. Decreasing the amount of activation energy required allows more particles to pass the activation energy barrier, and therefore an increased reaction rate.
When particles are moving around, its kinetic energy. Energy is required to collide. By bringing them together, the enzyme increases the chance of successful collision. At the time, the reactants are unstable and will stabilize via the breaking or making of bonds.
Hope this helps.

I'll attach a detailed explanation from a biology book just in case. There's a pretty decent analogy. You definitely don't need to know in that depth, just the idea that the enzymes lower the activation energy and thus speed up the reaction.
Enjoy 

Alright that sort of clears things up, but it would be nice if you could answer just these more questions:

I get now that endergonic reactions require energy, so does this mean that endergonic reactions are those where two reactants form one product? And whereas exergonic reactions are when one reactant is broken down into two products, thus releasing energy.

Also what do you mean by 'by bringing them together, the enzyme increases the chance of successful collision" ?

[Jay.C]

Does anyone know if we need to know neurohormones? I am aware that the study design says we need to know:
- types of signalling molecules: neurotransmitters; animal hormones; pheromones; plant growth
regulators.

But is neurohormones also included?

Thanks 

[vox nihili]

What does splicing have to do with gene cloning/amplification?

Has anyone done the recombinant SAC already? Any things to look out for?

Nothing at all really. You can say, as HighTide suggested, that a gene has been spliced into a plasmid, but personally I think that this language is a bit unclear and it's not something you'd hear a lot in the literature nowadays because of its vagueness. HighTide is quite right though, that's probably the splicing they're talking about.

Alright that sort of clears things up, but it would be nice if you could answer just these more questions:

I get now that endergonic reactions require energy, so does this mean that endergonic reactions are those where two reactants form one product? And whereas exergonic reactions are when one reactant is broken down into two products, thus releasing energy.

Also what do you mean by 'by bringing them together, the enzyme increases the chance of successful collision" ?

Good explanation of endergonic vs exergonic, HighTide.

In most cases endergonic reactions are anabolic (i.e. two things react to make bigger things). Certainly in VCE Biology you wouldn't encounter reactions that don't follow this pattern; however, this is not always the case. You just need to remember the definitions. An endergonic reaction is any that requires an input of energy from the environment to take place; an exergonic reaction is one that releases energy to the environment. What happens with the energy, frankly, has nothing to do with whether or not the reaction is anabolic or catabolic. Most anabolic reactions are endergonic, most catabolic reactions are exergonic; however, there is nothing that really should let us assume that this is the case. Being able to differentiate between exergonic/endergonic and cataboic/anabolic is a really important skill for the Biochemistry part of the course.

For a reaction to take place, the things involved in the reaction have to come together; they have to collide with one another. Therefore, one way that enzymes can work is by orientating the substrates of a reaction in such a way that the chance of one substrate colliding with the other is increased dramatically; therefore, increasing the overall reaction rate. This is not the only way enzymes work (e.g. amylase, catalase, pepsin etc only operate on the single substrate, so obviously that explanation of enzyme activity doesn't work) but it is one way they do work and is one that, certainly, provides a nice conceptual explanation.

Does anyone know if we need to know neurohormones? I am aware that the study design says we need to know:
- types of signalling molecules: neurotransmitters; animal hormones; pheromones; plant growth
regulators.

But is neurohormones also included?

Thanks 

Yes, they are indeed

[cosine]

Nothing at all really. You can say, as HighTide suggested, that a gene has been spliced into a plasmid, but personally I think that this language is a bit unclear and it's not something you'd hear a lot in the literature nowadays because of its vagueness. HighTide is quite right though, that's probably the splicing they're talking about.

Good explanation of endergonic vs exergonic, HighTide.

In most cases endergonic reactions are anabolic (i.e. two things react to make bigger things). Certainly in VCE Biology you wouldn't encounter reactions that don't follow this pattern; however, this is not always the case. You just need to remember the definitions. An endergonic reaction is any that requires an input of energy from the environment to take place; an exergonic reaction is one that releases energy to the environment. What happens with the energy, frankly, has nothing to do with whether or not the reaction is anabolic or catabolic. Most anabolic reactions are endergonic, most catabolic reactions are exergonic; however, there is nothing that really should let us assume that this is the case. Being able to differentiate between exergonic/endergonic and cataboic/anabolic is a really important skill for the Biochemistry part of the course.

For a reaction to take place, the things involved in the reaction have to come together; they have to collide with one another. Therefore, one way that enzymes can work is by orientating the substrates of a reaction in such a way that the chance of one substrate colliding with the other is increased dramatically; therefore, increasing the overall reaction rate. This is not the only way enzymes work (e.g. amylase, catalase, pepsin etc only operate on the single substrate, so obviously that explanation of enzyme activity doesn't work) but it is one way they do work and is one that, certainly, provides a nice conceptual explanation.

Yes, they are indeed

Thankyou Mr.T-Rav, and also HighTide!

So you said that amylase and other enzymes do not work that way. Because amylase breaks down carbohydrates in our mouth, is this a catabolism? Also is it true that enzymes like amylase collide with the substrate, destabilises the carb's bonds and hence have broken down the carbohydrate into it's constituent simpler sugars?

What about anabolism and enzymes? Do the two substrates both bind to the active site, and so what does the enzyme actually do to them? Does it just 'glue' (not a good term, but you know what I mean) them together, or could you say it forms new bonds between the two reactants and hence they are joined together?

Cheers