VCE Biology Question Thread

[CarterGray12]

Although they all contained the same amount of enzymes, and there was sufficient substrate, the reason that the bubbles didn't reach the same height eventually is because of surface area. I would presume that the ground liver would produce the most bubbles, as an increase in surface area to volume ratio means that there is more enzymes (in this case catalase) available to bind with a substrate. Furthermore, as a result in such an increased rate in reaction you would have also observed a change in temperature in each of your beakers, with faster reactions exhibiting higher temperature changes.

Hey, Thanks for the response. All of the cells were ground thoroughly. However, now that you mention it, could it be that liver cell have a higher amount of enzyme compared to the other cells? Still, what would stop the enzymes from continually acting on the substrate? in all instances the reaction occurred quite quickly then crept a little bit then there were no more bubbles produced.

[cosine]

Are we really required to know the two photosystems and their specific processes, or can we just learn the light-independent stage as a whole? Thanks

[Rishi97]

Are we really required to know the two photosystems and their specific processes, or can we just learn the light-independent stage as a whole? Thanks

You dont need to learn photosystems for yr 12. That's uni stuff. Something that I have to learn in the next few days for mid sem tests lol

[cosine]

Can someone explain why there are ribosomes in the stroma of the chloroplasts? Does this mean that the enzymes used in phtosynthetic processes are produced already inside the chloroplast?

Thanks

[Reus]

Can someone explain why there are ribosomes in the stroma of the chloroplasts? Does this mean that the enzymes used in phtosynthetic processes are produced already inside the chloroplast?

Thanks

Read up on the symbiotic theory.

[cosine]

Read up on the symbiotic theory.

Right, thanks. That will also explain why there is DNA in the stroma, too, right?

[vox nihili]

Can someone explain why there are ribosomes in the stroma of the chloroplasts? Does this mean that the enzymes used in phtosynthetic processes are produced already inside the chloroplast?

Thanks

To actually explain:

Chloroplasts and mitochondria are actually the remnants of bacteria that got gobbled up by a eukaryotic ancestor. They have DNA and ribosomes because they are, in some ways, their own cell.

[cosine]

In the ATP-ADP cycle, where does the energy come from to bond the Phosphate to the ADP to make ATP again? The book says energy input from: Photosynthesis and respiration, can someone explain?

[vox nihili]

In the ATP-ADP cycle, where does the energy come from to bond the Phosphate to the ADP to make ATP again? The book says energy input from: Photosynthesis and respiration, can someone explain?

Variety of sources. In respiration, it comes from breaking down glucose. The gradual break down is exergonic, so it produces energy that can be used to whack Pi back on. It also comes from concentration gradients, but forget about that.

In photosynthesis, the energy required to make ATP ultimately comes from sunlight.

[adnauseam]

Hello.
Can someone please explain exactly how the ion channels at the nodes of ranvier open because of previous ion channels opening?
Is it simply a matter of 'triggering' the next ion channels?
 thanks

[cosine]

In the Calvin-Benson cycle, the first step is a carbon from CO2 attaching to a 5C molecule called RuBP. Is RuBP an enzyme? If so, does the carbon dioxide bind to the enzyme's active site, but where does the oxygen gas go to?

[CarterGray12]

I did my enzyme prac the yesterday. We added various ground up cells to hydrogen peroxide and detergent. The control was distilled water as opposed to a cell. Im not sure specifically what the control is? is it the presence of enzyme, the concentration of enzyme or something else?

[Reus]

In the Calvin-Benson cycle, the first step is a carbon from CO2 attaching to a 5C molecule called RuBP. Is RuBP an enzyme? If so, does the carbon dioxide bind to the enzyme's active site, but where does the oxygen gas go to?

No, RuBP is not an enzyme, the enzyme involved is known as Rubisco (RuBisCO) which catalyses the attachment of CO2 and RuBP.

Note: Pretty sure this is not needed, check the study design.

[cosine]

No, RuBP is not an enzyme, the enzyme involved is known as Rubisco (RuBisCO) which catalyses the attachment of CO2 and RuBP.

Note: Pretty sure this is not needed, check the study design.

So RuBP (5C) is attached to a CO2 molecule via Rubisco, then what?

[StupidProdigy]

In the Calvin-Benson cycle, the first step is a carbon from CO2 attaching to a 5C molecule called RuBP. Is RuBP an enzyme? If so, does the carbon dioxide bind to the enzyme's active site, but where does the oxygen gas go to?

It is a protein so with a complex structure and I'm pretty sure it is also an enzyme (not certain). As for the other question, isn't the oxygen given off as a waste product in stage one when the hydrogen splits from the water molecule. The main thing I wanted to say though is that I don't think this much depth is need (in terms of RuBP) but do make sure you have a good understanding of the inputs and outputs. All that I think is necessary in relation to RuBP is that carbon fixates to RuBP which then creates glucose (don't think we need to know about pgal or anything)
edit: I thought RuBP was rubisco, sorry, and thanks reus