nexttttt (6 Viewers)

[Takuto]

Risk assessment = safety issues.

haha ok, i know what safety issues are, lol

didnt know they were the same

 

[danz90]

Draw transverse and longitudinal sections of phloem and xylem tissue (hope this question hasn't been asked before)

here's what i posted in another thread for this guy. lol i just did them in paint, very simplified. this is how our teacher taught them to us:

 

[Takuto]

haha i saw that, thats cute. LOL


btw, transverse = top view?

 

[luucy]

does anyone here do the genetics topic?

 

[midifile]

I like your diagrams =]

I can never be bothered doing them on the computer I always hand draw them in

 

[midifile]

does anyone here do the genetics topic?

I do

 

[danz90]

haha i saw that, thats cute. LOL


btw, transverse = top view?

yeah, that's even easier. just like this:

http://www.botany.hawaii.edu/facult...iophytaLab99/Prim-SecStemXSBIODColrLab400.jpg

Just remember, xylem is always on the inside, and is made up of a vascular bundle of heaps of narrow xylem vessels. The phloem is on the outer part, towards the mesophyll cells where photosynthetic products are produced. It just makes logical sence, so if u forget which is where, think about photosynthesis products and where they located, etc.

 

[luucy]

I do

Sweet can you please help me with this dot point

oultine the current understanding of gene expression......im really confused!

 

[danz90]

who here does the communication option?

 

[Takuto]

i do communications

lol, there was a past hsc MC question that had a crazy diagram and you had to name which was xylem and phloem + whether they were active or passive transport

anyone remember this? so confusing

 

[danz90]

Question: Identify the current technologies that allow measurement of oxygen saturation and carbon dioxide concentration in blood and describe and explain the condition under which these technologies are used.

 

[midifile]

Sweet can you please help me with this dot point

oultine the current understanding of gene expression......im really confused!

Gene expression is pretty much a fancy name for polypeptide synthesis.

What I have in my notes is that:

A gene is either on all the time unless there is enough product present, or off all the time unless there is too much substrate present.

In the first case, when there is enough of the product (ie the polypeptide) this acts as a repressor, stopping polypepetide synthesis until the concentration of that polypeptide decreases.

In the second case, when there is too much of the substrate present, this activates the gene, resulting in polypeptide synthesis, until the concentration of the substrate decreases

 

[danz90]

i do communications

lol, there was a past hsc MC question that had a crazy diagram and you had to name which was xylem and phloem + whether they were active or passive transport

anyone remember this? so confusing

YESSS!
I got that wrong.. stupid me.

The thing to that question was that realising the vessel with the squiggly, spirally things in the middle was the xylem (the advice line guy said that they are the tracheids - and thats how u distinguish from phloem). Hence passive transport occurs in xylem... and obviously the opposite for phloem.

However, one confucious thing... is all translocation in phloem active? Because if there is a pressure gradient, and the substances are moving along it.. is it passive? or is it active because the pressure gradient is required for the translocation?

 

[midifile]

YESSS!
I got that wrong.. stupid me.

The thing to that question was that realising the vessel with the squiggly, spirally things in the middle was the xylem (the advice line guy said that they are the tracheids - and thats how u distinguish from phloem). Hence passive transport occurs in xylem... and obviously the opposite for phloem.

However, one confucious thing... is all translocation in phloem active? Because if there is a pressure gradient, and the substances are moving along it.. is it passive? or is it active because the pressure gradient is required for the translocation?

According to the answer of the MC question (I remember doing it too) it is active.

I think it is becasue when loading and unloading occurs these occur through active transport (once the concetration of sucrose in the phloem is greater than in the source cell, or less than the sink cell), which is why it is considered active

 

[luucy]

Gene expression is pretty much a fancy name for polypeptide synthesis.

What I have in my notes is that:

A gene is either on all the time unless there is enough product present, or off all the time unless there is too much substrate present.

In the first case, when there is enough of the product (ie the polypeptide) this acts as a repressor, stopping polypepetide synthesis until the concentration of that polypeptide decreases.

In the second case, when there is too much of the substrate present, this activates the gene, resulting in polypeptide synthesis, until the concentration of the substrate decreases

okay that makes alot more sense compared to the notes i was looking at....another question are we meant to know what the substrate is?

 

[pbillabong]

hey for ppl doing human story, i get confused with difference between polymorphism and clinal gradation, anyone got any good definitions for each? thanx

 

[danz90]

Im pretty sure there was a MC question in a past paper which asked whether it was passive or active and the answer was active.

I think it is becasue when loading and unloading occurs these occur through active transport (once the concetration of sucrose in the phloem is greater than in the source cell, or less than the sink cell), which is why it is considered active

maybe it was this one?

basically here i think all we had to realise was that the xylem was in the centre (notice the smaller vessels).. and thats where passive transport occurs. phloem, larger vessels, were on outside, where active transport occurs.

Edit: well well.. i'm wrong again. The answer is B. But why would xylem be on the outer part??

 

[midifile]

okay that makes alot more sense compared to the notes i was looking at....another question are we meant to know what the substrate is?

No you dont have to know any specific substrates, but just know that the gene codes for the production of an enzyme which catalyses a specific reaction, converting a specific substrate(s) into a specific product(s).

You dont have to know what the substrate, enzyme or product is

 

[homijoe]

hey guys just a general question when u draw or look at a cross section view of an arterty do the elastic fibres form a layer then comes a thick muscular wall or are both muscle and eastic fibres present in one layer? kinda confused about that

 

[midifile]

maybe it was this one?

basically here i think all we had to realise was that the xylem was in the centre (notice the smaller vessels).. and thats where passive transport occurs. phloem, larger vessels, were on outside, where active transport occurs.

Edit: well well.. i'm wrong again. The answer is B. But why would xylem be on the outer part??

i dunno. That diagram doesnt seem right. Xylem are meant to be narrower than phloem (which would make xylem M) and there is no way that substances move by active transport in xylem.

Im confused