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[pbillabong]

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??

yeh i dont get this one either

 

[homijoe]

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??

in cases of those questions were they give u a transverse view, the vessels larger in diameter would always be xylem.

 

[danz90]

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

Well I think that it is just that one thick layer of elastic muscle fibres. The only layers I know of in arteries are:
Connective tissue (outer layer)
Smooth, elastic muscle fibres
Endothelium

Then comes the lumen (hole inside).

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

Yeah so am I.. but meh let's not confuse ourselves and stick with what we know.

 

[Takuto]

m is phloem

w is xylem

lol

 

[danz90]

in cases of those questions were they give u a transverse view, the vessels larger in diameter would always be xylem.

omgg yesssss so true
if u look at all other transerve diagrams, xylem is bigger than phloem.

 

[luucy]

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

thanks heaps!!

 

[dolbinau]

Are we ever asked to draw labelled diagrams of Arteries, veins and capillaries or do we just describe their function/structure?

 

[midifile]

Are we ever asked to draw labelled diagrams of Arteries, veins and capillaries or do we just describe their function/structure?

I dont think there has ever been a question asking you to draw diagrams, but I think there has been one where they have given you the diagram and you have to say what it is.

 

[homijoe]

Are we ever asked to draw labelled diagrams of Arteries, veins and capillaries or do we just describe their function/structure?

i think the only question that came in the hsc about the artery, vein adn capillary dotpoint is in 2001 were they gave a image of an artery and u had to label a feature and describe how it helps in its function.

 

[Kujah]

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

Polymorphism - the occurrence of a range of form of characteristics due to the expression of different genes within a population.

Clinal gradation- the gradual change in frequency of genetically-inherited characteristics as we move from one region to another.

And xylem usually have a larger diameter/size than phloem, hence their reduced numbers.

 

[pbillabong]

Polymorphism - the occurrence of a range of form of characteristics due to the expression of different genes within a population.

Clinal gradation- the gradual change in frequency of genetically-inherited characteristics as we move from one region to another.

And xylem usually have a larger diameter/size than phloem, hence their reduced numbers.

hey, thanx for definitions

 

[pooja_107]

Help!!!!!!!! Does anyone know what is the difference between cell mediated immunity (T cells) and antibody mediated immunity (B cells). I am really confused...

 

[WantToDoBetter]

who here does the communication option?

Communication right here!

 

[homijoe]

Help!!!!!!!! Does anyone know what is the difference between cell mediated immunity (T cells) and antibody mediated immunity (B cells). I am really confused...

Basically Bcells are effective against pathogens in the body fluid, thus they maintaint immunity of an individual by producing antibodies specific to those diseases. on the otherhand T cells control the immunity amongst cells, in other words they act on pathogens that are on cells (eg. in foreign tissue transplants), hence the name cell mediated response

 

[pooja_107]

thanks

 

[luucy]

I think we should start one of these threads for chemistry a few days before the exam....or perhaps sooner

 

[midifile]

I think we should start one of these threads for chemistry a few days before the exam....or perhaps sooner

I think there is already something like it, but no one posts in it

 

[luucy]

I think there is already something like it, but no one posts in it

excellent.....once bio exam is finished and after maths i might just spend some time there.

 

[WantToDoBetter]

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.

ABG (Arterial Blood Gas analysis): Specifically used to measure the the amounts of oxygen and carbon dioxide in blood (pH). In is an invasive technique requiring a blood sample. It is used to distinguish between diseases with similar symptoms.

Pulse Oximetry: Measures the oxygen carring capabilities of the patients haemoglobin. It passes two wavelenghts of light through the patients finger, the amount of absorption depends on the patients oxygen saturation.

Explain how one of the following strategies has controlled and/or prevented disease:

public health programs
pesticides
genetic engineering to produce disease resistant plants and animals

 

[Takuto]

Q: Outline methods used by plants to assist in internal salt regulation

Q: Outline methods used by a named Australian plant to assist in temperature regulation regulation

Q: Outline methods used of a named Australian ectotherm to assist in temperature regulation

Q: Outline methods used by a named Australian endotherm to assist in temperature regulation



4 in 1 but yeah, they are pretty much the same