nexttttt (5 Viewers)

[gloworm14]

just curious, what was the highest mark in your class's bio trial?

 

[bekmay]

ok here is a random question:
firstly, define what a transgenic speices is.

then

outline the process used to produce transgenic species. include an example and reason for its use.

now gogogogogo!

Salmon: - have been inserted with the BGH hormone that produces faster and larger fish.
- This provides food to many countries with salmon as their staple diet, thus providing food to a large number of people without adversely affecting salmon population.

Method:- a fertilised egg is removed from an organism and a particular gene is inserted, e.g. larger stature.
-A molecular vehicle is combined with the required gene and this combination is known as a transgene.
-The transgene is placed into the fertilised egg and this is allowed to develop in a mother, if this process has been executed correctly, a transgenic organism is resulted.

Describe the contribution of Pasteur and Koch to our understanding of infectious diseases.

YAY GO 2S1D3 you rock LOL.

 

[Takuto]

just curious, what was the highest mark in your class's bio trial?

1st was 96% in the independent paper

2nd was 90.5%

how about yours?

 

[sam2100]

in phloem both passive and active...water, which contains dissolves sugars enters tthe phloam via osmosis, however the rest is active as sugars are deposited at source sinks against diffusion gradient

i totally agree that both active and passive transport are used but i have the exact opposite understanding of the source-sink theorem

I was taught:


at the source (ie a leaf): glucose is converted to sucrose and loaded by ACTIVE transport into the phloem vessel (tube)

this increases the solute concentration in the phloem (because sugars entering constantly due to active transport) causing the water to flow in passively by osmosis, creating high turgor pressure.

sugar sink: where the supply of sucrose is low and the turgor pressure is also low

thus the high pressure at the sugar source causes the sugar to flow from source to sink by passive transport



please tell me if this is incorrect and why

p.s. where did you apply for pharmacy, ur goals for post hsc are like identical to mine

 

[imqt]

i totally agree that both active and passive transport are used but i have the exact opposite understanding of the source-sink theorem

I was taught:


at the source (ie a leaf): glucose is converted to sucrose and loaded by ACTIVE transport into the phloem vessel (tube)

this increases the solute concentration in the phloem (because sugars entering constantly due to active transport) causing the water to flow in passively by osmosis, creating high turgor pressure.

sugar sink: where the supply of sucrose is low and the turgor pressure is also low

thus the high pressure at the sugar source causes the sugar to flow from source to sink by passive transport



please tell me if this is incorrect and why

p.s. where did you apply for pharmacy, ur goals for post hsc are like identical to mine

hey yeh that seems more correct mine was a rushed quick explanation...i need to go over it

and i applied at USyd, how about you???

EDIT: im assuming you are apllying for pharmacy aswell =)

 

[bekmay]

hey PEEPS what do we know about artificial blood??
i really don't know much at all =[
help me =]

 

[gloworm14]

1st was 96% in the independent paper

2nd was 90.5%

how about yours?

came first with 88%
lolz

only 2 people got into the 80s range LOL

my class is not really that great.
once a girl asked how to spell DNA. rofl!

 

[imqt]

hey PEEPS what do we know about artificial blood??
i really don't know much at all =[
help me =]

(done before, il go over it roughly)
that its needed due to
- real blood shortage
- the need for it to be crossmatched-
- short shelf life
- the chance of carrying a disease...this is all expensive and timely, and not suitable for emergency situations

current artificial blood used is PERFLUROCHEMICALS which is inert, stable, does not contain biological matter, dissolve oxygen 5 more times than real blood etc. However needs to be mixed with other chemicals. Dextrose solution is also used which contains glucose, water, and salts. However, neither provide the best alternative. Thus, more research is undertaken.


someone go over how phloem is both passive and active transport...i think ive confused myself now

 

[sam2100]

UNSW USyd is too intimidating, does it need stat?

sweet, coz i read urs and was like omgwat has my teacher been smoking?!

sigh i just want this bio to be over and done with already.



um i basically gave my understanding in the last thing i wrote, but active transport is used to get the sucrose from cells in say a leaf, into the phloem vessel

once its in there water folllows by osmosis (low concentration moves to high concentration) [this is passive transport of water into the phloem]

this means that there is HIGH PRESSURE AND HIGH SOLUTE CONCENTRATION at the source, whilst at the sink there is LOW PRESSURE AND LOW SOLUTE CONCENTRATION

the natural diffusion gradient is high solute conc moves to low solute conc and this is sped up by the pressure at the source (like if u fill a hose from one end, the pressure forces it to the other) [this too is passive transport -- takes no energy -- naturally occurs]

thus the sucrose flows from source to sink



ask again if this still doesnt suffice

 

[imqt]

highes score in my year was 97% for bio exam CSSA trials

 

[imqt]

UNSW USyd is too intimidating, does it need stat?

sweet, coz i read urs and was like omgwat has my teacher been smoking?!

sigh i just want this bio to be over and done with already.

lolllllll my teachers not so great,

pharmacy in UNSW??? i thought its only only offered at USyd ? and yeh it needs stat

 

[Takuto]

came first with 88%
lolz

only 2 people got into the 80s range LOL

my class is not really that great.
once a girl asked how to spell DNA. rofl!

LOL hahaha!

88% is AWESOME. i would be freaking proud =]

and i just realized that almost all of the people in this thread came 1st in their bio class.. hahah nice guys.

lets all get b6 =D

 

[jozza80]

someone go over how phloem is both passive and active transport...i think ive confused myself now

I wrote down sam2100's cause it sounded very detailed.

My notes came from examplar answer from 2002 exam paper:

There are three main stages:
1. Movement from source into the phloem, usually against a concentration gradient, thus active transport is needed;
2. Movement in the phloem due to the pressure from the source and hydrostatic pressure;
3. Unloading from the phloem to the sink again needed active transport, expending cellular energy.

This movement of materials in the phloem is called translocation..

Dunno if it helps you, but.. hmmmm... not 100% on this either!

Haha.. I will agree with 90% of people in this thread being top of their game!!

 

[bekmay]

I wrote down sam2100's cause it sounded very detailed.

My notes came from examplar answer from 2002 exam paper:

There are three main stages:
1. Movement from source into the phloem, usually against a concentration gradient, thus active transport is needed;
2. Movement in the phloem due to the pressure from the source and hydrostatic pressure;
3. Unloading from the phloem to the sink again needed active transport, expending cellular energy.

This movement of materials in the phloem is called translocation..

Dunno if it helps you, but.. hmmmm... not 100% on this either!

Haha.. I will agree with 90% of people in this thread being top of their game!!

haha and i am the other 10%. bio is hard for me i don't get a lot of it LOL.

your answer makes sense... i don't understand where translocation in phloem would require passive transport. hmm.

 

[sam2100]

lolllllll my teachers not so great,

pharmacy in UNSW??? i thought its only only offered at USyd ? and yeh it needs stat

gah my bad, i HAVE applied at usyd, got it confused with my unsw optometry (pharmacy is my 2nd preference incase i bomb stat)

 

[imqt]

gah my bad, i HAVE applied at usyd, got it confused with my unsw optometry (pharmacy is my 2nd preference incase i bomb stat)

ah ok, so you havent done stat yet ? i thought i was gonna bomb it

 

[sam2100]

I wrote down sam2100's cause it sounded very detailed.

My notes came from examplar answer from 2002 exam paper:

There are three main stages:
1. Movement from source into the phloem, usually against a concentration gradient, thus active transport is needed;
2. Movement in the phloem due to the pressure from the source and hydrostatic pressure;
3. Unloading from the phloem to the sink again needed active transport, expending cellular energy.

This movement of materials in the phloem is called translocation..

Dunno if it helps you, but.. hmmmm... not 100% on this either!

Haha.. I will agree with 90% of people in this thread being top of their game!!

yer ur exemplar notes complement what i said, good good

 

[sam2100]

ah ok, so you havent done stat yet ? i thought i was gonna bomb it

not yet, i did umat (needed for optometry) and did ok

dyu know if theyre similar?

 

[2S1D3]

Excuse me if this question was asked before
The widespread use of antibiotics for the treatment of bacterial infections has led to the development of antibiotic resistance in some species of bacteria. From your studies of evolution and the mechanisms of inheritance, explain how resistance has been developed in bacteria.

Basically an hsc question that I did previously, found it hard but eventually got it, just want to see how you guys would answer it...

 

[gloworm14]

look look look!!

2002 qu 17 b)
Describe ONE current theory about the processes responsible for the movement of materials through phloem tissue in plants.

Materials are transported in the phloem by translocation.

Energy is used as sugars are actively loaded agianst the concentration gradient into the phloem at the site of photosynthesis (source).

Sap is carried along the phloem sieve tubes by water that enters by osmosis. The sugar is then unloaded by diffusion, which is passive, at the storage (sink) site.

indeed.