nexttttt (3 Viewers)

[hoochiscrazy]

they havent asked it before, so i dunno

experiments rarely come up

you're gonna have to take a big guess

but thats pretty much it. you'd want to know reliability, validity, accuracy cause they seem to add that on

They always bloody came up in our school exams lol always 4-7 marker but havnt really look at past HSC gonna do that tomorrow oh wait later today lol
ahhh forgot about reliability, validity and accuracy although u can normally have just some pretty broad answers that covers them thx though

 

[ALGALELE]

Outline, using a specific model the process by which DNA controls the production of Polypeptides

THIS IS IMPOSIBLE TO UNDERSTAND, SO IM JS GNA MEMROISE IT BY HEART! I HATE DNA, TRANSCRIPTION AD ALL THAT BULL CRAP, BAMBOOZLES THE CRAP OUTA ME!

 

[dolbinau]

Oh yeah, whats 'BT Cotton', someone mentioned it a few pages back

lol is it a transgenic species?

Yes. Transgene from bacteria allows crops to kill pests.


--

I have a question regarding Tracheids for Xylem; what are they? Are they the vessel it self or are they next to the vessel?

 

[gloworm14]

nice

Q: You performed a first-hand investigation to demonstrate the effect of dissolved carbon dioxide on the pH of water.

Outline your method, identifying the variables AND account for how you ensured the reliability of your data

(1/2 page, 5 marks)

i would describe the experiment where you blow through a straw into universal indicatored water. green turns into yellow. neutral ph 7--> ph 6.5
shows that CO2 dissolved in water lowers the pH to make it more acidic.
you can relate it to the presence of CO2 in a cell, when CO2 dissolved in cell creates carbonic acid.

variables- i guess would probably be the pH

reliability- repetition for larger sample size

on the other hand i think theres another experiment with reacting marble chips with HCL in a test tube. (this is the answer they have in success one).[/B][/B]

Q: Discuss a first-hand investigation used to estimate the size of red blood cells on a prepared microscope slide

Include: list of equipment used, safety precaution, step-by-step method, a scaled diagram of a red blood cell



and... the other one like 20 pages back which was asking you to test the rate of reaction of two enzymes

method
1. measure field of view in a x400 view
2. convert into micrometres µm ( move decimal place to the right 3 times if converting from mm to µm)
3. get blood slide and measure how many rbc cells across a x400 view
4. field view size / number of rbc across (make sure its in µm)

equipment
microscope
clear ruler
blood slide

approx it is arond 7-10 µm. wbc is usually larger.

diagram
i cant be bothered LOL. google it =)
its pretty much biconcave [ i remember because it caves into the middle like a cave LOL]

i can only suggest to make sure you put under your diagram the scale (e.g. x400 or whatever) and draw it in pencil.

the enzyme one is the milk and rennin experiment, but it says compare so im assuming you need to know another one.

 

[dolbinau]

i would describe the experiment where you blow through a straw into universal indicatored water. green turns into yellow. neutral ph 7--> ph 6.5
shows that CO2 dissolved in water lowers the pH to make it more acidic.
you can relate it to the presence of CO2 in a cell, when CO2 dissolved in cell creates carbonic acid.

variables- i guess would probably be the pH

reliability- repetition for larger sample size

on the other hand i think theres another experiment with reacting marble chips with HCL in a test tube. (this is the answer they have in success one).[/B][/B][/B]




method
1. measure field of view in a x400 view
2. convert into micrometres µm ( move decimal place to the right 2 times if converting from mm to µm)
3. get blood slide and measure how many rbc cells across a x400 view
4. field view size / number of rbc across (make sure its in µm)

equipment
microscope
clear ruler
blood slide

approx it is arond 7-10 µm. wbc is usually larger.

diagram
i cant be bothered LOL. google it =)
its pretty much biconcave [ i remember because it caves into the middle like a cave LOL]

i can only suggest to make sure you put under your diagram the scale (e.g. x400 or whatever) and draw it in pencil.

the enzyme one is the milk and rennin experiment, but it says compare so im assuming you need to know another one.

Can you be more specific with finding the FOV? I remember we put 1mmx1mm grid paper at 40X times and then, IIRC the grid fitted in the screen perfectly so 1000 micrometres. Then at 400 times its 250 micrometres so for blood cells to be 8 micrometres in diameter they'd need to be about 32 across. Does this sound right? I don't have notes so It needs to seem realistic when I 'make it up', lol.

 

[luucy]

anyone who does genetics how do you

Outline the ability of DNA to repair itself?

 

[gloworm14]

Can you be more specific with finding the FOV? I remember we put 1mmx1mm grid paper at 40X times and then, IIRC the grid fitted in the screen perfectly so 1000 micrometres. Then at 400 times its 250 micrometres so for blood cells to be 8 micrometres in diameter they'd need to be about 32 across. Does this sound right? I don't have notes so It needs to seem realistic when I 'make it up', lol.

its actually moved 3 places to the right from mm to µm so my bad lol

in my notes it says
using 100x mag on a microscope measure the field of view mm
look at a prepared slide of human blood under 100 x. count number of rbc across field of view.
if too many, count the number across the field of view at 400x

results
field of view 100x = 1.4 mm = 1400µm
field of view 400 x = 350

number of rbc across field of view 400x =44 cells
field of view 400x= 350µm

size of rbc = 7.95µm

 

[Takuto]

haha, i doubt an experiemtn would repeat itself in the hsc, i was just giving past hsc pracs to the person that asked for them


you guys actually did them, im amazed


hmm lets start to theorise what prac they will include this year

effect of environment on phenotype? lol

 

[midifile]

My friend called up the advice line and they said modelling pasteurs experiment has never been in there, so it might be this year

 

[danz90]

haha, i doubt an experiemtn would repeat itself in the hsc, i was just giving past hsc pracs to the person that asked for them


you guys actually did them, im amazed


hmm lets start to theorise what prac they will include this year

effect of environment on phenotype? lol

well yeah i think there will be a prac, and something on validity/reliability

effect on phenotype is possible... so is the prac on effect of substrate concentration on rate of enzyme activity, thats never been asked.

 

[dolbinau]

What about that experiment with growing cultures of pathogens from food?

 

[Kujah]

A prac could form part of a 8 marker this year - they haven't done that for a while.

 

[gloworm14]

id rather do pasteurs experiment than the experiments from maintaining a balance.
all those heaps of test tubes, chemicals argh... its very hard to put it clearly in a method, especially if ur trying to bs lol

hope its not the substrate concentration... although its not that hard to understand, i just cant be bothered writing all the different concentrations up lol

 

[Takuto]

well yeah i think there will be a prac, and something on validity/reliability

effect on phenotype is possible... so is the prac on effect of substrate concentration on rate of enzyme activity, thats never been asked.

its been asked but disguised lol you guys were talking about it before the temp/pH one variable one

 

[gloworm14]

ummm i have a feeling they're gonna put something about rbc or wbc count in the multiple choice.

for the prac? i think there will definately be at least one question on a prac, if not the big question.

im just hoping its not a 'design an experiment' qu.
i just hope it just asks us to write an experiment we've already done

haha how bs is the safety procedure questions rofl

 

[dolbinau]

id rather do pasteurs experiment than the experiments from maintaining a balance.
all those heaps of test tubes, chemicals argh... its very hard to put it clearly in a method, especially if ur trying to bs lol

hope its not the substrate concentration... although its not that hard to understand, i just cant be bothered writing all the different concentrations up lol

We got that in the CSSA trial. I just said 100% Water 0% Milk, 80% Water 20% Milk 50% Milk 50% Water 100% Milk 0% water.

 

[Takuto]

What about that experiment with growing cultures of pathogens from food?

the cheese one? that models pasteurs?

there was that agar plate one too.. we put it in all diff environments.. forgot what was that called and our class never ended up finshing it

 

[dolbinau]

This one:

identify data sources, plan and choose equipment or resources to perform a first hand investigation to identify microbes in food or in water

How do you guys define Reliability/Accuracy/Validity?

 

[danz90]

My friend called up the advice line and they said modelling pasteurs experiment has never been in there, so it might be this year

yeah, we did that one, im pretty sure.

we got two cans of canned beans, opened only ONE, partially, and the other was left unopened and sealed, for a few days. hence one was not exposed to pathogens, and didn't spoil, while the other did.

 

[gloworm14]

are these notes substantial for macfarlane burnet?

australian virologist best know for his contributions to immunology

experimented with influenza viruses by growing them in fertilised hen's eggs

proposed radical theory 'clonal selection theory' about wbc called lymphocytes

burnet and co-workers also researched other viruses like herpes, myxomatosis and smallpox-like viruses