*Biology Paper 5 tips*

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knowitall10 said:
Assalamu 'Alaykum Everyone!!
Al7amdulillah, my SAT exam is over....so I have decided to complete my promises:

Topics we have to study from IGCSE:
  1. Sigmoid Curve
  2. Respiration
  3. Tropism and Taxic Responses
  4. Food Tests
  5. Germination
Alice123 MaxStudentALevel Zari PhyZac gary221 sumaiyarox:) cyclone94 Irfan 1995 geek101 xtremeforums biba Soldier313


What are error bars?
-the Physics students probably know better than I do:
I've uploaded a photo of what error bars are.
The overlapping of error bars:
Consider an example of O/N 2010 p53 Q1 (open it in another tab):
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w10_qp_53.pdf

In this question, we have to calculate the standard error of glucose, and that of fructose is given:
for glucose, we calculated the SM as 1 and for fructose it's given as 2. So, in the next part, where we have to plot our graphs, we'll make the bar chart as normal, but we'll make an extra line in between...look at the uploaded photo labelled: P5.
I'm sorry i made a mistake in naming my files..it's the other way round actually..
Please let me know if i missed out anything :)
Click to expand...

Thank you knowitall10, you're doing such an amazing, selfless job over here and going to far ends to help us out. I wanted to check something with you though. Are you sure the error bars are correct like that? Isn't one supposed to be 2 units above and below?
 
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I'm sorry I still didn't practice drawing error bars and I'm kind of confused a bit after I saw the bars you drew. Can you please explain to me how you did it?
 
knowitall10

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Marks&Spencers said:
Thank you knowitall10, you're doing such an amazing, selfless job over here and going to far ends to help us out. I wanted to check something with you though. Are you sure the error bars are correct like that? Isn't one supposed to be 2 units above and below?
Click to expand...

I actually did that on a graph paper :LOL: I kinda did it in a hurry on a new copy of the past paper..so ur right, i just wanted to clear the concept here tho :)
And Thanks a lot:) Anything to help my fellow friends..
 
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knowitall10 said:
I actually did that on a graph paper :LOL: I kinda did it in a hurry on a new copy of the past paper..so ur right, i just wanted to clear the concept here tho :)
And Thanks a lot:) Anything to help my fellow friends..
Click to expand...

Woah! You're unbelievably fast masha'Allah! Like I was just pressing reply then DANG one new alert! I'm gob smacked right now
 
scarface007

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Woah! Thank you so much for the tips! they really are amazing for a last minute revision! :D
Best of Luck everyone for you P5 exam, I hope we all ace em (y)
 
knowitall10

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scarface007 said:
Woah! Thank you so much for the tips! they really are amazing for a last minute revision! :D
Best of Luck everyone for you P5 exam, I hope we all ace em (y)
Click to expand...

You're welcome :) And Good Luck to you too!! May you rock the world..like a boss:cool:
 
Alice123

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http://papers.xtremepapers.com/CIE/...and AS Level/Biology (9700)/9700_w04_qp_5.pdf
knowitall10
Correct me if im wrong, im kinda confused with Q1a
  • Amylase concentration is the independent variable here
  • a range of amylase concentration is prepared
  • water is used as a control
  • substrate (ie volume of starch used) is kept constant
  • different concentrations of amylase is added to fixed volume of starch in different test-tubes
  • iodine is added to each test-tube at a time
  • time is recorded ( as dependent variable) for the colour to change from brown to blue-black
  • end point is determined when no further change occurs
  • repeats are made for each concentration and the mean time calculated
  • Rate is determined by 1/t
  • A graph can be plotted rate against concentration of amylase
 
knowitall10

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Alice123 said:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w04_qp_5.pdf
knowitall10
Correct me if im wrong, im kinda confused with Q1a
  • Amylase concentration is the independent variable here
  • a range of amylase concentration is prepared
  • water is used as a control
  • substrate (ie volume of starch used) is kept constant
  • different concentrations of amylase is added to fixed volume of starch in different test-tubes
  • iodine is added to each test-tube at a time
  • time is recorded ( as dependent variable) for the colour to change from brown to blue-black
  • end point is determined when no further change occurs
  • repeats are made for each concentration and the mean time calculated
  • Rate is determined by 1/t
  • A graph can be plotted rate against concentration of amylase
Click to expand...
It doesn't seem wrong....dude, why are you practicing very old papers..i thought the syll. changed after 2007...but your explanation seems pretty much ok...
 
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I am sorry to be asking this but can someone explain how should we describe Serial Dilution ?
( and the use of microscope to count cells, etc... A lot of questions are like this and I don't know how to write it in the right form :S )
 
knowitall10

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narutogirl said:
I am sorry to be asking this but can someone explain how should we describe Serial Dilution ?
( and the use of microscope to count cells, etc... A lot of questions are like this and I don't know how to write it in the right form :S )
Click to expand...

Please...don't be sorry..this is why you're here:)
Serial Dilution isn't difficult...
Say you have 1.00 moldm^3 sucrose solution, and you have to prepare a minimum of 5 conc...
0.0- 0.2- 0.4- 0.6- 0.8
then you use the formula: C1V1=C2V2
C1-- ur original conc
C2-- the concentration you want to prepare
V1--the volume of the conc--ur going to find it
V2- the total volume of the solution

For eg: Our total volume must be 50 cm3.
So to prepare 0.8 moldm^3 from 1.00 moldm, this is what you do:
C1V1=C2V2
1.00 x y = 0.8 x 50
then you find y ...subtract this from 50 to see how much water you're going to add to 1.00 to make 0.8..get it? :)
 
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