Qualification > Sciences
ALL CIE BIOLOGY DOUBTS HERE !!!
NidZ- Hero:
how do we measure the rate at which the amylase break down into starch ?
In my boook its says that : To measure the rate of this reaction is to measure the rate at which the starch disappears from the reaction mixture
This can be done by taking samples at known times n doing the iodine test. starch forms blue-black colour with this solution using a colorimeter to measure the intensity of the blue-black colour obtained using this yu can measure the starch remaining...... so yes i was wondering as the amount of starch disappear means that reaction is proceeding rght so lighter the intensity of the colour in the colorimeter the faster the reaction
**RoRo**:
Guys, what's the correct steps for calibrating the eyepiece graticule?
Let's say that 2 eyepiece divisions correspond to 65 stage micrometer divisions and that one division on the stage micrometer is equal to 0.01 mm, how would you calibrate it?
& if you want to find the actual length of something that you measured that turned out to have 3.5 eyepiece graticule divisions, what would your answer be?
I've got 2 ways to calculate, I get 2 answers that when rounded off to 2 s.f. are the same, but when you calculate the size of a specimen, with the 2 values, I get 2 different answers!
HUSH1994:
--- Quote from: Nidzzz on May 08, 2011, 07:04:29 am ---how do we measure the rate at which the amylase break down into starch ?
In my boook its says that : To measure the rate of this reaction is to measure the rate at which the starch disappears from the reaction mixture
This can be done by taking samples at known times n doing the iodine test. starch forms blue-black colour with this solution using a colorimeter to measure the intensity of the blue-black colour obtained using this yu can measure the starch remaining...... so yes i was wondering as the amount of starch disappear means that reaction is proceeding rght so lighter the intensity of the colour in the colorimeter the faster the reaction
--- End quote ---
you can use benedict's test to find the rate at which reducing sugar is formed from starch
Master_Key:
--- Quote from: The Secret on May 08, 2011, 09:01:06 am ---Guys, what's the correct steps for calibrating the eyepiece graticule?
Let's say that 2 eyepiece divisions correspond to 65 stage micrometer divisions and that one division on the stage micrometer is equal to 0.01 mm, how would you calibrate it?
& if you want to find the actual length of something that you measured that turned out to have 3.5 eyepiece graticule divisions, what would your answer be?
I've got 2 ways to calculate, I get 2 answers that when rounded off to 2 s.f. are the same, but when you calculate the size of a specimen, with the 2 values, I get 2 different answers!
--- End quote ---
2 = 65
2 Eyepiece divisions = 0.65 mm
3*0.65 / 2 = 1.1375 mm.
Thats the calculation.
I think you made some mistake though i gave the calculation, its the method. Now when you xamine microscope always the eyepiece divisions are large in number compared to stage micrometer divisions like
47 Eyepiece graticule divisions (arbitrary units) = 1 Stage micrometer because stage micrometer is always magnified and it always corresponds to a large number of Eyepiece graticule divisions. Check it!
**RoRo**:
--- Quote from: Master_Key on May 08, 2011, 04:03:21 pm ---2 = 65
2 Eyepiece divisions = 0.65 mm
3*0.65 / 2 = 1.1375 mm.
Thats the calculation.
I think you made some mistake though i gave the calculation, its the method. Now when you xamine microscope always the eyepiece divisions are large in number compared to stage micrometer divisions like
47 Eyepiece graticule divisions (arbitrary units) = 1 Stage micrometer because stage micrometer is always magnified and it always corresponds to a large number of Eyepiece graticule divisions. Check it!
--- End quote ---
But I remember during my lab classes that the eyepiece graticule we used had values from 0-10, so how can you say there's '47' eyepiece graticule divisions?
The stage micrometer is the one that's in the 'slide', right, that one usually has divisions from 0-100!
I'm sorry for the confusion! :s
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