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Applied science, unit 8c, biology: digestive system practical write up
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This is the write up for the practical that I created . It up to distinction level. graded my teacher
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Biology practical reportIodine test to determine starch content
Use: it is use to determine if there is start present
Equipment:
Iodine
Safety googles
Gloves
Lab coat
Spatula
Stotting tiles
Foodstuff to be identified
Sugar
Egg powder
Apple
Potato
Soup mix
Porridge oats
Health and safety
Place all bags and coats out of place or away from the experiment
Always wear your gloves, safety googles and lab coat.
Tie your hair back
Method
I used a spatula to place the 6 individual food stuff into separate wells in the spotting tile. I then
add around 3 droplets of iodine to each of the samples wells then observed the colour change. the
colour will change from orange/ to black if starch is present
Iodine test for starch
Food sample Colour change observed Results(positive/
negative)
, sugar No colour change (stayed orange) negative
egg powder No colour change (stayed orange) positive
apple No colour change (stayed orange) negative
potato Orange - black negative
Soup mix Orange - black positive
Porridge oats Orange - black negative
Biuret test for protein
Use: it tests if there is a presence of protein
Equipment
Pipette
Biuret solution
Distilled water
Test tube
Lab coat
Gloves
Safety goggles
spatula
Foodstuff to be identified
Sugar
Egg powder
Apple
Potato
Soup mix
Porridge oats
Health and safety
Place all bags and coats out of place or away from the experiment
Always wear your gloves, safety googles and lab coat.
Tie your hair back
Method
I used a spatula to add a tiny amount of the 6 sampled foodstuffs to place into a correctly labelled
test tube. I filled ¼ of each test tube with water then added 1 pipette full of biuret solution and
mixed steadily. I observed the colour change, if the sample change from blue to lilac then there is
protein present.
Food Colour change observed Result (positive/negative
Sugar No colour changes (stayed blue) Negative
Egg powder Blue to lilac Positive
Apple No colour changes (stayed blue) Negative
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