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How starch can give a negative iodine test?
Starch can give a negative iodine test when starch is mixed with iodine in water. The iodine gets stuck in the coils of beta amylase molecules and the starch forces the iodine atoms into a linear arrangement in the central groove of the coil.
Do proteins give positive iodine tests?
Yes it give positive result
Which reacts to iodine glucose or starch?
Starch turns blue when Iodine is introduced. Added: Though it's not quite a chemical reaction, Iodine will give starch a bluish purple color but it stays chemically UNchanged. Iodine stays reddish brown with glucose and many other oligosaccharides (up till about 10 to 15 monomeric glucose units)
When multiplying two numbers with different signs the result will be?
Multiplying a positive and negative number will give a negative result. The result is a negative number.
Do glucose give a positive result for anthrone test?
Yes .
What are positive and negative controls in an experiment?
Positive controls : an experimental treatment that will give the desired result Negative controls: An experimental treatment that will NOT give the dersired result.
Would glucose give a positive result with the Biuret test?
No because glucose does not consist of two or more peptide bonds
Why sucrose does not give a positive Benedict's test but hydrolyzed sucrose does give a positive beneditcts test?
Sucrose is formed from glucose and fructose.Sucrose is formed from glucose and fructose. Glucose and fructose gives positive test for benedict becuz both of them are reducing sugars whereas sucrose is not a reducing sugar so it gives negative test for benedict. On prolonged heating,sucrose will form glucose and fructose (reducing sugars)which ultimately gives a positive result .
Why doesn't cellulose give a positive iodine test?
cellulose is derived from D-glucose units, which condensed through beta(1->4)-glycosidic bond. This give cellulose to be a straight polymer therefore, it can't coil around iodine to produce blue color as starch does.
Can drinking too much water give a negative result for infection?
No
Does escherichia coli give a negative result for citrate test?
No, it is present/positive. • Cocci* • Gram-Positive* • Non-motile* • No Capsules* • No Spores* • Facultative Aerobe* • No Glucose, Lactose*, Mannitol* Fermentation • No Urease*, Catalase*, Oxidase*, Ligase*, Protease* Production • Production of Indole*, tryptophonase*
Does starch gives positive result for Benedict test?
Starch is made up of repeating glucose units. Though it is a non reducing sugar, its hydrolysis gives out pure glucose, which is known as dextrose. And glucose, as we know, is a reducing sugar and hence would give a positive result in Benedict's test.
