Homework Help is Here – Start Your Trial Now!
Science
Biochemistry
Starch is a polysaccharide 1.Is starch positive in Bial‘s test？（what color ？） 2.Is starch positive in （Seliwanoff‘s）ketohexoses test？（what color would it be if negative）

Starch is a polysaccharide 1.Is starch positive in Bial‘s test？（what color ？） 2.Is starch positive in （Seliwanoff‘s）ketohexoses test？（what color would it be if negative）

Biochemistry
Biochemistry
9th Edition
ISBN:9781319114671
Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Chapter1: Biochemistry: An Evolving Science
Section: Chapter Questions
Problem 1P
See similar textbooks
icon
Related questions
Question
Starch is a polysaccharide 1.Is starch positive in Bial‘s test？（what color ？） 2.Is starch positive in （Seliwanoff‘s）ketohexoses test？（what color would it be if negative）
**Testing for Sugars: Bial’s and Resorcinol (Selivanoff's) Tests** **1. Bial’s Test (Distinguishing between Pentoses and Hexoses):** - Used to identify pentoses. - Procedure: - Add 0.5 mL of a 1% carbohydrate solution in water to 1 mL of Bial's reagent. - Use a glass Pasteur pipette and avoid mechanical pipetting. - Place in a boiling water bath for 2 minutes. - Results: - A blue-green colored product indicates the presence of pentoses. - A yellow-green color indicates hexoses, nucleotides, or disaccharides. **2. Resorcinol (Selivanoff's) Test (Ketoses):** - Used to test for ketoxoses. - Procedure: - Add 0.1 mL of a 1% carbohydrate solution in water to 1 mL of the reagent. - Heat the solution in a boiling water bath for 5 minutes. - Results: - A deep red colored precipitate within 5 minutes indicates ketoxoses. - Sucrose gives a positive ketoxose test due to partial hydrolysis into glucose and fructose. - Other sugars turn red upon prolonged heating. **Annotations on the Document:** - Handwritten notes mention "Structure of the product the resorcinol & ketoxes give red color upon unknown why blue." - Chemical structure depicted: "H-C=CH-O". These tests help in distinguishing between different types of sugars by observing color changes under specific conditions.
Transcribed Image Text:**Testing for Sugars: Bial’s and Resorcinol (Selivanoff's) Tests** **1. Bial’s Test (Distinguishing between Pentoses and Hexoses):** - Used to identify pentoses. - Procedure: - Add 0.5 mL of a 1% carbohydrate solution in water to 1 mL of Bial's reagent. - Use a glass Pasteur pipette and avoid mechanical pipetting. - Place in a boiling water bath for 2 minutes. - Results: - A blue-green colored product indicates the presence of pentoses. - A yellow-green color indicates hexoses, nucleotides, or disaccharides. **2. Resorcinol (Selivanoff's) Test (Ketoses):** - Used to test for ketoxoses. - Procedure: - Add 0.1 mL of a 1% carbohydrate solution in water to 1 mL of the reagent. - Heat the solution in a boiling water bath for 5 minutes. - Results: - A deep red colored precipitate within 5 minutes indicates ketoxoses. - Sucrose gives a positive ketoxose test due to partial hydrolysis into glucose and fructose. - Other sugars turn red upon prolonged heating. **Annotations on the Document:** - Handwritten notes mention "Structure of the product the resorcinol & ketoxes give red color upon unknown why blue." - Chemical structure depicted: "H-C=CH-O". These tests help in distinguishing between different types of sugars by observing color changes under specific conditions.
Expert Solution
steps

Step by step

Solved in 2 steps

SEE SOLUTIONCheck out a sample Q&A here
Blurred answer
Recommended textbooks for you
Biochemistry
Biochemistry
Biochemistry
ISBN:
9781319114671
Author:
Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.
Publisher:
W. H. Freeman
Lehninger Principles of Biochemistry
Lehninger Principles of Biochemistry
Biochemistry
ISBN:
9781464126116
Author:
David L. Nelson, Michael M. Cox
Publisher:
W. H. Freeman
Fundamentals of Biochemistry: Life at the Molecul…
Fundamentals of Biochemistry: Life at the Molecul…
Biochemistry
ISBN:
9781118918401
Author:
Donald Voet, Judith G. Voet, Charlotte W. Pratt
Publisher:
WILEY
Biochemistry
Biochemistry
Biochemistry
ISBN:
9781305961135
Author:
Mary K. Campbell, Shawn O. Farrell, Owen M. McDougal
Publisher:
Cengage Learning
Biochemistry
Biochemistry
Biochemistry
ISBN:
9781305577206
Author:
Reginald H. Garrett, Charles M. Grisham
Publisher:
Cengage Learning
Fundamentals of General, Organic, and Biological …
Fundamentals of General, Organic, and Biological …
Biochemistry
ISBN:
9780134015187
Author:
John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
Publisher:
PEARSON
SEE MORE TEXTBOOKS