Docsity
Log inSign up
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search Store documents

The best documents sold by students who completed their studies

Search through all study resources
Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

University Rankings

Discover the best universities in your country according to Docsity users

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

From our blog

Exams and Study
Go to the blog

Analysis of Carbohydrates: A Medical Biochemistry Experiment, Study Guides, Projects, Research of Biochemistry

Atilim UniversityBiochemistry

understand the basis and principle of the lowry method/assay

Typology: Study Guides, Projects, Research

2018/2019

Uploaded on 12/27/2019

ahmed-adilee
ahmed-adilee 🇹🇷

3 documents

1 / 4

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
Atılım University School of Medicine
MED103 Medical Biochemistry
EXPERIMENT 4: Analysis of Carbohydrates
Name: Ahmed Al-Adilee
ID: 19261084003
Group: A
Objectives:
In this experiment we aim to understand the difference between reducing and non-reducing
sugars and to distinguish between them, this can be achieved by carrying Benedict’s test which
we also aim to understand the basis of its principle at the same time. In this lab, we will be
concerned with the nature and activities of the carbohydrates and with their structure.
Note: structure dictates how the carbohydrate will react under certain conditions.
Introduction:
Carbohydrates are compounds that contain carbon, hydrogen and oxygen. Carbohydrates include
a variety of compounds, such as sugars, starches, and celluloses. While sugars and starches serve
as energy sources for cells; celluloses are structural components of the walls that surround plant
cells.
The term carbohydrate literally means "hydrated (H20) carbon" Carbohydrates may contain one
sugar molecule (monosaccharides)simplest carbohydrates, two sugar molecules
(disaccharides)that give 2 identical or different monosaccharides molecules when hydrolyzed, or
many sugar units (polysaccharides) which is carbohydrates composed of numerous
monosaccharides.
Carbohydrates are also polyhydroxy alcohol-based substances which have an active aldehyde or
ketone group or give those groups when hydrolyzed, so those who have a free ketone or
aldehyde groups have the ability to reduce solutions containing various metallic ions like Cu+2 to
Cu+, and thus the ability of a sugar to reduce alkaline test reagents is limited by the presence of
an aldeyde or a keto group, these are called reducing sugars;
A reducing sugar is a carbohydrate that is oxidized by a weak oxidizing agent (an oxidizing
agent capable of oxidizing aldehydes but not alcohols) in basic aqueous solution. The
characteristic property of reducing sugars is that, in aqueous medium, they generate one or more
compounds containing an aldehyde group.
pf3
pf4

Partial preview of the text

Download Analysis of Carbohydrates: A Medical Biochemistry Experiment and more Study Guides, Projects, Research Biochemistry in PDF only on Docsity!

Atılım University School of Medicine

MED103 Medical Biochemistry

EXPERIMENT 4: Analysis of Carbohydrates

Name: Ahmed Al-Adilee ID: 19261084003 Group: A

Objectives:

In this experiment we aim to understand the difference between reducing and non-reducing sugars and to distinguish between them, this can be achieved by carrying Benedict’s test which we also aim to understand the basis of its principle at the same time. In this lab, we will be concerned with the nature and activities of the carbohydrates and with their structure. Note: structure dictates how the carbohydrate will react under certain conditions.

Introduction:

Carbohydrates are compounds that contain carbon, hydrogen and oxygen. Carbohydrates include a variety of compounds, such as sugars, starches, and celluloses. While sugars and starches serve as energy sources for cells; celluloses are structural components of the walls that surround plant cells. The term carbohydrate literally means "hydrated (H 2 0) carbon" Carbohydrates may contain one sugar molecule (monosaccharides)simplest carbohydrates, two sugar molecules (disaccharides)that give 2 identical or different monosaccharides molecules when hydrolyzed, or many sugar units (polysaccharides) which is carbohydrates composed of numerous monosaccharides. Carbohydrates are also polyhydroxy alcohol-based substances which have an active aldehyde or ketone group or give those groups when hydrolyzed, so those who have a free ketone or aldehyde groups have the ability to reduce solutions containing various metallic ions like Cu+2^ to Cu+, and thus the ability of a sugar to reduce alkaline test reagents is limited by the presence of an aldeyde or a keto group, these are called reducing sugars; A reducing sugar is a carbohydrate that is oxidized by a weak oxidizing agent (an oxidizing agent capable of oxidizing aldehydes but not alcohols) in basic aqueous solution. The characteristic property of reducing sugars is that, in aqueous medium, they generate one or more compounds containing an aldehyde group.

Example : α-D-glucose, which contains a hemiacetal group and, therefore, reacts with water to

give an open-chain form containing an aldehyde group as shown in the diagram below, All of the monosaccharides are considered to be reducing sugars, while disaccharides can be a reducing or a non-reducing sugar. Non-reducing sugars are sugars that do not have an aldehyde group. Thus, they cannot reduce Cu2+^ ions to Cu+. Sucrose is the most common disaccharide non- reducing sugar. Disaccharides are hydrolyzed to monosaccharides when boiled in dilute hydrochloric acid in Benedict’s Test for non- reducing sugars.

Benedict’s test: is used to test

for simple carbohydrates. The Benedict’s test identifies reducing sugars (monosaccharide’s and some disaccharides), which have free ketone or aldehyde functional groups. Benedict’s solution can be used to test for the presence of glucose in urine. Some sugars such as glucose are called reducing sugars because they are capable of transferring hydrogens (electrons) to other compounds, a process called reduction. When reducing sugars are mixed with Benedicts reagent and heated, a reduction reaction causes the Benedicts reagent to change color. Principle when Benedict’s solution and simple carbohydrates are heated, the solution changes to orange red/ brick red. This reaction is caused by the reducing property of simple carbohydrates. The copper (II) ions in the Benedict’s solution are reduced to Copper (I) ions, which causes the color change. The red copper(I) oxide formed is insoluble in water and is precipitated out of solution. This accounts for the precipitate formed. As the concentration of reducing sugar increases, the nearer the final color is to brick-red and the greater the precipitate formed. Sometimes a brick red solid, copper oxide, precipitates out of the solution and collects at the bottom of the test tube.

Experiment procedure:

  1. Put 5 ml of Benedict’s reagent in a test tube.
  2. Add 8 drops of sugar solution to the tube (2% glucose solution).
  3. After stirring, heat the tube for 5 minutes in boiling water and then let it cool down.
  4. Observe the color change and note the test results.
  5. Put 5 ml of sucrose solution in a new test tube (2% sucrose solution).
  6. Add 1 ml of 2 N HCl and heat the tube for 3-5 minutes.
  7. After cooling down, neutralize the solution by adding 1 ml of 2 N NaOH.
  8. Repeat the steps 1-4 for sucrose solution.

Discussion:

In the first test tube after the test I observed a change in the color after approximately 3 min after heating and stirring, the color of the solution was yellowish green which indicates traces of reducing sugars in the glucose tube and thus we can conclude that id reduced copper (II) ions to copper (I) ions and that caused a color change in the mixture. The other one of concern is the sucrose mixture test tube which produced no color change and remained blue for it is a non- reducing agent and cannot reduce copper ions as observed in the test. In conclusion, if reduced sugars do not exist then no color precipitate will be observed, and so the experiment helped in the understanding of the mechanisms of reducing and non-reducing sugars and their reaction on Benedict's test as we explored its principle and observed the test’s applications.