Life’s Molecules. Carbohydrates Monosaccharide (Glucose) Carbohydrates.
Carbohydrates
description
Transcript of Carbohydrates
4.2 Carbohydrates
activity
Task Read the passage in the textbook. Complete the concept map.
After that, in your group, discuss about following topics.
Group1:types of carbohydrates
Group2:reducing and nonreducing sugar
Group3:process of formation and breakdown of disaccharides and polysaccharides
You have 10 minutes to complete the tasks.
Carbohydrates
• An important source of energy that can be used by cell
• Contain C, H and O
• Ratio H:O = 2:1
Types of Carbohydrate
s
disaccharides
monosaccharides
polysaccharides
Monosaccharides
• Monomer of carbohydrates
• Simplest type of carbohydrates
• Known as simple sugar = main source of energy.
• Combine with protein = glycoprotein
• Combine with lipid = glycolipid
Monosaccharides
• Examples – glucose, fructose and galactose
• Glucose – plants and fruit
• Fructose – sweet fruits and honey
• Galactose - milk
Disaccharides
• Formed when 2 monosaccharides combine through condensation process.
• Condensation = process which involves the removal of a water molecule when a bond is formed between 2 molecules of monosaccharides.
• Examples – sucrose, lactose and maltose
Disaccharides
Glucose + glucose
Glucose + fructose
Sucrose + water
Glucose + galactose
Maltose + water
Lactose + water
Condensation Hydrolysis
Polysaccharides
• Polymers formed by the condensation of glucose monomers.
• Insoluble in water due to large molecular size
• Do not taste sweet and do not crystallize.
• Examples – starch, glycogen and cellulose.
Polysaccharides
• Starch – wheat, rice, potatoes, bread and corn.
• Cellulose – plant cell wall
• Glycogen – animal (liver & muscle cell) and yeast.
• Glycogen = animal starch
• Glycogen is highly branched
Polysaccharides
Polysaccharides
• Can be broken down into smaller molecules through hydrolysis by adding diluted acid or through enzymatic reaction.
Polysaccharides + water
Monosaccharides
activity
Differentiating between reducing and non-reducing sugars.
Objective
To investigate the properties of reducing and non-reducing sugar
Hypothesis
Reducing sugar will reduce the color of Benedict’s solution from blue to red brick precipitate
Variables
1.Manipulative = types of sugar
2. Responding = changes in the color of Benedict ‘s solution
3. Constant = volume of sugar, volume of Benedict’s solution.
Procedures
Observation
Solution
Observation Inference
Glucose Blue red brick
precipitate
Glucose reduces CuSO4 to CuO
Sucrose Remain blue Sucrose do not reduces CuSO4 to CuO
Sucrose + HCl
Blue red brick
precipitate
Sucrose is hydrolyzed into glucose and fructose. Both of them can reduce CuSO4 to CuO
Question
1. What information can you draw from the result that you have obtained?
2. What is the effect of dilute HCl acid on sucrose?
3. Classify the glucose and sucrose sugars according to their properties based on the experiment?
Discussion
1.When glucose is heated with Benedict’s solution, it reduces the blue copper(II) sulphate in the Benedict’s solution to form a precipitate of copper(I)oxide.
Therefore, glucose is a reducing sugar.
Discussion
Sucrose do not reduce the Benedict solution upon heating.
Therefore, sucrose is a non-reducing sugar.
Discussion
2.When heating sucrose with dilute HCl, it is hydrolysed into glucose and fructose.
When the solution containing glucose and fructose is boiled with Benedict’s solution, it produces red brick precipitate.
Discussion
3. Glucose is a reducing sugar.
Sucrose ia a non-reducing sugar.
Conclusion
• Glucose is a reducing sugar.
• Sucrose ia a non-reducing sugar.
Benedict’s test
Increasing amount of reducing sugar
green
orange
Red brick precipitate
All monosaccharides are reducing sugar
Lactose and maltose are reducing sugar but sucrose are non-reducing
sugar
activity
We are the millionaire
Rules
1. Makes sure you have the answer before you raised your hand.
2. Your turn will be given to other group if you are taking time to give your answer.
3. If you give the correct answer, you given a chance to draw a letter stating the value your group have win.
4. For the wrong answer, you will lose rm1000
1
State 3 types of carbohydrates
Monosaccharides, disaccharides and
polysaccharides
2
Gives 3 groups of monosaccharides sugar
Glucose,Fructose and
Galactose
3
Galactose can be found in ___________milk
4
Disaccharides can be broken down by the process of ________hydrolysis
5
State 3 group of polysaccharides
StarchGlycogenCellulose
6
What is condensation?
Process which involves the removal of a water molecule
when a bond is formed between 2 monosaccharides
7
What is the monomer of polysaccharides?
glucose
8
What is the effect of adding dilute HCl acid into sucrose solution?
Sucrose is broken down into glucose and fructose.
Sucrose is hydrolysed.
9
Name all the reducing sugars
GlucoseFructose
GalactoseMaltoseLactose
10
Monomers of maltose is ____________glucose
11
The presence of reducing sugar in a solution can be test using Benedict’ solution. What is the observation if the reducing sugar is present in the solution?
Blue color change to red brick precipitate
assessment
Question
1. List all 3 elements in the carbohydrates.
2. List all 3 types of carbohydrates
3. Explain the formation and breakdown of sucrose, lactose and maltose
4. Explain the formation and breakdown of polysaccharides
conclusion