1. Starter
Name the following molecules: 3 2 1 5 4

2. Carbohydrates
Must: Be able to state how monomers are linked together by condensation reactions
Should: Be able to name 3 monosaccharides, 3 disaccharides and 3 polysaccharides
Could: Be able to explain the structure and function of cellulose in plants and glycogen in humans.

3. Lesson plan
Show students slide 2 and ask them to identify each molecule, question students about the purpose and use of each and recap the key functional groups.
Students make notes on slides 4 and 5.
Use slide 6 and 7 to illustrate the difference between a hydrolysis reaction and a condensation reaction.
Class challenge – students should try and build models of alpha and beta glucose, they should then be instructed on how to join them up to make either starch, cellulose or glycogen
Take this opportunity to highlight the key differences between the 3 molecules
Use slide 10, computers, I pads or smart phones to answer questions, share answers with class
Finish with plenary questions and ask one student to come out the front to answer each question.
Set exam questions for homework or they could be used during the lesson.

4. List three examples each of monosaccharides, disaccharides and polysaccharides.
Glucose, galactose and fructose are all monosaccharides.
Maltose, lactose and sucrose are all disaccharides.
Starch, glycogen and cellulose are all polysaccharides.

5. Condensation vs. hydrolysis

6. Use this animation to illustrate condensation of hydrolysis reactions:

8. Class challenge Each make an alpha-glucose molecule.
Now try and join them up to make glycogen – you will need to look at the diagrams given to you by your class teacher and think carefully about the glycosidic bonds between the molecules

10. Using your textbooks or ipads
Use diagrams to illustrate the difference between alpha and beta glucose.
What happens during a condensation reaction? Give an example
What happens during a hydrolysis reaction?
Describe the structures of starch, cellulose and glycogen.

11. Uses of carbohydrates In animals,
Glucose is used as an energy source for the body.
lactose is the sugar found in milk which provides energy to new borns until they are weaned.
glycogen is used as an energy source (short term only) and is stored in muscles and the liver.
In plants,
fructose is what makes fruits taste sweet which attracts animals and these then eat the fruits and disperse the seeds found in the fruits.
Sucrose is used as an energy source for the plant whereas
cellulose fibres are what makes the plant cell wall strong.

12. Test yourself
Explain the difference between a molecular formula and a structural formula.
Alpha-glucose and beta-glucose are isomers. What does this mean?
What is the difference between a pentose and hexose sugar?
Starch is a polymer, what is meant by a polymer?