Test review Any annotations have to be in a different colour!

Reading outside the classroom For each topic you are expected to read in your own time. Minimum expectation is to read the recent chapter in the textbook. On the day of the end of topic test you have to hand in your notes on the topic: Essay Bullet points Mind map/ spider diagram/ concept map

Carbohydrates

Bell Ringer: Organic molecules What is a macromolecule?

Bell ringer – organic molecules SIGN UP FOR REMIND! @37k7hk Chemistry crash course: Bozeman Science – The Molecules of Life

What are Carbohydrates? Organic compounds which comprise of only C, H and O Carbo-Hydr-ate C H O

Types of Carbohydrate Monosaccharides Disaccharides Polysaccharides

Monosaccharides Simplest – ‘Single sugars’ Same no. of C as O atoms e.g. Glucose is C6H12O6 Have the general formula (CH2O)n Where n is any number between 3 and 7 White crystalline solids Dissolve in water to form sweet tasting solutions

The structure of glucose You only need to be able to draw α-glucose in its simplified form….

The structure of glucose α-glucose and β-glucose are ISOMERS (compounds with the same formula but a different arrangement of atoms)

Monosaccharides form Disaccharides in condensation reactions + Maltose H2O

Monosaccharides form Disaccharides The bond formed is a glycosidic bond A condensation reaction occurs to join the 2 monosaccharides α 1-4 glycosidic bonds

Disaccharides hydrolyse to form Monosaccharides H2O

Disaccharides form Polysaccharides Starch

Starch The α-helical structure of starch makes it good for storage (it’s compact!) Starch is insoluble due to its structure It is therefore the main plant storage sugar

Cellulose Polymer of β-glucose Each monomer is inverted. Has consequences for its properties

Cellulose Forms chains which run parallel with hydrogen bonds between the chains to form microfibrils Microfibrils are strong Being fibrous, cellulose is structurally important in plant cell walls

Glucose is not the only monosaccharide... Fructose: Glucose and fructose combine to form sucrose (a disaccharide)

Glucose is not the only monosaccharide... Galactose Glucose Galactose Glucose and galactose combine to form Lactose

Summary α-glucose + α-glucose = maltose The polymer of α-glucose is starch The polymer of β-glucose is cellulose Glucose + fructose = sucrose Glucose + galactose = lactose

You should be able to draw examples of carbohydrates from memory! – practise using look-cover-write-check Task Use the molymods to build the following molecules: α-glucose, β-glucose, fructose and carry out a condensation and a hydrolysis reaction. Use the molymods and the textbook to complete the worksheets on carbohydrates Challenge Use the structure of α- and β–glucose to explain the difference in structure between cellulose and starch

Check your work

HW: ESSAY Compare the structure and function of a cellulose molecule and starch. [7]