Unit 1: Biochemistry Macromolecules A. Carbohydrates

Macromolecules macromolecules are large molecules that are often composed of repeating sub-units (monomers) some of the biologically important macromolecules are: carbohydrates -lipids proteins -nucleic acids

Carbohydrates carbohydrates are our most important energy source can be simple (mono- or disaccharides) or complex sugars (polysaccharides) Image from: http://www.lifetime-fitness.ca/pages/meet-our-trainers/trainer-tips--nutritional

1. Monosaccharides single sugars in straight chain or ring form C:H:O usually in 1:2:1 ratio (glucose is C6H12O6) examples: glucose, fructose, deoxyribose Image from: http://www.phschool.com/science/biology_place/biocoach/bioprop/glucose.html

1. Monosaccharides some monosaccharides are isomers, e.g., glucose & fructose (same formula-C6H12O6, different structure) Image from: http://course1.winona.edu/sberg/241f08/Lec-note/Biochem.htm

Isomers of Glucose - & ß

2. Disaccharides = double sugar Glucose Fructose + Sucrose

2. Disaccharides sugar molecules made from 2 single sugars formed by a dehydration reaction Image from: http://mansfield.osu.edu/~sabedon/biol1020.htm Sucrose, maltose (malt sugar used in making beer), lactose (in milk), etc.

Dehydration reactions - a chemical reaction where monomers are joined by the removal of water (H+ & OH-) (aka condensation) Hydrolysis Reactions - reverse of dehydration - H+ & OH- are added to molecules to break them into smaller subunits

Find the sugars… Image from: http://amerthehammer.com/2010/12/04/understanding-ingredient-labels-todays-tip/

Granola bars healthy. Image from: http://healthyeatingnaturally Granola bars healthy? Image from: http://healthyeatingnaturally.wordpress.com/2009/02/11/the-truth-about- granola-bars/

Let’s make some sugars....

Self-test What is the difference between a monosaccharide and a disaccharide? What is an isomer? Give an example of biological isomers.

What is the formula of glucose? (Draw a simple structure.) What is the formula of fructose? (Draw a simple structure.) When are carbohydrates in chains versus rings?

Identify the following molecule as either alpha glucose or beta- glucose. How do you know?

What type of reaction is this?

3. Polysaccharides oligosaccharides are shorter-chain sugars with 3- 10 single sugars longer chain carbohydrates are called polysaccharides examples: starch, cellulose, glycogen, chitin Polymerization- linking identical subunits (i.e., monomers) to make a larger molecule

1. Cellulose humans cannot digest this cellulose (=fibre) long chains of ß-linkages structural molecule in plants (cell wall)

very easy for humans to digest alpha-linkages in sugars 2. Starch very easy for humans to digest alpha-linkages in sugars fast source of energy storage molecule for plants Glucose (Note: all sugars line up the same way)

3. Glycogen a large molecule that is used by humans to store energy found in muscles & liver cells similar in structure to starch (i.e., alpha links) but branching molecule

Let’s take a look at starch (crystals, that is...) Make a wet mount of a banana cell. Stain the cells with iodine. Draw and label the starch crystals. --> Note: starch crystals do not look like glucose molecules!

Carbohydrate Summary Type Examples Function Drawing monosaccharide disaccharide Polysaccharide