Chemistry of life: Carbohydrates

37. Carbohydrates

Organic molecules made of carbon, hydrogen and oxygen that provide energy, particularly for the brain and muscles.

38. Monosaccharides

Simple sugars that cannot be broken down into simpler sugars; they are the building blocks of more complex carbohydrates and dissolve in water.

39. Examples of monosaccharides

Glucose, fructose and galactose.

40. Disaccharides

Sugars formed when two monosaccharides bond together; they dissolve in water.

41. Sucrose

A disaccharide made of glucose and fructose.

42. Lactose

A disaccharide made of galactose and glucose.

43. Polysaccharides

Complex carbohydrates made of chains of many monosaccharide molecules.

44. Starch

A polysaccharide found in plants that stores carbohydrates.

45. Glycogen

A polysaccharide used to store glucose in the liver and muscles of humans.

46. Cellulose

A polysaccharide found in plant cell walls that also acts as dietary fibre.

47. Benedict's test for glucose

Add Benedict's solution to the sample and heat it. A change from blue to orange or brick-red indicates glucose is present.

48. Iodine test for starch

Iodine solution changes from brown to blue-black when starch is present.