Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Carbohydrates - mscyr11biology
Document related concepts
Transcript
Carbohydrates Which of these foods contain carbohydrates? Carbohydrates in food • Nearly all foods contain carbohydrates • Different food have different amounts of carbohydrates • Meats which have not been processed contain no carbohydrates • Water contains no carbohydrates Diet • Carbohydrates should make up 50-55% of our diet • Important source of energy • Carbohydrates can be either ‘high GI’ or ‘low GI’ • Low GI carbohydrates are harder to break down, so the energy from the food is released slower Structure of carbohydrates • Carbohydrates are made up of carbon, hydrogen & oxygen • Carbohydrates are described as ‘simple’ or ‘complex’ according to their structure Monosaccharide • Simplest carbohydrates • Single ring structure (‘mono’=one) • Glucose is a type of monosaccharide • Chemical formula is CH O 6 12 6 • Fructose and galactose are other types of monosaccharides Glucose • Glucose is produced during photosynthesis • Carbon dioxide and water molecules are broken apart by enzymes and sunlight • The atoms then join together to form glucose, water and oxygen Disaccharide • When two monosaccharides join togther, they form a disaccharide • Maltose: glucose + glucose • Sucrose: fructose & glucose • Lactose: galactose & glucose Polysaccharides • If many monosaccharides or disaccharides join together, a polysaccharide is formed • Cellulose is a type of polysaccharide, found in plant walls, that is formed from many glucose molecules joining together • The bonds between the glucose molecules are tough to break down or bend • Cellulose is also known as ‘dietary fibre’ Starch • Made of two polysaccharides joined together • Contains over 6000 glucose molecules • Most plants store excess starch in their roots, and break it down when they require glucose Storage of carbohydrates in humans • Excess carbohydrates are stored as glycogen in the liver and muscles • When our blood sugar levels drop, glycogen is converted to glucose, and released into the bloodstream • Excess carbohydrates are NOT stored as fat
