carbohydrates

• Carbohydrates = C, H and O

  Lipids = C, H and O

  Proteins = C, H, O, N and S

  Nucleic acids = C, H, O, N and P
• Carbohydrates are molecules that contain only carbon, hydrogen and oxygen.

  they Provide energy and they are needed for production of cell walls in plants and bacteria
• Carbohydrates can also be referred to as saccharides or sugars.

  A single sugar unit is a monosaccharide.

  When two monosaccharides link together they form a disaccharide

  When two or more monosaccharides are linked they form a polymer called a polysaccharide.
• alpha glucose

  
• beta glucose

  
• ribose

  
• When two or more monosaccharides are linked they form a polymer called a polysaccharide. This is due to a condensation reaction.

  A covalent bond called a glycosidic bond is formed between the two glucose molecules and a molecule of water is formed.

  
• Lactose- a disacharide

  an a-lactose molecule is formed from one B-galactose molecule and one a-glucose molecule

  a water molecule splits out- this is a condensation reaction

  and the two monosaccharide units are linked by a glycosidic bond

  
• Maltose - Formed from alpha and alpha glucose joining in a condensation reaction
• sucrose - Formed from fructose and glucose joining in a condensation reaction.
• lactose - Formed from a galactose and a glucose molecule joining in a condensation reaction
• sucrose (glucose+fructose)

  
• lactose (galactose + glucose)

  
• maltose (glucose + glucose)

  
• Di/Polysaccharides can be broken down by hydrolysis reactions in which the glycosidic bonds are broken and water is added

  
• hydrolysis of sucrose

  a sucrose molecule reacts with a water molecule to form one a-glucose molecule and one a-fructose molecule

  the glycosidic bond is broken in the reaction

  and the two monosaccharide units are formed

  
• Name the disaccharide formed in the condensation reaction between two alpha glucose molecules.

  maltose
• Name the reaction in which glycosidic bonds form between monosaccharides.

  condensation
• Which disaccharide stored in plants?

  sucrose
• Name the reaction in which polysaccharides are broken down into their constituent monosaccharides

  hydrolysis