Carbohydrates, Lipids and Proteins

Topic 2.3

3.2.1: Organic versus Inorganic

Organic compounds are those compounds containing carbon (except hydrogencarbonates, carbonates, and oxides of carbon e.g., carbon dioxide, methane, etc). Most biologically important molecules are organic. Inorganic compounds are those compounds without carbon plus hydrogencarbonates, carbonates, and oxides of carbon.

3.2.2: Carbohydrate, Lipid and Protein Structures

Shown below are the different structures (organic) of key carbohydrate, lipid and protein structures. Can you guess the identity of each structure?

Place your mouse over the chemical structure for identification.

Glucose structure
Amino acid structure
Ribose structure
 Glycerol structure
Fatty acid structure

3.2.3: Examples of monosaccharides, disaccharides and polysaccharides

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3.2.4: The roles of carbohydrates in animals and plants

The table below outlines one of the many roles of glucose, lactose and glycogen in animals, and of fructose, sucrose and cellulose in plants.

Carbohydrate Animals Carbohydrate Plants
glucose Used as an energy source in cellular respiration for the production of ATP. fructose Used to make fruit sweet-tasting, attracting animals to eat the fruit and disperse the seeds found in the fruit.
lactose The sugar in milk which provides energy to young mammals until they are weaned of their mother's milk. sucrose Carried in the phloem (sap) of plants thus allowing the transport of stored-energy to cells throughout the plant.
glycogen Short-term energy storage (made up of glucose monomers) in the liver and muscles. cellulose Strong fibers that are used to construct plant cell walls.

3.2.5: Condensation Reactions

Condensation reactions involve joining together monomers to form larger, more complex macromolecules. This chemical process involves the removal of water molecules. A monomer is a chemical subunit that serves as a building block of a polymer. Outlined below are the condensation reactions of: (i) monosaccharides into disaccharides with the formation of a glycosidic bond, (ii) amino acids into dipeptides with the formation of a peptide linkage,(iii) fatty acids and glycerol into triglycerides with formation of an ester bond, (iv) monosaccharides into polysaccharides through the formation of glycosidic bonds and (v) amino acids into polypeptides through the formation of peptide linkages.

Place your mouse over the particular number to see the products of the reaction.

(i)Glucose Condensation
(ii)Dipeptide Condensation
(iii)Lipid Condensation
(iv)Glucose Condensation
(v)Dipeptide Condensation

3.2.5: Hydrolysis Reactions

Hydrolysis reactions involve macromolecules which are broken down by the chemical addition of water molecules to the bonds that join their monomers. This chemical process is an important part of digestion. Outlined below are the hydrolysis reactions of: (i) disaccharides which breaks the glycosidic bond producing two monosaccharides, (ii) dipeptides which breaks the peptide linkage producing two amino acids, (iii) triglycerides which breaks the ester bond into fatty acids and glycerol, (iv) polypeptides into monosaccharides and (v) polypeptides into amino acids.

Place your mouse over the particular number to see the products of the reaction.

(i)Glucose Condensation
(ii)Dipeptide Condensation
(iii)Lipid Condensation
(iv)Glucose Condensation
(v)Dipeptide Condensation

3.2.6: Function of lipids

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3.2.7: Compare the use of carbohydrates and lipids in energy storage

Show comparison of carbohydrates and lipids | Hide comparison of carbohydrates and lipids
Carbohydrate Lipid Comparison
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