Week 3 - Biomolecules

• Carbohydrates are molecules made from aldehydes and ketones containing numerous hydroxyl groups.
• All carbohydrates contain carbon, hydrogen and oxygen.
• Carbohydrates are the most abundant organic molecule in nature.
• Carbohydrates are also referred to as saccharides.
• The carbohydrates which are soluble in water and sweet in taste are called sugars.
• Carbohydrates are used by living organisms as accessible energy to fuel cellular reactions.
• Carbohydrates are the most abundant dietary source of energy (4kcal/gram) for all living beings.
• Carbohydrates are stored as glycogen in animals and starch in plants.
• Monosaccharides - from the word mono, it is the simplest sugar and the basic subunit of a carbohydrate.
• The most common monosaccharides are glucose (aka dextrose), fructose or fruit sugar and galactose (sugar in milk).
• Disaccharides - consists of two monosaccharides that are chemically combined.
• The sugar we use to sweeten our coffee is a disaccharide. It is also called sucrose or table sugar.
• When two glucose molecules are combined, maltose is formed. Another important disaccharide is lactose or milk sugar. Lactose is made up of a sugar called galactose and glucose.
• Maltose (or malt sugar) is an intermediate in the intestinal digestion (ie. hydrolysis) of glycogen and starch, and is found in germinating grains (and other plants and vegetables).
• There are 3 common polysaccharides:

  1. Starch
  2. Glycogen
  3. Cellulose
• 3 common polysaccharides:

  1. Starch - is made up of two types of polysaccharides: amylose, which is a coiled of helical structure, and amylopectin, which is branched. Plants make starch.
• Glycogen - is similar to starch but it contains more branches than starch. Glycogen is stored in animal cells such as liver and muscle cells.
• Glycogen is the major carbohydrate storage form in animals, and corresponds to starch in plants. Glycogen:animals, starch: plants
• 3 common polysaccharides:

  3. Cellulose - The glucose molecules in cellulose chains ate arranged in such a way that hydrogen bonds link hydroxyl groups of adjacent glucose molecules to form insoluble fibrous sheets. These sheets of cellulose are the basic components of plants.
• Proteins are polymers of amino acids. They have many functions in our body. One of which is found as structural materials in hair, nails and connective tissues.
• Proteins are made up of the elements carbon, hydrogen, oxygen, nitrogen and sulfur. Enzymes are proteins that act as biological catalysts.
• Egg whites, fish, meat and cheese are foods rich in proteins.
• Proteins are the second most common molecules found in the human body (after water) and make up about 10% to 20% of the mass of a cell.
• Amino acids are the building blocks of proteins.
• Of the 20 amino acids found in human protein, only 11 can be synthesized by the body and 9 have to be supplied by the foods we eat. These 9 amino acids are also called essential amino acids.
• Your body doesn't store amino acids, so it needs a regular daily supply of these essential building blocks. Of the 11 nonessential amino acids, 8 are called conditional amino acids.
• Proteins are polymers of amino acids.
• Proteins are made up of the elements carbon, hydrogen, oxygen, nitrogen and sulfur.