Carbohydrates, Lipids and Proteins
outline the role of condensation and hydrolysis in the relationship between amino acids and polypeptides
- A condensation reaction occurs between the amino group of one amino acid and the carboxylic acid group of another amino acid. - This reaction forms a dipeptide, plus a molecules of water, that is held together by a peptide bond. - Multiple amino acids can be joined together to form a polypeptide chain. - In the presence of water, polypeptides can be broken down into individual amino acids via hydrolysis reactions.
Outline the role of condensation and hydrolysis in the relationship between fatty acids, glycerol and triglycerides.
- The condensation reaction occurs between three hydroxyl groups glycerol and the carboxyl groups of three fatty acids. - This reaction forms a triglyceride, which is three molecules of water. - The bond between the glycerol and fatty acids is an ester linkage. - One of the fatty acids is replaced by a phosphate groups and this forms the phospholipid. - Hydrolysis reactions will, in the presence of water, break these molecules down into their constituent sub units.
Outline the role of condensation and hydrolysis in the relationship between mono, di, and poly saccharides
- condensation, also seen as dehydration occurs when the molecules are joined covalently and off this reaction water is formed. - When the bond that forms in carbohydrates forms it is called a glycosidic linkage. - The opposite of a condensation reaction is called a hydrolysis reaction (opposite to first step) this requires a water to molecule to break the covalent bond between two subunits. - Monosaccharides are single monomers, when they join they are called disaccharides, while sugars containing more than 10 subunits are called polysaccharides.
State one function of glucose, lactose and glycogen in animals and of fructose, sucrose and cellulose in plants
Animals: Glucose: a source of energy which can be broken down to form ATP via cellular respiration. Lactose: sugar in the milk of mammals, source of energy for their infants. Glycogen:in between meals it is used for storage in the liver Plants: Fructose: a source of energy and sweetness, can be found in honey and onions. Sucrose: contains energy that is transportable, examples are sugar beets and sugar cane. Cellulose: Plant cells use to strengthen the cel wall.
Identify glucose and ribose from diagrams showing their structure
Glucose - is hexagonal Ribose - is pentagon
List three example each of monosaccharides, disaccharides and polysaccharides.
Monosaccharides: Glucose, galactose, fructose (Mono eats glue and galactic fruit) Disaccharides: Lactose, maltose, sucrose (die for some milk and malt sucrose) Polysaccharide: cellulose, glycogen, starch
Organic and Inorganic Compounds
Organic compunds are compounds containing carbon that are found in living things - except hydrogen carbonates, carbonates and oxides of carbon. Inorganic compounds are all other compounds (There are less different inorganic compounds than organic compounds.)
Proteins:
Proteins are large organic compounds made of amino acids arranged in a linear chain. The sequence of amino acids in a protein is defined by a gene and encoded in the genetic code.
Compare the use of carbohydrates and lipids in energy storage.
Similarities: - Complex carbohydrates, for example polysaccharides, and lipids both contain alot of chemical energy and can be used for energy storage. - Complex carbohydrates and lipids are both insoluble in water, they are not easily transported. - Carbohydrates and lipids both burn cleaner than proteins, no nitrogenous waste. Differences: - Lipid molecules contain about twice as much energy per gram than carbohydrates. - Carbohydrates are more easily digested than lipids and release energy more rapidly. - Mono and di are water soluble and are easier to transport to and from storage sites than lipids. - Animals ten dot use carbohydrates primarily for short-term energy storage, while lipids are used for more long term energy storage. - Carbohydrates are stored as glycogen in animals while lipids are stored as fats. In plants carbohydrates are stored as cellulose and lipids are stored as oils. - Lipids have less effect on osmotic pressure with a cell than complex carbohydrates.
Three functions of lipids
Structure: The structure is a phospholipid which is a main structural component of cell membranes Hormonal Signalling: Steroids are involved in hormonal signalling for example, oestrogen, progesterone and testosterone. Insulation: fats in animals can serve as heat insulators while sphingolipids in the myelin sheath of neurones can serve as electrical insulators. Protection: Triglycerides may form a tissue layer around many key internal organs and provide protection against physical injury. Storage of energy: Triglycerides can be used as a long term energy storage source.
Lipids
lipids are a group of organic molecules that are insoluble in water but soluble in non-polar organic solvents. Common lipids include triglycerides (fats and oils), phospholipids and steroids.
