Carbohydrates

• Variations in form allow diversity of function in carbohydrates and lipids
• Carbohydrates and lipids are composed of carbon, hydrogen, and oxygen
• Differences in the form of their molecules give carbohydrates and lipids very different properties
• Carbohydrates and lipids compare as energy storage compounds
• Carbohydrates store energy in the form of starch or glycogen
• Lipids store energy in the form of fats or oils
• Energy is released when carbohydrates and lipids are oxidized by cellular respiration
• Chemical properties of a carbon atom
• Carbon has four electrons in its second shell and can form four strong, stable covalent bonds
• Carbon can form covalent bonds with oxygen, nitrogen, and sulfur
• Carbon's ability to form covalent bonds with other carbon atoms allows for the formation of diverse compounds
• Carbon atoms with four different atoms or groups attached are asymmetric, leading to variety among organic molecules
• Carbon atoms can form double bonds with other carbon atoms, nitrogen, and oxygen
• Functional groups attached to a carbon atom make molecules reactive and able to form larger molecules
• Production of macromolecules by condensation reactions
• Macromolecules are composed of a large number of atoms with a relative molecular mass above 10,000 atomic mass units
• Main classes of macromolecules are polysaccharides, polypeptides, and nucleic acids
• Polymers are formed by linking monomers together via condensation reactions
• Different types of macromolecules are formed by linking specific subunits into chains
• Polymers are broken down into monomers by hydrolysis reactions using water
• Digestion of polymers into monomers by hydrolysis reactions
• Hydrolysis is the process by which polymers are broken down into monomers using water
• Hydrolysis reactions deconstruct polysaccharides, polypeptides, and nucleic acids into monosaccharides, amino acids, and nucleotides
• Enzyme action increases the rate of hydrolysis reactions breaking glycosidic bonds in polysaccharides
• Digestion is brought about by hydrolysis reactions, where the glycosidic bonds in polysaccharides are broken with the addition of water
• The rate of these reactions is increased by enzyme action
• Amylase, an enzyme found in the salivary glands and pancreas of mammals, is secreted onto food to facilitate the hydrolysis of polysaccharides
• Polypeptides (Proteins) are digested into shorter chain peptides and ultimately amino acids through hydrolysis reactions
• In animals, protease enzymes catalyze these reactions
• In nucleotides, the phosphodiester bond is the linkage between the third carbon atom of one sugar molecule and the fifth carbon atom of another sugar molecule
• Glucose is a polar molecule that dissolves in water due to the formation of hydrogen bonds with their slightly charged hydroxyl groups (OH)
• The structure of glucose gives it chemical stability
• Glucose is the main substrate used in respiration in cells
• Glucose can be completely broken down via aerobic respiration to release large amounts of energy in the form of ATP, releasing carbon dioxide and water as waste products
• Compounds that have the same component atoms in their molecules, but which differ in the arrangement of the atoms are known as isomers
• In the ring structure of glucose, the positions of the -H and -OH groups that are attached to carbon atom 1 may interchange, giving rise to two isomers known as alpha(𝝰) glucose and beta(𝞫) glucose
• Starch, Cellulose, and Glycogen are made by linking together glucose molecules
• Cellulose is the most abundant carbohydrate, making up more than 50% of all organic carbon
• Cellulose is a polymer of (𝞫) glucose combined together by glycosidic bonds between the carbon 4 of one beta glucose molecule and the carbon 1 of the next
• Starch is formed by linking together Alpha-glucose molecules