Organic Chemistry Basics

Organic Chemistry

• Organic chemistry is the chemistry of organisms, while inorganic chemistry is the chemistry of the non-living world.
• Organic molecules contain both carbon and hydrogen atoms.
• The four major classes of organic compounds are carbohydrates, lipids, proteins, and nucleic acids.
• A bacterial cell contains 5,000 different organic molecules, and a plant or animal cell contains twice that number.
• The elements CHNOPS (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur) make up most of the weight of living things.

Carbon Atom

• Carbon has six electrons: two in the first shell and four in the outer shell.
• To complete its outer shell, carbon shares electrons with other atoms.
• Methane (CH4) is one of the simplest organic compounds.
• Four covalent bonds link four hydrogen atoms to the carbon atom.
• Carbon can share electrons with other carbon atoms, forming long carbon chains.
• Carbon chains can branch and form rings.
• Carbon can form double and triple bonds with itself and other atoms.

Biomolecules of Cells

• Certain foods are rich in biomolecules, like carbohydrates in bread and proteins in meat.
• Digestion breaks down food into smaller molecules; bread releases glucose and meat releases amino acids.
• The body uses these subunits to build up cells and tissues.

Synthesis and Degradation of Biomolecules

• Synthesis: Cells use condensation (dehydration) reactions to build biomolecules, removing a water molecule (OH and H) as subunits join.
• Degradation: Cells use hydrolysis reactions to break down biomolecules, adding OH and H from water to the subunits.
• Enzymes are required for both dehydration and hydrolysis reactions.
• Enzymes speed up reactions by bringing reactants together.
• Polymers are large biomolecules formed by linking many monomers.
• Polysaccharides are polymers of monosaccharides.
• Proteins are polymers of amino acids.
• Nucleic acids are polymers of nucleotides.

Carbohydrates

• Carbohydrates are chains of sugars that serve as an immediate energy source and play structural roles in organisms.
• The majority of carbohydrates have a 1:2:1 ratio of carbon to hydrogen to oxygen.

Monosaccharides

• Monosaccharides are single sugar molecules with a carbon backbone of three to seven carbons.
• The molecular formula for a simple sugar is a multiple of CH2O.
• Their polar hydroxyl groups make them soluble in water.
• Glucose, a hexose with the formula C6H12O6, is a major source of cellular fuel.
• Glucose is transported in the blood of animals and broken down during cellular respiration to produce ATP.
• Ribose and deoxyribose, pentoses found in RNA and DNA, respectively.

Disaccharides

• Disaccharides contain two monosaccharides joined by dehydration reactions.
• Maltose is a disaccharide used in brewing.
• Sucrose, found in sugarcane and sugar beets, is glucose combined with fructose.
• Lactose, found in milk, is glucose combined with galactose.

Polysaccharides

• They are polymers of monosaccharides that serve as energy storage and structural molecules.

Energy Storage Molecules

• Plants store glucose as starch (non-branched or branched).
• Animals store glucose as glycogen (highly branched).
• The release of insulin from the pancreas promotes the storage of glucose as glycogen.
• Polysaccharides are larger and less soluble in water than monosaccharides, making them ideal for storage.

Structural Molecules

• Cellulose, found in plants, is the most abundant organic molecule on Earth.
• Chitin, found in animals and fungi, is also a structural polysaccharide.
• Peptidoglycan, in bacteria, is another structural polysaccharide.
• Cellulose cannot be digested by animals.
• Chitin is used in medicine as a wound dressing and in cosmetics.

Lipids

• Lipids are insoluble in water due to their hydrocarbon chains.
• Fats are used for insulation and long-term energy storage in animals.
• Plants use oils instead of fats.
• Phospholipids and steroids are major components of cell membranes.

Triglycerides

• Triglycerides are fats and oils composed of fatty acids and glycerol.
• Fatty acids are long hydrocarbon chains with a carboxyl group at one end.
• Fatty acids can be saturated (no double bonds) or unsaturated (double bonds).
• Glycerol is a soluble compound with three polar hydroxyl (OH) groups.
• A dehydration reaction forms a fat molecule, where the acid portions of three fatty acids react with glycerol, releasing three water molecules.
• Hydrolysis breaks down fats.
• Fats and oils are also known as triglycerides because they have three fatty acids attached to glycerol.
• Diets high in animal fats are associated with circulatory disorders due to the accumulation of fatty material in blood vessels.
• Unsaturated fats melt at lower temperatures than saturated fats.
• Butter, a solid fat, contains mostly saturated fatty acids.
• Corn oil, a liquid fat, contains mostly unsaturated fatty acids.

Phospholipids

• Phospholipids have a structure similar to fats, but with a polar phosphate group attached to glycerol instead of the third fatty acid.
• The phosphate group forms a hydrophilic polar head, and the hydrocarbon chains of the fatty acids form hydrophobic non-polar tails.
• In water, phospholipids form a bilayer (double layer) with hydrophilic heads facing outward and hydrophobic tails facing inward, forming the plasma membrane.

Steroids

• Steroids have a four-fused ring structure.
• Cholesterol is a major component of animal cell membranes and a precursor for other steroids like testosterone and estrogen.
• High levels of cholesterol can contribute to circulatory disorders.

Proteins

• Proteins are large biomolecules and macromolecules made of one or more amino acid residues.
• They make up about 50% of the dry weight of most cells.
• Over 100,000 proteins have been identified.

Functions in Animals

• Metabolism: Enzymes speed up chemical reactions in cells by bringing reactants together.

This quiz explores the fundamentals of organic chemistry, including the characteristics of organic molecules, the significance of carbon atoms, and the four main classes of organic compounds. Test your knowledge of how these compounds form and their role in living organisms.