Biology (2nd Quarter)

• Meiosis is a process that produces genetically unique cells.
• During meiosis, a single cell undergoes mitosis and becomes specialized until it becomes an organism.
• The first cell produced by meiosis and fertilization is genetically unique.
• Lipids are the group of fats or fat-like long chain of hydrocarbons which are insoluble in water due to large numbers of uncharged carbon-carbon and carbon-hydrogen bonds.
• Fats are lipids composed of one molecule of glycerol (an alcohol containing three carbon) and three fatty acid molecules.
• An ester bond connects the glycerol and fatty acids.
• Fats can be broken down into simpler compounds by the addition of water or hydrolysis.
• Three molecules of water are needed to break one molecule of fat into its component glycerol and three fatty acids with the aid of an enzyme called lipase.
• Saturated fatty acids are solid at room temperature and are mostly found in animals.
• Unsaturated fatty acids occur in liquid state at room temperature and are found mainly in plants.
• Phospholipids are important components of cell membranes and are made up of two fatty acid molecules and one phosphate group.
• The non-polar fatty acid components of phospholipids are hydrophobic, while the polar phosphate group is hydrophilic.
• Steroids are lipids with a carbon skeleton of four fused ring and can be easily recognized by its tetracyclic skeleton consisting of three(3) fused six-membered (cyclohexane) rings and one (1) five-membered (cyclopentane).
• Cholesterol is found in the tissues of animals, but not in plants.
• Cholesterol adds strength to the plasma membrane of animal cells and serves as a precursor to the formation of steroids.
• Triglycerides, also known as blood fats, circulate in the blood stream along with cholesterol and are obtained from food such as meat and plant oils.
• Terpenes are non-saponifiable lipids which are synthesized from isoprene (5-carbon hydrocarbon) and have different kinds based on the number of isoprenes bonded together.
• Terpenes have characteristic odors and flavors and are major components of essential oil derived from plants.
• Waxes are long chain of fatty acids and one hydroxyl group (-OH) or alcohol group made up waxes.