BOTANY WITH BASICS OF HYDROBOTANY (AQUATIC PLANTS OF UKRAINE) - B.Ye. Yakubenko - 2011

IV. PLANT ANATOMY AND MORPHOLOGY

Primary Organic Compounds

Lipids

Fats and fat-like substances (lipoids) are called Lipids. Their common property is Structure/106.html">Hydrophobicity, meaning they are insoluble in Water yet soluble in organic Solvents.

Lipids are involved in regulating membrane permeability and adsorption processes within the protoplast of a living Cell. Due to the polarity of lipid molecules, a specific molecular orientation is established in the Cytoplasm and On the surface of its structural components.

Based on their Structure and function in the living cell, lipids are divided into the following groups: fats, cutin, suberin, Waxes, and lipoids.

Fats. A portion of the reserve substances accumulated in the seeds and fruits of many plants consists of fats. Chemically, they are mixtures of esters formed from the trihydric alcohol glycerol and high-molecular-weight Fatty acids. Fatty acids are classified into saturated (palmitic, stearic, arachidic, behenic) and unsaturated (oleic, linoleic, linolenic). The molecules of the latter contain double bonds. Plant fats (oils) are rich in Unsaturated fatty acids and remain liquid at room Temperature. Solid fats include coconut oil and cocoa butter.

Waxes are fat-like substances that are solid at room temperature. Their components are esters of high-molecular-weight monohydric alcohols and fatty acids. Waxes also contain free fatty acids, high-molecular-weight alcohols, and paraffin Hydrocarbons. Waxes form a thin protective layer on plant leaves, stems, and fruits, shielding them from desiccation and the penetration of microorganisms. Among animal-derived waxes, beeswax is the best known and is widely used in medicine.

Cutin is a complex mixture of hydroxy fatty acids linked by ester bonds. Cutin coats the epidermal Cells.

Suberin is a fat-like substance that impregnates cell walls, causing them to undergo suberification (corking). Chemically, it is a glyceride of phenolic and other unsaturated fatty acids.

Lipoids are fat-like substances in which one or more hydroxyl groups of glycerol are bound not to a fatty acid, but to Other Compounds. These include Phospholipids and Glycolipids.

Phospholipids are glycerides bound to two fatty acid residues and one phosphoric acid residue linked to a nitrogenous base. Phospholipid molecules are polar and comprise both hydrophobic and hydrophilic regions. Together with Proteins, phospholipids form lipoprotein membranes that regulate The transport of various substances into The Cell and its Organelles. The phospholipid lecithin improves protein assimilation in humans and animals and promotes phosphorus accumulation; therefore, it is used in the Treatment of anemia, neurasthenia, and delayed bone growth.

Glycolipids are glycerides bound to Fatty Acids and one or more monosaccharide residues (e.g., galactosylglycerides of METABOLISM/14.html">Chloroplasts and Mitochondria).