10.7 - Summary

Carbohydrates are classified as organic compounds that can either be aldehydes or ketones, having multiple hydroxyl (–OH) groups. The term 'optically active' means that they can rotate plane-polarized light, a characteristic due to their specific molecular arrangements. When we say they can provide such units on hydrolysis, it means that breaking down these compounds yields simpler sugars, which can be classified as either mono-, di-, or polysaccharides.

Monosaccharides are the simplest form of carbohydrates, consisting of single sugar units like glucose or fructose. Disaccharides are formed from two monosaccharides linked together, such as sucrose (table sugar) which is made up of glucose and fructose. Polysaccharides are complex carbohydrates containing many monosaccharides linked together, like starch and cellulose, which serve as energy storage and structural components in plants.

Glucose is critical for cellular respiration, where it is broken down to release energy for the body's functions. Starch, a polysaccharide found in foods like bread and potatoes, is digested into glucose, which can then be utilized by cells for energy. Thus, glucose is often referred to as 'blood sugar' as it circulates in the bloodstream providing essential energy.

Glycosidic linkages are the covalent bonds that connect monosaccharide units. When two monosaccharides combine, they release a water molecule in a reaction known as dehydration synthesis, forming a disaccharide. These same linkages allow the formation of larger polysaccharides from multiple units, playing a crucial role in energy storage and structural integrity of cells.

Proteins are essential biomolecules made from amino acids, which are organic compounds that contain both amino (–NH2) and carboxyl (–COOH) functional groups. The sequence and arrangement of these amino acids, linked by peptide bonds, determine the protein's structure and function. Proteins serve various roles in the body, including providing structure, catalyzing reactions (as enzymes), and facilitating communication between cells.

Denaturation refers to the process where proteins lose their functional shape due to external stressors like changes in temperature or pH. This disturbance in structure can impair the protein's ability to perform its specific functions within biological systems. For example, cooking an egg denatures the proteins in egg whites, causing them to solidify.

Enzymes are specialized proteins that facilitate biochemical reactions by lowering the activation energy required for those reactions to occur. They are highly specific for their substrates (the molecules they act upon) and function within particular conditions (like temperature and pH) to ensure effective biochemical processes. Without enzymes, many biological reactions would occur too slowly to sustain life.

Vitamins are organic compounds that are crucial for normal metabolism and health but cannot be synthesized by the body in sufficient quantities—they must be ingested through diet. They are classified into two main categories: water-soluble and fat-soluble, each playing unique roles in physiological functions. For instance, vitamin C is pivotal for immune function, while vitamin D is vital for bone health.

Nucleic acids, primarily DNA and RNA, encode the genetic instructions for the development, functioning, growth, and reproduction of all known organisms. DNA stores the hereditary information that is passed from parent to offspring, while RNA plays an integral role in translating that information into proteins. This molecular basis of heredity ensures that traits are perpetuated over generations.

Biomolecules are essential components of all living organisms. Carbohydrates provide energy, proteins contribute to cellular structure and function, lipids store energy and form cell membranes, while nucleic acids carry genetic information. Together, these molecules interact in complex ways to sustain life and facilitate biological processes.