Mind Maps in Clinical Biochemistry

The eukaryotic cell is a complex structure capable of replication, carrying out reactions to maintain its intracellular environment and protect it from surrounding environmental hazards.

Enzymes are catalysts of biological systems, and most enzymes are proteins in nature. They increase the rate of reaction and decrease the energy of activation of a reaction to speed up the reaction. They are specific for substrates and products and function within a moderate pH and temperature range.

Many human diseases result from a mutation in enzymes and enzymes are used as important diagnostic tools and therapeutic targets in a number of diseases.

Carbohydrates are hydrates of carbon and have empirical formula: (CH2O) n. Polyhydroxy aldehydes or ketones form major constituents of living systems. The primary source of energy, and provides a structural component of the cell membrane and participates in cell growth, signaling, lubrication, and immunity..

Lipids of major physiologic significance are fatty acids, their ester, cholesterol, and steroids. They constitute an important dietary constituent, are hydrophobic, insoluble in water, and soluble in polar solvents..

Proteins are complex macromolecules composed of amino acids. Each body protein has a unique sequence pattern of amino acids. Amino acid sequence of a protein dictates its 3D arrangement, and the three-dimensional structure of a protein defines its size, shape, and function. Any change in the amino acid sequence of a protein can lead to structural changes to proteins or enzymes.

The central interconnecting metabolic pathway (pathways of synthesis, degradation, and interconversion of important metabolites) common to most cells and organisms is referred to as intermediary metabolism. Co-ordination of metabolic activities of different organs serves to support glucose homeostasis and provides a steady supply of glucose to meet the needs of the brain and RBCs. This also helps in the storage of fuel when available in plenty. The liver supplies glucose and ketone bodies to other tissues. Adipocytes make FA available to other tissues. The circulatory system transports metabolic fuels, intermediates, and waste products among tissues. Also, certain metabolic pathways occur in multiple tissues, namely, Cori cycle, glucose alanine cycle.

DNA is a double-stranded helix with major and minor grooves. It is composed of two polynucleotide chains joined by hydrogen bonds between bases. DNA is composed of a nitrogen base (A, G, C, T), deoxyribose, and phosphates. Four nitrogenous bases include purines (A, G), and pyrimidines (C, T). Adenine base pairs with thymine (two bonds) and Guanine base pairs with cytosine (three bonds). RNA is usually a single-stranded molecule. Three types of RNA are mRNA, rRNA, and tRNA. RNA differs from DNA as RNA contains ribose sugar instead of deoxyribose and uracil (U) rather than thymine.

This chapter discusses the functions of ECM, its structure, function and disorders of collagen, glycosaminoglycans (GAGs) and proteoglycans. For the proper functioning of the cell, it is important that each of its proteins must be localized to the correct organelle, such as mitochondria and lysosome. Also, the process of protein targeting, sorting and its biomedical importance are discussed here. Mislocalized proteins have been associated with human diseases. Therapeutic manipulation of protein localization in human diseases is promising.

Genes involved in carcinogenesis include tumor suppressor genes and oncogenes. They produce products involved in the control of cell cycle, intercellular adhesion and DNA repair. Oncogenes arise from protooncogenes that encode proteins having a role in cell’s normal activities. Most tumors contain alterations in both tumor suppressor genes and oncogenes They are derived from protooncogenes and activation of oncogenes can occur by mutation of the gene, duplication of the gene causing gene amplification to produce an excess of encoded protein; or chromosomal rearrangement that causes or alters expression of the gene leading to aberrant cell cycle control. Loss of function of one or more tumor suppressor genes or getting silenced epigenetically can cause cancer. Cells with irreparable genomic damage are destroyed by apoptosis normally. Apoptosis is involved in neurodegenerative disorders (Alzheimer, Parkinson’s, Huntington’s). The immune system is a unique adaptive defensive system to protect from invading pathogenic microorganisms and cancer. The immune response depends on pathogens and can be categorized as innate or adaptive and is produced in response to foreign substances (antigens).

Disorders of immune regulation can be aberrations of quantity, quality or direction of response. Autoimmune diseases can arise from a malfunctioning immune system. Deficiency in antibody production results in agammaglobulinemia, hypogammaglobulinemia and specific immunoglobin deficiency.

Vaccination induces a protective immune response against target pathogens without the risk of acquiring the disease and its potential complications.

This chapter gives an overview of the basic principles, components, types, and applications of equipment such as a spectrophotometer, colorimeter, ELISA reader, radioimmunoassay (RIA) analyzer, electrophoresis and chromatography and centrifugation. This chapter also makes the learner know about the basic principles, different types of laboratory tests, and their applications. At the end of this chapter, the diagnostic approaches are being discussed.