Introduction to Biochemistry PDF

**CHAPTER 1: INTRODUCTION** At the end of the chapter, student will be able to: 1. Define Biochemistry 2. Determine the significance and relation to other fields of science 3. Differentiate the difference between biochemical reaction and chemical reaction 4. List the characteristics of...

**CHAPTER 1: INTRODUCTION** At the end of the chapter, student will be able to: 1. Define Biochemistry 2. Determine the significance and relation to other fields of science 3. Differentiate the difference between biochemical reaction and chemical reaction 4. List the characteristics of biochemical reactions **What is Biochemistry?** Biochemistry is a field of science that deals with the characteristics, interplay, mechanisms of all biological reactions. Conformation of biomolecules, structure and their relationship to biological activity, synthesis and degradation of major metabolites, production and storage of energy, biocatalyst and their application, inter and intracelluar communication by hormones, and molecular events in gene expression and regulation are included in the scope of studying biochemistry (Adugna, et al., 2004). **Significance and Relation to other Fields of Science** -- -- -- -- Scope of Biochemistry 1. *Cell Biology* - refers to the structural chemistry of the components of living matter and relationship of biological function to chemical structure. 2. *Molecular Biology* - describe all biological phenomena in terms of molecular interaction such as molecular synthesis, modification, mechanisms and interactions. 3. *Molecular Genetics* - the chemistry of process and substances that store and transmit biological information **Characteristics of Biochemical Reaction** Biochemical reaction and chemical reaction are two different reactions due to the difference in the composition of the substances. A chemical reaction pertains to the process in which one or more reactions are converted to one or more different products regardless of the surroundings. Contratry, biochemical reaction is process of transforming on molecule into a different molecule inside a biological cell. *Biochemical Reaction is a Subset of an Ordinary Chemical Reaction*. To date, there are 118 elements that are identified and characterized on earth. All these elements have unique properties and function. Fusion of each element as reactant will result into a product through various chemical reactions. However, cells cannot recognize all these elements. Only carbon, hydrogen, oxygen, nitrogen, phosphorous, and sulfur plays major role in the biological system. Biochemical reaction is a subset of chemical reaction due to limited important ions namely: Na^+^, K^+^, Mg^2+^, Ca^2+^, Zn ^2+^, Fe^2+^ and Fe^3+^. Moreover, elements such as iodine, cobalt, molybdenum, selenium, vanadium, nickel, arsenic, chromium, fluorine, and silicon are present yet in small amount. The type of covalent linkages and functional groups in biochemical reactions are limited. *Biochemical Reactions Take Place on the Catalytic Surfaces of Enzymes.* The similarity and differences of these two reactions are summarized in the table below. Table 1. Summary of similarity and differences of biochemical and chemical reactions on the use of enzymes **Biochemical Reactions** **Chemical Reactions** --------------------------------------------------- ------- ------------------------------------------------------------------------------------------------ Carried out in aqueous solution Carried out in aqueous solution Occur in mild condition Occur in hard condition like high temperature, high pressure, harsh reagents, acids, and bases Proceed at substantially faster because of enzyme rates Do not proceed at reasonable rate *Many Biochemical Reactions Require Energy.* Two main classes of biochemical reactions are degradative or catabolic reaction and synthetic or anabolic reaction. Catabolic reaction refers to the process that breaks down complex molecules into smaller molecules and usually release energy. An example is glycolysis and respiration. Conversely, anabolic reaction is the process which builds the body needs and requires energy for completion. An example is photosynthesis. *Biochemical Reactions are Organized into Pathways*. Most biochemical reactions are integrated into a multi-step pathway using enzyme. An example is glycolysis, a ten-step degradative reaction of converting glucose to pyruvate molecules. *Biochemical Reactions are Regulated*. Living systems have evolved sophisticated hierarchy of controls so that it permits maintenance & stability in the intracellular environment, ensure the required amount of substances are sufficient or adequate without excess, and for the cell to make adjustments to physical factor i.e. light, temperature, ionic strength, acid concentration & nutrient concentration. *Many Biochemical Reactions Require Energy.* In photosynthesis, light energy is converted into chemical energy in the form of ATP. Microorganisms who cannot harness light breaks down organic nutrients originating from plants and other organism**s.** *Biochemical Reactions are Localized in the Cell**.*** Biochemical reactions are organized so that different reactions occur in different parts of the cell. This is shown by the localization of the organelles in eukaryotic cell. An example is the synthesis of DNA, RNA & protein in the cell. **Study Questions** 1. Why is it the biochemical reaction is a subset of chemical reaction? 2. Explain why biochemistry is important in understanding the biological processes of a species 3. What makes biochemical reaction an appropriate reaction inside the body? 4. What make biochemical reaction proceed at a faster rate? **References:** 1. Bettelheim F., Brown W., March J., 2001. **Introduction to Biochemistry**. Brooks/Cole Publishing Inc., New York 2. Le may E., Beall H., Robblee K. 2002. **Connection to our Changing World[. ]**Pearson Ed. Asia Pte. Ltd., London 3. Lehninger W. 2004. **Principles of Biochemistry**. 4th Edition. Worth Publishers, Inc., Wisconsin 4. Matthews C., Van Holde K.E., Ahern K. **Biochemistry** 3^rd^ Edition. Addison-Wesley Longman Inc. 5\. Wolsey W., Mortenton W. 2002. **Chemical Principles in the Laboratory[. ]**Brooks/Cole Publishing Inc., New York