Almost everyone knows that the genes, which are located in the nuclei of all cells of the body, control heredity from parents to children, but many people do not realize that these same genes also control the day-to-day function of all the body’s cells. The genes control cell function by determining which substances are synthesized within the cell—which structures, which enzymes, which chemicals.The entire process, from transcription of the genetic code in the nucleus to translation of the RNA code and the formation of proteins in the cell cytoplasm, is often referred to as gene expression.

Proteins are macromolecules made up of monomers called amino acids. Different proteins are constructed by varying the types and numbers of amino acids used and by varying the order in which they are linked together. However, proteins are not built haphazardly, by randomly linking together amino acids. Every protein in the body is deliberately and precisely synthesized under the direction of the blueprint laid down in the person’s genome.Some of the cellular proteins are structural proteins, which, in association with various lipids and carbohydrates, form the structures of the various intracellular organelles. However, the majority of the proteins are enzymes that catalyze the different chemical reactions in the cells. For instance, enzymes promote all the oxidative reactions that supply energy to the cell, along with synthesis of all the cell chemicals, such as lipids, glycogen, and adenosine triphosphate (ATP).

At the end of the lesson, students will be able to understand;

GENES IN THE CELL NUCLEUS CONTROL PROTEIN SYNTHESIS

THE PROCESS OF TRANSCRIPTION

THE PROCESS OF TRANSLATION

GENETIC REGULATION

THE DNA–GENETIC SYSTEM CONTROLS CELL REPRODUCTION

CELL DIFFERENTIATION

APOPTOSIS—PROGRAMMED CELL DEATH

CANCER