The structures andfunctions of
proteins are much more complicated than that of DNA, and proteinsare less stable than DNA.
study the relationship between protein structure andfunction.Researchers use biotechnology to gain insight into the precise detailsof cell processes: the specific tasks assigned to various cell types; themechanics of cell division; the flow of materials in and out of cells; the pathby which an undifferentiated cell becomes specialized; and the methods cellsuse to communicate with each other, coordinate their activities and respond toenvironmental changes. This requires identifying the
molecular players involvedin each facet of the process, elucidating the nature of their interactions anddiscovering the molecular control mechanisms that govern these interactions. Oncethey have teased apart details of the process, they must then reassemble thepieces in a way that provides insight into the inner workings of cells and,ultimately, of whole organisms. Scientists are optimistic about elucidating themany steps in the differentiation pathway and identifying the external andinternal factors regulating the process. The breakthroughs that gave birth tothis optimism are the development of a protocol for maintaining human stemcells in culture and the birth of the cloned sheep Dolly. All cells progress throughessentially the same cycle: They increase in size up to a certain point, thegenetic material replicates, and the cell divides in two. Understanding whatcontrols the cell cycle is essential to understanding the cause of manyhuman and animal diseases, the basis of increasing crop plant yields, and ameans for quickly increasing the cells used to manufacture products as diverseas fermented foods and medicines. Improvements in cellculture technology have allowed us to better understand the molecular basis ofthe cell cycle. The rigorously controlled sequence of steps in the cell cycledepends on both genetic and nutritional factors. One cell differentiates intothe cell type the tissue needs for replenishment or replacement, and the otherremains undifferentiated. The birth of Dolly proved that assumption wasincorrect. The egg develops into a 5- or 6-day-old embryo that is geneticallyidentical to the animal that provided the nucleus, and cells taken from theembryo can develop into any cell type found in the animal. With the propercoaxing, scientists converted those cells into nerve and liver cells and eveninto blood vessels, which consist of two cell types with very differentfunctions: muscle cells for contraction and cells lining the inner surface formovement of substances into and out of the blood.
Proteins are the molecularplayers that regulate and drive each minute step of the overall process.One of the primaryapplications of molecular cloning is to identify the protein product of aparticular gene and to associate that protein with the appearance of a certaintrait. To truly understand gene function, we need to monitor the activity ofmany genes simultaneously. The physical manifestation of a certain trait or diseaseis the culmination of many or all of these steps. Genomics is the scientific study of the genome and the role genes play,individually and collectively, in determining structure, directing growth anddevelopment, and controlling biological functions. The field of structuralgenomics includes the construction and comparison of various types of genomemaps and large-scale DNA sequencing. In addition to genome mapping andsequencing, the objective of structural genomics research is gene discovery,localization and characterization. In addition, in the spring of 2003, theHuman Genome Project was completed (“rough drafts” were completed in 2000). Thisfield of study, known as functional genomics, enables researchers to navigatethe complex structure of the human genome and to make sense of its content.It is not, however, thenumber of genes that is important to our understanding of the various species,but, rather the compositional, functional, chemical and structural differencesthat dictate differentiation. Molecular evolutionists use comparative genomicstechniques and biofinormatics technologies to analyze the number of changesthat DNA sequences undergo through the course of evolution. The fruit fly (Drosophilamelanogaster) has proven to be an invaluable model in the study ofinherited genes. As a result, a wealth of research and data produced from thestudy of the fruit fly are publicly available. This collection of proteins in acell is known as its proteome, and proteomics is the study of the structure,function, location and interaction of proteins within and between cells. Thegenome is largely constant, irrespective of cell type and age, but the proteomevaries from one cell type to the next, from one year to the next, and even frommoment to moment. The cellular proteome changes in response to other cells inthe body and external environmental conditions. charting the progression of aprocess—such as disease development, the steps in the infection process or thebiochemical response of a crop plant to insect feeding—by measuring waxing andwaning protein production. discovering how a protein interactswith other proteins within the cell and from outside the cell. Systems biologists developa series of mathematical models of processes and pathways to elucidate the fullcomplexity of the interactions that occur in biological systems. The tools andtechniques of biotechnology are helpful not only in product discovery but alsoare useful throughout the development process. What is more, biotechnology iscreating the tools to pinpoint the winning compounds far earlier in theprocess.tests to identify the presence of geneticallymodified food products.The deconstruction of disease pathways and processes into their molecular andgenetic components illuminates the exact point in the process that ismalfunctioning and, therefore, the point in need of therapeutic intervention. Pharmaceuticalcompanies can use cell culture and microarray technology to test the safety andefficacy of drugs and observe adverse side effects early in the drugdevelopment process. This tailoring of therapeutics to the genetic makeup ofthe patient is known as pharmacogenomics.