From the identification of the pathogens causing major human diseases, through the understanding of the most basic forms of life, and in the struggle to develop new antibiotics to counter the increasing bacterial resistance to these widely used substances, research on microbial growth and survival has rightfully seen a booming interest across the last two centuries. The guanosine tetraphosphate (ppGpp) signaling system is of particular significance for these fields of research. It is a bacterial response to stress and starvation which allows these organisms to activate the necessary genes to survive in these conditions. It also plays a key role in modulating the abundance of various machineries necessary for growth in order to maximize the rate at which bacteria are growing in different nutrient conditions. In poorer nutrient conditions requiring more enzymes to import and digest these nutrients into the same amount of essential building blocks for growth, production of ppGpp is triggered in response to the lack of these building blocks. Higher ppGpp concentrations lead to downregulation of the abundance of ribosomes, the machineries operating growth, allowing larger abundance of enzymes producing the building blocks from nutrients. Recent advances, by genetically modifying bacteria, allowed to finely tune ppGpp concentrations independently of growth conditions. Using this approach, we investigate the scope of the regulation operated by ppGpp: which proteins does it influence in changing growth conditions and to what extent? We present novel quantifications of different proteins and other relevant biomolecules in E. coli strains artificially modified to have higher or lower ppGpp concentration than naturally found. These results allow us to identify which proteins are regulated by ppGpp and why the right concentration of ppGpp is necessary for bacteria to achieve optimal growth. We confirm the role of ppGpp in upregulating the proteins related to the synthesis of new proteins: translation. We also show that, apart from translation-related proteins, ppGpp is not responsible for consistently regulating other groups of proteins, including some that do vary with growth rate variations caused by change in nutrient source, which were suspected to be under ppGpp’s control. With a simplified mathematical model of the ppGpp regulation mathematical model, we attempt to understand why slowing down bacterial growth by artificially increasing ppGpp requires a lot more ppGpp than naturally found. By doing so, we identify characteristics that a model seeking to explain ppGpp perturbations should have. These conditions strengthened our understanding of the ppGpp system by refuting some of our intuitions and laying a foundation for future models elucidating the missing pieces. We also present another story regarding how yeast can survive one of the harshest stress: being completely desiccated. With these different studies, we extend our knowledge of two different systems relevant to growth and survival of microorganisms, which leads to potential new directions for those who seek to investigate such systems and answer some of the questions that our findings raise.