MCB 3020 Lecture Notes - Lecture 6: Endospore, Toxic Waste, Nucleoid
Document Summary
Exponential phase: also called log phase, rate of growth and division is constant and maximal, population is most uniform in terms of chemical and physical properties during this phase. Balanced growth: during log phase, cells exhibit balanced growth. Cellular constituents manufactured at constant rates relative to each other. Unbalanced growth: rates of synthesis vary relative to each other, occurs under a variety of conditions. Stationary phase: closed system population growth eventually ceases, total number of viable cells remains constant. Active cells stop reproducing or reproductive rate is balanced by death rate. Possible reasons for stationary phase: nutrient limitation, limited oxygen availability, toxic waste accumulation, critical population density reached. Stationary phase and starvation response: entry into stationary phase due to starvation and other stressful conditions activates survival strategy. Decrease in size, protoplast shrinkage, and nucleoid condensation. Rpos protein assists rna polymerase in transcribing genes for starvation proteins. Starvation responses: production of starvation proteins increase cross-linking in cell wall.
