Microorganism Cultivation Methods

The three main mechanisms for generating metabolic energy are fermentation, respiration, and photosynthesis.

The two main considerations are choosing a suitable medium and isolating the bacteria in a pure culture.

The three goals are: 1. To raise a crop of cells of a particular species. 2. To determine the number and type of organisms present in a given material. 3. To isolate a particular type of organism from a natural source.

<p>The ideal gelling agent is agar, an acidic polysaccharide extracted from certain red algae.</p> Signup and view all the answers

<p>The dilution method involves reducing the density of microorganisms in a sample through serial dilution. The diluted sample is then plated or inoculated to isolate single cells, each of which can grow into a pure colony.</p> Signup and view all the answers

<p>Agar is a gelling agent that forms a solid medium allowing the formation of isolated colonies from individual cells.</p> Signup and view all the answers

<p>The population of microorganisms in the biosphere is roughly constant: growth is counterbalanced by death.</p> Signup and view all the answers

<p>Factors that must be controlled include nutrients, pH, temperature, aeration, salt concentration, and ionic strength.</p> Signup and view all the answers

<p>The lag phase is crucial because it allows bacteria to adapt to their new environment, synthesize essential molecules like enzymes and proteins, and prepare for active cell division. This adaptation is necessary for optimal growth and survival.</p> Signup and view all the answers

<p>In the exponential phase, bacteria divide at a constant rate, leading to rapid population growth. In contrast, the stationary phase sees a slowdown in growth as nutrients become depleted and waste products accumulate, resulting in a stable population size with an equal balance of cell division and death.</p> Signup and view all the answers

<p>The decline or death phase is characterized by the depletion of nutrients, accumulation of toxic waste products, and a decline in the bacterial population as cells die at an exponential rate. Some bacteria may form spores or enter a dormant state to survive these harsh conditions.</p> Signup and view all the answers

<p>During the exponential phase, DNA replication, protein synthesis, and active metabolism are key processes driving the rapid cell division and population growth. Bacteria are very metabolically active during this phase, efficiently utilizing available nutrients.</p> Signup and view all the answers

<p>Unicellular microorganisms, such as bacteria, grow by increasing their number through cell division. In contrast, multicellular organisms grow by increasing the size and number of their cells, leading to an increase in overall size and mass.</p> Signup and view all the answers

<p>Bacteria can be maintained in the exponential phase by repeatedly transferring them into fresh medium of identical composition while they are still growing exponentially. This ensures a continuous supply of nutrients and prevents the buildup of toxic waste products.</p> Signup and view all the answers

<p>In the stationary phase, bacteria face challenges like nutrient depletion and waste accumulation. They adapt by adjusting their metabolism to survive these stressful conditions. This often includes producing secondary metabolites, like antibiotics, to compete for resources or defend against other microorganisms.</p> Signup and view all the answers

<p>The survival of a microbial group depends on its ability to maintain a pool of living cells that can withstand nutritional deprivation and effectively compete for nutrients with other microorganisms in the environment.</p> Signup and view all the answers