Environmental Test Two Key

Hydrolysis, Oxidation/Reduction, and Synthesis

List the three basic types of enzymatic reactions that are important in microbial metabolism.

Each individual cell increases in mass until it reaches a "critical mass". Each cell then divides to produce two "daughter cells" that except for mutation are identical to the original cell.

What does the term binary fission mean within the context of bacterial reproduction?

The use of oxygen as the electron acceptor results in the maximum amount of energy that can be obtained from a given quantity of substrate.

Given a choice, facultative bacteria will use molecular oxygen in preference to any other electron acceptor. Why?

Relatively complex insoluble substances must be converted to simpler soluble substances that can pass through the cell membrane for further processing inside the cell.

Why is hydrolysis so important for a bacterial cell attempting to consume an insoluble substrate?

Carbon, Nitrogen, Phosphorus, Hydrogen, and Oxygen

List three of the five most commonly found chemical elements in a bacteria cell.

Somewhere in the process there will be a "rate-limiting" step. That is, a step that controls the overall rate at which the process can proceed.

In class, we noted that although the Michaelis-Menten Expression was initially developed to describe a single enzymatic reaction involving a single substrate and a single enzyme, it turns out to be applicable to complex processes involving many substrates, reactions, and enzymes. Why is this true?

We would expect to see a lag phase if the organisms need time to adjust to their new environment ( for example, if the temperature, pH, available substrate, etc. differs from what they are used to, or if they need to produce extracellular enzymes to hydrolyze insoluble substrates). Otherwise, we would not expect to see a lag phase.

In class we noted that if we conducted a batch culture experiment in the lab, we might, or might not, observe a lag phase if we plotted biomass concentration vs. time. Why is this true? That is under what circumstances would we expect to see a lag phase and under what circumstances would we not expect to see a lag phase?

In the exponential growth phase, the organisms are limited only by their own capabilities. However, in the declining growth phase, substrate availability becomes a growth-limiting factor.

When we discussed batch culture growth kinetics in class, we noted that the log (or exponential) growth phase was followed by a declining growth phase (i.e. growth that continues but at an ever decreasing rate). Why is this true? That is what causes the shift from exponential growth to declining growth?

Cell wall, cytoplasm, cytoplasmic (or cell) membrane and nuclear matter ( or region/area).

In class, we discussed cell morphology and we noted that there are certain basic functional areas that are common to all bacterial cells and there are other basic functional areas that are present under some circumstances, but not under other circumstances. Those that are common to all bacterial cells include but are not limited to what?