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Science Clinic => Biology => Microbiology => Topic started by: shofmannx20 on Oct 17, 2019

Title: A bacterial genome is typically
Post by: shofmannx20 on Oct 17, 2019

Question 1

Explain the similarities and differences between direct and indirect methods of measuring microbial growth, and give examples of each.

Question 2

A bacterial genome is typically
◦ a single circular DNA molecule.
◦ a single linear piece of DNA.
◦ a linear RNA molecule.
◦ multiple linear pieces of DNA.
◦ multiple circular DNA molecules.

Title: A bacterial genome is typically
Post by: diesoon on Oct 17, 2019

Answer 1

Direct methods of measuring microbial growth involve quantifying the number of microbes in a specimen through actual counting of cells in a microscope or cytometer, or counting the numbers of colonies produced from the plating of a specimen. The advantage of these techniques lies in their usefulness for counting very large and very small populations of bacteria. Indirect methods, by contrast, seek to quantify cells by measuring some characteristic related to the number of cells present. For example, spectrophotometry measures the amount of light transmitted through a culture; the less light that is transmitted, the more cells are present. The amount of light transmitted gives an approximation of the number of cells present. Indirect methods are useful for quantifying microbes, such as filamentous microbes, that are hard to count directly. Both direct and indirect methods seek to arrive at an approximation of the actual number of cells present. Because that number is changing even during the measurement process, neither technique can give an exact number of cells.

Answer 2

a single circular DNA molecule.