Explain the similarities and differences between direct and indirect methods of measuring microbial growth, and give examples of each
What will be an ideal response?
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.
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When individuals have mitochondrial disorders, why are the skeletal and heart muscles and the brain most often affected?
a. They are the most important organs. b. They have the highest energy needs. c. They are generally very fragile. d. They have fewer mitochondria in the cell. e. They are the most complex organs.
Water and small solutes are filtered under pressure out of the blood plasma into nephrons through the porous walls of _________, tufts of capillaries in the renal cortex.
A. Loops of Henle B. collecting ducts C. juxtaglomerular apparati D. vasa rectae E. glomeruli
Identify the distinguishing characteristics of phylum Cnidaria. Then outline the classes within this phylum and their
major characteristics. Include at least one representative for each class. What will be an ideal response?
Proteus species often cause urinary tract infections.
a. true b. false