Assume that one counted 67 plaques on a bacterial plate where 0.1 ml of a 10-5 dilution of phage was added to bacterial culture. What is the initial concentration of the undiluted phage?
What will be an ideal response?
67 × 105 × 10 = 6.7 × 107 pfu/ml (pfu = plaque-forming units)
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Which one of the following is a type of species interaction with impacts that depend on prey density and effectiveness of defenses to determine the short-term impact on the prey population?
A) competition B) consumption C) mutualism D) commensalism
Which would be the most accurate endomembrane route through which a protein is secreted from a cell?
A. Golgi apparatus?lysosome?vesicles?plasma membrane B. plasmid?plasma membrane?nuclear envelope?smooth endoplasmic reticulum C. nuclear envelope?vesicles?Golgi apparatus?plasma membrane D. rough endoplasmic reticulum?lysosomes?vesicles?cell membrane E. rough endoplasmic reticulum? Golgi apparatus?vesicles ?plasma membrane
Which statement is true?
a. The production of gametes via meiosis is much simpler than mitosis because the resulting gametes only contain half as much genetic material. b. Chromatid crossover rarely results in viable zygotes because gametes lack a mechanism for lining up homologous gene sequences when this happens. c. The potential genetic variation between two zygotes is greater than the potential genetic variation between skin cells from the same organism. d. Because they are not homologous chromosomes, X and Y chromosomes do not form synaptonemal complexes during meiosis.
Which of the following basic functions is not associated with the lymphatic system?
What will be an ideal response?