Concept explainers
Introduction:
Microbes are of two types: cellular and acellular. Acellular microbes are those microbes which contain some infectious agents like viruses and prions. Generally, acellular microbes do not have cells, for example, viruses, viroids and plasmids.
Answer to Problem 1MC
Correct answer:
Rickettsia is not an acellular agent; it is bacteria having cell wall. Therefore, option (c) is correct.
Option (c) is given as “rickettsia”,
Explanation of Solution
Justify reason for the correct statement:
Rickettsia is a gram negative, non spore forming and non motile bacteria. It found in the shape of cocci and rods. They have their own DNA and protein; they have their own metabolizing machinery. Acellular agents do not have their own DNA and they cannot
Hence, option (c) is correct.
Justify reasons for incorrect statements:
Option (a) is given as “viroid”.
Viroid is the smallest, single stranded, circular RNA infectious pathogen, it do not contain protein capsid. Viroids cause plant diseases. Viroid only contain RNA particle not other cells, so, they come under acellular agents. Hence, it is a wrong answer.
Option (b) is given as “virus”.
Virus is the small agents, made up of DNA or RNA and coated with protein coat. Viruses cause diseases, they are made up of only DNA, RNA or protein, and they do not contain any cell so they come under the acellular agents. Hence, it is a wrong answer.
Option (d) is given as “prion”.
Prions are the smallest organism, made up of protein and are the infectious agents. Prions mainly affect the brain. They do not have their own DNA and cannot metabolize, they are also acellular agents. Hence, it is a wrong answer.
Hence, options (a), (b) and (d) are incorrect.
Acellular microbes are those microbes which contain some infectious agents like viruses and prions. Generally acellular microbes do not have cells and DNA, for example, viruses, viroids and plasmids.
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Chapter 13 Solutions
Microbiology with Diseases by Taxonomy Plus Mastering Microbiology with Pearson eText -- Access Card Package (5th Edition)