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Unit 1 Viruses and Bacteria
Reading Comprehension
Viruses and Bacteria
Bacteria and viruses are often spoken of in similar terms, especially in
regard to their ability to cause disease. However, beyond this common
trait, the two differ in a number of important ways. For Instance, bacteria
are living organisms, and as such can survive independently of other
living things. Viruses, on the other hand, are inactive unless they find
their way into a living host, at which time they are able to grow and
reproduce.
One major difference between bacteria and viruses is their composition.
Bacteria are the simplest forms of life on Earth, but are rather complex in
their make-up when compared to viruses. Like any cell, a bacterium is
surrounded by a protective wall, or membrane, that holds its contents
together. Inside the membrane is a bundle of DNA that carries the
bacterium's genetic information. Viruses are similar in that they also
contain genes in the form of either DNA or RNA, though in far smaller
quantities. In viruses, however, these materials are contained not in a cell
membrane, but in a thinner outer coating of proteins.
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Reading Comprehension
Viruses and Bacteria
Bacteria and viruses are often spoken of in similar terms, especially in
regard to their ability to cause disease. However, beyond this common
trait, the two differ in a number of important ways. For Instance, bacteria
are living organisms, and as such can survive independently of other
living things. Viruses, on the other hand, are inactive unless they find
their way into a living host, at which time they are able to grow and
reproduce.
One major difference between bacteria and viruses is their composition.
Bacteria are the simplest forms of life on Earth, but are rather complex in
their make-up when compared to viruses. Like any cell, a bacterium is
surrounded by a protective wall, or membrane, that holds its contents
together. Inside the membrane is a bundle of DNA that carries the
bacterium's genetic information. Viruses are similar in that they also
contain genes in the form of either DNA or RNA, though in far smaller
quantities. In viruses, however, these materials are contained not in a cell
membrane, but in a thinner outer coating of proteins.
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