Ecology and Evolution

Student

Instructor

December 2005

How a Virus Finds a Host

Introduction

AIDS and the bird flu have raised concerns about virus attacks in the public eye . Infectious transfer of virus also very often causes the common cold . We are able to tolerate or overcome the vast majority of viruses , but some of them succeed in causing us to fall ill , even to the point of death . Not everyone responds to a virus epidemic in the same way : some overpower the pathogen , while others succumb . A fundamental understanding of the

nature of a virus can solve these apparent paradoxes its mechanism of taking shelter in living tissue is also relevant . It is worth noting at the outset that viruses search for all forms of plants and animals as hosts . Each type of virus has a particular preference of host . A virus is versatile and can change form with ease

Basic genetic structures and systems

A virus is a kind of bridge between a form of life and an inanimate object . All living things are made from permutations and combinations of four nucleic acids , adenine , cytosine , thymine , and guanine . Sequences of nucleic acids form genes . Genes are in turn banded together , to form chromosomes . The nucleic acids are joined together by ribose sugars . The latter has one molecule of sugar absent . The structure is entwined in the form of double helix coils inside the nucleus of each living cells The latter are grouped together in higher forms of life to form tissues and organs . The nucleic acid structure inside each nucleus is called Deoxyribonucleic acid or DNA

DNA is used by life forms to produce Ribonucleic acids or RNA . RNA has ribose sugar with the oxygen molecule missing in DNA . RNA has just one strand of nucleic acids , as opposed to two in DNA . RNA has uracil instead of thymine . RNA moves out from the nucleus to the cytoplasm of living cells . RNA is used to produce proteins , which act as the materials of life forms . DNA and RNA physiology is at the heart of all life . It is a common system from unicellular life forms to human beings Protein production by RNA and RNA production by DNA is the chemical basis of life . This is a process , which continues without ceasing from conception to death

Insidious nature

We are now ready to look at the nature and structure of a virus . A virus has a structure similar to RNA (Lewin , 744 . However , the host DNA does not produce it . It also differs from RNA in that it may have a protective membrane made of protein . A virus is a kind of imposter . It finds a way inside a cell and abuses the host 's DNA to produce proteins of its own . Since a virus has no DNA , it does not qualify as a life form in the strict sense . However , as it able to use host DNA to produce protein , and since it has the ability to replicate , it shares an...