 general properties of viruses now after the original of the viruses now we will see that what are the general properties of viruses why they are different from the bacteria or from the parasites or from the other organisms organelles are present in the world why they are a little bit different general properties first of all the adult viruses they are called virions virions they are variable in size and their size range is really really too big for example if the we will take the one example of the photon mouth disease virus that is 27 nanometer while at the similarly the pox virus or the for that the first vaccine was developed is 300 nanometer so the pox photon mouth virus is so small as compared to the pox virus this is the size range of the viruses which can see that variable in size that the at the same time the virus of the 20 about the 20 nanometers is present at the same time the virus of 300 nanometer is present and prevailing in the world and causing different diseases so the general properties of the viruses structure what kind of structure of the viruses is present I think we have already taken a bird's eye view about the general structure you can say once again that there are two kind we can divide them simple viruses are the complicated viruses the simple viruses are only composed of the nucleic acid and a protein coat just you can see in the PPT the bacteriophage and the influenza virus the bacteriophage has the protein coat influenza virus has the protein coat then there is nucleic acid present inside that is the DNA is present that is deoxyribonucleic acid similarly the RNA is present in the influenza virus the bacteriophage is DNA virus and as it's clear and influenza virus is RNA virus so RNA is present in the influenza virus while DNA is present in the bacteriophage then the bacteriophage has the tail and some fibers which are prevalent in the PPT however the membrane envelope influenza virus is different this is you can see from these two viruses this is also prevalent at how different of different viruses are from the structure point of view from the from the size point of view that's why it is the there is a one reason that why it is difficult to control the viruses why it's not possible to produce some potent viral disease because it's not it's very difficult to produce because of their what was tellety in the size and was tellety in the structure two simple viruses but they are totally different from each other similarly from the structure point of view this is the we give an example of the some small simple viruses so here just we have studied already that viruses need the host to replicate themselves what what the what the things are not present in the viruses why viruses need the host they have no enzymes of their own which enzymes are needed metabolism things are needed and this require the host machinery so what viruses do viruses just infect the host they take charge of the host machinery the genetic machinery and then they replicate by themselves at the expense of the host so there are some complex viruses also after the simple viruses there are some complex viruses the simple viruses only contain the proteins and DNA maybe the DNA or RNA any kind of nucleic acid may be present however the lipids polysaccharide and carbohydrates trace elements they can also be present in the complicated viruses in this PPT we have given some examples of the complicated viruses which are prevalent these days and which are the some new viruses you can see the HIV or the Ebola virus has been some recent recently recognized that there is some kind of viruses similarly the HIV virus is prevalent for a long time but still we are not able to to able to produce some potent remedy against this kind of viruses because this is producing autoimmunity hepatitis B virus we are able to produce vaccines against it then adenovirus influenza virus and bacteriophage we have already seen the influenza and bacteriophage they are composed of the protein and nucleic acid and some just the protein code and they are also called the simple viruses however the other viruses are the complex viruses and they can they may contain the polysaccharides some kind of trace elements and the lipids also inside their body