Viruses are the smallest living organisms and can only reproduce inside host cells. They transfer between cells as inert virus particles and have different shapes like spheres or cubes. Viruses have a protein capsid that protects their nucleic acid and may have an envelope that attaches to host cells to aid in penetration. Retroviruses contain RNA and use reverse transcriptase to change their RNA into DNA which can then be inserted into the host genome.

1. VirusesName:_________<br />Introduction to viruses<br />Smallest living organisms _________________<br />_________________ parasites<br />Only reproduce in _________________ cells<br />Viruses transferred between cells as inert particles known as _________________<br />Virus structure<br />Different Shapes<br />Name of shape:<br />Example:<br />Functions of capsid and envelope<br />_________________ the nucleic acid from enzymes and chemicals when virus is outside host cell<br />_________________ to the surface of the host cell<br />_________________ in penetration of the host cell <br />Methods of entry into host cell<br />virusHost cell membrane<br />Retroviruses<br />Have _________________ not _________________<br />Use reverse transcriptase to change:<br />What is a cDNA library<br />_________________DNA (cDNA)<br />cDNA created from mRNA using _________________ _________________<br />_________________: complete set of all the molecules contained within a cell or organism<br />