The Cell Theory Robert Hooke an English scientist is the one who came up with the cell theory. Cell theory (3 parts) 1. All organisms are composed of one or more cells 2. The cell is the basic unit of organization or organisms 3. All cells come from preexisting cells
Two Basic Cell Types Prokaryotes: unicellular organisms, such as bacteria, composed of prokayotic cells. Prokaryotic cells lack internal membrane- bound structures
Two Basic Cell Types Eukaryotes: unicellular or multi- cellular organisms, such as yeast, plants, and animals, composed of eukaryotic cells, which contain a true nucleus and membrane-bound organelles.
Two Basic Cell Types Eurkaryotic cells contain membrane- bound structures called organelles. Each organelle has a specific function for cell survival. Example: Nucleus, mitochondria, and Golgi apparatus
Viruses Definition:disease- causing, nonliving particles composed of an inner core or nucleic acids surrounded by a capsid. Examples HIV Influenza Common Cold Polioviruses Rabies viruses
Viruses Not considered living Don’t carry out respiration Don’t grow Don’t develop Can replicate (copy themselves) by using a host cell. Host cell is any cell which viruses can replicate
Viral Structure Contain Inner core of nucleic acid, either RNA or DNA Outer coat of protein called capsid. The DNA and RNA contains instructions for making copies of the virus. The protein arrangement in the capsid determines the virus’s shape, which determines how the virus infects the cell.