Students see that plant cells indeed have a plasma membrane in addition to a cell wall.
Bacterial, yeast, animal and plant cells have all been transformed. Different techniques are used to transform different types of cells, and the mechanisms of most of these techniques, while useful, are incompletely understood. Some types of plants can be transformed via infection with Agrobacterium tumefaciens. In the case of plants, removal of the cell wall is a first and crucial step required before introduction of DNA directly through the plasma membrane. Microinjection of DNA is used less often.