Multicellular organisms can be much larger and more complex. This is because the cells of the organism have specialised into many different types of cells such as nerve cells, blood cells, muscle cells all performing different functions.
He begins by discussing how horizontal transfer can move genetic material between bacteria. Transformation, transduction, and conjugation in bacteria are all included. He also explains how crossing over, random assortment, and random fertilization can maintain genetic variation in eukaryotes.
Pulmonary surfactant is a mixture of lipids and proteins which is secreted into the alveolar space by epithelial type II cells. The main function of the surfactant is to lower the surface tension at the ir/liquid interface within the alveoli of the lung. In babies born prematurely, pulmonary surfactant may not be present in adequate amounts due to insufficient exocytosis in type II alveolar cells.
