Cell organelles structure functions cell membrane a double membrane composed of lipids and proteins present both in plant and animal cell provides shape p rotects the inner organelle of the cell and a cts as a selectively permeable membrane centrosomes composed of centrioles and found only in the animal cells. Organelle structure and function organisms are composed of cells and these cells have specific structures within in them that allow them to carry out their functions these structures are called organelles the fine detail of the cell which may be revealed by an electron microscope is called the cells ultrastructure. Cell biology organelle structure and function jones and bartlett books in mathematics jones and bartlett series in biology life science series author david e sadava edition illustrated. Cells are characterized by their ability to grow reproduce respond to external stimuli and perform the different metabolic processes the cell is made up of a protoplasmic mass surrounded by the a cell membrane the protoplasm is differentiated into a nucleus and cytoplasm cytoplasm contains a group of cellular structures called cell organelles