The cell is the basic unit of structure, function, and organization of all organisms.
Certain cell types have organized structures within them called organelles. Each
organelle has a specific function to perform in maintaining homeostasis. Our
understanding of structure and function of the cell has been a direct result of
advances in scientific technology.

Supporting Ideas:
1. Cumulative historical observations using microscopes and conducting
experiments have led to the development of the three principles comprising the
cell theory: all living things are made of cells, life processes occur in cells, and
cells come from existing cells.
2. Cells can be classified as prokaryotes (which lack membrane-bound organelles)
or eukaryotes (which have membrane-bound organelles).
3. Eukaryotic cells may have arisen from the joining together of more primitive cell
types.
4. Advances in centrifugation and fractionation techniques have allowed scientists
to determine the functions of individual organelles.
5. The nucleus of the living cell directs cellular activity and stores hereditary
information.
6. Ribosomes, the sites of protein synthesis, are located on rough endoplasmic
reticulum and are dispersed throughout the cytoplasm.
7. The endoplasmic reticulum is involved in the transport of proteins from the
ribosome to the Golgi apparatus.
8. The Golgi apparatus packages and transports lipids and proteins for export or
distribution throughout the cell.
9. The cell membrane, composed of proteins and phospholipids, separates the
inside of the cell from its outside environment and as a semipermeable
membrane, it regulates what enters and leaves the cell.
10. There are several ways in which substances are transported across cell
membranes: diffusion (passive transport and osmosis), active transport, and
facilitated transport.
11. Mitochondria and chloroplasts perform energy transformations in respiration and
photosynthesis.
12. Cells in the body of multicellular organisms are arranged in structural and
functional groups called tissues: tissues form organs and organs form organ
systems.