Chapter 3 Cell Structure Notes
The cell is the basic unit of biologic organization of the human body
Protoplasm: an aqueous colloidal solution of carbohydrates, proteins, lipids, nucleic acids, and inorganic salts surrounded by a limiting cell membrane
Cells in our respiratory tract produce mucus to trap dust and microorganisms that get past the hairs in our nose then move the material to our throat to be swallowed and passed out through the digestive system
The most prominent structure in the cell is the nucleus and cells are measured in microns/micrometers
Nucleoplasm: protoplasm inside the nucleus
Cytoplasm: protoplasm outside the nucleus
Robert Hooke was an English scientist who first described cells in 1665. Later, Anton von Leeuvenhoek (Dutch naturalist) observed pond water under his microscope and called the tiny organisms, macules.
Matthias Schleiden, a botanist, stated that all plants are composed of individual units called cells. Theodor Schwann, a zoologist, stated that all animals are also composed of cells.
Modern Cell Theory:
Cells are the smallest complete living thing
All organisms are composed of cells
Cells arise from preexisting cells through cellular division
All of today’s existing cells are descendants of the first cells formed early in the evolutionary history of life on Earth
The plasma membrane (plasmalemma) is composed of a double phospholipid layer w/ proteins embedded in the phospholipid layer. The rounds balloon-like part is hydrophilic (attracts water) and the double tails are hydrophobic (repels water). Arrangement like fluid mosaic pattern.
Functions of a protein in the double phospholipid layer: allow for the passage of molecules and ions across the make transport channels for ions act as enzymes for active transport receptor sites for hormones to gain entrance into the cell cell identity marker cementing materials for cell adhesion on the outside of cells to hold cell together structural support inside