Harvard Human Anatomy Chapter 1: Tissues and Organization

Cell Membrane

Forms a selective barrier between the inside and outside of the cell.

Cytoplasm

Comprised of a network of tubules and filaments (the cytoskeleton), which is suspended in the cytosol, a gel-like material

Cytoskeleton

a network of tubules and filaments

Cytosol

a gel-like material that suspends the cytoskeleton

Organelles

Functional components surrounded by a membrane, segregating their functions from other organelles.

Nucleus

Largest of all organelles. Contains genetic material and serves as the control center. Contains DNA found as chromosomes

Nuclear membrane

Surrounds the nucleus

Chromosomes

Contains DNA, which is located in the nucleus

Nucleolus

Site of ribosomal RNA synthesis and ribosome assembly.

Ribosomes

Directs protein synthesis within the cytoplasm after leaving the nucleus.

Endoplasmic Reticulum

System of membrane-bound tubules and cisternae.

Smooth ER

found in cells specializing in hormone synthesis or detoxification

Rough ER

synthesizes proteins and enzymes. Rough because covered with ribosomes clinging to the membrane surface.

Golgi Apparatus

Stack of membranous sacs that sort, process, and package proteins produced in the rough ER. These proteins may be used within the cell or secreted at cell surface

Lysosomes

Small membrane-bound packets of enzymes that digest microorganisms, cell debris, or excess organelles.

Peroxisomes

Smaller membrane-bound packets of enzymes that oxidize organic substances and form hydrogen peroxide.

Mitochondria

Energy sources of the cells, sites of oxidative phosphorylation and ATP formation. # of mitochondria reflects energy requirements. Numerous in cells that actively synthesize and secrete protein