Structure: Double layer of lipids; embedded with proteins.
Function: An external cell barrier; acts in transport of substances in/out of cell.
- Structure: Part of cell that lies internal to plasma membrane, external to nucleus. Jelly like.
- Water, ions and enzymes.
- Function: The cytoplasm plays an important role in a cell, serving as a
- "molecular soup" in which the organelles are suspended and
- held together by a fatty membrane.
- Structure: Dense particles of two sub units; each composed of ribosomal RNA and protein; free or
- attached to rough ER.
- Function: The sites of protein synthesis.
Rough Endoplasmic Reticulum
- Structure: Membrane system enclosing a cavity, the cisterna, and coiling through the cytoplasm;
- externally studded with ribosomes.
- Function: Makes proteins that are secreted from the cell; makes the cell’s membranes.
Smooth Endoplasmic Reticulum
- Structure: Membranous system of sacs and tubules; free of ribosomes.
- Function: Site of lipid and steroid synthesis, lipid metabolism and drug detoxification.
- Structure: A stack of smooth membrane sacs close to the nucleus.
- Function: Packages, modifies, and secretes proteins for secretion from the cell, inclusion in
- Structure: Rod-like, double membrane structures; inner membrane folded into projections called
- Function: Site of ATP synthesis; powerhouse of the cell.
- Structure: Membranous sacs containing acid hydrolases.
- Function: Sites of intracellular digestion.
- Structure: Membranous sacs of oxidase enzymes
- Function: The enzymes detoxify a number of toxic substances; the most important enzyme,
- catalase, breaks down hydrogen peroxide
- Structure: Cylindrical structures made of tubulin proteins
- Function: Support the cell and give it shape. Involved in intracellular movements, form
- Structure: Paired cylindrical bodies, each composed of nine triplets of microtubules.
- Function: Organize a microtubule network during mitosis to form the spindle and asters; form the
- bases of cilia and flagella.
- Structure: Surrounded by the nuclear envelope; contains fluid nucleoplasm, nucleoli and chromatin.
- Function: Control center of the cell; responsible for transmitting genetic information and
- providing the instructions for protein synthesis.
- Structure: Dense spherical (non-membrane bounded) bodies
- Function: Site of ribosome subunit manufacture.
- Structure: Granular, thread-like material composed of DNA and hystone proteins.
- Function: DNA constitutes the genes.