A&P1 CH4 Cell Structures

Peroxisomes

contain enzymes that neutralize toxins produced by cellular metabolism or are taken in from the outside; they also break down fatty acids.

Lysosomes

are filled with digestive (hydrolytic) enzymes.

They digest old, worn-out organelles and destroy harmful bacteria, viruses, and toxins.

Centrioles

are paired cylindrical structures, arranged at right angles to one another and located at one end of the nucleus in an area of the cytoplasm known as the centrosome.

They produce microtubules for the cytoskeleton, form the basal bodies from which the cilia and flagella are produced, and form the mitotic spindle for mitosis.

Microvilli

are tiny, fingerlike extensions that increase the surface area along the cell membrane of cells that absorb substances. They contain bundles of microfilaments that are anchored to the terminal web, a filamentous band that runs just below the cell surface.

Golgi apparatus

is a series of flattened membranous sacs, resembling a stack of pancakes. This organelle modifies and packages proteins that are produced by the rough endoplasmic reticulum.

endoplasmic reticulum (ER)

is a highly folded membranous structure that encloses a network of fluid-filled cavities.

rough endoplasmic reticulum (RER)

is studded with ribosomes (fixed ribosomes), the sites of protein synthesis. It produces proteins that are secreted by the cell, incorporated into the plasma membrane, or used by lysosomes.

smooth endoplasmic reticulum (SER)

which lacks ribosomes, synthesizes lipids and glycogen and detoxifies poisons and various drugs.

Nucleus: nucleolus

is suspended in a gel-like matrix called the nucleoplasm. it produces ribosomes.

Chromatin

is composed of complex molecules of DNA and protein. DNA is the genetic material of the cell.

nuclear envelope

is a double membrane that separates nucleoplasm from cytoplasm. It is dotted with numerous nuclear pores that allow the passage of various substances into and out of the nucleus.

Free ribosomes

produce proteins used for cellular metabolism.

Mitochondria

are bean-shaped structures surrounded by a double membrane. The inner membrane, which contains numerous inward folds, encloses a gel-like material called the matrix. Mitochondria produce most of the cell's energy in the form of ATP.

plasma (cell) membrane

is composed of phospholipids, proteins, and carbohydrates and acts as a selectively permeable barrier between the cell and its external environment.

cytoskeleton

consists of three types of protein filaments: microtubules, intermediate filaments, and microfilaments. They provide strength and flexibility for the cell and support for the various other organelles.