Chapter 4: Organization of the Cell (copy)

Cell Theory

Cells are the basic living units of organization and function in all organisms; all cells come from other cells.

Plasma Membrane

The membrane surrounding the cell that separates its inner environment from the external environment.

Prokaryotic Cells

Cells that are enclosed by a plasma membrane but have little or no internal membrane organization and no membrane-enclosed nucleus.

Eukaryotic Cells

Cells that contain a membrane-enclosed nucleus and a variety of organelles.

Nucleus

The organelle containing genetic information coded in DNA, bounded by a nuclear envelope.

Endoplasmic Reticulum (ER)

A network of folded internal membranes involved in lipid synthesis and protein modification.

Golgi Complex

Stacks of flattened membranous sacs that process, sort, and modify proteins synthesized on rough ER.

Lysosomes

Organelles that contain enzymes to break down worn-out cell structures, bacteria, and debris.

Plastids

Organelles that produce and store food in the cells of plants and algae.

Cytoskeleton

A dynamic internal protein fiber framework that provides structural support and facilitates cell movement.

Cell Fractionation

A technique used to purify organelles and study their functions in cell biology.

Microtubules

Hollow cylinders formed from tubulin that are part of the cytoskeleton and involved in cell movement.

Cilia

Thin, movable structures that project from the cell surface and are involved in movement.

Cell Wall

A rigid outer covering of plant cells made mainly of polysaccharides, such as cellulose.

Chloroplasts

Plastids involved in photosynthesis, containing chlorophyll to trap light energy.

Vacuoles

Organelles that store materials, water, and wastes; maintain hydrostatic pressure in plant cells.

Mitochondria

Organelles that are the sites of aerobic respiration, producing ATP from nutrients.

Nuclear Envelope

A double membrane surrounding the nucleus, perforated with nuclear pores.

Rough ER

A type of endoplasmic reticulum studded with ribosomes for polypeptide synthesis.

Smooth ER

A type of endoplasmic reticulum involved in lipid synthesis and detoxification.

Glycocalyx

A cell coat formed by polysaccharides extending from the plasma membrane.

Ribosomes

Cellular structures found in all living organisms that facilitate the process of synthesizing proteins from mRNA.

Peroxisomes

Organelles containing enzymes that perform oxidation reactions producing hydrogen peroxide, crucial for fatty acid metabolism.

Centrioles

Cylindrical structures that are essential in organizing spindle fibers during cell division.

Nucleolus

A dense area within the nucleus where the synthesis of ribosomal RNA (rRNA) occurs and where ribosomes begin to assemble.

Secretory Vesicles

Membrane-enclosed vesicles responsible for transporting proteins and other substances to the cell membrane for release.

Endosomes

Membrane-bound structures involved in the sorting of material that is taken into the cell through endocytosis.

Flagella

Long, whip-like appendages that allow certain cells to move through liquid environments.

Fibroplast

Cells that produce and maintain the extracellular matrix and collagen in connective tissue.