Prokaryotic and Eukaryotic Cell Structures and Functions

Prokaryote

Cell that does not have a nucleus or membrane-bound organelles. DNA is located in the nucleoid.

Nucleoid

Region in a prokaryotic cell where the DNA is located; it is not surrounded by a membrane.

Eukaryote

Cell that has a nucleus and membrane-bound organelles. Plants, animals, fungi, and protists are eukaryotes.

Cell membrane

Selectively permeable phospholipid bilayer that controls what enters and leaves the cell and helps with cell communication.

Mitochondria

Site of cellular respiration; produces most of the cell's ATP from energy stored in organic molecules.

Chloroplast

Organelle in plants and algae that performs photosynthesis, converting light energy into chemical energy stored in sugars.

Lysosomes

Membrane-bound organelles containing digestive enzymes that break down macromolecules, damaged cell parts, and waste.

Peroxisomes

Organelles containing enzymes that break down fatty acids and detoxify harmful substances, including hydrogen peroxide.

Cytosol

Fluid portion inside the cell where organelles are suspended and many metabolic reactions occur.

Flagellum

Long, whip-like structure that helps a cell move.

Centrosome

Region that organizes microtubules and helps form the spindle during cell division in animal cells.

Cytoskeleton

Network of protein fibers that provides shape, support, movement, and intracellular transport.

Microfilaments

Thin cytoskeleton fibers made mainly of actin; involved in cell shape, movement, and muscle contraction.

Microtubules

Hollow cytoskeleton fibers made of tubulin; maintain cell shape, move organelles, form spindle fibers, and help form cilia and flagella.

Microvilli

Small folds/projections of the cell membrane that increase surface area for absorption.

Nucleus

Membrane-bound organelle containing the cell's DNA; controls gene expression and many cell activities.

Nuclear envelope

Double membrane surrounding the nucleus; contains pores that regulate movement between the nucleus and cytoplasm.

Nucleolus

Region inside the nucleus where rRNA is produced and ribosomal subunits are assembled.

Chromatin

DNA associated with proteins; packages and organizes the cell's genetic information.

Endoplasmic Reticulum (ER)

Membrane network involved in the production and transport of proteins and lipids.

Rough ER

ER covered with ribosomes; synthesizes and modifies proteins that will be secreted, placed in membranes, or sent to organelles.

Smooth ER

ER without ribosomes; involved in lipid synthesis, detoxification, and calcium storage.

Ribosomes

Structures made of rRNA and proteins that carry out protein synthesis (translation).

Cell wall

Rigid outer layer that provides support, protection, and shape. Plant cell walls are primarily made of cellulose.

Plasmodesmata

Channels connecting neighboring plant cells, allowing substances and signals to pass directly between them.

Central vacuole

Large organelle in plant cells that stores water and other substances and maintains turgor pressure for structural support.

Golgi apparatus

Modifies, sorts, and packages proteins and lipids into vesicles for transport.

Vesicles

Small membrane-bound sacs used to transport or store substances within or outside the cell.

Glycoproteins

Proteins with attached carbohydrate groups that help with cell recognition, communication, and adhesion.

Food vacuoles

Membrane-bound sacs that contain food particles and help with intracellular digestion.