Organelles Quiz

Flagellum

Motility structure present in some animal cells, composed of a cluster of microtubules within an extension of the plasma membrane.

Centrosome

Region where the cell’s microtubules are initiated; contains a pair of centrioles.

Cytoskeleton

Reinforces cell’s shape; functions in cell movement; components are made of protein, including microfilaments, intermediate filaments, and microtubules.

Microvilli

Projections that increase the cell’s surface area.

Peroxisome

Organelle with various specialized metabolic functions; produces hydrogen peroxide as a by-product and converts it to water.

Mitochondrion

Organelle where cellular respiration occurs and most ATP is generated.

Endoplasmic Reticulum

Network of membranous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes; has rough and smooth regions.

Nuclear envelope

Double membrane enclosing the nucleus; perforated by pores and continuous with the ER.

Nucleolus

Nonmembranous structure involved in the production of ribosomes; a nucleus has one or more nucleoli.

Chromatin

Material consisting of DNA and proteins; visible in a dividing cell as individual condensed chromosomes.

Plasma membrane

Membrane enclosing the cell.

Ribosomes

Complexes that make proteins; free in cytosol or bound to rough ER or nuclear envelope.

Golgi apparatus

Organelle active in synthesis, modification, sorting, and secretion of cell products.

Lysosome

Digestive organelle where macromolecules are hydrolyzed.

Cell wall

Outer layer that maintains the cell’s shape and protects it from mechanical damage; made of cellulose, other polysaccharides, and protein.

Central vacuole

Prominent organelle in older plant cells; functions include storage, breakdown of waste products, and hydrolysis of macromolecules; enlargement of the vacuole is a major mechanism of plant growth.

Chloroplast

Photosynthetic organelle; converts energy of sunlight to chemical energy stored in sugar molecules.

Plasmodesmata

Cytoplasmic channels through cell walls that connect the cytoplasms of adjacent cells.