Specialized Cell Structures

Cell Wall

• Description:– Rigid outer layer– Outside of cell membrane

• Function:– Support– Protection– Helps cell maintain its

shape

Cell Membrane

• Description:– Outside covering of cell made of lipid

bilayer

• Function:– Barrier between cell and its environment– Controls what substances can enter or

leave the cell– Provides support and protection,

especially in cells without a cell wall

Ribosomes

• Description:– Made of protein and RNA– Very small, spherical shaped

• Function:– Make proteins

Cytoplasm

• Description:– Jelly-like substance that fills the cell and

surrounds the organelles

• Function:– Fills space between organelles– Contains materials needed by the

organelles

Flagella

• Description:– Long, thread-like extension of a cell

• Function:– Helps cell move

Cilia

• Description:– Short, hair-like projection on the cell

surface

• Function:– Used to sweep away things from the

cell surface or help the cell move through fluid

Nucleus

• Description:– Core, central portion of cell

• Function:– Contains genetic information (DNA)– Directs cell activities

Nuclear Membrane

• Description:– Double-layer membrane surrounding the

nucleus

• Function:– Separates nucleoplasm from cytoplasm

Nucleolus

• Description:– Round structure within nucleus– Made of protein and RNA

• Function:– Makes ribosomes

Chloroplast

• Description:– Oval or bean shaped structure with green

color

• Function:– Helps capture sunlight to produce food

(energy) for plants

Golgi Apparatus

• Description:– Flattened sacs called cisternae

• Function:– Modifies and packages materials

created in the cell for transport (inside or outside of the cell)

Lysosome

• Description:– Small sacs

• Function:– Use digestive enzymes to breakdown

old/worn-out organelles, viruses or bacteria, and/or food particles

Mitochondrion

• Description:– Spherical or rod-shaped– Inner and outer membranes

• Function:– Converts sugars into ATP (energy) for the cell

Plastid

• Description:– Double-membrane bound organelle

• Function:– Involved in food storage; function

depends mostly upon which pigments are present

Rough Endoplasmic Reticulum

• Description:– System of membranous tubes and sacs with

ribosomes on the surface (making it appear rough)

• Function:– Helps make and transport new proteins to

Golgi apparatus or outside of the cell

Smooth Endoplasmic Reticulum

• Description:– System of membranous tubes and sacs

• Function:– Makes lipids– Creates and stores steroids– Stores ions that cells might need– Metabolizes carbohydrates

Vacuole

• Description:– Sacs: smaller in animal cells, larger in plant

cells

• Function:– Store a variety of things such as water,

nutrients, or waste products

Vesicle

• Description:– Small sacs

• Function:– Stores, transports, or digests materials within

the cell