FINAL REVIEW: CELLS STRUCTURES AND FUNCTIONS

Cell Membrane

Structure:  Lipid bilayer with embedded proteins Function:  Regulates what enters and leaves the cell

Cell Wall

Structure:  Rigid rectangular structure around the cell; made of cellulose Function:  Maintains cell shape and protects the cell

Nucleus

Structure: 

Sphere-like surrounded by membrane

Function: 

Holds DNA

Cytoplasm

Structure: 

Fluid

Function:

Suspends internal parts of the cell; contains buffers

Mitochondria

Structure:

Two membrane layers with folded inner layer (cristae); “kidney bean” shaped 

Function:

Converts food energy to chemical energy 

(cellular respiration)

Chloroplasts

Structure:

Two membrane layers; oval shape with stacks of connected thylakoids

Function:

Converts light energy to chemical energy (photosynthesis)

Ribosome

Structure:

Small spheres

Function:

Makes proteins

Rough Endoplasmic Reticulum (RER)

Structure:

Interconnected network of tube-shaped membrane; dotted with ribosomes

Function:

Modifies and packages proteins

Smooth Endoplasmic Reticulum (SER)

Structure:

Interconnected network of tube-shaped membrane

Function:

Detoxifies the cell; synthesizes lipids

Golgi Apparatus

Structure:

Flattened membranous sacs with vesicles budding off of one side

Function:

Further modifies, sorts and ships molecules (such as proteins and lipids) within the cell

Lysosome

Structure:

Small spheres

Function:

Contains digestive enzymes to break down materials within the cell

Vacuoles

Function:

Small spheres

 (or large, central structure in plant cells)

Structure:

Storage

Cytoskeleton

Structure:

Microscopic support beams/rods

Function:

Multiple functions depending on type, including: 

maintaining shape of cell; responsible for movement

Vesicle

Structure:

Small spheres of membrane from RER, SER or Golgi

Function:

Transport molecules (such as proteins and lipids) around or out of the cell.

DNA/chromosomes

• Structure: DNA is a double helix (twisted ladder) wrapped around proteins to form chromosomes in the nucleus.

• Function: Stores genetic information and provides the instructions for making proteins and controlling cell activities.

Cilia

• Structure: Short, tiny hair-like projections that cover the surface of some cells.

• Function: Move the cell or sweep substances (like mucus or dust) across the cell's surface.

Flagella

• Structure: Long, whip-like tail(s) attached to a cell, usually one or a few.

• Function: Propel the cell through liquids, helping it move from one place to another.