Cell Structure

& Function

1/23/2013 4

Definition of Cell

A cell is the smallest unit that is

capable of performing life

functions.

Cell Theory (Teoría)

1. All living things are made up of cells.

2. Cells are the smallest working units of all

living things.

3. All complex cells come from preexisting

cells through cell division.

Two Major Types of Cells

•Prokaryotic- “simple” cells

•Eukaryotic- “complex” (complejo) cells

•Most living things you are familiar with (including

humans) have eukaryotic cells.

Prokaryotic

• Do not have a

nucleus or other

organelles

• One-celled

organisms,

bacteria, etc.

Bacteria cell in

the process of

reproducing

(dividing)

Eukaryotic • Contain a nucleus and other organelles (smaller parts)

surrounded by membranes

• Most living organisms have these type of cells

Plant cell Animal cell

Prokaryote vs. Eukaryote

Prokaryote:

-has no

organelles

(no nucleus)

Eukaryote:

-has organelles

(has a nucleus)

Both:

-are living

-have DNA

-are cells

“Typical” Animal Cell

“Typical” Plant Cell

Cell Parts

Organelles: “little organs”

Think of a cell as a factory- lots of separate people,

departments, and machines that each have their own task, but they work together to get a job done.

Surrounding the Cell

• Cell Membrane (like

factory doors and gates):

surround the cell

• provide communication

with other cells

• control entrance and exit

of materials, thereby

maintaining internal

balance

Cell Membrane

• Cell Wall (like factory outer walls): further

protects the cell and provides strength

Cell Wall (plants only)

Inside the Cell

Nucleus

• Cell nucleus (like the factory

central office): the “boss” of

the cell

• Directs all cell activities

• Separated by a nuclear

membrane (it’s own “cell

wall”)

• Contains genetic material -

DNA

Cytoplasm

• Cytoplasm (like the

factory floor): contains

and carries all other

organelles

• Gel-like material; the

“goop” of the cell

Endoplasmic Reticulum

• Endoplasmic reticulum

(like factory conveyor

belts): move materials

around in cell

• Smooth type: has no

ribosomes

• Rough type (pictured): has

ribosomes in surface

Ribosomes

• Ribosomes (like the

factory assembly line):

put together proteins

• Each cell contains

thousands

• Found on reticulum and

floating throughout the

cell

Mitochondria

• Mitochondria (like the factory

generator): the “power plant”

of the cell

• Produces energy through

chemical reactions –

breaking down fats &

carbohydrates

Golgi Bodies (Apparatus)

• Golgi bodies (like the

factory packing and

shipping department): the

UPS or Fed-Ex of the cell

• Transports and packages

proteins and other

materials in the cell

– Moves materials within the

cell

– Moves materials out of the

cell

Lysosome • Lysosomes (like the factory

waste management

dpartment): the “wrecking

crew” and “trash can” of

the cell

• Transports undigested

material to cell membrane

for removal

• Cell breaks down if

lysosome explodes or

ruptures

Vacuoles

• Vacuoles (like factory

storage/factory water

tower): the “storage

container” of the cell

• Sacs for storage,

digestion, and waste

removal

• Help plants maintain

shape- very large in

plants

Chloroplast (plants only)

• Chloroplasts (like factory

solar energy plants):

turns energy from the

sun (with CO2 and

water) into food

• Contains green

chlorophyll

• Where photosynthesis

takes place

Flagella

• Flagella (like factory

trucks/18-wheelers): can

move the whole factory if

needed

• Allow the cell to move

(many single-celled

organism have flagella)