Cell Structure & Function

04/19/23 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 PartsOrganelles: “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

Today’s Assignment

• Cell Analogy Project(cell structures)

• Your cell analogy can be a factory, a store, a school, a garage.

• You may choose a plant or animal cell

• 100 pts possible

How about an

example?