Eukaryotic Cells
The Inside Story
2 Types of Cells
Prokaryotic
Cells
• No nucleus
• No membranecovered
organelles
• Circular DNA
• Bacteria
Eukaryotic
Cells
DNA
Cells
• Nucleus
• Membrane covered
organelles
• Linear DNA
• All other cells
Which is which?
Cells come from..

1 of the 3 parts of the Cell Theory states that


All cells come from pre-existing cells
So just as large multicellular organisms like
humans, dogs, and trees reproduce, your cells
do as well
So What is Inside a Cell?

It turns out that there is a lot more inside a cell
than Robert Hooke or Anton von Leeuwenhoek
probably would have guessed.

Everything, from the structures covering the cells to
the structures inside, perform tasks to help keep
the cells alive.

These structures are called organelles.
Holding It All Together

All cells have outer coverings that separate what’s
inside the cell from what is outside.
 Cell
Membrane
Covers all cells, both eukaryotic and prokaryotic
 Duties include keeping cytoplasm inside
 Allow nutrients in and waste products out
 Also interacts with things outside the cell

Holding It All Together
 Cell Wall

Only found in plant and bacteria(prokaryotic) cells

Cell wall in plants is made of cellulose

Provides strength and support to the cell membrane

The strength of billions of cell walls in plants enables a
tree to stand tall and its limbs to defy gravity
The Cell’s Library
 Nucleus
Largest and most visible organelle
 Covered by a membrane
 Control center of cell
 Stores the DNA

 Nucleolus
Dark spot inside the nucleus
 Stores the materials that will be used later to make
ribosomes in the cytoplasm

Protein Factories
 Ribosomes


Smallest but most abundant organelles

Their job is to hook together amino acids to make proteins

Found in both eukaryotic and prokaryotic cells

Not covered by a membrane
All cells have ribosomes because all cells need protein to
live.
The Cell’s Delivery System
 Endoplasmic
Reticulum
Internal delivery system of a cell
 Is divided into Smooth and Rough ER based on
appearance and function

 Rough
ER
Ribosomes are attached making it look pebbled
 Specializes in protein synthesis
 Connected to nuclear membrane
 Proteins synthesized by ribosomes collect in the ER for
transport throughout the cell

Difference Between
Rough and Smooth ER
 Smooth
ER

Does not have ribosomes attached

Has different functions depending on the cell type

Can be responsible for lipid and hormone synthesis

Breaks down drugs and certain other chemicals that
could damage the cell
The Cell’s Power Plants
 Mitochondria
 Convert the chemical energy stored in food into ATP
which is the molecular fuel that cells use to do work
 Inner membrane of mitochondria that has many folds is
where most of the ATP is made.
 The reason you breathe air is so that mitochondria have
the oxygen they need to make ATP

Highly active cells, like those in the liver and heart,
may have thousands of mitochondria while other
cells may have only a few.
The Cell’s Power Plants
 Chloroplasts
Additional kind of energy-converting organelle found
in plants and algae
 Contain flattened, membrane-covered sacs that look
like stacks of coins which contain chlorophyll
 Chlorophyll is what makes plants green and also
traps the energy in sunlight which plants use to make
sugar
 The sugar that is produced is used by mitochondria
to make ATP

The Cell’s Packaging Center
Golgi Apparatus
Looks like ER but is located closer to the cell
membrane
 Receives and modifies lipids and proteins sent from
the ER
 Final products are then enclosed in a piece of the
Golgi’s membrane that pinches off to form small
compartment
 Compartment transports contents to other parts of
cell or outside the cell

The Cell’s Storage Centers
 Vacuoles
Very large in plant cells, much smaller in animal cells
 Store water and other liquids
 If full of water they help support the cell

Store the liquids that make roses red and violets
blue
 Contain the juices you associate with oranges and
other fruits

The Cell’s Storage Centers
 Vesicles


Some form when part of the membrane pinches
off the ER or Golgi
Others are formed when part of the cell
membrane surrounds an object outside the cell
Packages of Destruction
 Lysosomes
Special vesicles in animal cells that contain
enzymes that digest food particles and wastes
 Destroy worn-out or damaged organelles
 Get rid of waste materials and protect cell from
foreign invaders

 If
lysosome membrane breaks, the enzymes
spill out into the cytoplasm which kills the cell
Plant or Animal?
Plant or Animal?
Homework

You are going to create a drawing of a eukaryotic
cell.

However, instead of making it a realistic cell, your
cell should be made of drawings of objects that
represent the organelle’s job.

For example, the Golgi Apparatus, which transports
materials, could be a bus or a car.