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Cells
The basic unit of all living
things.
Are made up of “little
organs” called organelles.
There are many types of cells.
Cells can be divided
into two types:
Prokaryotic
Eukaryotic
Prokaryotes
Bacteria
Very small
Oldest cells on Earth
Very simple: No
membrane- bound
organelles or nucleus
DNA circular found in
cytoplasm
Eukaryotes
Plant, Animal, Fungus, Protists, etc
(ANYTHING living that is not Bacteria)
Larger
Newer, more recently evolved
Have membrane-bound organelles
Have membrane bound nucleus that
contains DNA in double helix.
The following organelles are
found in all cells
Cell membrane
-plasma membrane
Controls what enters
and leaves the cell.
Made of phospholipids.
Cell Membrane
Cytoplasm or Cytosol
 Fluid that
surrounds all
organelles.
 Mostly made of
water (cells are
75%-90% water)
Ribosomes
Where amino acids are
made into proteins.
 Can be “loose” in the
cytoplasm or on the
Rough E.R.
Ribosomes
Where amino acids are
made into proteins.
Structures for movement
Pseudopodia –false foot
Movement
Flagella (whip-like structure)
MovementCilia (hairlike structures)
Cytoskeleton
 Made of protein
filaments.
 Maintains cell shape.
Cytoskeleton
The cytoskeleton is made up of
microtubules and filaments. It is typically not
depicted in cell diagrams but is the structural
beams and support of the cell
Chromosomes
Prokaryote
Eukaryote
Typically eukaryotic cells (cells with nuclei)
have large linear chromosomes and
prokaryotic cells (cells without defined
nuclei) have smaller circular chromosomes
Prokaryotic Cell
Eukaryotic Cell
Organelles Found in
Eukaryotes
Organelles found in
both plant and animal
cells.
Purpose of a Cell
Before we get into the jobs of the cell you
must first understand the PURPOSE of a cell
Oddly enough, it all boils down to proteins.
Remember all the functions of proteins
Larger Structures: Hair, nails, skin, muscles, eyes,
etc.
Cellular Structures: Proteins in the membrane, and
that make up the organelles
Chemical messengers: Hormones
Regulating Reactions: Enzymes
Nucleus
Control center
of the cell.
 Houses DNA,
which is the
template for
making
proteins.
“The Brain”
Nuclear envelope
The nuclear
membrane
has many
small holes
called nuclear
pores that
allow material
to move in
and out of the
nucleus.
Chromosomes
Chromosomes are threadlike structures located inside
the nucleus of animal and
plant cells. Each
chromosome is made of
protein and a single
molecule of
deoxyribonucleic acid
(DNA). Passed from parents
to offspring, DNA contains
the specific instructions that
make each type of living
creature unique.
Nucleolus
 The nucleolus is a round body located inside
the nucleus of a eukaryotic cell. It is not
surrounded by a membrane, but sits in the
nucleus. The nucleolus makes ribosomal
subunits from proteins and ribosomal RNA
(rRNA).
Endoplasmic Reticulum
Smooth E.R.:
Assembles/Makes
Lipids
Rough E.R.:
Changes proteins
made on
ribosomes (where
proteins are made)
Golgi Apparatus or Golgi Body
 Proteins from rough E.R. then go
to the Golgi body.
 Further modify proteins and
send to final destination
Vesicles
When a cell needs to move a molecule many
times, it uses vesicles. Vesicles are cellular
organelles that are composed of a lipid bilayer.
You can think of vesicles as cellular envelopes
that are used to transport materials from one
place to another. Vesicles also function in
metabolism and enzyme storage as well.
Mitochondria
 Converts carbohydrates and
lipids into cellular energy.
 “Kidney bean” shape with
many inner folds.
Organelles Only
Found In Plants
Cell Wall
Very outside of plant cells
Made of cellulose.
Protects & provides
structure.
(Bacteria have a
cell wall made of a
chitin, not CELLULOSE)
Chloroplasts
 Performs Photosynthesis
Converts sunlight into glucose.
Then glucose into cell energy.
 Green color.
Vacuoles
 Rarely found in
animal cells. Often
called vesicles.
 Often single &
large
 Store water and
starch.
Typical Plant Cell
 Has cell wall,
chloroplasts,
vacuoles
 Rarely has
lysosomes
 Square shape
Lysosomes (animals and
sometimes plants)
 Filled with digestive
enzymes
Breakdown molecules for cell
food
 Breakdown old organelles
 Lysosomes
digest food
particles
brought in
during
phagocytosis
(endocytosis)
as well as break
down dead
organelles and
waste.
Typical
Animal Cell
 No cell wall,
chloroplasts,
(few) vacuoles
 Has
lysosomes
Has centrioles
 Many
different shapes
Eukaryotes:
Larger cells
Contain a nucleus
Contain membrane bound organelles
Protists, fungi, plants and animals classified as
Eukaryotes
Differences in prokaryotic and eukaryotic
cells
Prokaryotes:
Lack a nucleus
Bacteria are classified as prokaryotes
Older than eukaryotes (earliest fossils prokaryotic)
Smaller cell than eukaryotes
Wrap-up
 What organelle do prokaryotes lack that a
eukaryotes contain?