2. OVERVIEW: THE FUNDAMENTAL
UNITS OF LIFE
• All organisms are made of cells
• The cell is the simplest unit of matter that is
alive
• Cell structure is correlated to cellular function
(STRUCTURE DETERMINES FUNCTION!)
• All cells are related by their descent from
earlier cells (Pre-existing cells)
3. EUKARYOTIC CELLS HAVE INTERNAL MEMBRANES
THAT COMPARTMENTALIZE THEIR FUNCTIONS
Eukaryotic
-True nucleus
-membrane-bound
organelles
-cytoplasm in region
b/n plasma
membrane & nucleus
*Protists, fungi,
animals & plants
Prokaryotic
-No true nucleus
-No membrane-
bound organelles
-DNA in an unbound
region called the
nucleoid
-cytoplasm bound by
plasma membrane
*Bacteria & Archaea
-Plasma
membrane
-Cytosol
-Chromosomes
-Ribosomes
5. EUKARYOTIC CELLS
A eukaryotic cell has internal membranes that
partition the cell into organelles
Plant and animal cells have MOST of the same
organelles
8. The plasma membrane is SEMI-PERMEABLE
• The plasma membrane is a SELECTIVE BARRIER
that allows certain molecules to move in and out
of the cell
9. FIGURE 6.6
Outside of cell
Inside of cell
0.1 m
(a) TEM of a plasma
membrane
Hydrophilic
region
Hydrophobic
region
Hydrophilic
region
Carbohydrate side chains
ProteinsPhospholipid
(b) Structure of the plasma membrane
10. WHAT MOLECULES CAN AND CANNOT MOVE
FREELY ACROSS THE MEMBRANE? WHY?
Nonpolar molecules pass through cell membranes more readily than polar molecules because
the center of the lipid bilayer (the fatty acid tails) is nonpolar and does not readily interact
with polar molecules.
11. PROTEIN FACTORIES
Ribosomes use the information from the DNA to make
proteins
• Ribosomes are like “factories”
• Site of protein synthesis
Ribosomes are located in the cytosol as free ribosomes or attached to
the rough endoplasmic reticulum
12. INFORMATION ZONE
The nucleus contains most of the DNA in a eukaryotic cell
• The nucleus is the “brain” of the cell
• DNA is organized into units called CHROMOSOMES, which contain genetic information
The nuclear envelope encloses the nucleus, separating it from the cytoplasm
Pores control which molecules enter and leave the nucleus
Chromatin
Nucleus
Nucleolus
Nuclear envelope:
Inner membrane
Outer membrane
Nuclear pore
13. BIOSYNTHETIC FACTORY OR CONVEYOR BELT
The endoplasmic reticulum (ER) accounts for
more than half of the total membrane in many
eukaryotic cells
The ER membrane is continuous with the
nuclear envelope
There are two distinct regions of ER
• Smooth ER, which lacks ribosomes
• Rough ER, surface is studded with ribosomes
14. Smooth ER
Rough ER
ER lumen
Cisternae
Ribosomes
Smooth ER
Transport vesicle
Transitional ER
Rough ER
200 nm
Nuclear
envelope
15. ENDOPLASMIC RETICULUM
Smooth
Synthesizes lipids
Metabolizes
carbohydrates
Detoxifies drugs &
poisons (liver &
kidney cells)
Stores calcium ions
Rough
Has bound
ribosomes
Production of
glycoproteins
(proteins covalently
bonded to
carbohydrates)
Is a membrane
factory for the cell
Distributes
transport vesicles,
proteins surrounded
by membranes
16. SHIPPING AND
RECEIVING CENTER
The Golgi apparatus consists of flattened
membranous sacs called cisternae
Functions of the Golgi apparatus
• Modifies products of the ER
• Manufactures certain macromolecules
• Sorts and packages materials into transport
vesicles
17. GARBAGE DISPOSAL OR JANITORS
• A lysosome is a membranous sac of
hydrolytic enzymes that can digest
macromolecules
• Lysosomal enzymes work best in the
acidic environment inside the lysosome
18. VACUOLE: WATER HOLE
A plant cell or fungal cell may have one or
several vacuoles, derived from endoplasmic
reticulum and Golgi apparatus
Central vacuoles, found in many mature plant
cells, hold organic compounds and water
22. CHLOROPLASTS: CAPTURE OF LIGHT
ENERGY
Chloroplasts contain the green pigment
chlorophyll, as well as enzymes and
other molecules that function in
photosynthesis
Chloroplasts are found in leaves and
other green organs of plants and in algae
Chloroplast structure includes
Thylakoids, membranous sacs, stacked to
form a granum
Stroma, the internal fluid
24. CELL WALLS OF PLANTS
Animal cells DO NOT have cell walls
• Plants, Prokaryotes, Fungi, and some Protists have
cell walls
The cell wall protects the plant cell, maintains
its shape, and prevents excessive uptake of
water
Plant cell walls are made of cellulose fibers
25. CREATE A MIND MAP OF THE
CELL STRUCTURES FOUND IN A
TYPICAL EUKARYOTIC CELL
Editor's Notes
Within cells there is an intricate network of organelles that all have unique functions. These organelles allow the cell to function properly.
