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Section 1
Cellular Structure and Function
Cell Discovery and Theory
Prokaryotic Cell
 Prokaryotes are singlecelled organisms that
lack a nucleus and
other internal
compartments
 They do not contain
membrane-bound
organelles
Steven P. Lynch
Section 1
Cellular Structure and Function
Prokaryotic Cell
 Prokaryotic cells includes all bacteria
 Prokaryotes contain only the following
structures:
1. Cell wall (peptidoglycan)
2. Plasma membrane
3. Genetic material as a single circular molecule of
DNA
4. Ribosomes
5. Cytoplasm
6. Plasmid (Small circular piece of DNA that only
some bacteria possess)
Section 1
Cellular Structure and Function
Cell Discovery and Theory
Prokaryotic Cell
Section 1
Cellular Structure and Function
Eukaryotic Cell
 More complex structure than prokaryotes
 In addition to the prokaryotic structures,
eukaryotes also have membrane bound
organelles, including a nucleus
Section 1
Cellular Structure and Function
Cell Discovery and Theory
Section 1
Cellular Structure and Function
Cell Discovery and Theory
Comparing Prokaryotic and Eukaryotic Cells
The
Section 1
Cellular Structure and Function
The Plasma Membrane
Plasma Membrane
 Thin, flexible boundary between the cell
and its environment
 Allows nutrients into the cell
 Allows waste to leave the cell
Section 2
Cellular Structure and Function
The Plasma Membrane
Selective Permeability
 The plasma membrane controls the movement
of substances into and out of the cell.
 The plasma membrane
is selectively permeable,
meaning it chooses what
enters and leaves the
cell
Section 2
Cellular Structure and Function
The Plasma Membrane
 The plasma membrane is composed of the
phospholipid bilayer.
 A phospholipid molecule is composed of a
glycerol backbone, two fatty acid chains, and
a phosphate group.
Section 2
Cellular Structure and Function
The Plasma Membrane
Section 2
Cellular Structure and Function
The Plasma Membrane
Fluid Mosaic Model
 The phospholipid
bilayer allows other
molecules to “float”
in the membrane.
Other Components
 Proteins
 Cholesterol
 Carbohydrates
Section 2
Cellular Structure and Function
The Plasma Membrane
Proteins
 Transmit signals inside the cell
 Act as a support structure
 Provide pathways for substances to enter and
leave
Section 2
Cellular Structure and Function
Section 3
Cellular Structure and Function
Structures and Organelles
Plant and Animal Cell Structures
 Organelles are bodies within the cytoplasm
that serve to physically separate the various
metabolic reactions that occur within the cells
1. Nucleus
7. Mitochondria
2. Ribosomes
8. Chloroplasts
3. Endoplasmic reticulum
9. Cytoskeleton
4. Golgi Apparatus
10. Flagella & Cilia
5. Lysosomes
11. Centrioles
6. Peroxisomes
12. Vacuoles & Vesicles
Section 3
Cellular Structure and Function
Structures and Organelles
Section 3
Cellular Structure and Function
Structures and Organelles
Nucleus
• The nucleus is bounded by the nuclear
envelope consisting a phospholipid bilayer,
similar to the plasma membrane
• The nucleus contains the DNA
(deoxyribonucleic acid), the heredity
information of the cell
The nucleus is the brain of the cell
Cells
Nucleus
• Also visible within the
nucleus are one or more
nucleoli, concentrations
of DNA in the process of
manufacturing the
components of
ribosomes
Cells
Ribosomes
• Ribosomes are manufactured
in the nucleus and consist of
ribosomal RNA and protein
• Ribosomes are the site of
protein synthesis
• Ribosomes translate genetic
information (DNA) into specific
polypeptide chains & proteins
Cells
Endomembrane System
• Composed of the same phospholipid bilayer as the
cell membrane
• They are membrane-bound organelles in
eukaryotic cells
– Similar to the organs of our bodies
• Endomembrane systems only occur in
eukaryotic cells
Endomembrane System
• Components of the endomembrane system:
– Nuclear envelope
– Endoplasmic reticulum
– Mitochondria (has 2 lipid bilayers)
– Chloroplasts (has 2 lipid bilayers)
– Golgi apparatus
– Lysosomes
– Vacuoles
– Vesicles
Endoplasmic Reticulum
• The endoplasmic reticulum or ER, consists
of stacks of flattened sacs of membrane
• The best way to determine if the structure is
the ER or Golgi apparatus is if it is
connected to the nucleus.
– ER is connected
Cells
Endoplasmic Reticulum
Cells
Endoplasmic Reticulum
Rough ER
• When ribosomes are
present, the ER is called
the rough ER and
provides
• Aids in protein synthesis
Cells
Smooth ER
• Smooth ER, without
ribosomes, is responsible
for the synthesis of lipids
and hormones.
Golgi Apparatus
• The Golgi apparatus
– The Golgi modifies and
package proteins and
lipids into vesicles
– The Golgi also produces
lysosomes
Think of it as Fed Ex
Cells
Mitochondria
• Mitochondria carry out aerobic respiration, a
process in which energy (in the form of ATP)
is obtained from organic molecules (glucose)
– It’s the powerhouse of the cell
• Mitochondria are found in both plant and
animal cells
• Since it converts food to usable energy
(ATP), what type of cell would have a lot of
mitochondria??
Mitochondria
Chloroplasts
• Chloroplasts are specialized organelles
found in algae and plants that carry out
photosynthesis, the process of capturing
energy from sunlight and converting it into
useable energy (carbohydrates)
Chloroplasts
Cells
Chloroplasts
• Chloroplasts contain chlorophylls, which are
responsible for the green color of a plant and
are the key light-trapping molecules in
photosynthesis
• Chloroplast are not found in animal cells.
Why not??
Chloroplasts and Mitochondria
• Add this to your notes!!!!
• Both chloroplasts and mitochondria have
their own circular DNA and ribosomes, just
like bacteria
• They also reproduce the same way as
bacteria
• This suggests that chloroplasts and
mitochondria may have once been bacteria
Vacuoles & Vesicles
• Vacuoles/ Vesicles are fluid-filled membrane
bound bodies
– They may contain food particles or digestive
enzymes (found in lysosomes)
– Transport substances throughout the cell
– Release of cellular waste products
Vacuoles & Vesicles
• -Central vacuoles are large
bodies that store water
and occupies most of the
interior of plant cells
• -If the central vacuole runs
low on water, the plant will
begin to wilt
• -The central vacuole in
plants stores starch,
pigments, and toxic
substances
Cells
Lysosomes
• Lysosomes are vesicles from the Golgi
apparatus that contain hydrolytic digestive
enzymes
– They are the cell’s stomach
• Lysosomes play an important role in:
– Intracellular digestion such as breaking down
food, cellular debris, and foreign invaders such as
bacteria
Lysosomes
Cells
Cytoskeleton
• The cytoskeleton is the internal structure of
the cytoplasm and is involved in establishing
the shape of the cell and coordinating
movements
Cells
Cytoskeleton
Cells
Section 3
Cellular Structure and Function
Structures and Organelles
Cilia
 Short, numerous projections that look like hairs
Flagella
 Longer and less numerous than cilia
 Create movement with a whiplike motion
Section 3
Cellular Structure and Function
Table 7.1 Summary of Cell Structure
Table 7.2 Summary of Cell Structure
Table 7.3 Summary of Cell Structure
Section 3
Cellular Structure and Function
Structures and Organelles
Plant and Animal Cell Structures
Structures only found in Plant
Cells
cells:
 Cell Wall
 Chloroplasts
 Central Vacuole