Human Biology
Sylvia S. Mader
Michael Windelspecht
Chapter 3
Cell Structure
and Function
Lecture Outline
Part 2
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1
3.2 How Cells are Organized
What are the 2 major types of
cells in all living organisms?
• Prokaryotic cells
– Thought to be the first cells to evolve
– Lack a ________
– Represented by bacteria and archaea
• Eukaryotic cells
– Have a _________ that houses _____
– Many membrane-bound organelles
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3.2 How Cells are Organized
What do prokaryotic and
eukaryotic cells have in common?
• A ___________________ that surrounds and
delineates the cell
• A ____________: the semi-fluid substance
inside the cell that contains organelles
• DNA
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3.2 How Cells are Organized
What do eukaryotic cells look like?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
mitochondrion
chromatin
nucleolus
nuclear
envelope
endoplasmic
reticulum
Plasma membrane:
outer surface that
regulates entrance and
exit of molecules
protein
a.
2.5 µm
phospholipid
NUCLEUS:
Nuclear envelope: double
membrane with nuclear pores
that encloses nucleus
CYTOSKELETON: maintains
cell shape and assists movement
of cell parts:
Chromatin: diffuse threads
containing DNA and protein
Microtubules: cylinders of
protein molecules present
in cytoplasm, centrioles,
cilia, and flagella
Nucleolus: region that produces
subunits of ribosomes
Intermediate filaments:
protein fibers that
provide support
and strength
ENDOPLASMIC RETICULUM:
Rough ER: studded with
ribosomes, processes proteins
Smooth ER: lacks
ribosomes, synthesizes
lipid molecules
Actin filaments: protein
fibers that play a role in
movement of cell
and organelles
Ribosomes:
particles that carry
out protein synthesis
Centioles: short,
cylinders of microtubules
Centrosome: microtubules
organizing center that
contains a pair of centroles
Mitochondrion: organelle
that carries out cellular
respiration, producing
ATP molecules
Lysosome: vesicle that
digests macromolecules
and even cell parts
Figure 3.4 The
structure of a
typical
eukaryotic cell.
Polyribosome: string of
ribosomes simultaneously
synthesizing same protein
Vesicle: membrane-bounded
sac that stores and transports
substances
b.
Cytoplasm: semifluid
matrix outside nucleus
that contains organelles
Golgi apparatus: processes, packages,
and secretes modified cell products
© Dennis Kunkel/Visuals Unlimited
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3.2 How Cells are Organized
Where did eukaryotic cells come from?
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Original
prokaryotic cell
DNA
1. Cell gains a nucleus by the
plasma membrane invaginating
and surrounding the DNA
with a double membrane.
Nucleus allows specific functions
to be assigned, freeing up cellular
resources for other work.
2. Cell gains an endomembrane
system by proliferation
of membrane.
Increased surface area allows
higher rate of transport of
materials within a cell.
3. Cell gains mitochondria.
aerobic
bacterium
Ability to metabolize sugars in
the presence of oxygen enables
greater function and success.
mitochondrion
4. Cell gains chloroplasts.
Ability to produce
sugars from sunlight
enables greater
function and success.
Animal cell
has mitochondria,
but not chloroplasts.
Figure 3.5 The evolution of
eukaryotic cells.
photosynthetic
bacterium
chloroplast
Plant cell
has both mitochondria
cnd chloroplasts.
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3.3 The Plasma Membrane and How Substances Cross It
What are some characteristics
of the plasma membrane?
•
•
•
•
•
It is a ____________ bilayer.
It is embedded with proteins that move in space.
It contains ____________ for support.
It contains carbohydrates on proteins and lipids.
It is _____________________.
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3.3 The Plasma Membrane and How Substances Cross It
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plasma membrane
carbohydrate
chain
extracellular
matrix (ECM)
glycoprotein
glycolipid
hydrophilic
hydrophobic
heads
tails
phospholipid
bilayer
filaments of cytoskeleton
peripheral protein
Outside
Inside
integral protein
cholesterol
Figure 3.6 Organization of the plasma membrane.
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3.3 The Plasma Membrane and How Substances Cross It
What does selectively permeable
mean?
• The membrane
allows some
things __ while
keeping other
substances ____.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
–
+
charged molecules
and ions
H2O
aquaporin
noncharged
molecules
macromolecule
+
–
phospholipid
molecule
protein
Figure 3.7 Selective permeability of the
plasma membrane.
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3.3 The Plasma Membrane and How Substances Cross It
How do things move across the
plasma membrane?
1.
2.
3.
4.
5.
Diffusion
Osmosis
Facilitated transport
Active transport
Endocytosis and exocytosis
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3.3 The Plasma Membrane and How Substances Cross It
What are diffusion and osmosis?
1. ___________ is the random movement of
molecules from a ________ concentration to a
__________ concentration.
2. Osmosis is the __________ of water molecules.
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3.3 The Plasma Membrane and How Substances Cross It
What are diffusion and osmosis?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
particle
plasma
membrane
water
cell
cell
time
a. Initial conditions
Figure 3.8 Diffusion across the plasma membrane.
b. Equilibrium conditions
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