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Chapter 4
Cell Structure and
Function
Lectures by
Gregory Ahearn
University of North Florida
Copyright © 2009 Pearson Education, Inc..
4.1 What Features Are Shared By All Cells?
 Cells are the smallest unit of ______.
 Cells are enclosed by a ______ _________.
 Cells use ____ as a hereditary blueprint.
 Cells contain _____________, the material inside the plasma
membrane and outside the DNA-containing nucleus.
• Fluid environment: H20, salts, organic molecules
• Metabolic activities: proteins, lipids, carbs, salts, sugars, AA
and nucleotides
 Cells obtain __________ and ___________ from their
environment.
Copyright © 2009 Pearson Education Inc.
4.1 What Features Are Shared By All Cells?
Copyright © 2009 Pearson Education Inc.
4.1 What Features Are Shared By All
Cells?
 Relative sizes
Diameter
100 m
tallest trees
10 m
10 cm
1 cm
visible with unaided
human eye
1m
adult human
chicken egg
frog embryo
10 mm
1 mm
Units of measurement:
1 meter (m) = 39.37 inches
1 centimeter (cm) = 1/100 m
1 millimeter (mm) = 1/1,000 m
1 micrometer (mm) = 1/1,000,000 m
1 nanometer (nm) = 1/1,000,000,000 m
10 nm
1 nm
0.1 nm
visible with
special electron
microscopes
100 nm
most eukaryotic cells
visible with conventional
electron microscope
100 mm
visible with
light microscope
1 mm
mitochondrion
most bacteria
virus
proteins
diameter of DNA double helix
atoms
Fig. 4-1
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4.1 What Features Are Shared By All Cells?
 Cell function limits cell size.
• Diffusion of molecules across cell
membranes limits the diameter of cells.
• As cells get bigger, their nutrient and waste
elimination needs grow faster than the
membrane area to accommodate them.
• The volume of cytoplasm grows faster than
the plasma membrane area
Copyright © 2009 Pearson Education Inc.
4.1 What Features Are Shared By All Cells?
Fig. 4-2
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4.2 How Do Prokaryotic And Eukaryotic
Cells Differ?
 There are two kinds of cells.
• 1) _______________ cells
• Are found only in two groups of singlecelled organisms: bacteria and archaea
• 2) _______________ cells
• Are structurally more complex cells
• Possess a membrane-enclosed nucleus
• Probably arose from prokaryotic cells
Copyright © 2009 Pearson Education Inc.
4.3 What Are The Main Features Of
Eukaryotic Cells?
 Eukaryotic cells possess a number of membrane-enclosed
organelles that perform specific cell functions.
•
•
•
•
•
_____________: contains DNA
_____________: produce energy
_____________________: synthesizes proteins and lipids
_____________________: molecule sorting center
_________________: digest cellular membranes or
defective organelles
Copyright © 2009 Pearson Education Inc.
4.3 What Are The Main Features Of
Eukaryotic Cells?
 A generalized animal cell
flagellum
cytoplasm
rough endoplasmic
reticulum
ribosome
lysosome
nuclear pore
chromatin (DNA)
nucleus
nucleolus
nuclear envelope
centriole
intermediate
filaments
plasma
membrane
Golgi
apparatus
vesicle
microtubules
free ribosome
smooth
endoplasmic
reticulum
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vesicle
mitochondrion
Fig. 4-3
4.3 What Are The Main Features Of
Eukaryotic Cells?
 A generalized plant cell
microtubules
(part of cytoskeleton)
mitochondrion
chloroplast
central
vacuole
Golgi
apparatus
plasmodesma
smooth
endoplasmic
reticulum
vesicle
cell wall
rough
endoplasmic
reticulum
plasma
membrane
nucleolus
nuclear pore
chromatin
nuclear
envelope
intermediate
filaments
nucleus
ribosomes
free ribosome
Fig. 4-4
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4.4 What Role Does The Nucleus Play?
Nucleus: bound by a nuclear envelope, contains chromatin
and nucleolus. Largest organelle.
nuclear
envelope
nucleolus
nuclear
pores
nucleus
nuclear
pores
chromatin
(a) Structure of the nucleus
(b) Yeast cell
Fig. 4-5
Copyright © 2009 Pearson Education Inc.
4.4 What Role Does The Nucleus Play?
 The nuclear envelope is a _________ membrane.
• The membrane is perforated with channels called
nuclear _______.
• Some smaller materials can move through the pores,
while others, such as _______, cannot.
 The nucleus contains chromosomes.
• DNA and protein are closely associated in the nucleus
in chromatin.
• Chromatin can become condensed into
chromosomes.
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4.4 What Role Does The Nucleus Play?
chromatin
chromosome
Fig. 4-6
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4.4 What Role Does The Nucleus Play?
 Ribosomes are composed of ______ and
_________, and serve as a “workbench”
for the manufacture of __________.
 Ribosome components are made at the
___________.
• A darkly staining region in the nucleus is
called a nucleolus.
• The nucleolus contains DNA, RNA,
proteins, and ribosomes in various stages
of construction.
• Ribosome components leave the nucleus
and are assembled in the cytoplasm.
Copyright © 2009 Pearson Education Inc.
4.5 What Roles Do Membranes Play In
Eukaryotic Cells?
 The plasma membrane isolates the cell, and alternately,
helps it interact with its environment.
• The ___________ bilayer contains globular proteins that
regulate the transport of molecules into and out of the cell.
• Plant cells also have a rigid structure outside the plasma
membrane, called a _____ _____, which forms a protective
Copyrightcoating.
© 2009 Pearson Education Inc.