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Chapter 3
 Structure and Function of Cells
 Metabolism
 Anabolism
 Catabolism
 Cell respiration
 Aerobic
 Anaerobic
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Cells Are Classified by Internal Organization
 Eukaryotes have
 Plasma membrane
 Nucleus: information center
 Cytoplasm: fluid within membrane
 Organelles: structures with specialized
functions
 Prokaryotes have
 No nucleus
 No true organelles
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Cell Structure Reflects Cell Function
 Muscle cells
 Contain numerous organelles providing
energy needed for muscle contraction
 Nerve cells
 Long and thin to carry impulses over
distance
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The Plasma Membrane
Extracellular environment
Receptor
protein
Channel protein
(always open)
Gated channel
protein (closed
position)
Cytoskeleton Phospholipid
filaments
Cytoplasm
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Carbohydrate
groups
Lipid Transport Glycoprotein
bilayer protein
Cholesterol
Figure 3.5
Structural Features of the Plasma Membrane
 Lipid bilayer
 Phospholipids: polar head and nonpolar tail
 Cholesterol: makes membrane a bit more
rigid
 Proteins: provide means of transportation
through membrane
 Carbohydrates: recognition patterns for cells
and organisms
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Diffusion: Passive Transport Through
Membrane
 Passive transport
 No energy
required
 Diffusion
 Movement from
area of high
concentration to
low
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Figure 3.6
Osmosis: Diffusion of Water
 Osmosis: net diffusion of water across a
semipermeable membrane
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Figure 3.7
Variations in Tonicity
 Isotonic
 Extracellular and intracellular ionic
concentration equal
 Hypotonic
 Extracellular ionic concentration less than
intracellular
 Hypertonic
 Extracellular ionic concentration more than
intracellular
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Tonicity
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Figure 3.13a
Internal Structures of an Animal Cell
Cytosol
Semifluid gel material
inside the cell
Peroxisome
Destroys cellular toxic waste
Centrioles
Microtubular structures
involved in cell division
Cytoskeleton
Structural framework
of the cell
Nucleus
Information
center for the
cell. Contains
DNA
Smooth endoplasmic reticulum
Primary site of
macromolecule
synthesis other than
proteins
Rough endoplasmic reticulum
Primary site of protein
synthesis by ribosomes
Golgi apparatus
Refines, packages, and
ships macromolecular products
Secretory vesicle
Membrane-bound
shipping container
Ribosomes
Site of protein synthesis
Plasma membrane
Controls movement of
materials into and out of cell
Mitochondrion
Produces energy
for the cell
Lysosome
Digests damaged organelles
and cellular debris
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Figure 3.14
Endoplasmic Reticulum (ER) and Ribosomes
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Figure 3.16
Golgi Apparatus
 Receives substances from ER, refines and
packages them
Smooth ER
Golgi apparatus
Vesicle
Lysosome
Secretory vesicle
Plasma
membrane
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Figure 3.17 (1 of 2)
Vesicles Ship and Store Cellular Products
Harmless
waste
Alcohol
 Vesicles
 Ship and store
cellular products
 Secretory
membranebound spheres
 Examples:
secretory,
endocytic,
peroxisomes,
lysosomes
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Peroxisome
Golgi
apparatus
Cell toxic
waste
Lysosome
Residual
body
Bacterium
Plasma membrane
Figure 3.18
Mitochondria: Provide Energy to the Cell
 Double
membrane
 Inner
membrane
contains
enzymes that
break down
foods
 Liberated
energy is used
to create ATP
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Figure 3.19a
Energy Storage
 Fat
 Triglycerides
 Long-term energy storage in animals
 Glycogen
 Carbohydrate storage
 Short-term energy storage in animals
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Cytoskeleton Supports the Cell
 Microtubules
 Microfilaments
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Figure 3.20
Cell Structures for Support and Movement:
Cilia, Flagella, Centrioles
 Cilia and flagella
 Used in
movement
 9 + 2 microtubule
arrangement
 Centrioles
 Used in cell
division
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Figure 3.20
Cells Use and Transform Matter and Energy:
Two Basic Metabolic Pathways
 Anabolism
 Requires enzymes
 Making/assembling large molecules
 May require energy (ATP)
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Cells Use and Transform Matter and Energy:
Two Basic Metabolic Pathways
 Catabolism
 Requires enzymes
 Breakdown of molecules
 May release energy
 Used in breaking down nutrients and
recycling cell components
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Cellular Respiration: Cells Use Glucose and
Oxygen to Supply ATP
 Glucose provides
energy for the cell
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Figure 3.23
Stages of Cellular Respiration
 Glycolysis: in cytoplasm
 Splits glucose
 Produces two ATP and two pyruvate molecules
 Citric acid cycle: in mitochondria
 Also called the Krebs cycle
 Extracts high-energy electrons
 Produces two ATP and carbon dioxide
 Electron transport system: in mitochondria
 Energy from electrons is used to produce ATP
 Produces water and carbon dioxide
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Cellular Respiration: Overview
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Figure 3.29a
The Preparatory Step
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Figure 3.26
Fats and Proteins:
Additional Energy Sources
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Figure 3.30
Fats and Proteins:
Additional Energy Sources
 Fats
 Triglycerides have twice the energy of
carbohydrates
 Proteins
 Same energy as carbohydrates
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Anaerobic Pathways:
Energy Extraction Without Oxygen
Glucose
(Glycolysis)
(2) ATP
Lactic acid
buildup
Pyruvate
Mitochondrial
metabolism
blocked without
oxygen
Mitochondrion
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Figure 3.31