Transcript The Body in Motion

Biology, Seventh Edition
Solomon • Berg • Martin
Chapter 4
Organization of the
Cell
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
• Cell theory
• Cells are the basic living units of
organization and function
• All cells come from other cells
• Work of Schleiden, Schwann, and
Virchow contributed to this theory
• Each cell is a microcosm of life
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
Biological size and cell diversity
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
• Cell surface area-to-volume
ratio
• Plasma membrane must be large
enough relative to cell volume to
regulate passage of materials
• Cell size and shape related to
function
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
Cell surface area-to-volume ratio
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
• Microscopes
• Light microscope, referred to as
compound microscope, used by most
students
• Two features determine how clearly
an object is viewed
–Magnification
–Resolution
• Light microscope has 500 times more
resolution than human eye
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CHAPTER 4 Organization of the Cell
• Special optical mechanisms for
light microscopes
• Bright-field microscopy
• Phase contrast microscopy
• Differential-interference-contrast
microscopy
• Fluorescence microscope, including
confocal fluorescence microscope
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
• Electron microscope
• Developed in the 1950s
• Allows study of the ultrastructure of
cells
• 10,000 times more resolution than
human eye
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CHAPTER 4 Organization of the Cell
• Types of electron microscope
• Transmission electron microscope
• Scanning electron microscope
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
Comparing light and electron microscopy
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
• Cell fractionation
• Used to determine function of
organelles
• Cells broken apart and the resulting
cell extract spun in a centrifuge
• Centrifugal force separates extract
–Pellet
–Supernatant
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
Cell fractionation
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CHAPTER 4 Organization of the Cell
• Prokaryotic
• Bacteria and archaea
• DNA not enclosed in a nucleus
• Eukaryotic
• All other known organisms
• Highly organized membrane-enclosed
organelles
–Cytoplasm
–Nucleoplasm
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CHAPTER 4 Organization of the Cell
• Functions of cell membranes
• Divide cell into compartments,
allowing for specialized activities
• Interacting membranes form
endomembrane system
• Vesicles transport materials between
compartments
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CHAPTER 4 Organization of the Cell
Diagram of
a plant cell
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
Diagram of
an animal cell
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
• The cell nucleus
• Contains DNA
• Bounded by
–Nuclear envelope
–Double membrane perforated with
nuclear pores
• DNA forms chromatin, which is
organized into chromosomes
• Nucleolus
–RNA synthesis and ribosome assembly
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CHAPTER 4 Organization of the Cell
The cell
nucleus
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CHAPTER 4 Organization of the Cell
• Endoplasmic reticulum (ER)
• Network of folded internal
membranes in the cytosol
• Smooth ER
–Site of lipid synthesis
–Site of detoxifying enzymes
• Rough ER
–Ribosomes manufacture proteins
–Proteins may be moved into the ER
lumen
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CHAPTER 4 Organization of the Cell
Endoplasmic
reticulum (ER)
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
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Biology, Seventh Edition
CHAPTER 4 Organization of the Cell
• Golgi complex
• Cisternae that process, sort, and
modify proteins
• In animal cells, Golgi complex also
manufactures lysosomes
• Glycoproteins transported to the
cis face
• Golgi modifies carbohydrates
and lipids and packages into
vesicles
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CHAPTER 4 Organization of the Cell
Golgi complex
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CHAPTER 4 Organization of the Cell
• Lysosomes break down wornout cell structures, bacteria, and
other substances
• Peroxisomes
• Involved in lipid metabolism and
detoxification
• Contain enzymes that produce and
degrade hydrogen peroxide
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CHAPTER 4 Organization of the Cell
Lysosomes
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CHAPTER 4 Organization of the Cell
• Mitochondria
• Sites of aerobic respiration
• Organelles enclosed by a double
membrane
• Place important role in apoptosis
• Cristae and matrix contain enzymes
for aerobic respiration
–Nutrients broken down and energy
packaged in ATP
–Carbon dioxide and water by-products
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CHAPTER 4 Organization of the Cell
Mitochondria
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CHAPTER 4 Organization of the Cell
• Chloroplasts
• Plastids that carry out photosynthesis
• Inner membrane of chloroplast
encloses the stroma
• During photosynthesis, chlorophyll
traps light energy
• Energy converted to chemical energy
in ATP
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CHAPTER 4 Organization of the Cell
Chloroplast
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CHAPTER 4 Organization of the Cell
Cellular respiration and photosynthesis
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CHAPTER 4 Organization of the Cell
• Cytoskeleton
• Internal framework made of
–Microtubules
–Microfilaments
–Intermediate filaments
• Provides structural support
• Involved with transport of materials in
the cell
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CHAPTER 4 Organization of the Cell
The
Cytoskeleton
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CHAPTER 4 Organization of the Cell
• Cilia and flagella
• Thin, movable structures that project
from cell surface
• Function in movement
• Microtubles anchored in cell by basal
body
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CHAPTER 4 Organization of the Cell
Structure
of cilia
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CHAPTER 4 Organization of the Cell
• Glycocalyx, cell coat formed by
polysaccarides extending from
plasma membrane
• Many animal cells also
surrounded by an extracellular
matrix (ECM)
• Most bacteria, fungi, and plant
cell walls made of carbohydrates
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CHAPTER 4 Organization of the Cell
Extracellular matrix
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CHAPTER 4 Organization of the Cell
Plant
cell walls
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