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Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition Solomon • Berg • Martin
Chapter 4
Organization of the Organization of the CellCell
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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Biological size and cell diversity
Copyright © 2005 Brooks/Cole — Thomson Learning
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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Cell surface area-to-volume ratio
Copyright © 2005 Brooks/Cole — Thomson Learning
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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
• Types of electron microscope• Transmission electron microscope• Scanning electron microscope
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Comparing light and electron microscopy
Copyright © 2005 Brooks/Cole — Thomson Learning
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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Cell fractionation
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Diagram ofa plant cell
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Diagram ofan animal cell
Copyright © 2005 Brooks/Cole — Thomson Learning
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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
The cellnucleus
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Endoplasmicreticulum (ER)
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Copyright © 2005 Brooks/Cole — Thomson Learning
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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Golgi complex
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
• Lysosomes break down worn-out cell structures, bacteria, and other substances
• Peroxisomes• Involved in lipid metabolism and
detoxification• Contain enzymes that produce and
degrade hydrogen peroxide
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Lysosomes
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Mitochondria
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Chloroplast
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Cellular respiration and photosynthesis
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
TheCytoskeleton
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Structureof cilia
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition 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
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Extracellular matrix
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 4 Organization of the Cell
Plantcell walls