Class 2
Biological Themes
2
Diversity of life
Archaebacteria Eubacteria Protista
Biological Kingdoms
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Diversity of life
Fungi Plantae Animalia
Biological Kingdoms
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Diversity of life
Kingdoms
Archaebacteria
Eubacteria
Protista Fungi Plantae Animalia
Methanogens
Bacteria
ProtozoansAmoebasSlime molds
MoldsYeastsMushroomsRustsSmutsMildewToadstools
Algae Red Brown GreenMossFernsVascular plants
SpongesJellyfishHydrasPlanariaWormsSnailsInsectsFishReptilesBirdsMammals
100,000 25,000 30,000 520,000 1,080,000
No. of species:
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Naming of organisms
allows scientists to communicate unambiguously about organisms being studied
binomial nomenclature used:
Genus species names are in Latin and are written in
italics or underlined (to denote a foreign word)
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Naming of organisms
names often denote a property of the organism or something about its discovery: substrate utilized Saccharomyces product produced Clostridium acetobutylicum preferred temperature Streptococcus thermophilus color Aspergillus niger size Bacillus megaterium discoverer Trichoderma reesei geographic location Lactobacillus sanfrancisco
Shapes of bacteria
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Cell size
Cells range in size from 5-20 μm to 5 cm long. Most cells are small because larger cells
do not function as efficiently. As cell size increases, volume increases
more rapidly than surface area. Larger cells have less surface area per unit
volume, thus less opportunity to interact with the environment.
Cytoplasm fills cell interior.
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Plasma membrane
All cells contain a plasma membrane Encloses cell and separates contents from
surroundings. Phospholipid bilayer with embedded
proteins. Cell Surface Proteins – Act as markers to
identify particular types of cells. Transmembrane Proteins – Span entire
membrane. Provide channels for molecule passage.
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Lipid bilayer
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Plasma membrane
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Proteins in membrane structures
Nonpolar regions of a protein lock it into the lipid bilayer of the membrane
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Types of cell structures
Procaryotic do not have a nuclear membrane includes species from the kingdoms Archaebacteria
and Eubacteria Eucaryotic
possess nuclear membrane contain organelles 1,000 to 10,000 times larger than procaryotic cells includes species from all kingdoms except
Archaebacteria and Eubacteria
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Comparison of Procaryotic and Eucaryotic Organisms
Procaryotes EucaryotesOrganisms archaebacteria, bacteria protists, fungi, plants, animals
Cell linear dim. 1-10 m 10-100 m
Metabolism anaerobic or aerobic aerobic or anaerobic
Organelles no nucleus, chloroplasts, mitochondria, endoplasmic reticulum, etc.
DNA circular, in cytoplasm very long linear moleculesbounded by nuclear envelope
RNA and protein RNA and protein synthesizedin same compartment
RNA synthesized in nucleus;protein, in cytoplasm
Cytoplasm no cytoskeleton: no cytoplasmic streaming, no endocytosis, no exocytosis
cytoskeleton composed of protein filaments; cytoplasmic streaming; endocytosis and exocytosis
Cell division chromosomes pulled apart byattachment to plasma membrane
chromosomes pulled apart bycytoskeletal spindle apparatus
Cellular organization
mainly unicellular mainly multicellular, with differentiation of many cell types
Molecular Biology of the Cell, 2nd Ed.
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Origin of eucaryotes
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Procaryote structure
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Procaryote cell wall types
Gram positive
Gram negative
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Gram positive
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Peptidoglycan
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Gram negative
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Gram negative
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Procaryote structure
http://www.bact.wisc.edu/Bact303/TheProcaryotes
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Eucaryotic cells
Interior of eukaryotic cell contains numerous membrane-bound structures (organelles) that close off compartments to allow multiple simultaneous biochemical processes.
Eucaryotic cells also have a cytoskeleton – a dense network of protein fibers supporting cell shape.
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Cell Organelles
Eukaryotic cells thought to have evolved from endosymbiosis between different species of prokaryotes. Engulfed prokaryotes provided hosts with
certain metabolic advantages.
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Nucleus
Nucleus - Command and control center. Bound by nuclear envelope.
Nuclear pores filled with proteins permit passage of material in and out of the cell.
Contain chromosomes holding DNA. Nucleolus - Cluster of genes within nucleus
encoding rRNA. Ribosome reads RNA and directs protein
building.
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Nucleus
As a cell prepares to divide, DNA coils around histones (packaging proteins) into a highly condensed form, a nucleosome.
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Endoplasmic Reticulum
Internal membrane creating channels and membrane-enclosed vesicles. Carbohydrates and lipids manufactured on
the surface. Proteins for export produced on surface
covered with ribosomes (Rough ER).
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Ribosomes
Ribosomes are the site of protein synthesis. Made up of rRNA bound within complex of
several dozen different proteins. Composed of two subunits that join to form a
functional ribosome only when they attach to messenger RNA.
Assembled in nucleolus within the nucleus.
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Golgi Apparatus
Collection of interconnected flattened stacks of membranes (Golgi bodies). Function in collection, packaging, and
distribution of molecules synthesized in one place, and utilized in another place within the cell.
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Vesicles
Lysosomes – Membrane-bound digestive vesicles that arise from Golgi apparatus. Contain degrading enzymes that break
down old organelles and other structures. Microbodies – carry enzymes.
Glyoxysome – Convert fat into carbohydrates (Plants).
Peroxisome – Catalyze removal of electrons and associated hydrogen atoms.
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Endomembrane SystemCopyright © McGraw-Hill Companies
Permission required for reproduction or display
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Organelles With DNA
Mitochondria Contain own DNA. Double membrane organelles that extract
energy from organic molecules. (Oxidative Metabolism)
Inner membrane bent into numerous folds (cristae) that partition mitochondrion into inner matrix and outer compartment.
Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Mitochondrion
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Organelles With DNA
Chloroplasts Double membrane organelles that serve as
site of photosynthesis. Contain chlorophyll, a photosynthetic pigment
that gives most plants their green color. Inner membranes fused to form stacks of
thylakoids, which contain light-capturing pigments.
Thylakoids stacked on top of one another to form a column (granum).
Interior bathed with a semiliquid (stroma).
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Chloroplast Structure
Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Organelles With DNA
Centrioles - Barrel-shaped organelles usually located near nuclear membrane. Help assemble
microtubules. Some appear to
contain DNA.
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Cytoskeleton
Dense network of protein fibers supporting cell shape. Microfilaments – made of the protein actin Microtubules – made of the protein tubulin Intermediate Fibers
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Plant Cells
Central Vacuole - Functions as storage center and helps increase surface-to-volume ratio.
Cell Walls Primary Walls Middle Lamella Secondary Walls
Cell
Middle lamella
Secondary wall
Primary wall
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Eucaryotic cell structure
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookCELL2.html