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

43

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