Transcript cell_types
Three Domains of Life Arcahaea Eubacteria Eukarya S S Each cell type has unique characteristics Archaea Eukaryotic cell wwwsciencenews.org/view/generic/i d/42241/tit . Eubacteria cell Nucleus Organelles ARCHAEA AND EUBACTERIA Prior to 1970’s, were group called prokaryotes - still see this used. Archaea Recognized S Advances in molecular biology identified Archaea as unique type of cells (Carl Woese, late 70’s, U of Illinois0 S They had been thought of as bacteria S They have DNA that is very different from bacterial DNA Characteristics of Archaea S Archaea look like bacteria S rod, spiral, and marble-like shapes like bacteria. S Archaea and bacteria share certain genes S so they function similarly in some ways. S Archaeans also share genes (DNA) with eukaryotes, S Also have many genes that are completely unique 'archae' meaning 'ancient' S Archaea are believed to be the least evolved forms of life on Earth. S Called “Extremophiles” due to the extreme conditions they live in S similar to the conditions of early Earth EXTREME CONDITIONS Extremeophiles S Live at 100 ˚C or greater S hot springs, sea vents S extremely alkaline or acid conditions S digestive tracts of cows, termites, and marine life S they produce methane S anoxic muds of marshes and sea floors S petroleum deposits deep underground Archaea: Morphology S Size < one micron (1μ) S Shapes vary S spherical (coccus) S rod-shaped (bacillus) S hair-like S triangular S square Archaea: Morphology CONTINUDED S May have one or more flagella S If multiple flagella are present, they attached on one side S No internal membranes S DNA is a single loop called a plasmid S tRNAs are unique S "transfer RNA” are important in decoding the message of DNA and in building proteins. S Ribosomes are similar to eukaryotes. ARCHAEA Cell Structure S Have an outer cell membrane S Within the membrane is the cytoplasm S Around the outside of nearly all archaeal cells is a cell wall S a semi-rigid layer that helps maintain its shape and chemical equilibrium S All three structures are biochemically unique to Arcahaea Basic Archaea Cell Structure S Archaea do not require sunlight S Do not require oxygen S Archaea absorbs CO2, N2, or H2S chemically transforms them S Give off methane gas or sulfur as a waste product. EUBACTERIA S True Bacteria •Includes the spirochetes, gram-positive bacteria and cyanobacteria. •Bacillus bacteria are rod shaped. •Coccibacteria are round. •Spirillumare spiral shaped Gram Stain Eubacteria Nutrition S Photoautotrophs use the sun’s energy and manufacture sugars. S Chemoautotrophs need carbon dioxide to obtain energy from inorganic substances. S Photoheterotrophs are unique and use light to generate energy but must obtain carbon in organic forms. S Chemoheterotrophs use organic molecules such as sugar for energy. Eubacteria Morphology S Vary in size from 1.25 μm to 10μm S Largest know is 0.75mm Thiomargarita namibiensis, Eubacteria Morphology S Have rigid cell walls (contain peptidoglycan) and a capsule S May have flagella S Have pili – extensions of cell wall used to touch/exchange material with other cells S No nucleus or membrane bound organelles S Have a nucleotide region – circular nucleotides – plasmid S Cell membrane similar to Eukaryotic cells Prokaryotic flagella Nucleoid region (DNA) Plasma membrane Cell wall Capsule Pili Ribosomes Eukaryotic cells S Have a nucleus and membrane bound organelles S Are larger than Archaea and Eubacteria S Cell walls (if present) contain cellulose or chitin S DNA structured with Histones – not found in Eubacteria, are found in Archae S Task – cut and paste the picture with the appropriate description. S Create a summary chart comparing the three domains of cells. Model your chart after the following characteristics: S Size S DNA S Histones S RNA S Cell organelles S Cell wall S tRNA S Ribosomes S Cell membrane