Bio 111 - Lecture 4

Bio 111 - Lecture 4 - Biology 111 Lecture 4 - Prokaryotes...

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Biology 111 Lecture 4 - Prokaryotes Kingdoms Archaea and Monera September 10, 2007 I. Intro to Bacteria A. Bacteria are NOT viruses 1. Viruses are not organisms 2. Viruses do NOT metabolize on their own 3. Viruses are NOT cellular 4. So viruses are not placed in any kingdom - Not really alive, just a packet of RNA/DNA that invades cells and replicates - Parasitic, needs a host B. Prokaryotes are the most distinctive organisms 1. Prokaryotes are bacteria (monera) and ancient bacteria (archaea) a. Monera means single (nearly all single celled) b. Archaea means ancient (earliest life on earth) 2. Complex metabolism metabolism - chemical reactions during cell growth and repair 3. Cells have no nuclear membrane a. DNA is unbound in the cytoplasm (cell sap) b. DNA is circular in a ring - not linear chromosomes 4. Most reproduction is asexual a. no meiosis or true mitosis b. cells are not haploid or diploid c. Binary Fission: ring of DNA is replicated then the cell pinches in half (no nuclear) C. Extreme Prokaryotes
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1. Smallest - cells commonly 1-2 micrometers in diameter (1 = 0.001mm) 2.. Most abundant a. in numbers, 1 spoonful of soil has > 1 billion bacteria b. in biomass (amount of biological material, weight or volume) - prokaryotes exceed biomass of all other kingdoms together - reproduce EXTREMELY rapidly - can divide once every 10-20 minutes 3. Greatest Habitat Diversity - Prokaryotes in almost every habitat on Earth - temperature extremes from antarctica to boiling hot springs - water with pH 1.5 (same level as sulfuric acid) - high salt concentrations - high pressures at ocean depths - hundreds or thousands of feet underground 4. MOST ANCIENT a. in 3.5 billion year old rocks b. no other life found until 1.3 billion years ago II. Classifcation A. Domain and Kingdom Archaea - the ancient bacteria
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Bio 111 - Lecture 4 - Biology 111 Lecture 4 - Prokaryotes...

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