BIOL 152 9thEdition Lecture 9Outline of Last Lecture I. Morphological and Molecular HomologiesII. Sorting Homology from AnalogyIII. Evaluating Molecular HomologiesOutline of Current Lecture I. Cell-Surface StructuresII. Gram StainingIII. Motility-movementIV. Internal Organization and DNA V. Reproduction and AdaptationPart 2 I. Genetic RecombinationII. Transformation and TransductionIII. Conjugation and Plasmids Part 3I. The Role of Oxygen in MetabolismII. Nitrogen MetabolismCurrent Lecture- Prokaryoteso Archaea and Bacteria -> nucleus deprived!!27.1: Structural and Functional Adaptations Contribute to Prokaryotic Success- Most unicellular … MOST- Most 0.5-5 µm, (10-100 µm eukaryotic cells)- Variety of shapes- Most common = spheres (cocci), rods (bacilli), and spiralI. Cell-Surface Structureo Cell Wall Bacteria = peptidoglycan Archaea = polysaccharides and proteins  Eukarya = cellulose and chitinThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Function?  Shape, protection, doesn’t expand in hypotonic areaII. Gram Stainingo Classify Bacteria 2 outcomes – positive and negative o Gram-positive = simpler walls w/lots of peptidoglycan  Antibiotics attack peptidoglycan  DNA replication, transcription, and translation differences o Gram-negative = less peptidoglycan Outer membrane can be toxic - More likely to be antibiotic resistanto Capsule – polysaccharide or protein layer  Allows to stick to things More protectiono Fimbriae – hair – like structures – sticky!o Pili – (sex pili) – exchange DNA … remember gene transfer? Made of proteins -> chain of proteins III. Motility – Movemento Taxis – movement and toward or away o Chemotaxis  Positive – towards some chemical Negative – away from some chemicalo Flagella – meant for movement Evolutionary Origins of Bacterial Flagella - Flagella proteins – modified versions of other proteins o Mutation of DNA- Likely evolved while proteins were added to ancestral secretory system- Exaptation – existing structures take on new functions through evolution o Ex: porcupines had fur; fur turned into spikes for protectionIV. Internal Organization and DNAo Prokaryotes usually lack complex compartmentalization Some may have infoldings of the plasma membrane o Genetic Info Shorter than eukaryotes  Nucleiod region Circular DNA  Plasmid -> smaller circles of DNA V. Reproduction and Adaptationo Key features of prokaryotic reproduction: They are small They reproduce by binary fission They have short generation times -1-3 hrs Fast evolution – highly evolvedo Endospores 27.2: Rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes - Prokaryotes have considerable genetic variation- 3 Factors contribute to this genetic diversity o Rapid reproductiono Mutationo Genetic recombinationI. Genetic Recombination= combining of DNA from 2 sources- Contributes to diversity o 3 Processes- Transformation- Transduction (through viruses)- Conjugation (sex)o Horizontal gene transfer – movement of genes between different species II. Transformation and Transduction o Transformation - DNA from surrounding environmento Transduction – bacteriophages III. Conjugation and Plasmids o Conjugation – bacteria sex o F Factor – what does “F” stand for?o If present - piluso If not – receiver o The F can transfero Non sequilur – R plasmids and Antibiotic Resistance 27.3 Diverse Nutritional and Metabolic Adaptations Have Evolved in Prokaryotes- Prokaryotes can be categorized by how they obtain energy and carbono Energy Phototrophs Chemotrophs o Carbon Autotrophs Heterotrophs I. The Role of Oxygen in Metabolismo Prokaryotic metabolism varies with respect to O2 Obligate aerobes  Obligate anaerobes Facultative anaerobesII. Nitrogen Metabolismo N – needed for what?o Nitrogen fixation = N2 to NH3 (ammonia)o Mutalisms Cyanobacterium Anabaena, photosynthetic cells and nitrogen – fixing cells called heterocysts (or heterocysts) Biofillms – surface – coating