Bio 280 Exam 2

How many chromosomes are found in prokaryotes? - one What is another place that can have DNA in prokaryotes? - plasmid Bacteria generally have a? - single large chromosome Super Coiled DNA is - DNA packed and coiled which is held together by proteins. It is not bounded by a membrane. Plasmids - -Extrachromosomal circular DNA -Contain genes which are not necessary for the organism's survival but which may be useful to it (e.g antibiotic resistance genes, genes for enzymes which degrade pollutants for consumption by the cell, etc.). -Can be transferred 'horizontally' (from mature cell to mature cell) - Used as vectors for transferring DNA in genetic engineering Ribosomes - - Used for constructing proteins from messenger RNA (mRNA) (more on this later) - In two parts and made up of proteins and ribosomal RNA (rRNA) Poly beta-hydroxybutyrate (PHB) granules - a chemical some bacteria produce to store carbon and energy, much like we do with fats. Its significance to humans is that it is essentially biodegradable plastic. Storage bodies and inclusions are? - PHB, glycogen, sulfur, magnetosomes Endospores - -Formed for survival, not reproduction - Toughest, most resistant life form of all, partially due to the presence of dipicolinic acid in the spore coat.Can come back to life, only way to kill them is autoclaving. - Formed within cell (endo = inside) unlike fungal spores - Two major genera have them: Bacillus and Clostridium. - Have been found as far back as 40 million years ago. Raul Cano - extracted endospores out of wasp and it grew Clostridium tetani and C. perfringens is - obligated anaerobic C. Botulinum is - found in canned food, causal agent of botulism Bacillus anthracis - causal agent of anthrax Clostridium tetani - causal agent of tetanus C. perfringens - causal agent of gas gangrene Bacterial Motility - bacteria have either polar or peritrichous flagella, they run and tumble Capsule - clear thing surrounding cell Chemotaxis - In the presence of an attractant, runs become longer and tumbles fewer, thus effectively propelling the cell toward the attractant. A repellant causes the opposite effect (shorter runs, tumbles more often).