Bacteria - Introductory Biology - Lecture Slides, Slides of Biology

Download Bacteria - Introductory Biology - Lecture Slides and more Slides Biology in PDF only on Docsity! Bacteria Docsity.com Characteristics of Bacteria • ALL PROKARYOTIC – NO organelles with membranes – DO possess ribosomes • Smallest living things • Simplest living things • Single circular chromosome Docsity.com Reproduction • NO mitosis or meiosis • ASEXUAL reproduction Binary fission • Chromosome is copied • Chromsomes are separated • Cell divides in half • Reproduction is RAPID – Every 20 minutes – Limited resources keep growth in check – IF a mutated strain arises (resistant to an antibiotic, for example) it can spread QUICKLY. Docsity.com Exchange of Genes Among Bacteria • NO TRUE SEXUAL REPRODUCTION • However, bacteria can get new genes from sources other than mutation Docsity.com Exchange of Genes Among Bacteria • Conjugation – Exchange of all or SOME of genetic material from one bacterium to another – NOT equal; NOT sex Docsity.com Antibiotics • Antibiotics disrupt cell wall structure • Bacteria take on water and burst • Antibiotics do NOT work against – Viruses – not living; no cell wall – Animal cells – no cell wall – Plants – different cell walls (cellulose) Docsity.com Antibiotic Resistance • Lots of bacteria in an environment – Most are benign – Some may be pathenogenic • Some may be resistant to antibiotics • Application of an antibiotic will kill ALL bacteria present EXCEPT – Those with resistance gene • Once benign competitors have been eliminated from the environment…. – There is NO COMPETITION for the resistant bacteria – They grow and flourish – The next time an antibiotic is applied it doesn’t work Docsity.com Human Behaviors that Contribute to Antibiotic Resistance • Overuse of antibiotics and other antibacterial agents in general – By people • Antibacterial soaps, cleaners, etc. • Medication prescribed when not called for – Viral infection – In animals (farm animals) • Antibiotics prevent infection and improve growth • But YOU get a dose every time you eat a hamburger • Misuse of antibiotics – Not completing your prescription of antibiotics until all medication is taken – Sharing of antibiotics Docsity.com Eubacteria • Heterotrophic bacteria – Consume organic compounds and convert to energy – Found everywhere – Parasites • Cause disease – Saprobes • Decomposers • VERY important in carbon cycle • Return organic compounds to the soil as they decompose organisms, wastes, etc. Docsity.com Eubacteria • Autotrophic Bacteria – Photosynthetic autotrophs • Cyanobacteria – “blue-green algae” – Chemosynthetic autotrophs • Convert inorganic chemicals to energy • Important in NITROGEN CYCLE Docsity.com Eubacteria • Oxygen use – Obligate aerobes – require oxygen to live – Facultative anaerobes – oxygen or not…doesn’t matter – Obligate anaerobes – cannot be near oxygen • Syphilis Docsity.com More on disease • Lyme disease Docsity.com Other Impacts • Adaptations – Endospores – Hard covering – Survive anything – Botulism – tetanus Docsity.com