2 Introduction to Bacteria (3) Biology 11Mr. McCallum
3 Exit slip (previous class) Number of bacterial cells in/around usCommunication between bacteria – Multi-lingual“chemical words”Bacteria do good things for our bodies (digestion, educating immune system, etc.)Bacteria wait to attack – need numbersComplexity – not solitaryVibrio fischeri – bioluminescenceAdaptation of squid – relationship?Scope of medical applicationImpede signalling/communication enzymesEnhance current functioning of good bacteriaWE DO NOT KNOW IT ALL – SO MUCH MORE TO DISCOVERStudents are the engine of modern research
4 Reproduction (Binary fission) Cell division (but not technically Mitosis… why??)Doubles in size, replicates DNA, divides in halfProducing clones/identical copiesExample of exponential population growthAsexual reproduction
6 Reproduction (Binary Fission) BOTH start with one cell and result with two genetically identical cells Binary Fission: Prokaryotic organisms only. Single stranded RNA/DNA. Does not include “steps” of mitosis (does not involve centromeres, kinetochores, sister chromatids, spindle fibres, etc.) Mitosis: Eukaryotic organisms only. Does not occur in single celled organisms – rather in somatic cells or multicellular organisms
7 reproduction (Conjugation) Simple sexual reproduction – uncommonWay to introduce genetic varietyExchanging of genetic materialHollow bridge forms
11 Benefits of bacteria Benefits outweigh harmful effects Essential for decomposition and recycling matter into nutrients for living thingsThree examples of beneficial bacteria:Intestinal bacteria help us digest and synthesize vitamins!Streptococci and lactobacilli are responsible for dairy production (cheese, buttermilk, and yogurt)!Streptomyces are a source of antibiotics!
12 Harmful effects of bacteria Best known for causing diseaseTuberculosis, diphtheria, typhoid fever, bubonic plague (black death), and E. coliImpact of bacterial infectionSheer number = burden on hostDestroy cells and tissuesProduce poisons (toxins)
13 Bacterial resistance to antibiotics There are more than 2500 naturally occurring antibioticsOver the last 50 years, bacteria have slowly developed resistance to common antibioticsResistance develops from variations/mutations within a bacterial populationWeakest bacteria die out, those with variations/mutations can reproduce pass on this resistanceTheir plasmids contain R (resistance) factors have special genes that code for enzymes that inactivate specific drugsHave R factors always existed, or have they evolved with the introduction of antibiotics?