4. Chemical antimicrobial agents used to control microorganisms that are harmful to humans: ; kill or inhibit growth of microorganisms on living tissue Antiseptics & Germicides reduce the microbial load but may not eliminate all microorganisms Sanitizers kill microorganisms, but endospores are typically resistant Disinfectants destroy all forms of microbial life Sterilants
10. Bacterial cell with chromosomal mutation altering target of antibiotic Bacterial cell not resistant to antibiotic Transfer of free DNA Previously susceptible cell is now resistant to antibiotic Transformation Lysis of cell resistant to antibiotic
11. Bacterial cell with R plasmid resistant to antibiotic Bacterial cell not resistant to antibiotic Copy and Transfer of R plasmid Previously susceptible cell is now resistant to antibiotic Chromosomal DNA Conjugation
13. Fig. 14.7 Comparable to Fig. 11.8 in the 11 th edition Billion years ago Extinction of the dinosaurs Phanaerozoic Eon Evolutionary event Oxygen level Metabolic and other highlights Proterozoic Archaean Hadean Cambrian Precambrian 20% 10% Early animals Multicellular eukaryotes First eukaryotes Great oxidation event Cyanobacteria Purple and green bacteria 1% 0.1% Ozone shield (2H 2 O Oxygenic photosynthesis O 2 + 4H) Anoxic (H 2 S Anoxygenic photosynthesis S 0 + 2H) (CO 2 + 4H 2 Methanogenesis CH 4 + 2H 2 O) First cellular life Formation of crust and ocean Formation of Earth 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
14. Fig. 11-9 in the 11 th edition (aerobic) (oxygenic)
15. The Hydrogen Hypothesis – how the first eukaryotic was formed? Symbiont cell - Bacteria producing H 2 ; lipid gene transfer; precursor of mitochondrion Host cell - Archaea dependent on H 2 for electron source to make energy Symbiont cell – photosynthetic cyanobacterial-like ancestor
18. Internal nodes denote common ancestor Branches show order of descent and node ancestry. Branch length reprepresents number of nucleotide changes Nodes at the tips denote species/strains Fig. 14.14d
siRNA in plants can travel through plasmodesmata throughout the plant. siRNA in C. elegans can be passed on through several generations. siRNA in mammals is localized.