Lec 1&2 Flashcards
what is taxonomy
the science of classification, bacteria commonly classified using binomial nomenclature
are fungi plants
no, they do not share similarities with plants
what is the 3 domain classification
bacteria, archaea, eukarya
what is a dichotomous key
paired statements with either-or choices
what is the ‘shrub’ of life
where species can transfer genes to other species, lateral gene transfer, replaces the concept of 1 universal common ancestor, some bacteria gave rise to chloroplasts while other bacteria gave rise to mitochondria, mitochondria and nucleus have seperate DNA the former of which is more closely related to bacteria while the latter DNA is more closely related to archaea
what are the approaches to identifying bacteria (6)
1-microscopy (light or electron), 2-morphology, staining (gram or spore), biochemical tests (drop bacteria in hydrogen peroxide if bubbles form the bacteria produces catalase as catalase breaks down hydrogen peroxide), growth conditions (some growth media such as selective media encourages the growth of some microbes while suppressing the growth of others, differential media, enrichment media which encourages growth of some low abundance microbes but doesn’t inhibit any), molecular biology techniques (genetic homology, MALDI-ToF mass spec, immunological reactions, phage typing)
what are the differences between prokaryotes and eukaryotes
pro-genetic material is circular and not membrane enclosed, euk-genetic material is paired and membrane enclosed, pro-no membrane-enclosed organelles, euk-have endoplasmic reticulum golgi apparatus lysosomes etc, pro-DNA not associated with histones euk-DNA packaged and tightly folded around histones, pro-most cell walls contain polysaccharide peptidoglycan, euk-cell walls composed of chitin/cellulose, pro-divide by binnary fission only asexual reproduction, euk-divide by mitosis/meiosis sexual and asexual reproduction
3 basic bacteria shapes
baccilus (rod), coccus (sphere), spiral
what gives bacteria their shape
cell wall, technically all bacteria are spherical inside
bacterial arrangements
diplobacilli (pairs), streptobacilli (chains), tetrad (division in 2 planes), sarcinae (division in 3 planes), staphlococci (division in multiple planes 3+, like a bunch of grapes)
prokaryotic cell wall
external, maintains shape, prevents rupturing by osmosis, anchorage for flagella, often porous (why antibiotics pass through easily), contribute to virulence, composition varies but most important component is peptidoglycan which is thick in gram neg bacteria (up to 40 layers, hold stain) and thin in gram pos bacteria (1-2 layers),
what is the outer membrane (pro)
external, the phospholipid bilayer external to cell wall, mostly seen in gram neg bacteria, can be protective, contains lipopolysaccharide
what is the periplasmic space (pro)
between cell membrane and cell wall, composed of peptidoglycan proteins and metabolites, primarily seen in gram negs but is part of cell wall in gram pos, site of metabolism
what is the cell membrane (pro)
external, fluid-mosaic model - phospholipid bilayer and proteins, regulates entry/exit of materials, synthesizes cell wall components and assists with DNA replication, protein secretion and respiration and captures ATP
what is the nucleoid or nuclear region (pro)
internal, single large circular chromosome, no nuclear envelope/histones, plasmids present (which are usually circular, replicate independently, can be gained/lost/transferred)
