WEEK 2 (part I): BACTERIAL CELL STRUCTURE, CLASSIFICATION, AND MORPHOLOGY Flashcards
▪ Unicellular organisms
▪ Lack a nuclear membrane and nucleus
▪ Classified as prokaryotes
Bacteria
▪ Eukaryotic
▪ Exist as unicellular or multicellular
▪ Categorized by their locomotive structures
Parasites
▪ Eukaryotic
▪ Exist as unicellular (yeast) or multicellular (mycelial forms)
Fungi
▪ DNA or RNA core surrounded by a protein coat
▪ Acellular
▪ Obligate intracellular parasites
Viruses
Is the academic discipline of defining groups of organisms on the basis of shared common characteristics and giving names to those groups.
Taxonomy
three interrelated categories of Taxonomy
Classification, Nomenclature and Identification
Method to categorize organisms into groups such as genus or specie.
Classification
➢ Genetic makeup of the organism
➢ E.g. base sequencing of DNA or RNA
Genotype
➢ Readily observable physical and functional
features expressed by the organisms genotype
➢ E.g. Macroscopic and microscopic characteristics
Phenotype
Binomial system. Every organism is assigned a genus and a species name.
Nomenclature
It is always written with the capital
letter while species designation is never
capitalized. Both are printed in italics or
underlined when written in script.
Genus
Neisseria gonorrhoea
Gonococcus
Streptococcus pneumoniae
Pneumococcus
Mycobacterium tuberculosis
Tubercle bacilli
Salmonella typhosa
Typhoid bacilli
Klebsiella pneumoniae
Friedlander’s bacillus
▪ The process by which the microorganisms key features are delineated so that it can be assigned a genus and a species name.
➢ Genotyping
➢ Phenotyping
Identification
nucleus: membrane bound
chromosomal DNA: in the nucleus
organelles: present
cell wall: polysaccharides
pili and fimbriae: absent
Eukaryote
nucleus: no nuclear membrane
chromosomal DNA: in the nucleoid
organelles: absent
cell wall: peptidoglycan
pili and fimbriae: present
Prokaryote
single circular chromosome attached to a
mesosome
nuclear Area (nucleoid)
➢ small circular, dsDNA molecule
➢ antibiotic resistance
plasmid
➢ site of protein synthesis
➢ consists of RNA and protein
ribosomes
represents reserves of polyphosphates used in the
synthesis of ATP.
metachromatic granules
consist of glycogen and starch granules
polysaccharide granules
highly refractile resting cells that are highly
durable and dehydrated with thick walls
Spores/Endospores
A phospholipid bilayer with embedded
proteins that envelop the cytoplasm
Plasma Membrane (Cell membrane)