Microbiology test 2

Bacteria

Most well-known prokaryotes, divided into many phyla

Proteobacteria

Gram-negative bacteria, largest phylum, includes E. coli and Salmonella

Gram-positive bacteria

Distinguished by purple gram staining, large peptidoglycan component

Metabolic diversity

Variety in energy and carbon sources

Environmental diversity

Varied by temperature, pH, salinity, pressure, and oxygen levels

Quorum sensing

Bacteria communication to sense population and environment

Specialization

Differentiation in cells like spore formation for survival

Cyanobacteria

Oxygenic phototrophs, form filaments, have heterocysts

Spirochetes

Pathogens causing syphilis and Lyme disease

Chlamydia

Respiratory and sexually transmitted intracellular pathogens

Microbial Eukarya

Includes protists, fungi, and slime molds

Protists

Algae and protozoa with chloroplasts, simple nutritional needs

Fungi

Non-photosynthetic, crucial for nutrient recycling

Viruses

Parasitic, require host for replication, contain DNA or RNA

Prions

Misfolded proteins causing diseases like mad cow disease

Beneficial microorganisms

Essential for recycling, food production, and biotechnology

Pathogens

Microorganisms causing or capable of causing disease

Gram staining

Distinguishes bacteria based on cell wall composition

Peptidoglycan

Polymer in cell walls composed of NAG and NAM

Cell envelope

Structural layer of bacteria including cell wall and membrane

Lipopolysaccharide

Major component of Gram-negative outer membrane

Bacilli

Rod-shaped bacteria

Cocci

Spherical bacteria

Spiral bacteria

Bacteria with a spiral shape

Binomial nomenclature

Genus and species naming system for all living organisms

Lipid

Non-typical phospholipid in the outer membrane

Core polysaccharide

Attached to NAG in the outer membrane

Fatty acid chains

Medium- and long-chain FA (C6, C12, C14, C16, C18)

Outer Membrane

Composed of LPS layer and inner phospholipid bilayer with embedded proteins

Lipoproteins

Proteins with a lipid component anchoring the outer membrane to peptidoglycan

Structural rigidity

Function of outer membrane providing stability

Endotoxin

Toxic component often referred to as Lipid A in the outer membrane

Biofilms

Formed by polysaccharides aiding in attachment to surfaces

Fimbriae

Filamentous structures aiding in attachment to surfaces

Pili

Longer than fimbriae, aiding in attachment, conjugation, and invasion

Type IV Pili

Special class aiding in attachment and twitching motility

Subcellular storage compartments

Stores nutrients for survival off excess; carbon, sulfur, magnetic, polyphosphate

Gas vesicles

Found in planktonic prokaryotes for buoyancy and response to cues

Endospores

Dormant phase structures formed under unfavorable conditions

Spore Structure

Consists of exosporium, spore coat, cortex, and core wall

Appendages

Include pili and flagella for attachment and motility

Motility

Three types: swimming, gliding, twitching, responding to environmental cues

Bacterial Flagella

Long, thin appendages for movement and attachment

Flagellar Motor

Anchored in cytoplasmic membrane and cell wall, with different rings in Gram-negative and Gram-positive bacteria

Flagellar Speed

Rotates up to 300 rotations/sec, driven by pmf

Swim Patterns

Differ based on flagellum location and arrangement

Gliding Motility

Movement without flagella, slower and constant

Microbial Taxes

Responses to physical or chemical stimuli, like chemotaxis and phototaxis

Binary Fission

Bacterial cell division process resulting in two identical daughter cells

Generation time

Time taken for a population to double in number through binary fission/Time for one cell to divide into two identical cells

Balanced Growth

Cellular constituents increase proportionately during generation time

Exponential Growth

Cell number doubles over a constant time interval

Logarithmic Growth

Cell number plotted on a semilogarithmic scale against time

Arithmetic Growth

Cell number plotted against time on a linear graph

Stationary Phase

Phase where no net increase or decrease in cell population occurs

Death Phase

Stage where more cells die than divide, net decrease in population

Quorum Sensing

Bacteria produce virulence factors based on cell concentration

Chemostat

Device to maintain constant cell population by replenishing nutrients

Viable Counts

Counting live cells on a nutrient agar plate to estimate density

Turbidimetric Methods

Measure turbidity to estimate cell density, quick and inexpensive

Gene

Functional unit of genetic information

DNA

Genetic material consisting of deoxyribonucleic acid

RNA

Ribonucleic acid; expressed from DNA

Double Helix Structure

Formed by complementary strands binding in a double helix

Nucleic Acid

Consists of nucleotides with sugar, base, and phosphate

Polynucleotides

Formed by phosphodiester bond formation between nucleotides

mRNA

Messenger RNA carrying genetic information from DNA to ribosome

tRNA

Transfers RNA converting mRNA information into amino acids

rRNA

Ribosomal RNA, catalytic and structural components of ribosome

Replication

Duplication of DNA double helix

Transcription

Transfer of information from DNA to mRNA

Translation

Synthesis of protein from mRNA, tRNA, and ribosome

Whooping cough

The causation agent is the gram-negative cocci bacterium Bordetella pertussis, an infection of the respiratory tract that results in inflammation of the lungs and inability to clear the organism

Polar flagellation

flagellum at one or both ends of cell

Lophotrichous

numerous filaments as a tuft

Amphitrichous

single tuft at opposite ends

peritrichous

flagellum all over the cell

eukarya types

protist, protazoans, fungi, viruse, prions

Aerotaxis

response to oxygen levels

Osmotaxis

response to ionic strength

Protist

Include algae and protozoa, have chloroplast

protozoans

Lack cell wall; majority are motile ( flagellum/cilia)