Microbiology Flashcards
Gram staining
Used to differentiate two large groups of bacteria based on their different cell wall components
Eubacteria
- kill thousands each year
- can serve as antibiotic producers and food digesters in stomach
- reproduce asexually
- 3 shapes
Archaebacteria
- only live without oxygen
- microscopic beings
- reproduce sexually or asexually
- 3 shapes
- anceitn
- can livein various conditions of temperatures, acidity levels, salinity, and air altitude
Gram positive
-bacteria remains purple in color
Traits: cytoplasm lipid membrane, thick peptidoglycan layer (plasmic polymer), various acids, teichoic acids
Negative bacteria
-turns red or pink in color
Traits: cell membrane, thin peptidoglycan layer, outer membrane (lipopolysaccharides and phospholipids), surface layer, porins (pores) in outer membrane
Spirilla
- spiral shaped
- can be vibrio (short helix), spirillum (long helix), or spirochete (long, flexible helix)
Bacilli
Rod-shaped
Cocci
Spherical shape
Flagella
Thin, whip-like structure that provides movement in order to pass through liquid environments
Bacterial gliding
Movement across surfaces; changes the buoyancy to produce vertical movement
Appendages (pili)
Can cover the surface of bacterium like tiny hairs, bind receptors for movement
Chemotaxis
Move in the direction of a chemical stimulant (nutrient)
Bacteria can move toward each other through…
Attraction, forming a biofilm
Bacteria can obtain energy from…
- light (phototrophic)
- mineral sources
- absorbing hydrogen and electrons through organic matter
Chemoheterotroph
Organisms that don’t undergo carbon fixation, obtaining energy from organic and inorganic energy sources
Photoheterotrophs
Organisms that use light for energy but can’t use CO2 as only carbon source
Photoautotroph
Organism that uses sunlight for energy to convert inorganic to organic materials to use for respiration
Chemoautotroph
Organisms that obtain energy from chemical reactions and acquire organic compounds from CO2
Obligate anaerobes
Microscopic anaerobes that perish under normal atmospheric amounts of oxygen
Facultative anaerobes
An organism that produces ATP by aerobic respiration if oxygen is present of by fermentation
Obligate aerobes
An organism that requires oxygen to grow and uses cellular respiration
Photosynthetic autotrophs
- Use sun’s energy to make food for themselves
- can be found in streams, moist areas
Heterotrophic
- can make own food
- live almost anywhere
- use organic molecules as food
- some are parasites
Chemosynthetic autotrophs
- don’t need sunlight
- get energy by breaking down and releasing energy of inorganic compounds
- convert atmospheric nitrogen into organic nitrogen
Recombination
rearrangement of genetic material, especially by crossing over in chromosomes or by the artificial joining of segments of DNA from different organisms
recombination allows for new genetic types and variations
Bacteral conjugation
the direct transfer of DNA from one bacterial body to another bacterial cell- transferred through a structure called a pillus
Bacterial transformation
direct uptake, incorporation, and expression of exogenous genetic material from its surroundings
(processes where foreign DNA is introduced into the cell)
Bacterial Transduction
uses bacteria viruses to transfer DNA from one cell to another (DOES NOT require direct contact)
Viruses
- non-living
- no metabolism
- made from nucleic acid and proteins
- need living host to reproduce
What is a virus
- infective agent that typically consists of a nucleic acid molecule in a protein coat
- too small to be seen by light microscopy
- able to multiply only within the living cells of the host
common structures of viruses
- inner nucleic acid core (genetic material)
- some have DNA, some have RNA
- contains outer protein cut called a capsid
- outer envelope (membrane) that is derived from a cell membrane)
bacteriophages
- capable of infecting bacteria
- E. Coli can be infected by these
- viruses use ‘legs’ to attach to the surface of the cell and inject DNA
- virus multiplies inside of E. Coli until it bursts
Adenovirus
- Cause upper respiratory tract infections
- enter cell through phagocytosishttp://education-portal.com/cimages/multimages/16/phagocytosis-diagram.jpg
- replicate in nucleus of cell rather than in cytoplasm
retrovirus
- genetic blueprint in RNA
- cause certain cancers and slow virus infections (AIDS)
- use reverse transcriptase: RNA-DNA-RNA-protein
- lessens chance of mutation
- genetic material incorporated into genome of infected cell
Lytic Cycle
- first of two cycles of viral reproduction
- destroys infected cell’s membrane and the actual cell
- phage attaches to cell, injects DNA
- synthesis of mRNA begins in the cell
- phage DNA begins to replicate, host DNA deteriorates
- tail fibers and DNA filled heads form
- early phage particles assembled
- host bacteria releases 300 new phages
lysogenic cycle
- results: only a few virions being released
- advantages: virus can survive, replicated inside a host for many years
benefits of bacteria
- bacteria in intestines make acid environment prevent bad bacteria from growing
- bacterial fermentation preserves food
- bacteria decomposes and releases carbon and nitrogen
- exposure to baceria strengthens immune system
- helps break down fiber, asists in the digestive system
- provides us w/ biotin and vitamin k from digestive tract
disadvantages of bacteria
- diseases and infections
- microorganisms- some give off toxins, reproduce & overwhelm immune system
pathogen
biological agent that causes illness or disease in its host
disinfectants
- harm prokaryotic and eukaryotic cells
- used on abiotic structures
- most aren’t used in bodies, some are used topically
antibiotics
- prokaryotic bacteria
- bacteria mutates to resist
- side effects
- kill or stop growth of certain bacteria
penicillin
interferes with peptidoglycan and causes cell to explode
tetracycline
stops protein synthesis; attaches to ribosome and blocks key RNA interaction
macrolide
blocks bacterial ribosomes from making more proteins
what do we use antibiotics to treat
- infections caused by bacteria
- target microorganisms
ways they work:
- bactericidal- kills the bacteria
- bacteriostatik- stops bacteria from spreading
beneficial viruses
- viruses can fight for our bodies and protect from invading microbes
- benign viruses can transport vaccines into bloodstream and cells
harmful viruses
- many serious virus diseases come from viral infections
- some viruses can create non-infectious conditions in a body, including inflammation and cancer
- viruses infect specific tissues and are able to create disturbances in an organ, which leads to diseases
spread of viruses
- viruses attach to surfaces or can spread through the air
- invade through mouth, nose, cracks in skin
- once inside, attach to host cell and spread their genetic material to create new viruses, which then break free of the cell and spread to other cells
- leave the body and infect other people
vaccines
-use to immunize populations
inactivated vaccines
- virus is mass-produced
- this ‘kills’ the virus and when it is put into the body it cannot fight back against the immune system
attenuated vaccines
- these vaccines are mutated to not be able to replicate well within human cells
- cannot sustain themselves long enough to cause illness
subunit vaccines
- genetically made to create antigens in the virus
- mirror proteins in viruses without the ability to infect
