Test 1 Flashcards
basic taxonomy classification
Life, Domain, Kingdom, Phylum, Class, Order, Family, Genus Species
all living organisms are classified as either
prokaryotes or eukaryotes
prokaryotes vs eukaryotes: unicellular or multicellular?
prokaryotes: uni
eukaryotes: multi
prokaryotes vs eukaryotes: membrane bound organelles?
prokaryotes: no
eukaryotes: yes
prokaryotes vs eukaryotes: DNA
prokaryotes: single circle in the cytoplasm eukaryotes: chromosomal DNA
prokaryotes vs eukaryotes: cell division
prokaryotes: binary fission
eukaryotes: mitosis
Binary fission
Asexual reproduction of bacteria. DNA attaches to the plasma membrane cell wall stretches so cell volume enlarges DNA replicates Cell wall and plasma membrane begin to pinch inward at the center of the cell DNA pulls apart Cytoplasm is equally distributed cell wall and plasma membrane complete growth inward at the center finally divides into two identical daughter cells
prokaryotes vs eukaryotes: domains
prokaryotic domains: bacteria, archaea
eukaryotic domains: protista, animalia, plantae, fungi
Nitrogen fixation
Certain bacteria and cyanobacteria can transform atmospheric nitrogen into other nitrogenous compounds that can be used as nutrients by plants
prokaryotes vs eukaryotes: any other metabolic functions?
prokaryotes: nitrogen fixation, photosynthesis
eukaryotes: n/a
Kingdom within Domain Archaea
Archaebacteria
evolutionary theory of archaebacteria
it is thought that archaebacteria of domain archaea may be the oldest forms of life on earth, and domains bacteria and eukarya probably diverged from archaebacteria independently. Archaea were initially classified as bacteria but eventually were classified into their own group because they had their own distinct and unique properties from both bacteria and eukaryotes
what make archaebacteria distinct?
- evolutionary theory about them
- there are no known pathogens
- they are extremophiles
- they use organic compounds (sugar, ammonia, hydrogen gas) or sunlight for energy
what make archaebacteria distinct?
- evolutionary theory about them
- there are no known pathogens
- they are extremophiles (since they are survivors of ancient lines that have persisted in habitats that are like habitats from when bacteria first evolved. These habitats are extremely acidic, hot or salty)
- they are autotrophic
Autotrophs
organisms that use organic compounds (sugar, ammonia, hydrogen gas) or sunlight for energy. Most autotrophs use photosynthesis to derive these organic compounds.
Extremophiles
organisms that are found in extreme conditions (i.e. hot springs, salt lakes, oceans, marsh lands, human colon, oral cavity, skin)
kingdom within domain bacteria
kingdom bacteria
what makes bacteria distinct?
- the most abundant, diverse and widely distributed organism
- they live in symbiotic relationships with plants and animals
- they can live in soil, water, acidic hot springs and in radioactive waste
- they are characterized based on morphology, metabolism and biochemistry
- Most divide by binary fission, but some do genetic recombination by conjugation
what makes bacteria distinct?
- the most abundant, diverse and widely distributed organism
- they live in symbiotic relationships with plants and animals
- they can live in soil, water, acidic hot springs and in radioactive waste
- they are characterized based on morphology, metabolism and biochemistry
- Most divide by binary fission, but some do genetic recombination by conjugation
- some are pathogenic (can cause infectious diseases)
Conjugation
some bacteria have genetic recombination via conjugation, in which all or part of the genetic material of one bacterium is transferred to another bacterium and a new set of genes is assembled
differences in morphology of bacteria
3 basic shapes: bacillus (rods), coccus (circles), spirillum (spirals)
differences in metabolism of bacteria
heterotrophic (some are decomposers- a type of heterotroph) or autotrophic
decomposers
heterotrophic organisms that feed on dead organic matter and release nutrients locked in dead tissue- which is vital for recycling nutrients
decomposers
heterotrophic organisms that feed on dead organic matter and release nutrients locked in dead tissue- which is vital for recycling nutrients
difference in photosynthesis between bacteria and eukaryotes
photosynthesis in bacteria is diff from photosynthesis in eukaryotes because they don’t necessarily produce oxygen
where is bacteria found in humans?
the gut and skin
how can pathogenic bacteria be treated?
with antibiotics
antibiotic sensitivity
how susceptible a bacteria is to a specific antibiotic
Bacterial resistance-
the ability to resist an antibiotic that was once effective against it
how to determine if an antibiotic is effective against a certain bacteria
with a sensitivity plate: o An agar plate is inoculated (grown) with bacteria and paper discs are soaked in different antibiotics and placed on the agar surface. After 24 hrs, the plate is examined and if an antibiotic disk is effective against the bacteria, it will destroy the bacteria surrounding it, resulting in a clear area around the disk (a.k.a. the zone of inhibition/ZOI.) Then, by comparing the diameters of the ZOIs of different antibiotic disks on the same agar disks we can determine the most effective antibiotic. If it is ineffective, there will be no ZOI.
bacteria colony
when you grow bacteria, a visible growth of many identical bacterial cells from a single cell on the agar surface.
how to grow bacteria in a lab
in either a tube of broth (liquid nutrient) or on the surface of a plate of broth mixed with agar (gelatinous polysaccharide)
Gram positive bacteria
thick peptidoglycan cell wall, no outer envelope, retains purple die, more susceptible to antibiotics (easily killed with antibiotics)
Gram negative bacteria
thin peptidoglycan cell wall, cell wall is surrounded by a rich outer envelope, does not retain purple dye, less susceptible to antibiotics (harder to kill with antibiotics)
What is the gram stain procedure used for?
a procedure used to classify bacteria by susceptibility to an antibiotic:
PURPLE: gram positive/easy to kill VS PINK: gram negative/hard to kill
what is the gram stain procedure itself?
crystal violet and iodine are applied to both the gram positive and gram negative bacteria. The thick peptidoglycan cell wall of the gram positive bacteria retains the purple dye, while the gram negative bacteria’s thin peptidoglycan cell wall does not. Alcohol is used to remove the stain from the surface of the gram negative cell walls that do not bind the stain. Safranin is then used to counterstain the gram negative cell with a red color so they’ll be more easily distinguishable from the gram positive cells.
example of phylum of kingdom bacteria
cyanobacteria
what is distinct about cyanobacteria’s cells and structure?
- cyanobacteria are multi-cellular (even though it is a prokaryote)
- often surrounded by a jellylike sheath
are cyanobacteria autotrophs or heterotrophs
autotrophs; they are photosynthetic
what is distinct about cyanobacteria’s pigmentation?
pigment: chlorophyll a: blue-green or brown-green
how do cyanobacteria reproduce?
binary fission
are algae and cyanobacteria related?
similar to algae but NOT related because cyanobacteria are prokaryotes while algae are eukaryotes
what is the norm of how cyanobacteria live
most are free living and some live symbiotically
symbiotic relationship
a relationship between two organisms where at least one organism benefits
(i.e.) Parasitic relationship a type of symbiotic relationship in which one organism benefits and the other organism is harmed