L12 Bacteria & Archaea pt 1 Flashcards
what are prokaryotes?
simple, ancient, successful, all-over organisms that do not have a nucleus nor membrane bound organelles
what is included in the internal structure of a bacterial cell?
-cytoplasm
-specialized membranes
-genome organization (nucleoid region with one circular chromosome)
-plasmids
-ribosomes
what is included in the external structure of a bacterial cell?
-plasma membrane
-cell well (peptidoglycan)
-flagella
-capsule
-pili
how is bacterial diversity generated?
-mutations
-recombination through vertical gene transfer (mitosis)
-horizontal gene transfer
what are the metabolic roles of the prokaryotes?
regulating biogeochemical nutrient cycles (carbon, nitrogen, oxygen, sulfur) and waste cycles
how are prokaryotes classified?
through 2 domains based on structure, physiology, and biochemistry: archaea and bacteria
describe the size of prokaryotes and why it is that way
smaller than avrg eukaryotic protists, plant, fungal, and animal cell
-surface area to volume ratio (b/c of diffusion limits) causes it to remain in the 2nm to 2um range
prokaryotes are ____________ simple, but ____________ diverse. Why?
morphologically; metabolically
-have basic shapes
-have complex role in chemical cycles + help recycle nutrients on earth
describe bacteria in 3 ways
unicellular, simple shapes, very small in size (2nm to 2um)
what are the simples shapes of bacteria
coccus (spherical), bacillus (rod), and spirillus (helix)
name the types of horizontal gene transfer
conjugation, transformation, transduction (viruses)
describe the process of conjugation; what can it be used for
plasmids (DNA) transfer between cells through thinly synthesized cytoplasm strands (pili)
-spreading novel genes in bacterial populations (i.e. antibiotic resistance)
-plasmids used for GMOs/ genetic eng
describe the process of transformation
DNA is released into the environment by a dead donor, which is accepted by a recipient cell
describe the process of transduction
a donor is infected with a virus, which transfers genes (e.g. its own + additional bacterial DNA with them) to a recipient cell
-often used in research labs
photosynthesis is ________, cellular respiration is ___________
oxygenic; aerobic
carbon cycling is linked to __________. what are six types of carbon cycling?
other cycles (e.g. oxygen cycling)
-involving oxygenic photosynthesis and aerobic cellular respiration
-anoxygenic photosynthesis
-chemoautotropy
-fermentation
-anaerobic respiration
what organism led to the oxygenic photosynthesis evolution
cyanobacteria
explain what an autotroph is and what groups it is divided into
self-feeders + producers
-divided into photoautotroph and chemoautotroph
explain what a heterotroph is and what groups it is divided into
“other feeders”, consumers / decomposers
- divided into photoheterotroph and chemoheterotroph
what is a photoautotroph and what are some examples
uses light as energy source, CO2 as carbon source and includes photosynthetic prokaryotes like cyanobacteria; plants; certain protists like algae
what is a chemoautotroph and what are some examples
uses inorganic chemicals as energy source, CO2 as carbon source, and includes certain prokaryotes (e.g. sulfolobus)
what is a photoheterotroph and what are some examples
uses light as energy source, organic compounds as carbon source, and includes certain prokaryotes (e.g. rhodobacter, chloroflexus)
what is a chemoheterotroph and what are some examples
uses organic compounds as energy source and carbon source, and includes most prokaryotes (e.g. clostridium); fungi; animals; some plants
what is a microbial mat? describe the layers of this
a multi-layered sheet of prokaryotes that includes mostly bacteria, but also archaea
-surface layers use oxygenic photosynthesis and aerobic cellular respiration
-deeper layers use anoxygenic photosynthesis and anaerobic respiration and fermentation
anoxygenic photosynthesis; what pigment is used; structure/flow; e- donors?
photosynthesis in which O2 is not produced
-sunlight absorbed uses bacteriochlorophyll pigment
-has one photosystem and ETC to only make ATP
-electron donors are H2S, H2, Fe+2 (ferrous iron) and AsO3 -3 (arsenite)
anaerobic respiration (fermentation); e- acceptors?
Form of cellular respiration in which some decomposers get the energy they need through the breakdown of glucose (or other nutrients) in the absence of oxygen
-oxidants are reduced using electron acceptors like Fe +3 (ferric iron), sulfate, nitrous oxide, manganese, arsenate
what is the role of bacteria in the nitrogen cycle
Bacteria convert (fix) atmospheric nitrogen into ammonia and ammonium, and then into nitrate (through nitrification) so it can be used by plants.
sulfur cycle; what is the role H2S
Cyclic movement of sulfur in various chemical forms from the environment to organisms and then back to the environment.
-H2S quickly oxidized to sulfur when O2 is present
-H2S is toxic to eukaryotic organisms
