Chapter 22: Prokaryotes

microbial mat

multilayered sheet of prokaryotes composed of mainly bacteria but also includes archaea; represent the earliest form of prokaryotic life on Earth

stromatolites

mats of cyanobacterial cells that trap mineral deposits

photosynthesize

what is the superpower of cyanobacteria?

increasing oxygen in early Earth atmosphere 

what was the key role of cyanobacteria in Earth’s early atmosphere?

caused the formation of the ozone layer which can support human life on Earth

why was cyanobacteria increasing oxygen in the atmosphere so important?

billion

how many years were prokaryote abundant for before eukaryotes?

less than 10%

what percentage of prokaryotic species are known?

many are extremophiles or require unknown conditions to live

why do we only know such a small percentage of prokaryotic species?

bacteria and archaea

what two domains are encompassed within prokaryotes?

plasma membrane, cell wall, and gene expression

what are the three big differences between bacteria and archaea?

ester linkage of lipids to glycerol and unbranched lipids

what is the structure of the bacterial plasma membrane?

ether linkage of lipids to glycerol and branched or ringed hydrocarbons

what is the structure of the Archaean plasma membrane?

have peptidoglycan

does the bacterial cell wall have or lack peptidoglycan?

lack peptidoglycan

does the Archaean cell wall have or lack peptidoglycan?

archaeal transcription and translation are more similar to eukaryotes (like having introns)

what is the difference between bacterial and archaeal gene expression?

cocci, bacilli and spirilli 

what are the three structures of prokaryotes? 

unicellularity, cell size, chromosome structure, cell division, genetic recombination, internal compartmentalization, flagella, metabolic diversity, internal membrane, and pili

what are the shared prokaryotic characteristics?

single-celled

are most prokaryotes single or multi celled?

1μm

what is the average diameter of a prokaryote?

single circle of double-stranded DNA in the cell’s nucleoid region, containing plasmids

what is the structure and location of prokaryotic DNA? 

plasmid

small circle of DNA that can be transferred or inserted

binary fission

how to prokaryotes perform cell division?

horizontal gene transfer

how does genetic recombination occur within prokaryotes?

horizontal gene transfer

transfer of DNA between unrelated species 

no membrane-bound organelles, infoldings of plasma membrane, ribosomes are smaller and have different proteins

what are the internal compartmentalization characteristics of prokaryotes?

oxygenic and anoxygenic photosynthesis or chemolithotrophic

how do prokaryotes metabolize?

respiration and photosynthesis

what is the function of the “internal membrane” of prokaryotes?

pili

short, hairlike structures found in gram- bacteria that aid in attachment and conjugation

flagella

slender, rigid helical structures composed of proteins that are involved in locomotion

spins like a propeller

how does a prokaryotic flagella move?

like a wave

how does eukaryotic flagella move?

photosynthetic, movement, aggregations it forms, formation of spores, and is it pathogentic to humans

what are the observable characteristics used in prokaryote classification?

unicellular, colony-forming or filamentous

what are the three different aggregations a prokaryote can form?

maintains shapes and withstands hypotonic environments

what is the function of peptidoglycan in the cell wall of bacteria?

thicker peptidoglycan and stain a blue/purple color

characteristics of gram+ bacteria

less peptidoglycan and do not retain purple colored dye but retain the counterstain and look pink/red; second outer membrane leading to antibiotic resistance

characteristics of gram- bacteria

structure of the cell wall

what is the gram stain based on?

used to determine best antibiotic to use for treatment

what is the clinical purpose of the gram stain test?

endospores

thick walls around a prokaryote’s genome and small portion of the cytoplasm that are highly resistant to harsh conditions, and can germinate when conditions are better/correct

tetanus, botulism, and anthrax

what are some examples of endospores?

disease-causing organisms

where are endospores commonly found?

no, they perform horizontal gene transfer

do prokaryotes reproduce sexually?

transformation, transduction, and conjugation

what are the three types of gene transfer prokaryotes use?

transformation

picking up genetic material from the environment; plasma membrane becomes porous

transduction

infection via bacteriophage that changes genetic material

conjugation

plasmid travels via conjugation tube to another bacterial cell; cell-to-cell contact 

autotrophs and heterotrophs

what are the two broad categories of how prokaryotic metabolism takes place?

autotrophs

obtain carbon from inorganic CO2

heterotrophs

obtain carbon from organic CO2

photoautotrophs and chemolithoautotrophs 

what are the two types of autotrophs?

photoautotrophs

obtain energy from the sun

chemolithoautotrophs

energy from oxidizing inorganic substances

photoheterotrophs and chemoheterotrophs

what are the two types of heterotrophs?

photoheterotrophs

light as an energy source but obtain organic carbon make by other organisms

chemoheterotrophs

both carbon atoms and energy from organic molecules (ex: humans)

nitrogen

what is an important element in nutrient cycling and is within all cells?

20%

what percentage of children were killed by infectious disease before age 5 in the 20th century?

epidemic

disease in large numbers of individuals in one location

pandemic

widespread epidemic (e.g. global)

endemic disease

disease that is constantly present (often low numbers) in a population

vector

disease carrier

bubonic plague 

disease that killed 200,000 people that was vectored by fleas from rats; further enhanced by lack of antibiotics and good sanitation practices 

emerging disease

newly appearing or newly spreading disease in human populations

zoonotic disease

disease that primarily infects non-human animals, but can be transmitted to humans (ex: brucellosis)

tuberculosis, dental caries, and lyme disease

what are three human diseases caused by prokaryotes?

tuberculosis

respiratory disease that is easily transmitted through the air and has multidrug-resistant strains

dental caries

plaque consists of bacterial biofilms, streptococcus sobrinus ferments the sugar into lactic acid, degenerating the tooth enamel

lyme disease

often transmitted by ticks, if it develops into a chronic infection, it may lead to serious symptoms; can be difficult to diagnose

prisons due to confinement and lack of medical care after release

what is a population that is vulnerable to TB and why?

gonorrhea, chalmydia, and syphilis

what are three STDs caused by prokaryotes?

antibiotic resistance

mutations spontaneously arise in bacteria and the mutations can spread rapidly in a population and can be transferred between cells

1/200

how many bacterial cells are estimated to have some sort of mutation?

20 minutes

how long does it take bacterial populations to double under good conditions?

bacteria are inefficient at checking their DNA during reproduction

why do bacterial cells have so many mutations?

decomposers, photosynthesizers, and nitrogen fixers

what are the three categories of beneficial prokaryotes?

decomposers

prokaryotes that release a dead organisms’ atoms into the environment 

photosynthesizers

prokaryotes that can fic carbon into sugars

nitrogen fixers

prokaryotes that reduce N2 to NH3 (ammonia)

cheese, bread, and yogurt

what are three common food products that are produced using prokaryotes?

genetic engineering, integrated pest management, and bioremediation

what are three beneficial uses of bacteria?

genetic engineering

biofactories that produce various chemicals, including insulin and antibiotics

integrated pest management

using bacteria to help fight insect pests

bioremediation

using bacteria to help remove pollutants from air, water and soil; biostimulation

biostimulation

adding nutrients to encourage the growth of naturally occurring microbes; ex: fixing oil spills