Bacteria and Archaea

Chapter 27

Prokaryotes

the first organisms to inhabit the Earth

most are unicellular, some species form colonies

they have a variety of shapes: spheres(cocci), rods(bacilli), and spirals

cell wall

the ________ maintains cell shape, protects the cell, and prevents it from bursting in a hypotonic solution

cellulose or chitin

Eukaryote cell walls are made up of ___________

peptidoglycan

a network of sugar polymers cross-linked by polypeptides found in bacteria cell walls

Archea

_____ contain polysaccharides and proteins but lack peptidoglycan

bacteria

Cell walls contain peptidoglycan (sugar-polypeptide network

gram stain

classifies bacteria by cell wall composition

gram-positive

purple

bacteria have simpler cell walls with a large(thick) amount of peptidoglycan

gram-negative

pink

bacteria have less (thin)peptidoglycan and an outer membrane that contains lipopolysaccharides

antibiotics

many _______ target peptidoglycan and damage bacterial cell walls

particularly susceptible

Gram-positive bacteria are __________ to this type of antibiotics that target peptidoglycan and damage bacterial cell walls because of their membrane

capsule

a sticky outer layer of a polysaccharide or protein that is present in some prokaryotes

capsules purpose

the ___________ is to allow adherence to the substrate and add protection against pathogenic bacteria from the host immune system

metabolically inactive endospores

many prokaryotes form ___________ which can remain viable in harsh conditions for centuries

endospores

Dormant, resistant structures that allow survival in extreme conditions.

cocci

spheres

bacilli

rods

fimbriae

hairlike appendages in prokaryotes that allow them to stick to their substrate or other individuals in a colony

pili (sex pili)

longer than fimbriae and allow prokaryotes to exchange DNA

taxis

prokaryotes that exhibit the ability to move towards or away from a stimulus

chemotaxis

movement towards or away from a chemical stimulus

flagella

most common structures used by prokaryotes for movement

can be scattered about the surface or concentrated at one or both ends of the cell

structure, mechanism of propulsion, and molecular composition

the flagella of prokaryotes and eukaryotes differ in _____________

lack complex compartmentalization

prokaryotic cells usually _______

less DNA

the prokaryotic genome has ________ than the eukaryotic genome

circular chromosome

most of the genome consists of a ___________

nucleoid

the prokaryotic genome circular chromosome is located in the ________ region with no surrounding membrane

plasmids

smaller rings of independently replicating DNA in prokaryotes

genetic variation

prokaryotes have considerable __________

rapid reproduction

mutation

genetic recombination

three factors that contribute to prokaryotic genetic variation

asexually

prokaryotes reproduce ________

offsprings are generally identical

binary fission

Escherichia coli cells reproduce using ____________

short and population are long

mutation rates are low, but mutations accumulate rapidly because generation times are _______________-

transformation

transduction

conjugation

prokaryotic DNA from different individuals can be brought together by ________________________

genetic recombination

the combining of DNA from two sources that contributes to diversity

transformation

a prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment in this process

transduction

the movement of genes between bacteria by phages

conjugation

the process where genetic material is transferred between prokaryotic cells

one

in bacteria, DNA transfer is always _____ way

spirilla

spiral

pilus

A hair-like appendage required for the attachment of a donor cell to a recipient cell during conjugation.

mating bridge

The structure through which DNA is transferred from the donor cell to the recipient cell during bacterial conjugation.

F Factor

A piece of DNA required for the production of pili and necessary for bacterial conjugation.

F plasmid

A plasmid that contains the F factor, allowing a bacterial cell to function as a DNA donor during conjugation.

DNA donor cell

A bacterial cell containing the F plasmid, capable of transferring genetic material during conjugation.

DNA recipient cell

A bacterial cell that lacks the F factor and receives genetic material from a donor cell during conjugation.

recombinant cell

A recipient cell that has acquired new genetic material through the transfer of the F plasmid, leading to genetic variation.

R plasmids

Plasmids that carry genes for antibiotic resistance, allowing bacteria to survive exposure to antibiotics.

antibiotic resistance

The ability of bacteria to survive and multiply in the presence of antibiotics due to genes carried on R plasmids.

natural selection in bacteria

The process by which bacteria with R plasmids survive antibiotic exposure and increase in frequency within a population over time.

recipient

does not contain the f factor or f plasmid

donor

contains the f factor or f plasmid

fertility

F means _______

resistance

R stands for _______

energy and carbon

prokaryotes can be categorized by how they obtain __________

phototrophs

obtain energy from light

chemotrophs

obtain energy from chemicals

autotrophs

require CO2 or related compounds as a carbon source

heterotrophs

requires an organic nutrient to make organic compounds

obligate aerobes

require O2 for cellular respiration

obligate anaerobes

poisoned by O2 and live by fermentation or use substances other than O2 for anaerobic respiration

facultative anaerobes

can use O2 if it is present or carry out fermentation or anaerobic respiration if it is not

nitrogen

________ is essential for the production of amino acids and nucleic acids in all organisms

nitrogen fixation

some prokaryotes convert atmospheric

nitrogen (N2) to ammonia (NH3) in a process called _________

bacteria and archae

two divisions of prokaryotes

extremophiles

archaea that live in extreme environments

extreme halophiles

archaea that live in highly saline environments

extreme thermophiles

archaea that thrives in very hot environments

methanogens

archaea that live in swamps and marshes and produce methane as a waste product

anaerobes

methanogens are strict _________ and are poisoned by O2

cyanobacteria

gram-negative photoautotrophs that generate O2

plant chloroplast

evolved from the cyanobacteria by the process of endosymbiosis

freshwater and marine phytoplankton

cyanobacteria are abundant components of __________________

recycling of chemical elements

prokaryotes play a major role in the _____________ between the living and nonliving components of the environment

decomposers

some chemoheterotrophic prokaryotes function as ________, which break down dead organisms and waste products

symbiosis

the ecological relationship in which two species live in close contact

larger host and smaller symbiont

two species that live in close contact

larger organisms

prokaryotes often form symbiotic relationships with _____________

mutualism

both symbiotic organisms benefit

commensalism

one organism benefits while neither harming nor helping the other in any significant way

parasitism

an organism (parasite) that harms but does not kill its host

pathogens

diseases caused by parasites

500-1,000 species of bacteria

human intestines are home to about _________________

mutualist and break down food that is undigested by our intestines.

most of the bacteria inside the human intestines are _______________

half

bacteria causes about ______ of all human diseases

lyme disease

bacterial diseases that are transmitted by other species

caused by a bacterium and carried by ticks.

e. coli

prokaryote that has led to important advances in DNA technology

used in gene cloning

ethanol

bacteria are also being engineered to produce _________ from agricultural and municipal waste biomass, switchgrass, and corn

plastics

bacteria can be used to make natural __________