Chapter 27: Bacteria and Archaea Flashcards
Single-celled organisms
Prokaryotes
What domain do Prokaryotes belong to?
Bacteria and Archaea
What are the most abundant organisms on Earth?
Prokaryotes
What were the first organisms to inhabit Earth?
Prokaryotes
T/F: Prokaryotes are multicellular
F: Prokaryotes are unicellular
What are smaller: prokaryotic cells or eukaryotic cells?
Prokaryotic cells
What are the three kind of shapes of prokaryotes?
Spheres (cocci), rods (bacilli), and spirals
What are the 3 things that a cell wall does?
Maintains shape, protects the cell, and prevents it from bursting in a hypotonic environment
What happens to prokaryotes in hypertonic environment?
Lose water and experience plasmolysis
What is used as a preservative
Salt
What are two examples of eukaryotes?
Plants and fungi
What are the cell walls of eukaryotes made of?
Cellulose or chitin
What do bacterial cell walls contain?
Peptidoglycan
What is a peptidoglycan?
A network of sugar polymers cross-linked by polypeptides
What contains a variety of polysaccharides and proteins, but lack peptidoglycan?
Archaeal walls
What do scientists used to classify bacteria by cell wall composition?
The Gram stain
What kind of bacteria have simpler walls with a large amount of peptidoglycan?
Gram-positive
The walls of what bacteria have less peptidoglycan and are more complex with an outer membrane that contains lipopolysaccharides?
Gram-negative
What bacteria tend to be more resistant to antibiotics?
Gram-negative
Antibiotics target what?
Peptidoglycan
What kind of cells lack peptidoglycan and are unaffected by antibiotics?
Human cells
What is a dense and well-defined sticky layer of polysaccharide or protein surrounding the cell wall?
Capsule
What is not well organized sticky layer of polysaccharide or protein surrounding the cell wall?
Slime layer
What is formed when water or nutrients are lacking, to withstand harsh conditions?
Endospores
What can withstand extreme conditions and remain viable for centuries?
Endospores
What hairlike appendages allow them to stick to their substrate or other individuals in a colony?
Fimbriae
What are longer than fimbriae and function to pull cells together enabling the exchange of DNA?
Pili or sex pili
Half of prokaryotes exhibit _______, the ability to move toward or away from a stimulus
Taxis
What is the most common structure used by prokaryotes for movement?
Flagella
What are the three differences between flagella in prokaryotes and eukaryotes?
Structure, mechanism of propulsion, and molecular composition
How many kinds of proteins are bacterial flagella composed of?
42
What are the three parts of a bacterial flagella?
Motor, hook, and filament
How much of the flagellum’s proteins are essential?
Half
What do prokaryotic cells lack?
Complex compartmentalization
T/F: Prokaryotes have less DNA and produce fewer proteins than the eukaryotes.
T
Prokaryotes have one ______ chromosome.
circular
Eukaryotes have ______ _______ chromosomes.
Multiple linear
T/F: Prokaryotes have a nucleus.
F: They lack a nucleus; the chromosome is in the nucleotide, a region with no membrane
Prokaryotes have smaller rings of independently replicating DNA called _______.
Plasmids
How do prokaryotes reproduce quickly?
By binary fission
What are the three key features of prokaryote biology?
They are small, they reproduce by binary fission, and they have short generation times
What are the three factors that contribute to the high levels of genetic diversity observed in prokaryote populations?
Rapid reproduction, mutation, and genetic recombination
How do mutations accumulate rapidly?
Short generation times and large populations
The combining of DNA from two sources; contributes to prokaryotic diversity
Genetic recombination
What are the three ways that DNA from different individuals can be combined?
Transformation, transduction, and conjugation
Movement of genes between individual prokaryotes of different species
Horizontal gene transfer
Prokaryotic cells incorporate foreign DNA taken up from their surroundings
Tranformation
Phages (“bacteriophages”) carry prokaryotic genes from one host cell to another
Transduction
Generally an unintended result of the phage replicative cycle
Transduction
Process through which DNA is transferred between two prokaryotic cells
Conjugation
What direction is DNA transfer in bacteria?
Always one way
What piece of DNA is required for the production of pili?
F (fertility) factor
Cells that contain _ _____ (F+ cells) function as DNA donors
F plasmid
Cells lacking the F factor (F- cells) are _________
Recipients
An ___ cell can convert an ___ cell to an ___ cell if it transfers F plasmids to the ___ cell.
F+, F-, F+, F-
Antibiotics kill more bacteria except those with ________
R plasmids
Obtain energy from light
Phototrophs
Obtain energy from chemicals
Chemotrophs
Require CO2 or related compounds as a carbon source
Autotrophs
Require an organic nutrient to make other organic compounds
Heterotrophs
Energy and carbon sources are combined to give 4 major modes of nutrition:
Photoautotroph, chemoautotroph, photoheterotroph, and chemoheterotroph
Plants, algae, Cyanobacteria
Photoautotroph
Sulfolobus
Chemoautotroph
Aquatic and salt-loving prokaryotes (Rhodobacter, Chloroflexus)
Photohetertropoh
Many prokaryotes, protists, fungi, animals, some plants
Chemoheterotroph
Require O2 for cellular respiration
Obligate aerobes
Poisoned by O2 and live by fermentation or use substances other than O2 for anaerobic respiration
Obligate anaerobes
Can use O2 if it is present or carry out fermentation or anaerobic respiration if not
Facultative anaerobes
What is essential for the production of amino acids and nucleic acids in all organisms?
Nitrogen
What process do prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3)?
Nitrogen fixation
Cells of what prokaryote are specialized for nitrogen fixation or photosynthesis?
Anabaena
Nitrogen fixation is isolated in what cells that prevent oxygen penetration?
Heterocysts
Cells of one or more prokaryote species cooperate to form surface-coating colonies called _______
Biofilms
What causes tooth decay?
Biofilms
How many known species are there of bacteria?
16,000
Photoautotrophs, chemoautotrophs, and heterotrophs are what kinds of bacteria?
Proteobacteria and Gram-negative
Neisseria gonorrhoeae causes
gonorrhea
Vibrio cholerae causes
cholera
Helicobacter pylori causes
stomach ulcers
All species parasitize animal cells and have gram-negative wall lacking peptidoglycan
Chlamydias
Chlamydia trachomatis causes
nongonococcal urethritis
Gram-negative heterotrophs that spiral through the environment by rotating internal filaments.
Spirochetes
Treponema pallidum causes
syphilis
Borrelia burgdorferi causes
Lyme disease
What kind of bacteria are gram-negative photoautotrophs
Cyanobacteria
Staphylococcus aureus, Bacillus anthracis, and Clostridium botulinum are what kind of bacteria?
Gram-positive
Share certain traits with bacteria and other traits with eukaryotes
Archaea
Archaea that live in extreme environments, uninhabitable for most organisms
Extremophiles
Tolerate or require highly saline environments
Extreme halophiles
Have adaptations that make their DNA and proteins stable at high temperatures (even above 100C)
Extreme thermophiles
Obligate anaerobes that produce methane as a by-product of their metabolism
Methanogens
What kind of archaea are found in kilometers of ice in Greenland, swamps and marshes, and guts of cattle, termites and other herbivores?
Methanogens
The clade the includes many of the extreme halophiles, most methanogens, and some extreme thermophiles
Euryarchaeota
A supergroup composed of remaining closely-related clades of archaea
TACK
What group of TACK includes most extreme thermophiles?
C; Crenarchaeota
Sister group of the eukaryotes
Lokiarchaeotes
Play a major role in the recycling of chemical elements between the living and non living component of the environment
Prokaryotes
Ecological relationship in which two species live in close contact: a larger host with a smaller symbiont
Symbiosis
Both symbiotic organisms benefit
Mutualism
One organism benefits while neither harming nor helping the other
Commensalism
An organism called a parasite harms but does not usually kill its host
Parasitism
The name given to parasite that cause disease
Pathogens
What causes about half of all human disease
Bacteria
Proteins secreted by bacteria that can cause disease even if the bacteria are no longer present
Exotoxins
Lipopolysaccharide components of the outer membrane of gram-negative bacteria
Endotoxins
Vibrio cholerae
Exotoxins
Salmonella
Endotoxins
Effective against multidrug-resistant gram-positive pathogens
Malacidins
Which system helps prokaryotes defend against viral attack and has been developed as a gene altering tool
CRISPR-Cas 9
The use of organisms to remove pollutants from soil, air or water
Bioremediation