Bacteria and Archaea
27.3 Diverse nutritional and metabolic adaptations have evolved in prokaryotes.
27.4 Prokaryotes have radiated into a diverse set of lineages.
27.1 Structural and functional adaptations contribute to prokaryotic success
27.6 Prokaryotes have both beneficial and harmful impacts on humans.
27.2 Rapid repoduction, mutation, and genetic recombination promote genetic diversity in prokaryotes
27.5 Prokaryotes play crucial roles in the biosphere.
Prokaryotic Cells
Prokaryotic population have radiated extensively as a wide range of structural and metabolic adaptations have evolved with them since 3.5 billion years ago.
Eukaryotic Cells
Prokaryotic Cells are much SMALLER than Eukaryotic Cells.
Prokaryotic Cells have many different shapes.
Are adapted to more "normal" habitats such as the lands and waters
Eukaryotic Cells are much LARGER than prokaryotic cells.
Bacilli (Singular, Bacillus)
Spiral (Spirilla)
Cocci (Singular, Coccus)
Spherical Prokaryotes
Occur in Pairs (Diplococci), In Chains (Streptococci), In Clusters (Staphylococci)
Rod-Shaped prokaryotes
In Chains (Streptobacilli)
"Loose Coils in Shape"
Spirochetes- "Corkscrew-shaped"
The cell walls, such as plants and fungi, the walls are usually made of Chitin or Cellulose.
The cell walls contain peptidoglycan, a polymer composed of modified sugars cross-linked by a short polypeptides.
The Gram Stain technique developed by Danish physician Hans Christian Gram
Sample are first stained with crystal violet dye and iodine then rinsed in alcohol, and finally stained with a red dye such as safranin that enters the cell and binds to its DNA. To get a Positive or Negative.
Gram-Positive + : bacteria have relatively simple walls composed of a thick layer of peptidoglycan.
Gram-Negative - : bacteria have less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides (carbohydrates bonded to lipids).
The outer layer is called a Capsule or slime layer
Endospores: bacteria develop resistant cells to withstand harsh conditions.
To stick to their substrate or to one another by means of hairlike appendages were called Fimbriae.
Prokaryotes use Taxis a directed movement toward or away from a stimulus. The movement pattern in response to chemicals.
Eukaryotes have linear chromosomes
Prokaryotes generallly have circular chromosomes.
Prokaryotes lack a nucleus: unlike those of Eukaryotes.
Chromosomes were located in the Nucleoid
Smaller rings of independently replicating DNA molecules are called Plasmids.
The sexual processes of meiosis and fertilization combines DNA from two individuals in a single zygote. Three other mechanisms are used: Transformation, Transduction, and Conjugation.
A new mutation are a major source of variation in prokaryotic populations.
Prokaryotes can reproduce quickly in favorable environments.
Prokaryotic cells do not reproduce sexually
The increase genetic diversity quickly in species with short generation times and large populations, this helps lead to rapid evolution.
Single prokaryotic cells divide into 2 cells then 4,8,16, and so on.
Genetic recombination: the combining of DNA from two sources.
Horizontal gene transfer: the movement of genes from one organism to another.
Transduction: the viruses that infect bacteria carry prokaryotic genes from one host cell to another.
Conjugation: DNA is transferred between two prokaryotic cells (usually of the same species) that are temporarily joined.
Transformation: the genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings.
F Factor as a Plasmid; When an F+ cell conjugates/mates with an F− cell, the result is two F+ cells, both capable of transmitting the plasmid to other F− cells by conjugation.
The F Factor in the Chromosome;F factor, fertility factor. a plasmid in certain bacteria that enables transfer of genetic material from a donor cell to a recipient by conjugation, resulting in recombination.
R plasmids (R for resistance): resistance genes are often carried by plasmids. Provides resistance against Antibiotics or Poisons.
Prokaryotes have an astounding range of metabolic adaptations, much broader than that found in eukaryotes.
Prokaryotic metabolism role of Oxygen
Phototrophs: obtain energy from light.
Chemotrophs: obtain energy from chemicals.
Heterotrophs: require at least one organic nutrient.
Autotrophs: Organism that need only CO, or Carbon source
Prokaryotic metabolism role of Nitrogen
Obligate Anaerobes: are Poisoned by O2; lives exclusively by fermentation.
Nitrogen Fixation: Prokaryotes can metabolize nitrogen in many forms.
Anaerobic Respiration: extract chemical energy by substances other than O2 such as nitrate ions (NO3)
Obligate Aerobes: Use O2 for cellular respiration and cannot grow without it.
Facultative Anaerobes: use O2 it it is present but can also carry out fermentation or anaerobic respiration in an anaerobic enviorment.
A group of archaea convert atmospheric (nitrogen (N2) to ammonia (NH3))
Metabolic cooperation between prokaryotic cells allows them to use enviormental resources they could not use as individuals.
Hetorocysts: Carry out only Nitrogen Fixation.
Bioflims: metabolic cooperation between different prokaryotic species often occurs in surface coating colonies.
Heterocyst is surrounded by a thickened cell wall that restricts entry of O2 produced by neighboring photosynthetic cells.
Bacteria
Proteobacteria: The large and diverse clade of gram-negative bacteria includes photoautotrophs, chemoautotrophs, and heterotrophs.
Gammaproteobacteria are a class of bacteria. Several medically, ecologically, and scientifically important groups of bacteria belong to this class.
Deltaproteobacteria comprise a branch of predominantly aerobic genera, the fruiting-body-forming Myxobacteria that release myxospores in unfavorable environments.
Betaproteobacteria: a genus of soil bacteria that play an important role in nitrogen recycling by oxidizing ammonium (NH4+), producing nitrite (NO2) as a waste product.
Epsilonproteobacteria: Campylobacter bacteria are the number-one cause of food-related gastrointestinal illness in the United States.
Alphaproteobacteria is a class of bacteria in the phylum Proteobacteria
Chlamydias:Parasites can survive only within animal cells, depending on their hosts for resources as basic as ATP.
Spirochets: gram negative heterotrophs spiral through their enviroment by means of rotatiing, internal, flagellum-like lilaments.
Cyanobacteria: a group of photosynthetic bacteria, some of which are nitrogen-fixing, that live in a wide variety of moist soils and water either freely or in a symbiotic relationship with plants
Archaea
Archaea share certain traits with bacteria and other traits with eukaryotes.
Archaea live in enviorments so extreme that few other organisms can survive there.
Extremophiles- "Lovers" of extreme conditions.
Extreme halophiles: live in highly saline enviorments; Great Salt lake in Utah, the Dead Sea in Israel, and the Spanish lake.
Extreme thermophiles: thrive in very hot enviorments; sulfur volcano springs as hot as 90 degrees celsius.
Methanogens: archaea that release methane as by product of their unique ways of obtaining energy.
Ecosystems depend on the continual recycling of chemical elements between the living and non living components of the enviroment and prokaryotes play a major role in that process.
Decomposers: breaking down dead organisms as well as waste products and thereby unlocking supplies of carbon, nitrogen, and other elements.
Ecological interactons play a central role in many ecological systems.
Symbiosis: ecological relationship in which two species live in close contact with each other.
Mutualism: an ecological interaction between two species in which both benefit.
Host: the LARGER organism in a symbiotic relationship
Symbiont: the SMALLER organism in a symbiotic relationship
Commensalism: an ecological relationship in which one species benefits while the other is not harmed or helped in any significant way.
Parasitism: an ecological relationship in which a Parasite eats the cell contents, tissues, or body fluids of its host.
Pathogens: Parasites that cause disease.
Mutualistic Bacteria, many species are mutualists, digesting food that our own intestines cannot break down.
Bacteroides thetaiotaomicron, a large array of genes involved in synthesizing carbohydrates, vitamins, and other nutrients needed by humans.
Pathogenic Bacteria: The pathogenic prokaryotes, bacteria that causes about half of all human diseases which gives it a negative reputation as they deserve.
Mycobacterium tuberculosis: Lung disease tuberculosis. 1 million people die each year.
Exotoxins: proteins secreted by certain bacteria and other organisms.
Endotoxins: lipopolysaccharide components of the outer membrane of gram-negative bacteria.
Ex: Cholera-A dangerous diarrheal disease Vibrio cholerae.
Ex: Salmonella: Typhoid Fever Salmonella typhi
Through genetic engineering we can modify bacteria to produce vitamins, antibiotics, hormones, and other products.
CRISPR-Cas9 System: unique technology that enables geneticists and medical researchers to edit parts of the genome? by removing, adding or altering sections of the DNA? sequence.