Chapter 27 Bacteria and Archaea Flashcards
An organism that can grow in or tolerate saline conditions Example is the prokaryotes that make Salt Lake pink in a salt concentration of 32%
halophiles
Pro = Eu = Karyon =
Before True Nucleus
What are features that eukaryotes and prokaryotes share?
-plasma membrane -DNA -ribosomes -cytosol/cytoplasm -cell walls (most bacteria, plants, and fungal cells)
Which organisms are prokaryotes and which are eukaryotes?
Prokaryotes- bacteria and archaea Eukaryotes- algae, protists, fungi, animals, and plants
Bacteria and archaea always reproduce…..
Asexually
Cell walls of bacteria contain…
Petidoglycan Some lack cell walls
What do archaea cell walls contain?
Psudomurein Polymers other than petidoglycan
What environments do archaea live in?
Harsh environments
Genetic material in eukaryotes…. In prokaryotes….
-DNA in nucleus -paired, linear chromosomes -DNA in nucleoid region -Single circular chromosome
Different morphologies of bacteria?
Coccus- round Bacillus- rod Spiral
What structures are common to most bacteria?
-capsule or slime layer -cell wall (most) -cell membrane -cytoplasm (ribosomes, nucleoid region, some have granules) -some have flagella, pili, fimbriae
What type of arrangement are… Staphyla- Diplo- Strepto-
Cluster Paired Chain
Where are the external bacterial structures?
-glycocalyces (either capsule or slime layer) Flagella and pili extend from the cell membrane through cell wall and beyond
What are the two glycocalyces?
Capsule or slime layer (most common)
Explain capsules and slime layer
Capsule- tightly packed polysaccharides/proteins, better able to cause disease, WBC have a hard time grabbing onto them (slippery) Slime layer- helps them adhere to surfaces, prevent water loss, looser arrangement of polysaccharides and proteins
Do all bacteria have flagella? What’s the function?
Some bacteria Locomotion
What is taxis?
When flagella move toward (positive) or away (negative) from stimuli
What is the function of fimbriae?
Attachment -stick to substrate or other individuals in a colony -attach to living and non living
What are pili?
-tiny, hollow projections -conjugation (allows prokaryotes to exchange DNA) it gives one strand of DNA to be replicated
What is conjugation?
Allow prokaryotes to exchange DNA
Where are cell walls usually found in most bacteria?
Outside cell membrane
What are the two important functions of the cell wall?
Shape, protect
Describe the composition of peptidoglycan
sugar polymers cross-linked by polypeptides
Which type of cells have a thicker peptidoglycan layer? Which have a thinner layer with an outer membrane surrounding the cell wall?
Gram positive Gram negative
Simpler walls with a large amount of peptidoglycan
Gram-positive bacteria
Cell wall has less peptidoglycan and an outer membrane that can be toxic
Gram-negative bacteria
Many antibiotics target _____________ and damage bacterial cell walls
Peptidoglycan
Which type of bacteria are more likely to be an antibiotic resistant?
Gram-negative
Steps of gram staining?
-
What color do gram positive bacteria stain? It retains the purple stain
Purple
What color do gram negative bacteria stain?
Pink
Which bacteria’s cell walls contain lipopolysaccharide (LPS)?
Gram negative
Known as Whooping cough, caused by gram negative bacteria
Bordetella pertussis
Plasma membrane functions:
-energy storage -harvest light energy in photosynthetic bacteria -selectively permeable -naturally impermeable to most substances -proteins allow substances to cross membranes -maintain concentration and electrical gradients
Do prokaryotes have chloroplasts or mitochondria?
No
What is the function of the infolds of the plasma membrane in some prokaryote cells?
Can help perform cellular respiration They have chlorophyll
Inner folds =
Metabolism
-bacterial chromosomes -DNA -plasmids
Nuclear region (nucleoid)
-centrally located nuclear region -consists mainly of DNA -also contains RNA and prot
Bacterial chromosome
-usually 1 lg, circular chr -exception: vibrio cholerae 2chr - 1lg and 1 sm
DNA
Extrachromosomal pieces of smaller , circular DNA NON-essential but can be beneficial
Plasmids
Dormant survival form -non-vegetative -resistant to desiccation, heat, chemicals Bacillus,Clostridium spp.
Endospores
Endospore formation
Sporulation
Return to vegetative state Normal cell functions
Germination
Bacterial disease that affects nervous system Comes from endospores in soil
Clostridium tetani
Obligate forming anaerobe, causes muscles to not contract Releases potent neurotoxins Food borne 90% of cases (improperly canned foods) Infant - honey (endospores) Wound (least common)
Botulism
How is botulism toxin used clinically?
-paralysis of muscles by preventing release of acetylcholine -used to Tx spasms and wrinkles (Botox)
How do bacteria reproduce?
Binary fission
Key features of prokaryotic reproduction:
-they are small -they reproduce by binary fission -they have short generation times
Prokaryotes have little genetic variation. True or false?
False
What three factors contribute to genetic diversity in prokaryotes?
Rapid reproduction Mutation Genetic recombination
Movement of genes among individuals from different species
Horizontal gene transfer
What are the three different ways horizontal gene transfer can happen?
-transformation -transduction -conjugation
Mechanism that incorporates foreign DNA from the surrounding environment And What does it require?
Transformation Competence factor- DNA binding protein Mechanism of insertion- rec. A
In transformation, rec A…..
Is required to join the DNA
The movement of genes between bacteria by bacteriophages (viruses that infect bacteria)
Transduction
The process where genetic material is transferred between prokaryotic cells The transfer is one way
Conjugation
In conjugation with bacteria, the DNA transfer is always ….
One way (Sent to the F-)
In conjugation what must be present for pili to form?
F factor
F factor = pili Can be found in the plasmid ______ Or the chromosome ______
F+ HFR
Cells containing the F plasmid function as DNA ________ during conjugation Cells without theF factor function as DNA _________ during conjugation
Donors Recipients
When the plasmid DNA is integrated into bacterial DNA Bridge does not stay connected for long enough to give all the genetic material Can still be F negative because it did not get all of the genes, this is called….
Conjugation involving an HFR cell F- recombinant
Carry genes for antibiotic resistance What can this cause?
R plasmids Can cause all other cells to become resistant very quickly
How are prokaryotes categorized?
By how they obtain energy and carbon Energy -phototrophs -chemotrophs (inorganic chemicals) Carbon -autotrophs -Heterotrophs
What are the four modes of nutrition in prokaryotes?
-Photoautotrophy -chemoautotrophy -photoheterotrophy -chemoheterotrophy (most of the diseases we study are in this group)
Prokaryotes that require oxygen for survival Prokaryotes that die in the presence of oxygen And prokaryotes that can grow in the presence or absence of oxygen
Obligate aerobes Obligate anaerobes Facultative anaerobes
Some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3). What is this called? What is NH3 essential for?
Nitrogen fixation Amino acids
Nitrogen is essential for the production of?
Amino acids and nucleic acids
________________ between prokaryotes allows them to use environmental resources they could not use as individual cells
Cooperation
I’m the Cyanobacterium Anabaena, photosynthetic cells and nitrogen fixing cells called _____________ Exchange metabolic products***
Heterocysts (or heterocytes)
This could be made of many different components These surface-coating colonies makes bacteria harder to treat Growth is due to signaling Molecules recruiting cells
Biofilms
prokaryotes play a crucial role in the __________
biosphere
what are the major decomposers along with fungi that play a major role in the recycling of chemical elements between the living and nonliving components of the ecosystem?
increase the availability of nitrogen, phosphorus, and potassium for plant growth
can also “immobilize” or decrease the availability of nutrients
chemoheterotrophs
when the host is not harmed or benefited
the symbiont is benefited
commensalism
prokaryotes cause about _______ of all human diseases
half
pathogenic prokaryotes typically cause disease by releasing exotoxins or endotoxins
_________ are secreted and cause disease even if the prokaryotes that produced them are not present
_________ are released only when bacteria die and their cell walls break down
exotoxins
endotoxins
the use of organisms to remove pollutants from the environment
bacteria can be engineered to produce vitamins, antibiotics, and hormones
bioremediation
