Chapter 27

Question 1

Antoni van Leeuwenkoek

Answer 1

Made and used simple microscopes and examined water. Saw animalcules and was first to see and describe microorganisms.
Father of Protozoology and Bacteriology.
Documented and published work

Question 2

Pasteur

Answer 2

Hypothesized that microorganisms are also involved in disease. Germ Theory of Disease.

Question 3

Robert Koch
Koch Postulates

Answer 3

Studied causative agents of diseases and dominated etiology.
Koch Postulates
1 Suspected causative agent must be found in every case of the disease and be absent from healthy hosts.
2 Agent must be isolated and grown outside of host
3 When agent is introduced to a healthy, susceptible host, the host must get disease
4 Same agent must be found/isolated in the diseased experimental host.

Question 4

Prokaryotes

Answer 4

Oldest. Structurally the simplest (in comparison). Most abundant and ubiquitous form of life. Abundant for over 1 billion (closer to 2) before eukaryotes appeared.
Bacteria and Archaea Domains

Question 5

Domain Archaea

Answer 5

Extremephiles. Similar to bacteria morphologically. Genes and metabolic pathways more similar to eukaryotes, enzymes involved in transcription and translation. Unique biochemistry, ether lipids in cell membrane linkages. Can divide up tasks in clusters (colonies) using signals. Wide range of energy sources (more than euk): Organic compounds (sugar), ammonia, metal ions, hydrogen gas. (Not photosynthetic except for Halobacteria [No chlorophyll A or B])
Halophiles - salt lovers, salty environment
Thermophiles - Hotter Temperatures
Methanogens - in ruminants to help breakdown grass, release methane gas.
Nonextreme archaebacteria - 20% of ocean cells, mesophiles (moderate temps), swamps, marsh, sewage, ocean, soil, intestinal tracts

Question 6

Domain Bacteria

Answer 6

Mesophiles 38 C, Thermophiles (41-122 C), Gram-positive bacteria, spirochaetes (long), photosynthetic bacteria, Proteobacteria-gram negative bacteria often pathogen, also nitrogen fixating.

Question 7

Prokaryotes are fundamentally different from Eukaryotes

Answer 7

Cell size .5-1.0 micrometer in diameter (Biggest prok are bigger than smallest euk) . Nucleoid. Cell division and genetic recombination- no sexual cycle but can transfer genetic material. Internal compartmentalization. Flagella and pili. Metabolic diversity-different environments so exploit variety of organic and inorganic electron donors and acceptors to perform cellular respiration. Biofilms: formation of complex communities of different spp to be more antibiotic resistant, prevent dessication, or more resistant to environmental stressors than a single colony of a single type of microbe.

Question 8

Nucleoid
Cell wall
Glycocalyx
Pili
Flagella
Plasmids
Cytoplasm
Ribosomes

Answer 8

Nucleoid - Region where the DNA is
Cell wall - provides support and protection (from water)
Glycocalyx - Outer gelatinous covering. Some spp loose and slimy, others solid, used to stick to cells or environment. Prevent drying out. Prevent WBC from attacking
Pili- Hairs allows bacteria to attach to surfaces and to each other, exchange small genetic info
Flagella- Long tail allows certain spp to swim
Plasmids - Small DNA that can be exchanged
Cytoplasm- Site of metabolism
Ribosomes - Synthesize polypeptides (proteins) not membrane bound but is an organelle.

Question 9

Differences between Archaea and Bacteria

Answer 9

Plasma membrane - All have a plasma membrane with fluid mosaic structure. Archaeal membrane lipids composed of glycerol linked to hydrocarbon chains by ether linkages, bacteria and eukaryotes do not have ester linkages.
Cell wall: Bacteria have peptidoglycan. Most prokaryotes have a cell wall
DNA replication- initiation of replication in archaea is more similar to that of euk
Gene expression - Archaea have more than one RNA polymerase, more closely related to eukaryotic polymerases than the single bacterial RNA polymerase. Translation machinery for Archaea more similar to eukaryotes.

Question 10

Classification of Prokaryotes
Endospore

Answer 10

Old way - (Morphology) Photosynthetic ability, cell wall structure, motility, unicellular or colony or filamentous, spore forming ability, pathogenicity.
New Way (Molecular Approaches) AA sequences, GC content(guanine and cytosine), nucleic acid hybridiation between 2 spp., gene or ribosomal seq, whole-genome seq.
Endospore-created to survive harsh environments until more suitable

Question 11

Coccus
Bacillus
Spirillum
Vibrio
Spirochete
Star
Pleomorphic

Answer 11

Coccus-Circular
Bacillus-Rod
Spirillum-spiral
Vibrio- short one bend
Spirochete - long and spirally
Star
Pleomorphic - Different shapes
Some variations and combos, how it’s arranged, how it connects.

Question 12

Sarcinae
Diplococci
Tetrads
Staphylococci
Streptococci

Answer 12

Diplococci - Two coccus connected. Two spheres
Streptococci - Line of spheres
Tetrads - Four spheres
Sarcinae - Groups of 8ish spheres stacked in cubes
Staphylococci - bunch of grapes

Question 13

Single bacillus
Diplobacilli
Streptobacilli
Palisade
V-shape

Answer 13

Single bacillus
Diplobacilli - Two end to end rods
Streptobacilli - Multiple end to end rods
Palisade - Side by side IIIII
V-shape

Question 14

Bacterial Cell Walls

Answer 14

Most bacteria have cell walls. Provides structure and shape and protects cells from osmotic forces. Composed of peptidoglycan, target of lysozyme or antibiotics (unique to bacteria and makes it a target). Gram positive and gram negative (Purple or blue positive, pink negative)

Question 15

Peptidoglycan structure

Answer 15

Peptide(AA) + glycan (monosaccharides linked together). Alternating sugars (NAG and NAM) connected by protein linkages. Carbohydrate backbone (NAG & NAM) are linked by peptides (tetrapepetides). Tetrapeptides may be bond to each together directly or held together by short AA chains. Has rigidity and structure.

Question 16

Gram positive cell wal

Answer 16

Thicker peptidoglycan layer (open face sandwich). Contains unique polysaccharides-teichoic acids, lipoteichoic acids (anchor peptidoglycan to cell membrane). Retains crystal violet dye in gram staining procedure. One layer of cell membrane

Question 17

Gram negative cell wall

Answer 17

Thin layer of peptidoglycan in the periplasmic space (full sandwich) Has two layers of cell membranes (outer and inner). Outer membrane has porins (holes) and a layer of lipopolysaccharides. Outer membrane may be impediment to the treatment of disease. Do not retain crystal violet dye in gram staining procedure. Stronger barrier makes it harder to treat. Has 2 cell membranes

Question 18

Other external structures associated with cell wall

Answer 18

S-layer (Slimy) - Additional protein or glycoprotein layers outside of the outermembrane/peptidoglycan. Diverse Function: attach cells to surfaces, protection, trap molecules close to surface, selectively permeable structure.
Capsule and Slime layer (more compact/hard) Surrounds the other wall layers, functions are to adhere to surfaces, evade immune response- helps cause disease
Flagella and pili
endospores

Question 19

Flagella in prokaryotes

Answer 19

Long extensions (proteinaceous structures) beyond cell surface. Rotate in 360, responsible for cell motility.
3 Major parts: Filament (flagellin) [What you see], hook [Rotated by basal body (Motor)], and basal body [Powers the hook and filament with H+ protons moving from high to low conc. (facilitated diffusion)]

Question 20

Flagella types

Answer 20

Monotrichous - one end polar.
Lophotrichous - multiple
Amphitrichous - 1 at each pole, 2 total
Peritrichous - many scattered throughout
Endoflagella - inside cell

Question 21

Taxis (Tax-us) and it’s types

Answer 21

Movement in response to a stimulus
Positive taxis - movement towards a favorable stimulus (attractant)
Negative taxis - Movement away from an unfavorable stimulus (repellent)
phototaxis - light
chemotaxis - chem
magnetotaxis - magnetic field. Magnetotactic bacteria - can create magnetic molecules and find magnetic fields for food, mate, orientation, etc

Question 22

Pili

Answer 22

small hair like extensions. Function : Connection, can exchange plasmids (ex: antibiotic resistance). A little movement by moving in and out.

Question 23

Akinete
Heterocysts

Answer 23

Akinete - Thick walled dormant cell derived from the enlargement of a vegetative cell. Serves as a survival structure. Caused by changing of environment, can survive harsh times and reemerge later. cyanobacteria and unicellular and filamentous green algae
Heterocysts are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria. N Important for photosynthesis

Question 24

Endospore

Answer 24

Dormant, tough, and nonreproductive structure (wall) produced by certain bacteria from the Firmicute phylum to survive environmental stress. Within a cell

Question 25

Binary Fission

Answer 25

Cell division in which a parent cell copies genetic material and divides into 2 identical daughter cells

Question 26

Vertical gene transfer

Answer 26

Organisms replicate their genomes and provide copies to descendants

Question 27

Horizontal gene transfer

Answer 27

Transfer of plasmids between adult cells. No new offspring
Transformation - One bacterial cell dies and ruptures and chromosomal DNA or plasmids are absorbed by another cell and incorporating it in its DNA
Transduction -Virus mediated process. Generalized transduction (any genes transferred) and specialized transduction (only specific genes can be transferred). Virus (phage) puts its DNA in cell and it degrades hosts DNA. New phage synthesize within cell and gain host DNA. Phage inject DNA into different cell and it is absorbed by the new cell.
Conjugation - Sex pilus created from F+ to F- by f-factor. Plasmid is transferred to F- and are now identical.

Question 28

Autotrophs strategies

Answer 28

Obtain carbon from inorganic sources like CO2, oxidized forms of carbon.
Photolithoautotrophs - obtain energy from light and acquire carbon from inorganic sources like CO2 and electrons from inorganic compounds. Ex Cyanobacteria, H2O as reducing equivalent donor
Chlorobiaceae, chromatiaceae, hydrogen sulfide (H2S) photosynthesizing bacteria. Energy source: Light, E donor: Inorganic compounds, C sources: Inorganic sources, ex CO2

Chemolithoautotrophs: Obtain energy from oxidation of inorganic compounds and carbon from the fixation of CO2. Ex Nitrifying bacteria, sulfur-oxidizing bacteria, oxidizer bacteria. Energy Source: Inorganic substrates, E donor: Inorganic compounds, C Sources: Inorganic sources ex CO2

Question 29

Heterotrophs strategies

Answer 29

Consume other heterotrophs or autotrophs. Carbon in reduced form.
Photoorganoheterotrophs: source of energy is light however organic carbon is used as source of carbon and of elections. Energy source: Light, E Donor: Organic compounds, C source: Organic C sources
Chemolithoheterotrophs: Organsims which derives its energy from chemicals (inorganic, sulfide, ferrous iron, ammonia, hydrogen sulfide), and needs to consume other organisms in order to live. Stone eaters, only prokaryotes use this strategy, critical role in biochemical cycling of nutrients. Energy source: Inorganic substrates, E Donor: Inorganic compounds, C Source: Organic C sources
Chemoorganoheterotrophs : Obtain energy, carbon, and reducing equivalents for biosynthetic reactions from organic compounds. Ex most bacteria. All animals. Energy Source: Organic substrates, E Donor: Organic compounds, C Source: Organic C sources

Question 30

Respiration
Facultative anaerobes
Obligate anaerobes

Answer 30

Aerobic respiration: Final E acceptor is O2, cyanobacteria
Anaerobic respiration: Final E acceptor is iron, sulfur, etc.
Facultative anaerobes: Makes ATP by aerobic if O2 available, if not can switch to anaerobic
Obligate anaerobes: Killed by normal atmospheric O2, Some variance in tolerance but low (0%-8%)

Question 31

Microbial Ecology

Answer 31

Decomposition by prokaryotes and fungi important for releasing a dead organism to the environment.
Fixation of carbon, produce organic compounds from CO2 that et passed up food chains, can also oxidize methane to CO2 or convert CO2 to methane
Fixation of nitrogen, convert atmospheric nitrogen gas to ammonia, do that through enzymes called nitrogenase.

Question 32

Agrobacterium

Answer 32

Soil microbe (bacteria) transfers Ti-plasmid DNA to plant cells and forms tumors, conjugation through pili. Host plants grows root gall (habitat) and Opines (N- and energy rich.