MCROBIO - LE#1 (25-39)

A sticky coat of polysaccharide formed outside of the cell envelope.

The presence of polysaccharide molecules covalently bound to lipids in the outer membrane.

PHB is a carbon storage polymer that can vary in length and is synthesized by cells when there is an excess of carbon.

The L ring, P ring, MS ring, and C ring.

They initiate the degradation of polymeric substances.

They can take the role of the cell wall, providing structural strength, protecting from osmotic lysis, and conferring cell shape.

The forespore is separated by an outer spore membrane.

Hami attach cells to surfaces and to each other due to their barbed terminus.

Runs become longer and tumbles less frequent.

Vegetative cells are nonrefractile, while endospores are refractile.

Flagella are inserted around the cell surface.

Polyphosphate can be broken down to synthesize the energy-rich compound ATP from ADP.

A bacterium without flagella.

2–10 nm.

A clump of microorganisms that can form on solid surfaces, facilitated by the glycocalyx.

It grows from the tip, not from its base.

Approximately 20,000.

The cell moves backward.

Outgrowth, where the vegetative cell emerges and begins to divide.

They might function as ballast to maintain cell position or sequester carbonate to support autotrophic growth.

A type of polar flagellation where a tuft of many flagella arises at one end of the cell.

Flagellation where a tuft of flagella emerges from both poles of the cell.

Facilitate surface recognition, act as virulence factors, and contribute to the mechanical strength of the cell.

Extreme heat, radiation, chemical exposure, drying, and nutrient depletion.

The outer membrane.

Endospores have high heat resistance, while vegetative cells have low heat resistance.

At the expense of the proton motive force.

Type IV pili, which extend from one pole of the cell, attach to a surface, and then retract to pull the cell forward.

ATP hydrolysis.

The flagella counterpart in archaea, composed of proteins unrelated to those of flagella.

They can exist and replicate independently of the chromosome or may be integrated with it.

It results in distinctive colony morphology as cells can move out and away from the center of the colony.

A capsule is organized in a tight matrix and excludes small particles, while a slime layer is loosely attached and does not exclude particles.

A space of about 15 nm located between the outer surface of the cytoplasmic membrane and the inner surface of the outer membrane.

Biomineralized particles of magnetic iron oxides that allow bacteria to orient themselves within a magnetic field.

They can mediate conjugation, act as nanowires, and facilitate twitching motility.

The process of migrating along Earth's magnetic field lines.

By relying on Brownian motion when stopped.

They form a bundle at one end and rotate counterclockwise (CCW) for forward motion.

They facilitate cell surface interactions, such as attachment, and can increase the ability of some bacterial pathogens to cause disease.

They have cell walls made of pseudomurein that may or may not have an outer S-layer.

It is composed largely of archaeal isoprenoid lipids and lacks LPS.

Extrachromosomal DNA found in bacteria, often in hundreds within a cell.

They can carry genes for drug resistance, pathogenicity, and new metabolic activities.

Flavobacterium johnsoniae gliding away from the center of the colony.

Flagella are attached at one or both ends of a cell.

Hydrolytic enzymes, binding proteins, and chemoreceptors.

Vegetative cells have low calcium content, while endospores contain a calcium-dipicolinic acid complex.

A bacterium with a singular flagella at the polar end of the cell.

Movement with respect to a gradient of available water.

Cortex, which lays down layers of calcium and dipicolinic acid.

Formation of the outermost exosporium of the endospore.

Vegetative cells have high water content (80-90%), while endospores have low water content (10-25%).

They have an absence of a cell wall and contain sterols and lipoglycans in their cytoplasmic membrane.

Archaea swim much more slowly than bacteria.

Fimbriae and pili are hair-like structures on the surface of bacteria, while hami resemble tiny grappling hooks and are found in the SM1 group of Archaea.

They neutralize the negatively charged membrane and contribute to its mechanical strength.

Sulfur granules are formed from the oxidation of sulfide and are involved in oxidizing reduced sulfur compounds, generating electrons for energy metabolism.

It surrounds the inner rings and is anchored in the cytoplasmic membrane and peptidoglycan.

Movement with respect to a gradient of ionic strength, such as salt concentration.

Longer runs are triggered by a decrease in concentration of the repellent.

It can still rotate and be repaired with new flagellin units passed through the filament channel.

They contain sterols in their cytoplasmic membranes to add strength and rigidity, experiencing little osmotic pressure when living within another cell.

They sense a gradient of light and interact with cytoplasmic proteins that control flagellar rotation in chemotaxis.

Archaellum.

Structures that confer buoyancy, allowing cells to position themselves in optimal regions of the water column.

It contributes to infectivity and prevents dehydration by binding water.

Polyphosphate serves as a source of phosphate for nucleic acid and phospholipid biosynthesis when phosphate is limiting.

Membrane proteins that sense attractants and repellents and transduce this information to flagella.

They govern the chemotaxis response.

SASPs bind tightly to DNA, protecting it from damage and stabilizing it for survival in harsh conditions.

Nonspecific porins form water-filled channels for very small hydrophilic substances, while specific porins contain a binding site for one or a group of structurally related substances.

Beta-lactams, glycopeptides, and bacitracin.

Pseudomonas (a gram-negative bacterium).

It signals that the spore is developing into a vegetative cell.

Filamentous or rod-shaped bacteria.

About 10–13 nm.

A biased random walk toward the attractant.

Transmembrane proteins that allow nonspecific transport of solutes across the outer membrane.

Massive accumulations of cyanobacteria on or near the lake surface where sunlight is most intense for maximal photosynthesis.

Impermeable to water and solutes but permeable to gases.

Highly differentiated dormant cells that protect the bacterial genome and function as survival structures.

Vegetative cells have high enzymatic activity, whereas endospores have low enzymatic activity.

No, they are dormant stages of a bacterial life cycle, not reproductive structures like fungal spores.

The cell wall prevents lysis by maintaining high internal pressure due to concentrated solutes.

Movement with respect to gradients of O2.

Movement with respect to a gradient in light intensity.

The process that occurs when living conditions improve.

A type III secretion system.

Gliding is a smooth motion along the long axis of a cell without external propulsive structures.

Because gram-positive bacteria do not have an outer membrane.

It houses enzymes and proteins involved in oxidative phosphorylation and the electron transport chain, facilitating the creation of a proton motive force.

Gram-negative bacteria.

Glycogen is a polymer of glucose produced when carbon is in excess, serving as a carbon and energy storage polymer.

Runs become shorter and tumbles more frequent.

Toxins produced by microorganisms and released outside, distinct from endotoxins like Lipid A.

The process of cellular differentiation of vegetative cells that results in endospore formation.

Yes, endospores can remain dormant for years but can revert back rapidly.

It connects the filament to the flagellum motor in the basal body.

The spore begins to develop into a vegetative cell, typically a rapid process.

Swimming into darkness outside the illuminated field of view; response only to the absence of light.

ATP hydrolysis, unlike flagella which are driven by proton motive force.

The proton motive force.

A response to light, typically seen in filamentous cyanobacteria.

Granules of benstonite, a carbonate mineral containing barium, strontium, and magnesium.

Random movement.

Flagella are not just straight, but also helical.

Short pili that mediate attachment.

It is present in all gram-negative bacteria and is part of the lipopolysaccharide structure.

They begin the process of transporting substrates, similar to ABC transporters.

Asymmetric cell division occurs when nutrients deplete or conditions are unfavorable.

Proteins that function as channels for the entrance and exit of solutes in the outer membrane.

About 1200 protons.

The MS ring is synthesized first and inserted into the cytoplasmic membrane.

By producing proteins that bind to antibiotics like beta-lactams or by evolving to the dosages of antibiotics.

Archaella are smaller, not hollow, and are assembled from their bases with a center filled with proteins.

Usually between 1% and 5% O2.

A response to chemicals.

Sucrose.

A component of lipopolysaccharides that acts as an endotoxin and is a virulence factor for certain bacteria.

S-layers are found in many Bacteria (5-20 nm) and in nearly all Archaea (70 nm).

A method where a small glass capillary tube is immersed into a suspension of motile bacteria to create a chemical gradient.

Many copies of a protein called flagellin.

Activation, where the spore becomes less refractile as it is hydrated.

They move preferentially toward certain wavelengths of light.

The core contains DNA and ribosomes.

They require O2 and may swim toward increasing concentrations of it.

Tiny rotating machines that push or pull the cell through a liquid.

15–20 nm, depending on the species.

The cortex is composed of peptidoglycan.

It binds water, dehydrates the endospore, and stabilizes DNA against heat denaturation.

They assist flagellin molecules to assemble in the proper fashion at the flagellum tip.

Social motility (caused by twitching) and adventurous motility (caused by gliding).

Flagellum (plural, flagella).

Type IV pili and the secretion of extracellular polysaccharides.

Specialized structures found in magnetotactic bacteria that allow them to align with magnetic field lines.

It describes the random arrangement of carbohydrate molecules across the cell surface, giving a fluid-like appearance.