MCROBIO - LE#1 (25-39)

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

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

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

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

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

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

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

Gram-negative bacteria.

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

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

Random movement.

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

Sucrose.

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

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

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

Runs become longer and tumbles less frequent.

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

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

It contributes to infectivity and prevents dehydration by binding water.

Flagella are not just straight, but also helical.

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

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

Impermeable to water and solutes but permeable to gases.

Vegetative cells are nonrefractile, while endospores are refractile.

Runs become shorter and tumbles more frequent.

Hydrolytic enzymes, binding proteins, and chemoreceptors.

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

Short pili that mediate attachment.

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

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

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

Flagella are inserted around the cell surface.

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

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

They initiate the degradation of polymeric substances.

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

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

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

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

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

A bacterium without flagella.

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

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

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

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

The outer membrane.

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

2–10 nm.

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

By relying on Brownian motion when stopped.

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

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

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

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

They govern the chemotaxis response.

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

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

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

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

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

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

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

Movement with respect to a gradient of available water.

The forespore is separated by an outer spore membrane.

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

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

At the expense of the proton motive force.

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

It grows from the tip, not from its base.

Many copies of a protein called flagellin.

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

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

Movement with respect to gradients of O2.

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

The cortex is composed of peptidoglycan.

About 1200 protons.

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.

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

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

Approximately 20,000.

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

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

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

Movement with respect to a gradient in light intensity.

Formation of the outermost exosporium of the endospore.

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

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

Beta-lactams, glycopeptides, and bacitracin.

ATP hydrolysis.

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

The cell moves backward.

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

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

They move preferentially toward certain wavelengths of light.

The process that occurs when living conditions improve.

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

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

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

Pseudomonas (a gram-negative bacterium).

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

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

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

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

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

The core contains DNA and ribosomes.

A type III secretion system.

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

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

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

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

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

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

Type IV pili and the secretion of extracellular polysaccharides.

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

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

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

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

Archaea swim much more slowly than bacteria.

Flagellum (plural, flagella).

Usually between 1% and 5% O2.

Filamentous or rod-shaped bacteria.

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

Archaellum.

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

The proton motive force.

Flavobacterium johnsoniae gliding away from the center of the colony.

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

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

A response to chemicals.

About 10–13 nm.

15–20 nm, depending on the species.

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

A biased random walk toward the attractant.

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

A response to light, typically seen in filamentous cyanobacteria.