Chapter 3 Form and Function of Bacteria and Archaea

What specific structures are found in all bacteria?

1. Cell (cytoplasmic) membrane: a thin sheet of lipid and protein that surrounds the cytoplasm and controls the flow of materials into and out of the cell pool. 2. Bacterial chromosome or nucleoid: Composed of condensed DNA molecules. DNA directs all genetics and heredity of the cell and codes for all proteins. 3. Ribosomes: tiny particles composed of protein and RNA that are the sites of protein synthesis Cytoplasm: water based solution filling the entire cell.

Order of Steps in Gram Stain:

1. Crystal violet

What specific structures are found in some but not all bacteria?

1. S layer: monolayer of protein used for protection and/or attachment. 2. Fimbriae: fine, hairlike bristles extending from the cell surface that help in adhesion to other cells and surfaces. 3. Outer membrane: exra membrane similar to cytoplasmic membrane but also containing lipopolysaccharide. Controls flow of materials, and portions of it are toxic to mammals when released. 4. Cell wall: A semirigid casing that provides structural support and shape for the cell. 5. Cytoskeleton: long fibers of proteins that encircle the cell just inside the cytoplasmic membrane and contribute to the shape of the cell. 6. Pilis: an appendage used for drawing another bacterium close in order to transfer DNA to it. 7. Glycocalyx: (tan coating), a coating or later of molecules external to the cell wall. It serves protective, adhesive, and receptor functions. It may fit tightly (capsule) or be very loose and diffuse (slime layer). 8. Inclusion/Granule: Stored nutrients such as fat, phosphate, or particles that can be tapped into when needed. 9.Bacterial microcompartments: proein-coated packets w=used to localize enzymes and other proteins in the cytoplasm. 10. Plasmid: Double stranded DNA circle containing extra genes. 11. Flagellum: Specialized appendage attached to the cell by a basal body that holds a long rotating filament. The movement pushed the cell forward and provides motility.

What are some examples of encapsulated bacteria?

1. Streptococcus pneumonia (a cause of pneumonia, an infection of the lung) 2. Haemophilus influenzae (one cause of meningitis) 3. Bacillus anthracis (the cause of anthrax)

What 3 features are the same in bacteria and archaea?

1. cytoplasmic membrane is semipermeable 2. presence of a cytoskeleton 3. DNA is the genetic material

Order cellular structures, from outside to inside, placing the outermost layer at the top of the list.

1. glycocalyx 2. outer membrane 3. cell wall 4. cytoplasmic membrane

The functions of the cell wall include _______ and ______.

1. prevents destruction with changes in osmotic pressure 2. maintains the shape of the bacterium

2. The RN advises the patient that the tetanus vaccine must have been administered within the past ________ years in order to still be effective and protective.

10

How are endospores killed?

120 degrees celsius for 20 to 30 mins.

What is Clostridium difficile?

A bacteria that causes infectious diarrhea / colitis. It can occur when antibiotics "wipe-out" a person's normal gut flora. It is often considered to be a nosocomial or hospital acquired infection. It creates spores as a mode of infection. Spores are impossible to get rid of because of its die hard characteristics. C.diff is often contracted at hospitals to vulnerable people.

Spirochete (a type of bacteria)

A coiled, spiral-shaped bacterium that has endoflagella and flexes as it moves.

"branching" filaments

A helical structure composed of proteins that is part of bacterial flagella. Some bacteria produce multiple branches off of a basic rod structure, a form called branching filaments.

filament (structure a part of bacterial flagellum)

A helical structure composed of proteins that is part of bacterial flagella. It is about 20 nanometer in diameter and varies from 1 to 70 micrometer in length. Think: a nanometer is 1000 times smaller than a micrometer.

fimbria (Appendages for Attachment or Channel formation)

A short, hairlike fibers sprouting off the surface of many bacterial cells , mostly contain protein, that helps it adhere to other cells. Provides some type of adhesion. Fimbria make pathogens stronger. They provide tight adhesive properties and help the pathogen colonize to kill and create disease. Certainly, mutant forms of E.Coli forms of these pathogens that lack fimbriae, are unable to cause infections.

pilus (Appendages for Attachment or Channel formation)

A short, thick hair-like protein structure that allows a bacterium to attach to other bacteria and surfaces. Provides some type of adhesion.

Spirillum (a type of bacteria)

A type of bacterial cell with a rigid spiral shape and external flagella.

NCLEZ PREP: Why is an alcohol swab applied to skin as an antiseptic prior to administration of an injection?

Alcohol swabs prevent infection by dissolving the bacterial lipid membrane.

What is true regarding all bacterial cells?

All lack a nucleus

What bacteria are flagellated?

All spirilla, half of rods, and a small number of cocci. Furthermore, bacteria can have single or multiple flagella.

A unicellular microorganism was recovered from a hot spring (95°C) in Wyoming. The cells lack a nucleus, have a cell wall that lacks peptidoglycan, and have 70S ribosomes. Analysis of the plasma membrane reveals that the lipids contain long-chained branched hydrocarbons with ether linkages. Please choose the group in which this organism would be classified, based on the description provided.

Archaea

What are mycoplasmas?

Bacteria with no cell wall. Size is small 0.1 to 0.5 micrometers. Mycoplasma pneumoniae is deemed "walking pneumonia" because its sufferers can often continue their daily activities. It's cytoplasmic membrane is stablized by sterols and is resistant to lysis.

bacillus (a type of bacteria)

Bacterial cell shape that is cylindrical (longer than it is wide)

What are some endospore=forming baceria that are harmful pathogens to humans?

Bascillus anthracis (agent of anthrax) C. tetani (causes lockjaw) C.perfrignens

Why are rods (a type of bacteria) have a less varied arrangment?

Because they divide only in one plane. They occur either as single cells, as a pair of cells with their ends attached (diplobacilli), or as a chain of several cells (streptobacilli). A palisades (pal′-ih-saydz) arrangement, typical of the Corynebacterium species is formed when the cells of a chain remain partially attached by a small hinge region at the ends. The cells tend to fold (snap) back upon each other, forming a row of cells oriented side by side

Who developed the gram stain?

Christian Gram

When does the bacteria form endospores?

Endospores are produced by bacillus, clostridium, and sporosarcina. When the environmental conditions become challending, these bacteria will form endospores in a process called sporulation.

What three structures comprise a bacterial flagellum?

Hook, filament, basal body

What is the primary function of the cell membrane?

IT's a barrier between the internal and external contents of the cell.

What is a bacterial glycocalyx called?

IT's called a capsule when it is bound super right to the cell than a slime layer and it's super dense and much thicker.

Why do we use alcohol-based compounds to clean skin before puncture?

It dissolves the lipid outer membrane and therefore, damages the cell, killing it.

Do all bacterial cells have a surface coating called a glycocalyx?

No, but the majority have a glycocalyx.

If the flagella are found on the ends of a cell, what are they termed?

Polar, where the flagella are attached at one or both ends of the cell. Three subtypes of this pattern are: "monotrichous: with a single flagellum, lophotrichous with small bunches or tufts of flagella emerging from the same site, and amphitrichous with flagella at both poles of the cell.

What is the primary function of the capsule on a bacteria celll?

Provides protection mainly from the immune cell phagocytes.

One way to detect motility in the lab is to stab cells into what kind of medium?

Semisolid (not solid or liquid.)

What term describes cocci in irregular clusters?

Staphylococci

Which of the following describes cocci in chains? Staphylococci//Steptococci//Tetrads//Diplococci

Steptococci

What is present in both gram-positive and gram-negative cell walls.?

THEY BOTTHHTHTHHTHTHHH contain peptidoglycan (which mostly helps with the cell shape)

bacterial flagellum

The primary function of flagella is to confer motility, or self-propulsion—that is, the capacity of a cell to swim freely through an aqueous habitat. The flagellum has three distinct parts: the filament, the hook (sheath), and the basal body (a stack of rings firmly anchored through the cell wall) which allows it to rotate 360 degrees to propel itself.

nanotubes

These are used as channels for bacteria for nutrient or energy exchange. They're extensions of bacterial membranes that are channels for nutrient or energy exchange.

nanotubes1

They are very thin, long, tubular extensions of the cytoplasmic membrane that bacteria use as channels either to transfer amino acids (i.e., food) among one another or to harvest energy by shuttling electrons from an electron-rich surface in the environment. But many bacteria can generate their energy in the absence of oxygen by sharing electrons with substances in the environment containing iron, such as iron-rich rocks. They use long nanowires to do this, transferring electrons up and down the tubular extensions of the membrane. Scientists call this activity "breathing rock instead of oxygen."

What is special about encapsulated bacterial cells?

They have greater disease causing abilities because capsules protect the bacteria against white blood cells called phagocytes. The capsular coating blocks the mechanisms that phagocytes use to attach to and engulf bacteria.

How do colonies of bacteria communicate with each other?

They use structures called nanotubes or nanowires, which are appendages that can be many micrometers long and are used for tranferring electrons or other substances outside the cell onto metals in the environment and can be used for exchanging nutrients.

What is the thick surface slime known as plaque on the teeth?

This is produced by certain streptococci in the oral cavity. The slime protects them from being dislodged from the teeth and provides a niche for other oral bacteria that, in time, cause dental disease/

chemotaxis

This is when a flagellated bacteria responds to chemical signal. Positive chemotaxis is movement of a cell in the direction of a favorable chemical stimulus (usually a nutrient) and negative chemotaxis is movement away from a potientially harmful compound.

What is a peritrichous arrangment of bacterial flagella?

This is when the flagella are dispersed randomly over the surface of the cell.

What does psychrophilic mean? (this refers to the group of bacteria called psychrophiles)

This term refers to archaea (superkingdom, the domain archaea) that love cold temperatures. These are the ancient forms of life forms on Earth. Extreme temperatures from a long time ago. Sometimes they're refered to as extremophiles, meaning they love extreme conditions in the environment.

True or False: Mycoplasmas are pleomorphic because they do not contain a cell wall for shape.

True. Mycoplasmas have no cell wall and therefore can have various shapes which is known as pleomorphism.

Why and how do bacteria form endospores?

When the environment becomes hostile to live in, the vegetative bacteria will go through a series of steps to become an endospore which takes about 6-10 hours.

Is periodonatal disease caused my archaea?

Yes, severe periodontal disease had the presence of archaeal RNA sequences.

Is the flagella that archaea has different than the flagella that bacteria has?

Yes, the structure is quite different. IT's called archaellum by some scientists.

For the most part, does bacteria function as an independent single-celled, or unicellular organisms?

Yes.

Is motility one piece of information used in the lab to identify or diagnose pathogens?

Yes.

vibrio (a type of bacteria)

a gently curved, rod-shaped bacterial cell

coccus (a type of bacteria)

a spherical-shaped bacterial cell

What is the average size of bacterial cell?

about 1 micrometer.

appendages

accessory structures that sprout from the surface of bacteria. They can be divided into two major groups: those that provide motility (flagella and axial filaments) and those that provide attachment points or channels (fimbriae, pili, and nanotubes/nanowires).

Why are archaea more similar to Eukarya?

archaea and eukaryotes share a number of ribosomal RNA sequences that are not found in bacteria

Twisting or flexing of spirochete bacteria is attributed to the ________

axial filaments

Peptidoglycan is a component of the cell wall in _________

bacteria

What are L forms?

bacteria that loses its cell wall during some part of its life

What cleaning methods are endospores resistant to?

boiling water, soaps, and disinfectants

Which three structures are possessed by ALL bacteria?

cell membrane chromosomes ribosomes cytoplasm

The two main components of the cell envelops in most bacteria are the _________ and __________.

cell wall and cell membrane

Cell envelope includes

cell wall, cytoplasmic membrane, and in some bacteria, the outer membrane

The prefix "strepto" is used to indicate that the cells are arranged in _________.

chains

Bacteria that are spatially close to one another may be able to communicate via what two methods?

chemically via nanowires

During _________, bacterial cells move by flagellar motion in response to chemical signals.

chemotaxis

What bacteria has the greatest variety of arrangment?

cocci, which can be single, in pairs (diplococci), in tetrads (groups of four) , in irregular clusters (as in staphylococci and micrococci), or in chains of a few to hundreds of cells (streptococci). An even more complex grouping is a cubical packet of eight, sixteen, or more cells called a sarcina (sar′-sih-nah)

The transfer of genetic material through pili is termed ________

conjugation

nucleoid

contains bacterial chromosome

The intracellular gelatinous solution is referred to as ________

cytoplasm

4. When educating the patient about the organism Clostridium tetani, the patient asks what allows the bacterium to survive in the soil. Which of the following cell structures will the RN describe as being responsible for the bacterium's hardiness?

endospore

Lipopolysaccharide is a major component of gram-negative outer membranes, can stimulate shock and fever, and is also referred to as _______.

endotoxin

The cellular structure in which bacteria produce branches off a basic rod structure is called a __________

filament

The bacterial cellular appendages responsible for the mutual clinging of cells that lead to biofilm formation are ____________

fimbriae

What is the bacterial appendage that enables bacteria to stick to one another, to inanimate sufraces, and to host cells?

fimbriae

Appendages that propel bacterial cells through an aqueous environment include axial filaments and __________ .

flagella.

What two functions of the fimbriae are found covering bacterial cells?

formation of biofilms and colonization of epithelial cells

The __________ is a polysaccharide protective coating outside the bacterial cell wall that is called either a capsule or slime layer based on its structure.

glycocalyx

The technique that allows a microbiologist to differentiate bacteria based on their cell wall composition/structure is the ________ stain.

gram

To determine whether bacterial cells are motile, they can be observed microscopically in a ____________ drop slide.

hanging.

Which group of bacteria grows at very high temperatures?

hyperthermophiles

conjugation pili

in a bacterium, elongated, hollow appendage used to transfer DNA to other cells. "mating" process between cells called conjugation.

bacterial chromosome

is part of the nucleoid

What function does the cell wall have for a bacteria?

it helps determine the shape of a bacterium and it also provides the structural support during osmotic pressure changes.

Chemically, what is a ribosome?

it's a combination of a special type of RNA called ribosomal RNA or rRNA (about 60%) and protein (40%)

What factors influence the arragment of a particular cell type?

its pattern of division while it's growing and how the cells remain attached after it grows.

Archaea _______.

lack peptidoglycan in their cell walls.

What contributes to a bacteria's shape?

mainly pepridoglycan (WHICH IS THE CELL WALL NOT THE CELL MEMBRANE) and recently discovered, long polymers of proteins

All bacteria possess a cell _________ but not all bacteria possess a cell _________.

membrane wall

An average sized bacterial coccus cell is about one ________ in diameter.

micrometer.

An averaged-sized bacterium is about one __________ .

micrometer.

biolfilm

microorganism accumulation

The ability of a cell to move or self propel through an aqeous environment is known as __________ .

motlity.

Plasmids typically carry ________ and __________ genes

nonessential antibiotic resistance

plasmids

nonessential pieces of DNA. provides protective traits like resisting drugs and producing toxins and enzymes.

pleomorphism

normal variability of cell shapes in a single species.

Nanotubes or nanowires are long extensions of the cytoplasmic membrane that bacteria use as channels to transfer ____________

nutrients and electrons.

Only gram-negative bacteria possess _________

outer membrane

Which term is used to describe the phospholipid barrier surrounding the peptidoglycan layer in gram-negative bacteria?

outer membrane

The prefix "diplo-" is used to indicate that the cells are arranged in _______ .

pairs

Cells oriented in a __________ arrangement result from having a hinge region between cells so that the cells fold back on each other.

palisades.

The cell wall in bacteria is primarily composed of __________

peptidoglycan

The strength and rigidity of the cell wall is due to _________

peptidoglycan

Bacterial cells are protected from rupturing in hypotonic conditions by the rigidity of the _________

peptidoglycan in the cell wall

What makes a gram stain positive or negative?

peptidoglycan layer. Thick layer cell wall retains the color stain and is deemed gram positive. If the cell wall layer is thin then it gives off a red pigment indicating a gram negative.

Capsules protect bacteria against immune cells generally referred to as __________ .

phagocytes

A major structural component of the bilayer in a cell membrane are ___________, a type of lipids which comprise 30-40% of the membrane mass.

phospholipids

What is the cytoplasmic membrane made of?

phospholipids (30-40%) and proteins (60-70%)

An appendage which forms a channel for the exchange of genetic material during bacterial conjugation is called a ___________ .

pili

Small proteinaceous appendages in gram-negative bacteria that function in DNA exchange are called conjugation _______ .

pili

Streptococci in the mouth can produce a surface slime that permits attachment to teeth and results in the formation of __________

plaque.

Chains of ribosomes are termed ________

polysomes

The two main functions of glycocalyx are ______ and _______

protection and adherence

A pilis is composed of _________

protein

Which group of bacteria grows at very low temperatures?

psychrophiles

A pilis is a __________ structure on the surface of many bacteria.

rigid tubular

How does a flagellum move when detecting favorable or unfavorable chemical stimuli?

run: A cell will swim in a smooth linear direction toward to good stimulus. tumbles: runs will be interrupted at various intercals by tumbles when the flagellum decides to turn direction causes cell to stop change course. basically, when the bacteria wants something, it takes long "run" patterns towards the stimulus.

A cellular arrangement in which cells form a cubical package of 8 to 16 cells is termed ________ .

sarcina

____________ is a cellular arrangement in which cells form a cubical package of 8 to 16 cells.

sarcina

Functions of cytoplasmic membrane

site for functions like energy reactions, nutrient processing, and synthesis. Regulates transport of nutruents into cell and discharge of wastes. Selectively permeable.

ribosomes

site for protein synthesis

What is the outer membrane of a gram negative bacteria cell composed of?

specialized types of polysaccharides and proteins.

A collection of bacterial cells that shares an overall similar pattern of traits different from other groups of bacteria is defined as a bacterial ________.

species

Cocci that associate in chains are reffered to as __________

steptococci

Bacterial endospores usually function in ________

survival

What is the primary function of endospores?

survival

What does hyperthermophilic refer to?

the archaea that loves high teperatures above 122 degrees F. They live in volcanic waters and soils.

Which structure accounts for the different results of the gram stain?

the cell wall

S layer

the extra layer that bacteria produce to protect itself in a hostile environment. like armour.

cytoplasm

this is the gelatinous solution encased b the cytoplasmic membrane. Its major component is water (70-80%) which serves as a solvent for the contents of the cell.

Bacteria function as _________ organisms.

unicellular

Slime layer (bacteria)

unorganized layer of sugar/protein outside some bacteria that protects it from loss water and nutrients.

Pleomorphism

variations in size and shape among cells of a single species

Rods that are slightly curved are called _______

vibrio

What are some characteristics of endorspores?

withstands extreme head, drying, freezing, radiation, and chemicals that would readily kill other cells. Their heat resistance is due to high content of calcium and dipicolinic acid. Furthermore, the chemical in endospores called calcium dipicolinate removes water leaving it less vulnerable to the effects of heat. Bacterial endospores are capable of surviving indefinitely. WTF?