Chapter 2: Bacteria Flashcards by michael perna

T/F: most bacteria are the same shape/morphology

False! Bacteria can take many different shapes

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Spherical bacteria include…
Rod shaped bacteria include…
Comma-shaped bacteria include…
Sprial bacteria include

s. coccus, pl. cocci
s. bacillus, pl. bacilli
s. vibrio, pl. vibrios
s. spirillum, pl. spirilla

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These type of bacteria are of many shapes

Pleiomorphic

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Multicellular organization of bacteria into branching filaments of cells

Multicellular organization of bacteria into tufts of hyphae

Hyphae

Myclia

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Multicellular organization of cells into smooth, unbranched chains of cells (like stacked pennies)

Trichomes are usually found in

Trichomes

Cyanobacteria

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T/F: the size of bacteria can vary greatly and are usually smaller than eukaryal cells

True!

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This bacteria is an exception to the general size parameters of bacteria and is up to 700 micrometers in diameter

This bacteria is also an exception to the general size parameters of bacteria and is 200-700 micrometers x 80 micrometers

Thiomargarita namibiensis

Epulopiscium fishelsoni

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These type of cell are sometimes only 0.2 micrometers in diameter (quite small) and have no cell wall

Mycoplasma

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What is the largest area of the cytoplasm which houses the chromosome and DNA replication machinery?

Nucleoid Region

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Other than the nucleoid region, the remainder of the cytoplasm in bacterial cells is a stew of

What else may be present in the cytoplasm of bacterial cells?

Macromolecules (tRNA, rRNA, mRNA, proteins, etc)

Inclusion bodies

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This inclusion body is used as carbon storage

This inclusion body is used as sulfur storage

Polyhydroxybutyrate

Sulfur Globules

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These inclusion bodies are useful in buoyancy control

These inclusion bodies are the location of photosynthetic carbon fixation reactions

These inclusion bodies are the organelles associated with direction finding

Gas vesicles

Carboxysomes

Magnetosomes

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A series of internal proteins in bacteria that assists in keeping everything in the right locations or moving them to the right locations in cells.

How is it different from the eukaryotic version?

Cytoskeleton

Prokaryote cytoskeleton is made of different proteins than eukaryote cytoskeleton

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This cytoskeleton protein aids in cell division by forming a Z ring in the center of the cell, and thereby determines the septum where the cell divides into two

This cytoskeleton protein provides structure (rod) for cell division by polymerizing to form actin-like helical bands next to the plasma membrane, forming peptidoglycan cell wall

FtsZ

MreB

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Are cytoskeletons in eukaryotic cells and prokaryotic cells made of different proteins?

Yes.

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This cytoskeletal protein connects two plasmids

This cytoskeletal protein directs plasmid movement to opposite poles of the cell by associating with the above protein

This cytoskeletal protein coordinates the movement of magnetosomes

ParR

ParM

MamK

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What differentiates the bacterial cell membrane from the eukaryotic cell membrane?

The cell membrane of bacterial cells is important in energy production (ETC)

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What can cause a pleiomorphic shape in bacterial cells?

A lack of nutrients

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Hyphae and mycelia shapes are typically thought of as ____, but can be bacteria too

How would you determine which it is?

Fungi

Check for nucleus

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What technological advance allowed us to view microbial cells more closely?

Electron microscopes that had increased resolving power

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What shape is the DNA in prokaryotes

What is the extra DNA that separate from the main chromosome and can process nutrients that can’t be processed elsewhere? Also a site of antiobiotic resistant genes

A circle

Plasmids

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What are the 3 components of a phospholipid?

What is unique among phospholipids?

2 fatty acid tails
glycerol molecule
phosphate

Each has different R groups attached to Phosphate

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The plasma membrane of bacterial cells has sterol molecules called ______ that help with stability across various temperature ranges. It is found in some, but not all, bacteria.

What’s an example of an exception?

Hopanoids, aka bacteriopanetetrol

mycoplasma

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This type of membrane protein passes through the phospholipid bilayer

This type is only on the edges

integral membrane protein

peripheral membrane protein

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Which are more solid at the same temp, unsaturated fatty acids or saturated fatty acids?

Saturated fatty acids (think oils vs. butter

Higher temperatures trigger more of saturated fatty acids or unsaturated fatty acids? What effect does it have on hopanoids?

Saturated fatty acids. They increase the presence of hopanoids.

Lower temperatures trigger more saturated fatty acids or unsaturated fatty acids? What effect does it have on hopanoids?

Unsaturated fatty acids. They decrease the presence of hopanoids.

In the presence of ethanol, a compound that breaks down cell membranes, does in increase saturated fatty acids or unsaturated fatty acids. What effect does it have on hopanoids?

Saturated fatty acids. Increases hopanoids

Why can O2 and CO2 diffuse across the PM readily?

They are small

In simple diffusion is energy required? Solutes go from ____ concentration to ____ concentration

No High to low

Why can lipophilic molecules (like vitamins) diffuse easily across the PM?

Because of the lipophilic center in the PM

How does water get across the PM even though it's charged?

Aquaporin protein channels. It can also slip between phospholipids

What type of movement is water through aquaporin channels?

Facilitated Diffusion

A cell that has an equal concentration of water and solute as its environment is termed A cell that has less H2O than its surrounding environment and more solutes is termed A cell that has more H2O than its environment and less solutes is termed

Isotonic Hypotonic Hypertonic

What type of environment (tonicity) is the cell wall most useful? Why?

Hypotonic, because it prevents the cell from bursting.

What are most type of bacterial cells in terms of tonicity with their environment?

Hypotonic

In hypertonic cells, water moves out, the cell wall stays the same, but the inside of the cell shrivels. It explains why salt was commonly used as a preservative. What is this process called?

Plasmolysis. Bacteria can't grow because they shrivel up.

What type of tonic environment do mycoplasma function within, as they have no cell wall?

isotonic

This type of diffusion uses a protein channel to move particles with a concentration gradient and requires no energy. In other words, particles move from high concentration to low concentration

Facilitated Diffusion

This type of transport into the cell is used in environments where nutrients aren't very rich. It requires energy as it moves solutes from low concentrations to high concentrations and uses a protein.

Active transport

Do eukaryotes or prokaryootes depend upon active transport more?

Prokaryotes, they needed it to evolve in harsh environments

This type of active transport has the ion move in its gradient with the solute moving in the same direction.

Symport active transport.

This type of active has the ion moving in the direction of its gradient and the solute moving in the opposite direction

Antiport

Why does the ion gradient work to move ions?

Repulsive Charge

What is the space between the cell wall and the PM called? It is a fluid area with dissolved substances and proteins

Periplasma

What are the proteins in the fluid of the periplasm called?

Solute binding proteins

In ATP cassette transport there are proteins on the membrane. a nutrient binds to the ___________ binds to the protein channel, and opens it with the help of energy from _____

solute binding proteins ATP

The PM in bacterial cells can also be used for capturing energy. Name the three ways.

Embedded transport chains can help create proton motive force (PMF) Can be used for respiration/photosynthesis Can be used to derive energy for motion (flagella)

This process allows bacteria to know the population number in the surroundings in a chemical way

Quorum Sensing

Quorum Sensing can sometimes lead to virulence, because it produces toxins like this one that induces high fever and shock response

Superantigen

This type of protein that is secreted from cells leads to diseases This type binds to iron and brings it inside the cell This type is digestive for the cell

Toxins Siderophores Enzyme

During the process of protein secretion, this protein binds to a protein that will be secreted and blocks it from folding before moving through the channel. If this didn't occur the protein couldn't make it thru the channel

SecB

These 3 proteins form the channel used in protein secretion

SecY, SecE, SecG

This protein provides the energy for protein secretion by hydrolizing ATP to allow protein to move thru the channel

SecA

A crucial structure of the cell that gives them shape and protection from osmotic lysis/mechanical forces

The Cell Wall

The cell wall is composed of crosslinked strands of _________ subunits forming a matrix, similar to a chain-link fence

Peptidogylcan subunits

Peptidoglycan subunits connect to make a

Polymer, disaccharide

What two molecules is one peptidoglycan subunit composed of?

NAM + NAG N-Acetylmuramic Acid N-Acetylglucosamine

A peptide chain is linked to which subunit?

NAM

The peptide located closest to the NAM disaccharide is numbered The one furthest is numbered Note: tetra = 4 for the chain

1 | 4

The amino acids can vary on the peptide in which disaccharide? What else can vary about peptidoglycans?

NAM The way the peptides are linked

Which has less of the crosslinkages, Gram (-) or gram (+)

Gram (-)

Which is thicker, gram negative or gram positive cell walls? Why?

Gram positive It has more peptidoglycan layers in the VERTICAL plane

In the forming of the cell wall, the first step is synthesizing ______ and linking it to UDP (its peptide chain) in the cytoplasm In the second step, it is linked to..

NAM Bactoprenol

In the third step of forming the cell wall, after NAM is linked to bactoprenol, what is linked to the NAM? In the fourth step, what happens?

NAG Bactoprenol flips the NAM-NAH complex into the periplasm

In the fifth step of forming the cell wall, after bactoprenol flips the chaininto the periplasm, what is added to the chain? What else occurs? What is the final step

A dissacharide Cross linking of chains Bactoprenol flips back into the cytoplasm

What cuts the B1-4 linkage in the peptidoglycan chain in order for more pieces to be set in?

Autolysins

What cleaves the bactoprenol away from the chain when forming the cell wall?

An enzyme

What connects the newly formed peptidoglycan to the existing polymer?

Glycosidase

This is naturally released into tissue fluids to degrade the cell wall, and is particularly effective on gram + walls What does it target? Note: not the same thing as lysozome

Lysozyme B1-4 Linkage

This also degrades the cell wall, acts on the crossbridge of different Staphylococcus sp.

Lysostaphin

This molecule prevents the peptidoglycan crosslinking from forming by inhibiting the enzyme that crosslinks it. Antibiotics based upon this are only good during the log phase, because this is when linking occurs.

B-Lactam

When the cell wall is weakened by lysozyme, what results in isotonic conditions Why is that useful? What results in hypotonic conditions?

A protoplast It can be used to study the cell membrane A ruptured protoplast

What does B-lactamase, the antibiotic resistant enzyme, do to the B-lactam ring structure? How is this combated?

It destroys it We add a second drug that inhibits B-lactamase

The cell wall is critical, but are they all the same? What two classes can microbes be separated into based upon their cell wall? What procedure can differentiate which microbes are which category?

Gram + Gram - The Gram Stain

In the first step of the Gram Stain, bacteria are stained with In the second step _______ stabilizes the crystal violet within the cellular material

crystal violet Iodine

In the third step of the iodine stain, what is added to the bacteria to attempt to extract the crystal violet from the cell? In the fourth step, what are the bacteria stained with?

Alcohol Safranin

What behavior do gram positive and negative molecules exhibit under the gram stain

Gram positive - remains purple Gram negative - Cleaved of crystal violet, is clear until stained with safranin and then becomes pink

In this type of cell, there is a thick outer layer of peptidoglycan, and a narrow periplasmic space.

Gram Positive Cells

These are negatively charged molecules that are in the peptidogylcan of gram positive cells

Teichoic Acids

This type of teichoic acid only penetrates the peptidoglycan, is shorter

Wall Teichoic Acid

This type of teichoic acid goes all the way through the peptidoglycan, and penetrates through the periplasm to the lipid membrane

Lipoteichoic Acid

This structure on the surface of gram positive cells helps the cell attach to surfaces where they need to grow, and can be involved in virulence

Wall Surface Protein

This type of cell has a periplasmic space of varying width with a very thin layer of peptidoglycan, and has been termed asymmetrical due to the outer membrane

Gram-negative cell

What is the outer membrane of gram-negative cells composed of? How is it beneficial?

Lipopolysaccharide (LPS) It provides an additional barrier that lysozymes cannot get past, some antibiotics can't either

What aspect of LPS from gram-negative cells can be harmful when the cell isn't alive? It is released from the cell wall when a cell is dead. What effect can it have? Is it hydrophobic or hydrophillic?

Lipid A A strong inflammatory response Hydrophobic. That doesn't make sense to me at the moment since its outside of the membrane...

This portion of the LPS in gram-negative cells is a side chain of polysiccharides and it can vary dramatically, and even be changed by the microbe to evade host immune responses What is the core of the LPS made of?

O side chain Sugar (called core polysaccharide)

How can nutrients get through the gram-positive cell wall?

It has large pores throughout its matrix

How can nutrients get through the gram-negative cell? Where do they transfer molecules to? What then moves the molecule into the cytoplasm?

Porin and TonB proteins The periplasmic space Active Transport mechanisms

This protein is a channel protein in gram-negative cells and is a trimer (has 3 parts), it helps hydrophilic substances go through the cell wall This protein has more variety in types of receptors for more types of nutrients than the one above

Porin TonB

One way molecules get out of a gram negative cell, they move directly from the periplasm to outside and are rare. These use never enter the periplasm

Autotransporters Single Step Transport

In this type of secretion system, the cell releases chemical that can control the metabolism and behavior of other body cells. What is it related to because of the protein that makes it?

Type III Secretion System Flagella

This step of the gram stain shrinks the large pores in the gram-positive cell, helping to lock the crystal violet stain in. It also may strip away some of the outer membrane lipids in the gram negative cells, making them more likely to lose the initial crystal violet stain.

Alcohol Decolorization

What would happen in a gram stain with a percent ethanol that is too low? What would happen if you overdecolorized it Underdecolorize? like not colorizing long enough?

The pores wouldn't shrink and the gram positives would look pink The gram positives would look like gram negatives Gram negative look like gram positives

Can you perform a gram stain without a cell wall?

Yes, but it won't hold it in when the decolorizer is around it

Describe the movement of bacterial flagella

Rotation, not wiggling.

Type of flagella with tails at the end(s) of the structure Type of flagella with tails all over the place Type of flagella with a bunch of tails on one end

Polar Flagella Peritrichous Flagella Lophotrichous

Describe the structure of proteins in the flagella What is the structure between the tail and the basal body called? What part of the flagella generates movement?

Left handed helix The hook The basal body

Which type of bacteria has both inner and outer rings in the basal body, which produce torque on filament to turn the flagella like a propeller? What type of bacteria has only inner rings?

Gram-negative | Gram-positive think about the way that they are structured

Energy to spin the flagella is derived from the....

Proton Motive Force (PMF)

Protons are pumped into the periplasm, and the rings work like a revolving door of + and - charges, causing attraction and repulsion from the periplasm

Proton Motive Force (PMF)

What would happen if you starved the flagella?

The PMF doesn't work and the bacteria can't swim

The basal bodies spinning one of two ways causes two different types of movement. What are they? Note that the cell is always alternating between these two tpes of movement

Run (directional) and tumble (non-directional)

Is the cell usually going anywhere with run and tumble movement? When is it moving in a specific direction?

No. When it is repelled or attracted to something

This describes how bacteria move, which is movement in response to the presence of chemicals that bind to chemoreceptors in the plasma membrane. Movement happens when a _____ of the chemical is reached, and it runs longer and tumbles shorter

Chemotaxis Threshold

When there is a really high concentration of attractant, or peak, what happens to the bacteria?

It goes back to run and tumbling normally Opposite for repellants

Do all cells have external flagella?

NOPE!

This type of bacteria has flagella in the cytoplasm (internal) which causes the whole organism to rotate allowing it to bury into tissues

Spirochetes

For this type of cellular movement, it is commonly seen in long shaped bacteria. The bacteria squirts out a carbohydrate (polysaccharide) with enough force to cause it to glide over a smooth surface

Gliding Motility

For this type of cellular motility, short, hairlike projects called fimbrae (pili) made of protein attach to a surface and ca get long or shorter to move, or twitch, along that surface.

Twitching Motility

This is a non-flagella based motility where bacteria that are intracellular colonizers are ingested by a body cell. The cell can survive being ingested and grows and produces within the cell. It pushes from the plasma membrane of its host cell to another adjacent cell using actin made of protein from the host cell for movement

Actin Tail Propulsion

This type of bacteria using actin tail propulsion and is a foodborne illness that can even lead to meningitis

Listeria monocytogenes

These are important because disease it not possible without attachment to the surface to be infected

Adherence Structures

This is a protein based adherence structure formed by the pilin protein, and the tip can have other proteins that make attachment more specific

Fimbrae (pili)

This is a protein based adherence structure that comprises one structure that is used for conjugation by pulling the cell close

Sex Pilus

When a sex pilus occurs, the structure pulls the other cell close and forms what? What is conjugation? Does the plasmid go through the sex pilus?

Protein Bridge Sharing of plasmids No it goes through the protein bridge

This type of adherence structure is an extension of the cell envelope, aka the cell itself, and has carbohydrates on it that allow it to stick to a surface

Stalks, holdfast

What do stalks, or holdfasts, do for the cell?

They provide extra surface area for nutrient absorption as well as adherence capability

Chapter 2: Bacteria Flashcards

(118 cards)