Chapter 2: Bacteria Flashcards
T/F: most bacteria are the same shape/morphology
False! Bacteria can take many different shapes
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
These type of bacteria are of many shapes
Pleiomorphic
Multicellular organization of bacteria into branching filaments of cells
Multicellular organization of bacteria into tufts of hyphae
Hyphae
Myclia
Multicellular organization of cells into smooth, unbranched chains of cells (like stacked pennies)
Trichomes are usually found in
Trichomes
Cyanobacteria
T/F: the size of bacteria can vary greatly and are usually smaller than eukaryal cells
True!
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
These type of cell are sometimes only 0.2 micrometers in diameter (quite small) and have no cell wall
Mycoplasma
What is the largest area of the cytoplasm which houses the chromosome and DNA replication machinery?
Nucleoid Region
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
This inclusion body is used as carbon storage
This inclusion body is used as sulfur storage
Polyhydroxybutyrate
Sulfur Globules
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
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
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
Are cytoskeletons in eukaryotic cells and prokaryotic cells made of different proteins?
Yes.
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
What differentiates the bacterial cell membrane from the eukaryotic cell membrane?
The cell membrane of bacterial cells is important in energy production (ETC)
What can cause a pleiomorphic shape in bacterial cells?
A lack of nutrients
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
What technological advance allowed us to view microbial cells more closely?
Electron microscopes that had increased resolving power
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
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
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
This type of membrane protein passes through the phospholipid bilayer
This type is only on the edges
integral membrane protein
peripheral membrane protein
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
