p.8
Cytoplasmic Membrane Structure and Function
What types of proteins are embedded in the bacterial cytoplasmic membrane?
Integral membrane proteins and peripheral membrane proteins.
What is a key advantage of being small in cellular biology?
Higher surface area relative to cell volume (higher S/V ratio).
p.24
Chemotaxis and Directed Movement
What is taxis in biological terms?
Directed movement in response to chemical or physical gradients.
p.3
Size Range of Prokaryotes
What is the size range for prokaryotes?
0.2 μm to >700 μm in diameter.
p.16
Cell Surface Structures: Capsules and Fimbriae
What are capsules and slime layers considered in relation to the cell wall?
They are not considered part of the cell wall because they do not confer significant structural strength.
p.21
Flagella and Swimming Motility
What are the two main components of the flagellum motor?
The rotor and the stator.
p.27
Flagella and Swimming Motility
What are the two types of flagellation in prokaryotic cells?
Peritrichous and polar flagellation.
p.14
Lipopolysaccharides (LPS) and Outer Membrane
Which bacteria are linked to gastrointestinal symptoms due to LPS?
Salmonella, Shigella, and Escherichia.
p.11
Bacterial Cell Walls and Peptidoglycan
Are peptidoglycan cell walls present in Archaea or Eukarya?
No, they are not present in the cell walls of Archaea or Eukarya.
How does a higher S/V ratio benefit small cells?
It supports greater nutrient and waste product exchange per unit cell volume.
p.26
Chemotaxis and Directed Movement
What is chemotaxis in bacteria?
A movement response to chemical stimuli.
p.11
Bacterial Cell Walls and Peptidoglycan
How are species of bacteria classified based on Gram stain?
Into two groups: Gram-positive and Gram-negative.
p.19
Flagella and Swimming Motility
What are the different arrangements of flagella?
Polar, lophotrichous, amphitrichous, peritrichous.
p.8
Cytoplasmic Membrane Structure and Function
How are integral membrane proteins characterized?
They are significantly embedded in the membrane.
p.20
Flagella and Swimming Motility
What does the rotor of the flagellum consist of?
The central rod and the L, P, C, and MS rings.
p.14
Lipopolysaccharides (LPS) and Outer Membrane
What is the role of lipid A in LPS?
It can be toxic to animals and comprises the endotoxin complex.
p.21
Flagella and Swimming Motility
What does the rotor of the flagellum consist of?
The central rod and the L, P, MS, C rings.
p.16
Cell Surface Structures: Capsules and Fimbriae
How can capsules vary in their physical properties?
They may be thick or thin, rigid or flexible.
p.21
Flagella and Swimming Motility
What is the function of the stator in the flagellum motor?
The stator consists of Mot proteins that surround the rotor and generate torque.
p.27
Flagella and Swimming Motility
What is polar flagellation?
Flagella are located at one or both ends of the cell.
p.27
Flagella and Swimming Motility
How does peritrichous flagellation affect movement?
It allows for more versatile movement in various directions.
p.27
Flagella and Swimming Motility
How does polar flagellation affect movement?
It typically results in a more directed movement.
p.19
Flagella and Swimming Motility
What are flagella and archaella?
Structures that assist in swimming in Bacteria and Archaea, respectively.
Does morphology predict the physiology of a prokaryotic cell?
No, morphology typically does not predict physiology, ecology, phylogeny, or other properties.
Do smaller cells always grow faster than larger cells?
Not necessarily; for example, Pelagibacter ubique grows much slower than Ruegeria pomeroyi.
p.26
Chemotaxis and Directed Movement
How do polarly flagellated bacteria differ from peritrichous cells in chemotaxis?
They are similar but not identical.
What factors are discussed in relation to small cells?
Surface-to-volume ratios, growth rates, and evolution.
What is optimized for nutrient uptake in prokaryotic cells?
Small cells with a high surface-to-volume ratio, such as appendaged cells.
p.16
Cell Surface Structures: Capsules and Fimbriae
What materials are capsules and slime layers made of?
Polysaccharides or protein layers.
p.15
Lipopolysaccharides (LPS) and Outer Membrane
What does the periplasm house?
Many extracellular proteins.
p.27
Flagella and Swimming Motility
What is peritrichous flagellation?
Flagella are distributed all over the surface of the cell.
p.10
Cytoplasmic Membrane Structure and Function
How do transport proteins function in relation to solutes?
They accumulate solutes against the concentration gradient.
p.21
Flagella and Swimming Motility
What are Fli proteins responsible for in gram-negative bacteria?
They act as a motor switch, reversing the direction of rotation of the flagella.
What may influence the morphology of prokaryotic cells?
Selective forces may be involved in setting the morphology.
How does gliding motility compare to swimming?
It is slower and smoother than swimming.
p.8
Cytoplasmic Membrane Structure and Function
How are peripheral membrane proteins characterized?
They are loosely attached to the membrane.
p.26
Chemotaxis and Directed Movement
What happens to some bacteria like Rhodobacter during chemotaxis?
They stop and are affected by Brownian motion.
p.26
Chemotaxis and Directed Movement
What is Brownian motion?
The random motion of particles suspended in a liquid medium.
p.1
Prokaryotic Cell Shapes
What types of unusual shapes can prokaryotic cells have?
Appendaged bacteria and filamentous bacteria.
p.18
Cell Surface Structures: Capsules and Fimbriae
What are fimbriae?
Filamentous protein structures that enable organisms to stick to surfaces or form pellicles.
p.12
Bacterial Cell Walls and Peptidoglycan
What is the primary function of peptidoglycan in bacterial cell walls?
It provides strength and rigidity.
p.12
Bacterial Cell Walls and Peptidoglycan
How does the cross-linking of peptidoglycan differ in gram-negative and gram-positive bacteria?
It is cross-linked differently, often with 'interbridges' in gram-positive bacteria.
What drives the movement of gliding-specific proteins in the cytoplasmic membrane?
Proton Motive Force (PMF).
p.5
Size Range of Prokaryotes
What is the lower limit of cell size for cellular organisms?
Cellular organisms <0.15 μm in diameter are unlikely.
p.20
Flagella and Swimming Motility
What type of machine is the flagellum motor?
A reversible rotating machine.
p.11
Bacterial Cell Walls and Peptidoglycan
What are the main structural differences between Gram-positive and Gram-negative cell walls?
Gram-negative has at least two layers (LPS and peptidoglycan), while Gram-positive has a thicker, primarily one layer of peptidoglycan.
p.14
Lipopolysaccharides (LPS) and Outer Membrane
What are the major components of bacterial lipopolysaccharide (LPS)?
Lipid A, KDO, core, and O-specific polysaccharide.
p.10
Cytoplasmic Membrane Structure and Function
What is the primary function of the cytoplasmic membrane?
To act as a permeability barrier.
p.24
Chemotaxis and Directed Movement
What is osmotaxis?
Response to ionic strength.
What is notable about the genomes of ultramicrobacteria?
They are highly streamlined.
p.3
Size Range of Prokaryotes
Name another very large prokaryote.
Thiomargarita namibiensis.
p.15
Lipopolysaccharides (LPS) and Outer Membrane
What do nonspecific porins do?
Form water-filled channels for virtually any very small hydrophilic substance to pass.
p.15
Lipopolysaccharides (LPS) and Outer Membrane
What is the function of specific porins?
Contain a binding site for one or a group of structurally related substances.
p.13
Lipopolysaccharides (LPS) and Outer Membrane
What replaces most of the phospholipids in the outer half of the outer membrane?
Lipopolysaccharides (LPS).
p.18
Cell Surface Structures: Capsules and Fimbriae
What role do Type IV pili play?
They adhere to host tissues and support twitching motility.
p.17
Cell Surface Structures: Capsules and Fimbriae
What role do capsules and slime layers play in biofilms?
They assist in the development and maintenance of biofilms.
p.12
Bacterial Cell Walls and Peptidoglycan
Where is lysozyme found and what is its role?
Found in human secretions, it is a major defense against bacterial infection.
p.25
Chemotaxis and Directed Movement
What is the 'run and tumble' behavior in bacteria?
A movement pattern where bacteria move smoothly forward (run) and then stop and jiggle (tumble).
Why is a certain volume needed in cells?
To house proteins, nucleic acids, ribosomes, and other components.
p.15
Lipopolysaccharides (LPS) and Outer Membrane
What is the periplasm?
The space located between the cytoplasmic and outer membranes.
p.25
Chemotaxis and Directed Movement
What happens during a 'tumble' in bacterial movement?
The motor rotates clockwise, causing the flagellar bundle to come apart.
What type of cell shape is associated with swimming motility in viscous environments?
Helical or spiral-shaped cells.
p.10
Cytoplasmic Membrane Structure and Function
What must polar and charged molecules do to cross the cytoplasmic membrane?
They must be transported.
p.15
Lipopolysaccharides (LPS) and Outer Membrane
What are porins?
Transmembrane protein channels for entrance and exit of solutes.
p.10
Cytoplasmic Membrane Structure and Function
What role do protein anchors play in the cytoplasmic membrane?
They hold transport proteins in place.
p.13
Bacterial Cell Walls and Peptidoglycan
What is the primary composition of the cell wall in prokaryotes?
Most of the cell wall is composed of the outer membrane or the lipopolysaccharide (LPS) layer.
Are there variations on basic morphological types of prokaryotic cells?
Yes, many variations are known.
p.7
Cytoplasmic Membrane Structure and Function
What is the general structure of the bacterial cytoplasmic membrane?
A phospholipid bilayer containing embedded proteins.
p.7
Cytoplasmic Membrane Structure and Function
How do fatty acids orient in the bacterial cytoplasmic membrane?
They point inward to form a hydrophobic environment.
p.8
Cytoplasmic Membrane Structure and Function
What are hopanoids?
Sterol-like molecules that strengthen some bacterial species' membranes.
p.6
Cytoplasmic Membrane Structure and Function
What does the cytoplasmic membrane separate?
The cytoplasm from the environment.
p.21
Flagella and Swimming Motility
What role do protons play in the flagellum motor?
Protons flowing through the Mot proteins exert forces on charges present on the C and MS rings, spinning the rotor.
p.6
Cytoplasmic Membrane Structure and Function
What is transported in and out of the cytoplasmic membrane?
Nutrients are transported in and waste products out.
p.19
Flagella and Swimming Motility
How do flagella increase or decrease swimming speed?
By varying the rotational speed relative to the strength of the proton motive force.
p.25
Chemotaxis and Directed Movement
How do bacteria monitor their environment?
Using chemoreceptors that sense attractants and repellents.
p.13
Lipopolysaccharides (LPS) and Outer Membrane
What are the components of lipopolysaccharides (LPS)?
Core polysaccharide, O-polysaccharide, and lipid A.
p.18
Cell Surface Structures: Capsules and Fimbriae
What is the function of conjugative/sex pili?
They facilitate genetic exchange between cells through conjugation.
p.18
Cell Surface Structures: Capsules and Fimbriae
Which organisms are known to utilize Type IV pili for motility?
Pseudomonas and Moraxella.
p.9
Cytoplasmic Membrane Structure and Function
What are the major lipids found in Archaea?
Phosphoglycerol diethers and diphosphoglycerol tetraethers.
p.26
Chemotaxis and Directed Movement
Which bacteria can fully reverse flagellar rotation to avoid tumbling?
Many, such as Pseudomonas.
p.20
Flagella and Swimming Motility
What is the function of the stator in the flagellum?
To generate torque, a twisting force that causes rotation.
p.11
Bacterial Cell Walls and Peptidoglycan
What is the composition of the Gram-positive cell wall?
Primarily one layer of peptidoglycan, which is thicker than that of Gram-negative bacteria.
What are some characteristic arrangements of prokaryotic cells after division?
Chains of Streptococcus and grapelike clusters of Staphylococcus.
p.3
Size Range of Prokaryotes
What is the size range for eukaryotic cells?
2 to >600 μm in diameter.
p.10
Cytoplasmic Membrane Structure and Function
What is the relationship between energy consumption and the cytoplasmic membrane?
The cytoplasmic membrane is involved in energy conservation and consumption.
p.17
Cell Surface Structures: Capsules and Fimbriae
What are capsules and slime layers in bacteria?
Structures that assist in attachment to surfaces.
p.12
Bacterial Cell Walls and Peptidoglycan
Which amino acids are typically found in peptidoglycan?
L-alanine, D-alanine, D-glutamic acid, and either L-lysine or diaminopimelic acid (DAP).
p.9
Cytoplasmic Membrane Structure and Function
What are the side chains of diphosphoglycerol tetraethers in Archaea?
Biphytanyl C40 side chains.
p.16
Cell Surface Structures: Capsules and Fimbriae
What is a characteristic of a capsule?
It is tightly attached, has a tight matrix, and can exclude particles.
p.16
Cell Surface Structures: Capsules and Fimbriae
What is a characteristic of a slime layer?
It is loosely attached, easily deformed, and cannot exclude particles.
p.7
Cytoplasmic Membrane Structure and Function
What components are found in the bacterial cytoplasmic membrane?
Hydrophobic and hydrophilic components.
p.7
Cytoplasmic Membrane Structure and Function
What are the hydrophilic components of the bacterial cytoplasmic membrane?
Glycerol, phosphate, and another functional group (e.g., sugars, ethanolamine, choline).
p.7
Cytoplasmic Membrane Structure and Function
What remains exposed to the external environment or the cytoplasm in the bacterial cytoplasmic membrane?
The hydrophilic portions.
p.17
Cell Surface Structures: Capsules and Fimbriae
What is one function of capsules and slime layers regarding dehydration?
They prevent dehydration/desiccation.
p.14
Lipopolysaccharides (LPS) and Outer Membrane
What gastrointestinal symptoms are associated with lipid A from LPS?
Gas, diarrhea, and vomiting.
p.14
Lipopolysaccharides (LPS) and Outer Membrane
How does the chemistry of lipid A and O-specific polysaccharide vary?
It varies among species of gram-negative bacteria.
p.13
Lipopolysaccharides (LPS) and Outer Membrane
What role does the outer membrane play in prokaryotic cells?
It acts as a barrier against antibiotics and other harmful agents.
p.18
Cell Surface Structures: Capsules and Fimbriae
How do pili differ from fimbriae?
Pili are typically longer and fewer in number (1 or a few) compared to fimbriae.
p.12
Bacterial Cell Walls and Peptidoglycan
What are the two modified glucose components of peptidoglycan?
N-acetylglucosamine and N-acetylmuramic acid.
p.17
Cell Surface Structures: Capsules and Fimbriae
How do capsules act as virulence factors?
They block host immune cells.
p.9
Cytoplasmic Membrane Structure and Function
What are the side chains of phosphoglycerol diethers in Archaea?
Phytanyl C20 side chains.
p.13
Lipopolysaccharides (LPS) and Outer Membrane
What is lipid A in the context of LPS?
Lipid A is the toxic component of LPS, also known as an endotoxin.
Examples of gliding motility mechanisms
<p>excretion of polysaccharide slime, type IV pili/ twitching motility, gliding-specific proteins</p>
