Questions and Answers
What causes swimming motility in prokaryotic cells?
Which of the following describes the structure of bacterial flagella?
What is the role of the proton motive force in bacterial flagella movement?
In which type of flagellation are flagella located at one or both ends of the bacterial cell?
Signup and view all the answers
What is the main difference between bacterial and archaeal flagella?
Signup and view all the answers
How does the arrangement of flagella influence the swimming pattern of bacteria?
Signup and view all the answers
What is the first step in the synthesis of bacterial flagella?
Signup and view all the answers
What swimming pattern is typically associated with bacteria that have peritrichous flagella?
Signup and view all the answers
What is gliding motility?
Signup and view all the answers
Which mechanism uses the secretion of a slimy substance for movement?
Signup and view all the answers
How does the Type IV Pili Mechanism enable movement?
Signup and view all the answers
What describes chemotaxis?
Signup and view all the answers
In peritrichously flagellated bacteria, what movement occurs when they tumble?
Signup and view all the answers
What is true phototaxis?
Signup and view all the answers
Which type of taxis is specifically related to the presence of oxygen?
Signup and view all the answers
What does the capillary tube assay measure?
Signup and view all the answers
Study Notes
Introduction to Microbial Locomotion
- Motility enables prokaryotic cells to navigate their environments.
- Major prokaryotic cell movement types include swimming and gliding.
Swimming Motility
- Flagella, measuring 15-20 nm, facilitate swimming motility in bacteria.
Types of Flagellation
- Polar Flagellation: Flagella attached at one or both ends of a cell.
- Peritrichous Flagellation: Flagella dispersed over the entire surface of the cell.
Flagellar Structure
- Flagella are helical with a consistent wavelength.
- Components include:
- Tip
- Filament
- Hook
- Motor: Comprising L, P, MS, and C Rings.
- Mot proteins
- Fli proteins
Flagellar Movement
- Functions as a rotary motor allowing circular movement.
- Structure includes rotor (central rod and rings) and stator (mot proteins).
- Movement powered by the bacterial proton motive force.
Archaeal Flagella
- Have a width of 10-13 nm.
- Composed of various flagellin proteins and powered directly by ATP.
Flagellar Synthesis
- Begins with assembly of MS and C rings in the cytoplasmic membrane.
- Flagellin flows through the hook to form the filament; guided by cap proteins.
Speed and Motion Influences
- Speed and movement direction depend on flagella type and arrangement.
- Polar Flagella: Result in slow and linear swimming.
- Peritrichous Flagella: Cause erratic or tumbling swimming patterns.
Mechanisms of Gliding Motility
- Rod-shaped bacteria can glide without flagella, cilia, or pili.
Gliding Mechanisms
- Slime Extrusion: Secretion of a slimy substance for propulsion.
- Type IV Pili Mechanism: Involves retraction and extension of pili (e.g., Pseudomonas aeruginosa).
- Protein Adhesion Complex: Forms a sticky adhesion allowing movement (e.g., Myxococcus xanthus).
- Surface Protein Movement: Uses gliding-specific proteins for forward motion (e.g., Flavobacterium).
Chemotaxis
- Directed movement in response to chemical stimuli.
Differences in Chemotaxis
- Peritrichous Flagellated Bacteria: Exhibit runs (forward swimming) and tumbles (stopping and jiggles).
- Polar Flagellated Bacteria: Can reverse flagella rotation to change movement direction.
Measuring Chemotaxis
-
Capillary Tube Assay:
- Controlled: No change in microorganism movement.
- Attractant: Microorganisms swarm towards chemical.
- Repellent: Microorganisms move away from chemical.
Phototaxis
- True Phototaxis: Movement towards increasing light intensity.
- Scotophobotaxis: Random swimming out of illuminated areas under a microscope.
Other Types of Taxes
- Aerotaxis: Movement towards or away from oxygen.
- Osmotaxis: Movement influenced by ion concentration.
- Hydrotaxis: Movement towards or away from water.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz focuses on the types of microbial locomotion, particularly in prokaryotic cells. Students will explore the mechanisms of motility such as swimming and gliding, as well as the role of flagella in swimming motility. Test your knowledge on these critical aspects of microbial movement.
