Questions and Answers
How do axial filaments differ from regular bacterial flagella?
The axial filament is located between the cell membrane and the outer membrane.
What is the advantage to spirochetes of the corkscrew movement provided by axial filaments?
It allows the cells to move more easily through viscous human tissues and fluids, such as mucus.
Axial filaments are composed of?
endoflagella.
How is osmosis different from simple diffusion?
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What will happen to a cell that is placed in a solution containing a high concentration of sugar, a molecule that cannot pass across the cell membrane?
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How is simple diffusion different from other types of passive transport?
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Why is no energy required in passive transport?
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Once equilibrium is reached?
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Which of the following would not move freely across the cytoplasmic membrane?
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Which of the following scenarios is an example of bacterial motility?
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Axial filaments are found on?
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What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass?
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Integral proteins are mostly involved in?
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How does water enter and exit a cell?
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A glycoprotein?
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Tumbles occur when?
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Which of the following types of bacterial cells would have only a single flagellum?
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Peritrichous bacteria make a run when?
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Which of the following types of bacterial cells would have flagella located at only one end of the cell?
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What must happen before a cell can begin mitosis?
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The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?
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The chromosomes line up in the center of the cell during which phase of mitosis?
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The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?
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The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?
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At the end of the mitotic (M) phase, the cytoplasm divides in a process called __________.
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Which of the following structural features of E.coli is most responsible for the signs and symptoms of a urinary tract infection?
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Which statement best describes how streptomycin attacks bacterial cells?
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Why are most Gram-negative bacteria resistant to the actions of penicillin?
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Which of the following is NOT a classic sign and/or symptom of a urinary tract infection?
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Which of the following statements about bacterial flagella is true?
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Taxis is?
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Which of the following terms refers to a bacterium moving towards a light source?
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As a bacterium approaches a food source, one would expect?
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Why are receptors on the cell surface necessary for bacterial movement?
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What structural part of a bacterial flagellum is composed of flagellin?
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How are Gram-positive and Gram-negative flagella different?
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The rings?
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The basal body is comprised of which structural component(s) of flagella?
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Pathogenic bacteria?
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Which of the following molecules would be blocked by a cell membrane?
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Hydrophobic molecules move across a membrane?
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What would you expect to see as you look through the microscope at the Gram stain from a culture of Streptococcus pyogenes?
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Prokaryotes lack organelles.
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Study Notes
Axial Filaments and Bacterial Movement
- Axial filaments are found between the cell and outer membrane of spirochetes, enabling unique corkscrew movement.
- This movement aids spirochetes in navigating through viscous human tissues, improving mobility in environments like mucus.
- Axial filaments are composed of endoflagella.
Transport Mechanisms
- Osmosis involves water movement influenced by solute concentration rather than its own.
- Nonspecific permeases allow diverse molecules to cross the cytoplasmic membrane.
- When a cell is placed in a hypertonic solution (high sugar concentration), it loses water and may shrivel.
- Simple diffusion operates without permeases, unlike other passive transport methods.
- Passive transport relies on concentration gradients, eliminating the need for energy.
Cell Membrane Characteristics
- Positively charged ions, such as hydrogen, cannot freely cross the cytoplasmic membrane.
- Phospholipid membranes have hydrophilic and hydrophobic regions, providing selective permeability.
- Integral proteins predominantly facilitate transport across membranes.
- Water transport occurs via simple diffusion or integral protein channels.
Bacterial Motility and Flagella
- Tumbles in flagellar motion occur when flagella rotate clockwise, while counterclockwise rotation leads to runs.
- Bacteria with a single flagellum are classified as monotrichous; lophotrichous have flagella at one end.
- Peritrichous bacteria run when flagella bundle and turn counterclockwise.
- Taxis refers to bacteria's movement toward or away from stimuli, enhancing their ability to respond to environmental cues.
Mitosis Phases
- Mitosis begins with chromosome duplication preceding cell division.
- Key phases of mitosis include:
- Prophase: Centrosomes move apart; nuclear envelope disassembles.
- Metaphase: Chromosomes align at the cell center.
- Anaphase: Sister chromatids separate and move to opposite poles.
- Telophase: Chromosomes reach poles; nuclear envelopes reform.
- Cytokinesis follows the mitotic phase, dividing the cytoplasm.
Cell Structures and Characteristics
- Fimbriae on E. coli contribute to urinary tract infection symptoms.
- Streptomycin inhibits protein synthesis by targeting the 70S ribosome of bacteria.
- Gram-negative bacteria resist penicillin due to the outer membrane barrier.
- Bacterial flagella can rotate fully, aiding in movement.
Cell Wall Types and Structures
- Bacterial cell walls are categorized as Gram-positive (purple) and Gram-negative (pink/red) based on staining.
- These distinctions correlate with sensitivity to antibiotics and other structural characteristics.
- Common structures in prokaryotic cells include nucleoid, ribosomes, cytoplasm, and plasma membrane.
- Ions are typically blocked from passing through the cell membrane, while hydrophobic molecules move freely.
Microscopy Observations
- In a Gram stain of Streptococcus pyogenes, expect to see purple, spherical-shaped organisms in chain formations, indicative of its Gram-positive nature.
Studying That Suits You
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Description
Explore the fundamental concepts of axial filaments in this interactive set of flashcards from Microbiology Chapter 4. Dive into the differences between axial filaments and bacterial flagella, as well as the advantages of corkscrew movement for spirochetes. Perfect for students seeking to reinforce their understanding of this topic.
