Chapter 4 – Microbiology Flashcard
Unlock all answers in this set
Unlock answers| How are prokayotes different from eukaryotes (3)? |
| 1. no nucleus 2. cell wall makeup 3. no membrane-bound organelles |
| Which structures are common to ALL bacteria? (4) |
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| Which structures are found in MOST bacteria? (2) |
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| Which structures are found in SOME bacteria? |
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| What are the three parts of a flagellum? |
1. filament (long part) 2. hook 3. Basal body (anchors to cell) |
| What are the four types of arrangements of flagella? |
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| What is chemotaxis and what are two types of it? |
flagellated bacteria move in response to chemical signals
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| What is phototaxis? |
| Flagellated movement in response to light |
| How do flagella move? |
Runs and tumbles
Runs are longer going up gradient Tumbles to test environment |
| What are cork-screwed bacteria called? |
| Spirochetes |
| What type of flagella do spirochetes have, where are they located, and what kind of movement do they cause? |
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| What are pili and what's their function? |
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Pili are found on in gram-positive bacteria True or False |
| False- only found in gram-negative |
| What are Fimbriae? What's their function? |
Fimbriae are small, bristlelike fibers found on the surface of a bacterial cell and most of them contain protein.
They stick to each other and to surfaces, causing colonization |
| Where is the glycocalyx located and what is it made of? |
Outside the cell envelope
Made of repeating polysaccharide units, protein, or both |
| What are the functions of the glycocalyx (3)? |
Protects the cell
Helps the cell adhere to the environment
Protects the cell against phagocytes (biofilm) |
| When is a glycocalyx termed a slime layer? What does it do? |
1. When the glycocalyx is loosely shielding the bacteria
2. It protects the bacteria from loss of water and nutrients; also adherance |
| When is a glycocalyx termed a capsule? What's its function? |
1. When the glycocalyx is bound more tightly to the cell and is denser and thicker ; 2. Protects from phagocytosis |
| What are the differences between gram + and gram - cell envelope structures? |
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What is the cell wall made of? What does it keep the cell from doing? What medical technology targets the cell wall? |
peptidoglycan
keeps cell from rupturing because of changes in pressure due to osmosis
Antibiotics target the cell wall, giving it little protection from lysis |
| What are the two layers of the gram - outer membrane? |
Uppermost layer contains lipopolysaccharides (LPS)
Innermost layer made of phospholipid layer-- anchored to cell wall |
| What 3 types of bacteria have nontypical cell walls? |
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| Describe a mycoplasma and its cell membrane. |
Mycoplasmas are very small and range in shape and can be found in many habitats.
Its cell membrane is stabilized by sterols and is resistant to lysis.
*Important medical species: Mycoplasma pneumonia (aka walking pneumonia) |
| What are L-forms and specific names for them? |
L-form arise naturally from a mutation in the wall-forming genes. They have no distinct shape.
Gram + are called protoplast Gram - are called spheroplast |
| What's a bacterial cell membrane (cytoplasmic membrane) made of and what are its functions (3)? |
Provides site for functions such as energy reactions, nutrient processing, and synthesis
Regulates transport
Secretion |
What is a bacterial chromosome? Where is it located? What's its method of replication called? |
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| Describe Plasmids. |
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| What is the S count for prokaryotic ribosomes? |
70S
Humans have 80S |
| What's the function of inclusion bodies? |
Serve as storehouse of nutrients (bacteria lay down nutrients in them during periods of nutrient abundance; use when nutrients are depleted) |
| What does the actin cytoskeleton do? Where is it located? |
Contributes to cell shape
Arranged in helical ribbons around cell just under cell membrane |
| What are the two phases of a bacteria's life cycle? |
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| What are the only genus known to produce endospores (3)? Are they gram + or gram -? |
Bacillus Clostridium Sporosarcina
All Gram + |
| What are the three general shapes of bacteria? |
Coccobacillus= short and plump Vibrio= gently curved bacillus |
| What's pleomorphism? |
| when cells of a single species cary to some extent in shape and size |
| What is a sarcina? |
| cubical packet of cocci |
| What are palisades? |
| row of bacilli cells oriented side by side |
| What was the early classification system of prokaryotes? |
| the phenotypic traits (shape, arrangement, growth, habitat, color, etc) |
| What is the current classification system of prokayotes? |
| phenotypic information with rRNA sequencing |
| How do we define a bacterial species? |
| A collection of bacterial cells all of which share an overall similar pattern of traits |
| What is a bacterial subspecies/strain/type? |
| Bacteria of the same species that have differing characteristics (ex. extra plasmids) |
| What's a serotype? |
| Representatives of a species that stimulate a distinct pattern of antibody (serum) responses in their hosts, because of distinct surface molecules |
| What are examples of obligate intracellular parasites (2)? |
| Rickettsias and Chlamydias |
| Describe Rickettsias and their characteristics. |
Gram-negative
Alternate between mammals and blood-sucking anthropods
Cannot survive or multiply outside host cell
Cannot carry out metabolism completely on their own
Examples: Rocky Mountain Spotted Fever (Rickettsia rickettsii) and endemic typhus (Rickettsia typhi) |
| Describe Chlamydias and how they're different from Rickettsias. |
require host cells for growth and metabolism
Not closely related
Not transmitted by arthropods
Examples: Chlamydia trachomatis (STD) and Chlamydophilia pneumonia (lung infections) |
| What's distinct about photosynthetic bacteria? |
Some produce oxygen during photosynthesis
Give us most of the oxygen we have today |
| What are cyanobacteria also known as? Why are they distinct? |
AKA Blue-Green Bacteria
Contain chlorophyll and have gas filled inclusions which allow them to float on water
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What are Green and Purple Sulfur Bacteria? Where do they live? |
Photosynthetic but don't give off oxygen
Live in sulfur springs, freshwater lakes, and swamps |
What makes Archaea distinct? What types of environments can they live in? |
Type of prokaryotes that have been around the longest-- they have adapted to every environment
They love extreme environments including extreme heat/cold, salt, acid, pH, pressure, and atmospheres |
