Microbiology Ch 4

Microbiology Chapter 4 : Prokaryotic Cell Structure

What is the average size of bacteria?

0.5-2.0 micrometer

What are the 7 shapes bacteria could be?

Coccus, Bacillus, Vibrio, Coccobacillus, Spirillum, Spirochete, and pleomorphic

What are the 6 arrangements bacteria can be?

Diplo, Strepto, Tetrad, Sarcinae, Staph, and Palisades

What is the name for ‘round’ shape

Coccus

What’s the name for ‘rod-shaped’

BacillusW

What’s the name for ‘short rod, almost round”

Coccobacillus

What’s the name for ‘curved’ shaped?

VibrioW

What’s the name for ‘wavy’ shape?

Spirillum

What’s the name for ‘corkscrew’ shape?

Spirochete

What’s the name for ‘mixed’ shape?

Pleomorphic

What’s the name for ‘pairs’ arrangement

Diplo

What’s the name for ‘chain/line” arrangement?

Strepto

What’s the name for ‘four’ arrangement?

Tetrad

What’s the name for ‘group’ arrangement?

Sarcinae

What’s the name for ‘random clusters’ arrangement?

Staph

What’s the name for ‘side by side rows of cells’

Palisades

What would be the Shape and Arrangement of this picture?

Staphylococcus

What would be the Shape and Arrangement of this picture?

Streptobacillus

What does pleomorphic mean?

vary in shape and size

what is Prosthecae?

some aquatic bacteria have extensions that give them a star like apperance

How does binary fission work?

new cell wall material grows, chromosome duplicates, and “new cell” pinches off

What is a biofilm?

Bacteria living in a group/ community with one another

What’s a nanowire?

transfer electrons or other substances via appendages (modified pili) or extension of outer membrane

What’s the internal structure of bacteria?

cytoplasm with ribosomes, nuclear region (nucleoid), and granules and or vesicles

What’s the outer layer of bacteria?

the outer membrane, cell wall, and cell membrane

What’s the external structure of bacteria?

S layer, glycocalyx, flagella, pili, and fimbriae,

What is used for movement?

Flagella and Axial filaments

What is used for Attachment?

Pili (DNA) and fimbriae (Share DNA)

What is flagella?

long, thin extensions that allow for movement of bacteria

What is Monotrichous?

One flagellum at the end

What is Lophotrichous?

two or more flagella at one or both end

What is Amphitrichous?

two flagella, one at each end

Which of the flagella are Polar?

Monotrichous, Lophotricous, and Amphitrichous

What is Peritrichous?

flagella all over

What is Atrichous?

without flagella (example – most cocci)

What’s the external structure of Flagella

Filament structure, hook, and basal body

Describe the external structure of Gram Negative

have a pair of rings in cell membrane and a pair in peptidoglycan and LPS layers (4 rings total)

Describe the external structure of Gram Positive

have one ring in cell membrane and one ring in cell wall (2 rings total)

What is Chemotaxis?

Movement due to substances (attractants or repellents) in the environment

In which way do the bacteria ‘run’

Counterclockwise

In which way do the bacteria ‘tumble’

clockwise

What is the S layer?

big chain of protein

What is the Glycocalyx?

Polysaccharide-containing substance found external to cell wall, for coating and attachment

If the glycocalyx is attached loosely what is it called?

Slime Layer

If the glycocalyx is attached tightly what is it called?

Capsule

What is endflagella or periplasmic flagella?

Attached to the ends of spirochetes causing it to rotate like a corkscrew

What is Pili and Fimbriae?

Tiny, hollow projections that attach bacteria to surfaces Made of subunits of pilin protein

What is Conjugation pili/F pili (sex pili)?

Attaches two cells and serves as bridge to transfer DNA (conjugation)

What is Attachment pili/fimbriae?

Help bacteria stick to surfaces. Example gonorrhoeae – uses pili to stick to epithelial cells (cells lining the urogenital system)

What is the Outer Membrane?

Only in GM- . Attached to peptidoglycan by lipoprotein molecules. Contains LPS (lipopolysaccharide) “endotoxin” rather than phospholipids (Polysaccharides + lipid A very toxic!!) Released upon bacterial cell death

What is Porin Proteins?

Block Harmful chemicals

What is Periplasmic Space?

Gap between cell wall and cell membrane. Transports proteins and metabolites. Most common in GM-, rarely in GM+

Whats the Cell Wall?

Lies outside cell membrane. Two major functions: Maintains shape, Prevents cell from bursting

What is the Cell Wall made up of?

Peptidoglycan

What is part of the cell wall?

Alternating NAG (N-acetylglucosamine) and NAM (N-acetylmuramic acid) cross linked by tetrapeptides (4 amino acids)

What bacteria have a interbridge? and what is it made from?

Gram Positive with Lysine (3rd amino acid)

What is the 3rd amino acid for Gram Negative?

Diaminopimelic acid

What is Teichoic Acid and which gram bacteria is it in?

Polysaccharide polymers of glycerol, phosphates, and sugar attached to peptidoglycan (Gram Positive Only) Maintain cell shape and regulate cell division

What is Lipoteichoic Acid?

Polysaccharides that attach to the lipids in the cell membrane (Both), maintain cell shape and regulate cell division

What are endospores?

Dormant structure formed inside some bacteria to help the bacteria survive adverse conditions. Highly resistant to heat, drying, acids, bases, disinfectants, radiation Structure - core, cortex, spore coat As conditions become more favorable - the endospores germinate – develop into vegetative cells (cells that are metabolizing nutrients)

What are cytoskeletons?

Proteins located just under cell membrane (similar to eukaryotic actin). Helical ribbon shape. Unique to bacteria, thus potential target for drugs

What are BMCs (Bacterial microcompartments)

Shells of protein that contain enzymes that are involved in the same pathways (ensures closeness to one another)

What are Vesicles?

Membrane-enclosed structure. Place of storage of: gas (for floatation), lipids, proteins

What are Granules?

No membranes, contains densely compact substances (glycogen,polyphosphates, magnetosomes)

What’s the Sedimentation rate of ribosomes in Prokaryotes?

70S (Svedberg unit) – rate at which they move toward the bottom of a tube during

centrifugation. Round with one large subunit (50S) and one small subunit (30S) in prokaryotes

What are L-form Bacteria?

Bacteria that loss their ability to form cell walls due to natural occurrences or by chemical treatment. Can escape antibiotic treatment (b/c no cell wall) and may revert to walled forms after treatment stops (Mycobacterium paratuberculosis – Crohn’s disease)

What’s Archaea?

Contain pseudopeptidoglycan; cells walls are polysaccharides or pure protein (depending on species)

What are mycoplasma?

Lack cell wall, Cell membrane has sterols, which protect from swelling and bursting

Describe Acid Fast Bacteria

a group of bacteria that resist being decolorized by acids during laboratory staining procedures because they have thick, waxy cell walls. Turns Gram Positive Ziehl-Neelsen acid-fast stain – stain red

What’s the process of Sporulation?

The cell is separated into Sporangium and Forespore. The sporangium begins to develop the early stages of the endospore around the forespore. Cortex and outer coat layers are deposited to make the complete endospore. loosing the sporangium