question

What are he two major groups of accessory appendages on bacteria?

answer

Motility and Attachment or channels

question

What are the motility appendages on bacteria?

answer

flagella and axial filaments

question

What are the attachment or channels appendages on bacteria?

answer

fimbriae (attachment) and pilli (channels)

question

What is the glycocalyx - surface coating on a bacteria that is loosely organized?

answer

Slime layer

question

What is the glycocalyx - surface coating on a bacteria that is highly organized?

answer

Capsules

question

Three major parts of a flagella:

answer

Filament, hook, and basal body

question

long, thin, helical structure composed of protein flagellin

answer

filament

question

curved sheath

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hook

question

stack of rings firmly anchored to cell wall

answer

basal body

question

What are the flagellar arrangements?

answer

Monotrichous, Lophootrichous, Amphitrichous, and Pertrichous

question

single flagellum at one end

answer

Monotrichous

question

small bunches emerging from the same site

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Lophotrichous

question

flagella at both ends of cell

answer

Amphitrichous

question

flagella dispersed over surface of cell; slowest

answer

Peritrichous

question

Rotates 360 degrees
functions in motility of cell through environment

answer

Flagella

question

If a flagella is moving counterclockwise the bacteria is moving foward and this is called a

answer

run

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If a flagella is moving clockwise the bacteria to stop and change direction and this is called a

answer

tumble

question

A chemical stimuli that bacteria respond to either positively (attracted) or negatively (repel) is called

answer

Chemotaxis

question

A light stimuli that bacteria respond to is called

answer

phototaxis

question

What type of bacteria have a periplasmic flagella?

answer

spirochetes (corkscrew-shaped)

question

Type of internal flagella, enclosed in the space between the outer sheath and the cell wall peptidoglycan

answer

Periplasmic Flagella

question

What type of flagella produce cellular motility by contracting and imparting twisting or flexing motion (like a spring)?

answer

Periplasmic Flagella

question

Fine, proteinaceous, hairlke bristles emerging from the cell surace that function in adhesion to other cells and surfaces

answer

fimbriae

question

Rigid tubular structure made of pilin protein
Found only in gram-negative cells
Function to join bacterial cells for partial DNA transfer called conjugation

answer

Pili

question

Coating of molecules external to the cell wall, made of sugars and/or proteins

answer

Glycocalyx

question

What are the two types of glycocalyx?

answer

Slime layer - loosely organized and attached
Capsule - highly organized, tightly attached

question

What is the first function of Glycocalyx?

answer

Protects cell from dehydration and nutrient loss.

question

What is the second function of glycocalyx?

answer

Inhibit killing by white blood cells by phagocytosis, contributing to pathogenicity. (Works like a kid slipping out of his jacket when you grab him.)

question

What is the third function of glycocalyx?

answer

Attachment - formation of biofilms

question

The external covering outside the cytoplasm is called

answer

the cell envelope

question

What are the two basic layers that compose of the cell envelope?

answer

cell wall and cell membrane

question

What does the cell envelope do?

answer

Maintains cell integrity

question

What type of bacteria has a thick cell wall composed primarily of peptidoglycan and cell membrane?

answer

Gram-positive bacteria

question

What type of bacteria has an outer cell membrane, thin peptidoglycan layer, and cell membrane?

answer

Gram-negative bacteria

question

Who discovered a staining technique that could be used to make bacteria in infectious specimans more visible?

answer

Hans Christian Gram in 1884

question

What color does a Gram+ cell turn?

answer

Purple

question

What color does a Gram- cell turn?

answer

Pink

question

Unique macromolecule composed of a repeating framework of long glycan chains cross-linked by short peptide (amino acid) fragments

answer

peptidoglycan

question

What determines cell shape, prevents lysis (busting) or collapsing due to changing osmotic pressures?

answer

Structure of a Cell Walls

question

What is the primary component of a cell wall?

answer

Peptidoglycan

question

The region between the cell wall and cell membrane of the cell envelopes of gram-negative bacteria

answer

Periplasmic space

question

Has a thick homogeneous sheath of peptidoglycan
- 20-80 nm thick

answer

Gram-Positive Cell Wall

question

Includes teichoic acid and lipoteichoic acid: that functions in cell wall maintenance and enlargement during cell division; more cations across the cell envelope; stimulate a specific immune response

answer

Gram-Positive Cell Wall

question

Some cells have a periplasmic space, between the cell membrane and cell wall.

answer

Gram-Positive Cell Wall

question

any of a class of strongly acidic polymers found in the cell walls, capsules, and membranes of all gram-positive bacteria and containing residues of the phosphates of glycerol and adonitol

answer

teichoic acid

question

Compounds formed from teichoic acid linked to glycolipid and found in the walls of most gram-positive bacteria.

answer

lipoteichoic acid

question

Composed of an outer membrane and a thin peptidoglycan layer

answer

Gram-Negative Cell Wall

question

Outer membrane is similar to cell membrane bilayer structure

answer

Gram-Negative Cell Wall

question

Outermost layer contains lipopolysaccharides and lipoproteins (LPS)
Lipid portion (endotoxin)may become toxic when released during infections
May function as receptors and blocking immune response
Contain porin proteins in upper layer - regulate molecules entering and leaving cell

answer

Gram-Negative Cell Wall

question

Bottom layer is a thin sheet of peptidoglycan
Periplasmic space above and below peptidoglycan

answer

Gram-Negative Cell Wall

question

A molecular complex of lipid and carbohydrae found in the bacterial cell wall.

answer

Lipopolysaccharide

The LPS of gram-negative baceria is an endotoxin with generalized pathologic effects such as fever

question

Transmembrane proteins of the outer membrane of gram-negative cells that permit transport of small molecules into the periplasmic space but bar the penetration of larger molecules.

answer

porin

question

Any of a group of soluble proteins that combine with and transport fat or other lipids in the blood plasma

answer

lipoprotein

question

Number of major layers in a Gram-Positive Cell Wall

answer

One

question

Chemical composition of a Gram-Positive Cell Wall

answer

Peptidoglycan, Teichoic acid, Lipoteichoic acid, Mycolic acids and polysaccharides

question

Overall thickness of a Gram-Positive Cell Wall

answer

Thicker (20-80 nm)

question

Does Gram-Poitive Cell have an outer membrane?

answer

No

question

What is the periplasmic space in a Gram-Positive cell like?

answer

Narrow

question

What is the permeability to molecules like in a Gram-Positive cell?

answer

More penetrable

question

Number of major layers in a Gram-Negative cell

answer

Two

question

Chemical composition of a Gram-Negative cell

answer

Lipopolysaccharide (LPS), Lipoprotein, Peptidoglycan, Porin proteins

question

Overall thickness of a Gram-Negative cell

answer

Thinner (8-11 nm)

question

Does the Gram-Negative Cell have an outer membrane?

answer

Yes

question

What is the periplasmic space of a Gram-Negative Cell like?

answer

Extensive

question

What is the permeability to molecules like in a Gram-Negative cell?

answer

Less penetrable

question

retain crystal violet and stain purple

answer

Gram-positive

question

lose crystal violet and stain red from safranin counterstain

answer

Gram-negative

question

T/F Gram stains are important basis of bacterial classification and identification.

answer

True

question

T/F Gram stains are a practical aid in diagnosing infection and guiding drug treatment.

answer

True

question

Nontypical Cell Wall
Several bacterial groups lack the cell wall structure of gram(+) or gram(-) bacteria

answer

For example, cells of Mycobacterium and Nocardia have peptioglycan, but most of their cell wall is composed of unique lipids (e.g., mycolic acid which contributes to pathogenicity)

Such lipids can give the cell wall a thick, waxy nature with a high degree of resistance to certain chemicals and dyes. Such resistance is basis for acid-fast stain used for diagnosis of infections caused by these microorganisms.

question

Some bacteria have no cell wall at all! This is very rare!

answer

For example, Mycoplasma
Cell membrane is stabilized by sterols (alcohols)
These bacteria are extremely varied in shape (pleomorphic). Pleomorphic means they can change their shape.

question

Phospholipied bilayer with embedded proteins - fluid mosaic model

answer

Cell Membrane Structure

question

Providing site for energy reactions, nutrient processing, and synthesis
Passage of nutrients into the cell and the discharge of wastes. (Cell membrane is selectively permeable)

answer

Functions of the cell membrane structure

question

Primary stain in a gram stain

answer

Crystal Violet

question

Mordant (means glue) in a gram stain

answer

Gram's Iodine

question

Decolorizer in a gram stain

answer

alcohol

question

The red dye counterstain in a gram stain

answer

Safranin

question

The internal structure of a bacterial cell are

answer

Cell Cytoplasm, Chromosome, Plasmids, Ribosomes, Inclusions and granules, Cytoskeleton

question

Dense gelatinous solution of sugars, amino acids, and salts
70-80% water (serves as solvent for materials used in all cell functions)
Components of this pool serve as building blocks for cell sythesis or as sources of energy

answer

Cell Cytoplasm

question

Single, circular, double-stranded DNA molecule that contains all the genetic information required by a cell
Aggregated in a dense aea call the nucleoid (not enclosed, DNA is tightly coiled)
When exposed to special stains or observed with an electron microscope, chromosomes have a granular or fibrous appearance.

answer

Chromosome

question

small circular, double-stranded DNA
Free or integrated into the chromosome
Duplicated and passed on to offspring
Not essential to bacterial growth and metabolism
May encode antibiotic resistance, tolerance to toxic metals, enzymes, and toxins
Used in genetic engineering - readily manipulated and trnasferred from cell to cell

answer

Plasmids

question

Made of 60% ribosomal RNA and 40% protein
Consist of two subunits: large and small
Prokaryotic differ from eukaryotic in size and number of proteins
site of protein synthesis
Present in all cells

answer

Ribosomes

question

Intracellular storage bodies
Vary in size, number, and content
Bacterial cell can use them when environmental sources are delpleted
Examples: glycogen poly B-hydroxybutyrate, gas vesicles for floating, sulfur and phosphate granules (metachromatic granules), particles of iron oxide

answer

Inclusions and granules

question

Many bacteria possess an internal network of protein polymers that is closely associated with the cell wall

answer

Cytoskeleton

question

Inert, resting (dormant),cells produced by the bacteria:
ex: Clostridium, Bacillus, and Sporosarcina

answer

Endospores

question

Sporeforms have a 2-phase life cycle:

answer

Vegaetative Cell - metabolically active and growing
Endospore - when exposed to adverse environmental conditions; capable of high resistance and very long-term survival

question

formation of endospores that are the hardiest of all life forms and withstand extremes in heat, drying, feezing, radiation, and chemicals

answer

Sporulation
(This is not a means of reproduction)

question

return to vegetative growth

answer

Germination

question

Coccus

answer

spherical

question

Bacillus

answer

rod

question

Coccobacillus

answer

very short and plump

question

vibrio

answer

rod - gently curved

question

spirillum

answer

helical, comma, twisted rod

question

Spirochete

answer

spring like

question

resistance linked to high levels of calcium and dipicolinic acid
dehydrated, metabolically inactive
thick coat
longevity verges on immortatlity, 250 million years
resistant to ordinary cleaning methods and boiling
Pressurized steam at 120 C for 20-30 will destroy

answer

Endospores

question

Cocci

answer

singles

question

Diplococci

answer

in pairs

question

Tetrads

answer

groups of four

question

Stapho-

answer

irregular clusters

question

Strepto-

answer

chains

question

sarcina

answer

cubical packets

question

Bacilli arrangements

answer

Diplobacilli - pairs
chains
palisades (kind of like the chain of hearts you would draw as a child)

question

The sizes of vacteria range from those just barely visible with light microscopy (0.2 nm) to those measuring a thousand times that size.

answer

The Dimensions of Bacteria

Microbiology Lecture Exam #2 – Flashcards

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