7.1 Structural and Functional Diversity of Bacteria

Question 1

microscopic hair-
like organelle for locomotion through liquid or semi-solid media
• movement towards nutrient or away from harmful substance
• specialized ______ can act as sensory organelles which detect changes in the environment

Answer 1

flagella

Question 2

3 parts of flagella?
_____ - long, thin, helical structure composed of protein flagellin
_____ - curved sheath
_____ - stack of rings firmly anchored in cell wall

Answer 2

filament
hook
bas body

Question 3

Flagellar
Arrangements
• _____ - single flagellum at one end
• _____ - small bunches emerging from the same site
• _____ - flagella att both ends of cell
• _____ - flagella dispersed over surface of cell

Answer 3

Monotrichous
Lophotrichous
Amphitrichous
Peritrichous

Question 4

Flagellar Responses
Guide bacteria in a direction in response to external stimulus:
Chemical stimuli - _____; positive and negative
Light stimuli - ______
Signal sets flagella into motion clockwise or counterclockwise:
Counterclockwise - results in smooth linear direction - _____
Clockwise - _____

Answer 4

chemotaxis
phototaxis
run
tumbles

Question 5

Periplasmic, internal flagellum
• Contract → twisting/flexing motion

Answer 5

Axial Filament/Endoflagella

Question 6

fine, proteinaceous, hairlike bristles from cell surface
► Function: adhesion to other cells and surfaces

Answer 6

Fimbriae

Question 7

What would happen if a mutation inhibited production of fimbriae by Neisseria gonorrhoeae?

Answer 7

Fimbriae are commonly required for initiating the colonization that leads to disease, and their success as adhesion organelles lies in their ability to both initiate and sustain bacterial attachment to epithelial cells.

Question 8

PILI
► Rigid tubular structure made of ____ protein
► Found only in gram ____ cells
► Function: Joins cells for partial DNA transfer
► ______(conjugation)

Answer 8

PILIN
negative
Sexpilus

Question 9

How does pili contribute to the antibiotic resistance on microorganisms?

Answer 9

The plasmid is the self-replicating, autonomous, circular, extrachromosomal body that is responsible for antibiotic resistance in bacteria. Pili transfers this plasmid from one bacterial cell to another bacterial cell conferring antibiotic resistance this is how a pilus helps in promoting antibiotic resistance.

Question 10

GLYCOCALYX
Coating(sugar and/or proteins) external to cell wall
• Functions:
– Protects cell from _____ and _____
– Inhibits killing by WBCs by _______ (contributes to pathogenicity)
– Attachment (_____)
– _________ (EPS)

Answer 10

dehydration and nutrient loss
phagocytosis
biofilm
Extra polymeric substances

Question 11

BIOFILM FORMATION
5 stages?

Answer 11

attachment
growth
maturation
detachment
re-development

Question 12

Cell-to-cell signaling within and between different bacterial species, enabling the microorganisms to detect changes in the cell-population density in response to environmental conditions or external stimuli
• Important to regulate a diverse array of physiological activities:
• Symbiosis
• Virulence
• Competence
• Conjugation
• antibiotic production
• Motility
• Sporulation
• biofilm formation

Answer 12

QUORUM SENSING

Question 13

What might the role of quorum sensing in disease formation?

Answer 13

Quorum Sensing Within a Species Can Coordinate Disease Progression. The infamous gram-negative pathogenic bacteria Vibrio cholerae uses quorum sensing for virulence during a cholera infection. V. cholerae builds biofilms to help transport nutrients between colonies while simultaneously protecting them.

Question 14

enables prokaryotes to transfer genetic material even to organisms that are not their offspring
• Environmental stress triggers the large amount of genetic material exchange/transfer to for rapid acquisition of new genetic traits for survival
• transformation, conjugation, transduction

Answer 14

horizontal gene transfer

Question 15

Functions relevant to colonization
In ______, the recipient bacterium takes up extracellular donor DNA. In _______, donor DNA packaged in a bacteriophage infects the recipient bacterium. In ______, the donor bacterium transfers DNA to the recipient by mating.

Answer 15

transformation
transduction
conjugation

Question 16

How does genetic transfer affect the survival of bacterial species?

Answer 16

Still, genetic variation is key to the survival of a species, allowing groups to adapt to changes in their environment by natural selection.

Question 17

Gram-______ bacteria are surrounded by a thin peptidoglycan cell wall, which itself is surrounded by an outer membrane containing lipopolysaccharide. Gram-______ bacteria lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the former.

Answer 17

negative
positive

Question 18

Gram positive cell wall structure with mycolic acid (Mycobacterium, Nocardia)
– Pathogenicity
– High degree of resistance to certain chemicals and dyes → acid-fast stain

• No cell wall (Mycoplasma)
– Cell membrane stabilized by sterols
– Pleomorphic
– L forms (due to mutation in cell wall forming genes)
– Protoplast (Gram +), spheroplast (Gram -) loss of cell wall due to exposure to chemicals (lysozyme, penicillin)

Answer 18

Atypical Cell Wall

Question 19

Inert, resting cells
– ↑ Ca, dipicolinic acid (DPA)
– Longevity verges on immortality (25,250 M years)
– Pressurized steam at 120°C for 20-30 minutes
• Gram + (Clostridium, Bacillus, Sporosarcina)
• Sporulation → endospores
• Germination → vegetative growth

Answer 19

Endospores