lecture 1.6

Question 1

What are the different types of motility?

Answer 1

Flagellar movement
Spirochete motility
Twitching motility
Gliding motility

Question 2

Chemotaxis=

Answer 2

move toward chemical attractants such as nutrients, and away from harmful substances or environments

Question 3

Why would Bacteria/Archaea move in regards to chemotaxis?

Answer 3

Move in response to temperature, light, oxygen, osmotic pressure, and gravity
Changing concentrations of chemical attractants and chemical repellents bind chemoreceptors of chemosensing system

Question 4

Describe Flagellar movement

Answer 4

very rapid rotation up to 1100 revolutions/sec
in general, counterclockwise (CCW) rotation causes forward motion (run)
in general, clockwise rotation (CW) disrupts run causing cell to stop and tumble

Question 5

How fast does a flagellum rotate?

Answer 5

up to 1100 revolutions/sec

Question 6

What does counterclockwise rotation cause in flagellum?

Answer 6

forward motion (run)

Question 7

What does clockwise rotation cause in flagellum?

Answer 7

disrupts run causing cell to stop and tumble

Question 8

look at movement of flagellum mechanism

Answer 8

See notes at home

Question 9

Describe spirochete motility

Answer 9

Multiple flagella form axial fibril which winds around the cell
Flagella remain in periplasmic space inside outer sheath
Corkscrew shape exhibits flexing and spinning movements

Question 10

Describe twitching

Answer 10

pili at ends of cell
short, intermittent, jerky motions
cells are in contact with each other and surface

Question 11

Describe gliding

Answer 11

pili at ends of cell
smooth movements
cells are in contact with each other and surface

Question 12

What happens , in regards to chemotaxis movement, in the presence of an attractant?

Answer 12

tumbling frequency is intermittently reduced and runs in direction of attractant are longer
(it is the opposite response if there is a repellent)

Question 13

Biased Random Walk=

Answer 13

a random walk/series of motions with the goal of getting somewhere, but is random in the movement of how and when it will get there

Question 14

What is a bacterial Endospore?

Answer 14

Complex, dormant structure formed by some bacteria
Various locations within the cell
Resistant to numerous environmental conditions

Question 15

What are some of the enviromental conditions that an endospore is resistant to?

Answer 15

heat
radiation
chemicals
desiccation

Question 16

Describe the endospore structure

Answer 16

Spore surrounded by thin covering called exosporium
Thick layers of protein form the spore coat
Cortex, beneath the coat, thick peptidoglycan
Core has nucleoid and ribosomes

Question 17

exosporium=

Answer 17

thin covering surrounding the spore in an endospore

Question 18

What makes an endospore so resistant?

Answer 18

Calcium (complexed with dipicolinic acid)
Small, acid-soluble, DNA-binding proteins (SASPs)
Dehydrated core
Spore coat and exosporium protect

Question 19

sporulation=

Answer 19

process of endospore formation

Question 20

Describe the process of sporulation

Answer 20

Occurs in a hours (up to 10 hours)
Normally commences when growth ceases because of lack of nutrients
Complex multistage process

Question 21

What are the three stages of formation for a vegatative cell?

Answer 21

activation
germination
outgrowth

Question 22

Describe the stage of activation in the formation of a vegetative cell

Answer 22

prepares spores for germination

often results from treatments like heating

Question 23

Describe the stage of Germination in the formation of a vegetative cell

Answer 23

environmental nutrients are detected
spore swelling and rupture of absorption of spore coat
increased metabolic activity

Question 24

Describe the stage of outgrowth in the formation of a vegetative cell

Answer 24

emergence of vegetative cell

Question 25

What is common between Archaea and Eukarya

Answer 25

genes encoding proteins for DNA replication, transcription, translation

Question 26

What is common between Archaea and Bacteria

Answer 26

genes for metabolism | have multi-genic operons

Question 27

What is unique to Archaea?

Answer 27

unique rRNA gene structure | some are capable of methanogenesis

Question 28

What are Archaea best known for?

Answer 28

growth in anaerobic, hypersaline, pH extremes, and high-temperature habitats (Also found in marine arctic temperature and tropical waters)

Question 29

What are the common shapes of Archaea?

Answer 29

cocci, rods, branched/flat shapes

Question 30

What shapes can Archaea not form?

Answer 30

no spirochetes or mycelial forms yet

Question 31

How are Archaeal Cell walls different from Bacteria?

Answer 31

S layer may be only component outside plasma membrane some lack cell wall capsules and slime layers are rare

Question 32

Describe the lipids used in archaeal membranes

Answer 32

``` isoprene units (five carbon, branched) ether linkages rather than ester linkages to glycerol ```

Question 33

Do all archaea have a bilayer structured cell memrane?

Answer 33

No, some are monolayer

Question 34

Describe Bacterial/Eukaryotic lipds

Answer 34

Contain fatty acids in ester linkages to glycerol

Question 35

Describe Archaeal lipids

Answer 35

Contain hydrocarbons derived from isoprene in ether linkages to glycerolw

Question 36

Describe the differences between Bacterial/Eukaryotic lipids and Archaeal lipids

Answer 36

Bacterial have fatty acids and ester linkages | Achaeal contain hydrocarbons derived from isoprene and ether linkages

Question 37

Describe archaeal cell envelopes

Answer 37

varied S layers attached to plasma membrane pseudomurein (peptidoglycan-like polymer) complex polysaccharides, proteins, or glycoproteins found in some other species

Question 38

How do archeal cell walls differ from bacterial call walls?

Answer 38

Lack peptidoglycan Most common cell wall is S layer May have protein sheath external to S layer S layer may be outside membrane and separated by pseudomurein Pseudomurein may be outermost layer – similar to Gram-positive microorganisms

Question 39

pseudormurein

Answer 39

peptidoglycan-like polymer may be outermost layer – similar to Gram-positive microorganisms S layer may be outside membrane and separated by pseudomurein

Question 40

Describe the archaeal ribosome

Answer 40

bacterial/archaeal ribosome = 70S 16S small subunit, 23S and 5S in large subunit and 5.8S more similar to eukarya than bacteria

Question 41

Describe archaeal pili

Answer 41

not well understood as of yet | some composed of pilin protein and homologous to bacterial type IV pili proteins

Question 42

What is the archaeal pili structure like?

Answer 42

pili formed have a central lumen similar to bacterial flagella, but not bacterial pili

Question 43

What is archaeal pili used for?

Answer 43

may be involved in archaeal adhesion mechanisms

Question 44

What are the differences of Archaeal Flagella to Bacterial Flagella

Answer 44

thinner Flagellum are not hollow Hook and basal body difficult to distinguish Growth occurs at the base, not the end