Chapter 4

Question 1

Archaeal size, shape, and arrangement

Answer 1

Cocci and rods are common shapes, no spirochetes or mycelial forms yet.
sizes vary (typically 1-2um for rods, 1-5um in diameter for cocci)

Question 2

Archaeal Cell membrane

Answer 2

a phospholipid bilayer and proteins, lack fatty acids and ester bonds, have isoprene units in place of fatty acids, have ether linkages

Question 3

Archaeal cell envelope

Answer 3

varied S layers attached to plasma membrane. pseudomurein, complez polysaccharides, proteins, or glycoproteins found in some other species, only ignicoccus has outer membrane

Question 4

Ribosomes

Answer 4

bacterial/archaeal= 70S.
eukaryotic=80S.
Bacterial and archaeal ribosomal RNA= 16S small subunit, 23S and 5S in large subunit

Question 5

Nucleoid

Answer 5

Irregularly shaped region in bacteria and archeae, usually not membrane bound, location of chromosome, usually 1, supercoiling and nucleoid proteins aid in folding

Question 6

Pili

Answer 6

composed of pilin protein and homologous to bacterial type IV pili proteins. Pili formed have a central lumen similar to bacterial flagella, but not bacterial pili, may be involved in archaeal adhesions mechanisms

Question 7

Cannulae

Answer 7

hollow, tubelike structures on the surface of thermophilic archae in the genus pyrodictium, function is unknown, may be involved in formation of networks of multiple daughter cells

Question 8

Flagella

Answer 8

thinner, more than one type of flagellin protein, not hollow, hook and basal body difficult to distinguish, more related to type IV secretion systems, growth occurs at base, not the end

Question 9

Motility

Answer 9

Directed movement!
Taxis- directed cell movement in response to some stimulus.
Chemotaxis- move toward chemical attractants such as nutrients, away from harmful substances.
Also, can move in response to temp, light, oxygen, osmotic pressure, and gravity

Question 10

Fimbriae

Answer 10

short, thin, hairlike, proteinaceous appendages, mediate attachment to surfaces, some required for motility or DNA uptake

Question 11

Sex pili

Answer 11

similar to fimbriae except longer, thicker, and less numerous. genes for formation found on plasmids, required for conjugation

Question 12

Monotrichous flagella

Answer 12

one flagellum

Question 13

polar flagellum

Answer 13

flagellum at end of cells

Question 14

amphitrichous flagella

Answer 14

one flagellum at each end of cell

Question 15

lophotrichous flagella

Answer 15

cluster of flagella at one or both ends

Question 16

peritrichous flagella

Answer 16

spread over entire surface of cell

Question 17

Three parts of Flagella

Answer 17

Filament= extends from cell surface to the tip, hollow, rigid cylinder, composed of the protein flagellin,some bacteria have a sheath around filament.
Hook+ links filament to basal body, made of protein.
Basal body= series of rings that drive flagellar mototr

Question 18

Flagellar synthesis

Answer 18

Complex process involving many genes, gene products.New flagellin molecules transported through the hollow filament using Type3-like secretion system. Filament subunits self assemble with help of filament cap at tip, not base.

Question 19

Chemotaxis

Answer 19

movement toward a chemical attractant or away from a chemical repellent. Changing concentrations of chemical attractants and chemical repellents bind chemoreceptors of chemosensing system

Question 20

Bacterial Flagellar Movement

Answer 20

Flagellum rotates like a propeller, very rapid rotation up to 1100 revolutions/sec. Counterclockwise rotation causes forward motion (run). Clockwise rotation disrupts run causing cell to stop and tumble.

Question 21

Mechanisms of Flagellar movement

Answer 21

flagellum is 2 part motor producing torque. Rotor- C(FliG protein) ring and MS ring turn and interact with stator. Stator (Mot A and Mot B proteins) form channel through plasma memebrane, protons move through Mot A and B channels and produce energy through proton motive forces, torque powers rotations of the basal body and filament

Question 22

Spirochete motility

Answer 22

Have corkscrew shape which allows them to move in viscous media. 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 23

Twitching

Answer 23

Pili at ends of cell. Short, intermediate, jerky motions. Cells are in contact with each other and surface.

Question 24

Gliding

Answer 24

smooth movements

Question 25

Cytoplasm

Answer 25

material bounded by the plasmid memebrane. 90-94% water dissolved solutes, contains many enzymes and ribosomes.

Question 26

Cytoskeleton

Answer 26

network of fibrous proteins within cytoplasm. Homologs of all 3 eukaryotic cytoskeletal elements have been identified in bacteria and 2 in archaea. Functions are similar in eukaryotes, role in cell divisions, protein localization, and determination of cell shape

Question 27

intracytoplasmic membranes

Answer 27

1. Cell membrane infoldings- observed in many photosynthetic bacteria, analogous to thylakoids of chloroplasts, reaction centers for ATP formation

Question 28

Inclusions

Answer 28

membrane bound storage structures containing granules of organic or inorganic material that are stockpiled by the cell for future use. Some are enclosed by a single-layered membrane, but not a unit membrane.

Question 29

Storage inclusions

Answer 29

storage of nutrients, metabolic end products, energy, building blocks. Glycogen storage, carbon storage, phosphate, amino acid

Question 30

microcompartments

Answer 30

not bound by membranes but compartmentalized for a specific function. Carboxysomes= CO2 fixing bacteria. Contains the enzyme ribulose 1-5-bisphosphate carboxylase(rubisco), enzyme used for CO2 fixation.

Question 31

Gas vacuoles

Answer 31

fund in aquatic photosynthetic bacteria and archaea. Provide buoyancy in gas vesicles.

Question 32

Magnetosomes

Answer 32

found in aquatic bacteria, magnetite particles for orientation in Earth’s magnetic field. Cytoskeletal protein MamK

Question 33

plasmids

Answer 33

many prokaryotes have additional,smaller,circular but not supercoiled ds DNA in there cytoplasm. they contain nonessential genes. Extrachromosomal DNA found in bacteria, archaea, some fungi, usually small, closed circular DNA molecules. Exist and replicate independently of chromosome.

Question 34

Curing

Answer 34

loss of a plasmid

Question 35

Bacterial endospore

Answer 35

complex, dormant structure formed by some bacteria in various locations within the cell. Function is to survive extremem environments for the organism. Resistant to numerous environmental conditions (heat, radiation, chemicals, desiccation)

Question 36

Endospore structure

Answer 36

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 ribosome

Question 37

What makes an endospore resistant?

Answer 37

calcium (complexed with dipicolinic acid). Small acid soluble DNA binding proteins. Dehydrated core. Spore coat and exosporium protect

Question 38

Sporulation

Answer 38

Process of endospore formation. Occurs in a few hours. Normally commences when growth ceases because of lack of nutrients, or presence of toxic substances. Complex multistage process

Question 39

Germination

Answer 39

transformation of endospore into vegetative cell complex, multistage process

Question 40

Formation of vegetative cell

Answer 40

activation= prepares spores for germination, often results from treatment like heating.
Germination- env. nutrients are detected, spore swelling and rupture of absorption of spore coat, loss of resistance, increased metabolic activity.
Outgrowth- emergence of vegetative cell