Module 2: Shape, arrangement and size

Question 1

what is bacteriology

Answer 1

subdivision of microbiology that studies the morphology, ecology, genetics and biochemistry of bacteria

Question 2

what shape are bacteria cells

Answer 2

• come in limited assortment of shapes
• each species has a characteristic cell shape

Question 3

what is a cocci

Answer 3

• round like a ball

Question 4

what is a rod or bacilli

Answer 4

• tube like or sausage shaped

Question 5

spirochetes

Answer 5

long cockscrew shaped rodes
- short and flexible in length

Question 6

spirilla

Answer 6

• rigid spiral shaped cells
• usuall shorter

Question 7

what are stalks

Answer 7

• bacteria cells form stalks to anchor them to solid surfaces

Question 8

what is pleomorphic

Answer 8

no conistent cell shape

Question 9

T/F smaller bacteria typically can increase their populations faster then larger cell species

Answer 9

True

Question 10

plasma membrane

Answer 10

• the inner most layer
• encompasses the cytoplasm
• requirement for all living cells
• selective permeable memebrane (letting in certain things but not others)
• an anchor point - multiple receptors for detecting and responding to chemicals in the surrounding environment
• a lipid component of amphipathic lipids (hydrophilic and hydrophobic component)
• membrane proteins - loosely connected to the memebrane

Question 11

Bacterial cell wall

Answer 11

• essential for all bacteria as it helps maintain shape and protects cell from osmotic lysis (popping)
• gram negative or gram positive

Question 12

capsules

Answer 12

• well organized layers that are not easily washed off
• often composed of polysaccharides
• can be visualized by negative staining under light microscope
• are not required for growth in labroatory cultures
• can also protect against drying out
• can exclude viruses anf most hydrophobic toxic materials

Question 13

slime layer

Answer 13

• zone of difused unorganized material that is removed easily
• usually composed of polysaccharides but not as easily seen

Question 14

s layers

Answer 14

• extermal layers made by some species of bacteria that is made of protien or glycoproteins
• in gram negativve bacteria the s layer adheres noncovalently to the outer most layer where is is associated with the peptidoglycan surface of typical gram positive walls
• functions - protecting cell ahainst ion and pH fluctuations, osmotic stress, enzymes of predatory bacteria
• can also help maintain cell shape and regidity
• protect host defence for some pathogens

Question 15

ribosomes

Answer 15

• cells machinery for protein synthesis and nearly each cell has a large number of them
• synthesize proteins to remain in the cell
• large and complex
• bacterial ribosomes are called 70S ribosomes and are comprised of two subunits

Question 16

cytosol

Answer 16

• liquid component of bacterial cytoplams
• home to all the molecules dissolved within it
• holds inclusions, ribosomes and plasmids
• macromolecular crowding results in a viscosity about 10 times higher than water and affects physical and chemical processes

Question 17

inclusions

Answer 17

• common in all cells
• formed by the aggregation of substances that may be organic or inorgnanic
• form granuals, crystals, globules or be amorphous in shape
• used for storage or to reduce osmotic pressure
• storage varies with the nutritional status of the cell and by species

Question 17

nucleoid

Answer 17

bacterial chromosome is located within the nucleoid which is simply a zone within the cytoplasm where the DNA and numerous protiens resides

Question 18

plasmids

Answer 18

• extrachromosomal DNA molecules
• relatively few genes
• both circular and linear plasmids have been documented but most known are circular
• plamids can carrt unimportant cells and cells that offer a selective advantage

Question 19

episomes

Answer 19

cells that have the ability to exsists as integrated and as freely replicating in the cytoplasm

Question 20

pili and fimbriae

Answer 20

thin, hair like appendages that stick out from the cell surface

Question 21

flagella

Answer 21

• more motile bacteria move by the way of flagella
• threadlike locomotor appendages extending outward from the plasma membrane and cell wall
• attachment to surfaces or contribute to ability to cause disease ( virulence factors)

Question 22

chemotaxis

Answer 22

• random movement of little advantage to a cell
• movement in response to the environment
• cell uses temporal sampling of the environmnet to decide if it wants to move or not
• if going favourable it goes straight
• non favourable has to spin around

Question 23

ensopsores

Answer 23

• dormat cells that are formed within so call mother cell
• ## only in bacillus and clostridium (rods) and sporosarcina (cocci)

Question 24

T/F bacterial spore formation is a reproductive strategie?

Answer 24

FALSE - its a survuval strategie during adverse conditions
- environmental stress = heat ultraviolet radiation, gamma radiation, chemical disinfectants and desiccation

Question 25

Archaeal cells

Answer 25

• bacterial like cells that vary in size and shape
  either free or clustered
• can be either large or small

Question 26

what kind of linkages make up isoprene

Answer 26

ether linkages
- joined to glycerol with the third carbon in the glycerol containing a charged head goup such as phosphate

Question 27

lipid monolayer

Answer 27

• glycerol head attached to each end
• one hydrophobic tail taversing the hydrophibis region

Question 28

what do archaea cell walls lack

Answer 28

peptidoglycan

Question 29

do eukaryotic cells have walls

Answer 29

not always
- when they do its different from bacteria and crhaea

Question 31

virons

Answer 31

nucleocapsid - nucliec acid (DNA or RNA) and virus coat = capsid
- virons covered in a lipid memebrane are enveloped viruses

Question 32

lytic infection

Answer 32

replicating and bursting from its host cells

Question 33

lysogenic

Answer 33

turn off its lytic pathway and remain silent within the infected cell
- gets into host chromosomes and remains undetected - able to shoot stresses into the host cell

Question 34

can viruses replicate on their own?

Answer 34

• they cannot, susceptible host cell strain/line must be propagated and infected with the virus to allow more replication
• counting plaques which are distinct areas of killed or damaged cells created as the virus replicates

Question 35

viroids

Answer 35

• small infections RNAs molecules that cause disease in plants
• do not code proteins
  they RNA paring with mRNA of some essential gene