Introduction to bacteria

Question 1

ways in which bacteria can be identified

Answer 1

• size
• shape
• staining characteristics
• growth requirements

Question 2

bacterial chromosomes

Answer 2

bacteria contain one chromosome, no nucleus.

Question 3

Cell walls of gram positive bacteria

Answer 3

plasma membrane,

thick peptidoglycan layer above.

Question 4

cell walls of gram negative bacteria

Answer 4

plasma membrane, thin peptidoglycan layer, outer membrane, space in between the membranes called the periplasm, lipopolysaccharides embedded in outer membrane.

Question 5

penicillin binding proteins

Answer 5

cross links: transpeptidases, carboxypeptidases, endopeptidases.

Question 6

peptidoglycan

Answer 6

gives strength and shape to cells.

Question 7

lipopolysaccarides

Answer 7

elicit strong immune responses in animals and humans

Question 8

capsule

Answer 8

Mainly made of polysaccharides. prevents phagocytosis of the bacterial cell.
also prevents dessication of the cell

Question 9

Flagellum

Answer 9

allows motility

Question 10

monotrichous

Answer 10

single flagellum on one side of the bacteria

Question 11

lophotrichous

Answer 11

many flagella on one side of the cell

Question 12

amphitrichous

Answer 12

one flagellum on each side of the bacterial cell

Question 13

peritrichous

Answer 13

flagella all over bacterial cell

Question 14

Fimbrae

Answer 14

appendages of bacterial cells that allow adherence

Question 15

plasmid

Answer 15

extra rings of DNA used for horizontal transfer (conjugation)

Question 16

Bacteriophage

Answer 16

virus that infects bacterial cells

Question 17

spore

Answer 17

structure a bacteria can form during environmental stress so the bacteria can survive. Contains a complete copy of the bacteria’s DNA.

Question 18

bacterial nomenclature

Answer 18

names are based on genus and species.
Genus is named according to appearance under microscope eg. staphylo- clusters
-coccus round shape
strepto- chains
bacillus- rod shaped

Question 19

gram positive

Answer 19

stain purple, thick peptidoglycan layer in cell wall

Question 20

gram negative

Answer 20

stain pink, thin peptidoglycan layer in cell wall and contains lipopolysaccharides.

Question 21

how bacteria replicate

Answer 21

binary fission to produce two identical progeny

Question 22

detection and culture of bacteria

Answer 22

detected by microscopy. Cultured on agar plates.