Micro - Bacteria I

Question 1

crystal violet

Answer 1

stains blue for gram positive

-trapped in thick cross linked peptidoglycan wall

Question 2

safranin

Answer 2

stains red for gram negative
-outer lipid membrane of gram negative is dissolved with alcohol - washing out crystal violet and allows safranin to take with gram negative

Question 3

gram stain steps

Answer 3

1 - crystal violet stain
2 - wash off and flood with iodine solution
3 - wash off and decolorize with 95% alcohol
4 - counterstain with safranin and wash off

Question 4

peptidoglycan layer

Answer 4

in both gram + and -

repeating disaccharide with 4 amino acids

AAs will cross link with others

Question 5

transpeptidase

Answer 5

enzyme catalyzing cross-linking of peptidoglycan layer

Question 6

penicillin activity

Answer 6

inhibits transpeptidase

-no cross linking in bacterial cell walls

Question 7

gram positive cell wall

Answer 7

very thick

with extensive cross linking

Question 8

gram negative cell wall

Answer 8

very thin with simple cross linking

Question 9

teichoic acid

Answer 9

present in gram positive

useful in identification

Question 10

gram positive cell envelope

Answer 10

outer cell wall of cross linked peptidoglycan, teichoic acid, polysaccharides, and other proteins

inner surface of cell wall touches cytoplasmic membrane

no cholesterol or sterols in membrane

Question 11

gran negative cell envelope

Answer 11

3 layers and periplasmic space

1 - cytoplasmic membrane
-periplasmic space- gel of proteins and enzymes
2 - peptidoglycan layer
3 - outer cell membrane - phospholipid bilayer with LPS in outer portion

Question 12

murein lipoprotein

Answer 12

in gram negative

Question 13

LPS

Answer 13

outer portion of gram negative outer lipid bilayer

• O-specific side chain - outer carbohydrate chains
• core polysaccharide
• lipid A - gram negative endotoxin

Question 14

lipid A

Answer 14

gram negative endotoxin

-can lead to fever, diarrhea, endotoxic shock

Question 15

porins

Answer 15

in gram negative outer membrane - allow the passage of nutrients

Question 16

cocci

Answer 16

spherical

Question 17

bacilli

Answer 17

rod shaped

Question 18

coccobcilli

Answer 18

short bacilli

Question 19

spiral forms

Answer 19

comma, S, or spiral shaped

Question 20

pleomorphic

Answer 20

lack distinct shape

Question 21

gram positive bugs

Answer 21

1 - streptococcus
2 - enterococcus
3 - staphylococcus
4 - bacillus
5 - clostridium
6 - corynebacterium
7 - listeria

Question 22

gram positive cocci

Answer 22

streptococcus (strips)
enterococcus (strips)
staphylococcus (clusters)

Question 23

gram positive bacilli spore formers

Answer 23

bacillus

clostridium

Question 24

gram positive bacilli non-spore formers

Answer 24

corynebacterium

listeria

Question 25

gram negative cocci

Answer 25

neisseria

moraxella

Question 26

spiral shaped organisms

Answer 26

spirochetes

Question 27

trepenoma pallidum

Answer 27

syphilis

-spirochete

Question 28

acid fast stain

Answer 28

for mycobacteria

TB and leprosy

Question 29

darkfield microscopy

Answer 29

for spirochetes

-gram negative but too small to see

Question 30

spirochetes

Answer 30

need darkfield microscope to see

• also surrounded by phospholipid rich outer membrane with few exposed proteins
• protect from immune recognition

also have periplasmic flagella - spins it around

Question 31

mycoplasma

Answer 31

no cell wall

-only simple cell membrane

Question 32

bacteria with no cell wall

Answer 32

mycoplasma

Question 33

mycobacterium

Answer 33

gram positive

-seen with acid fast stain

Question 34

gram negative pleomorphic

Answer 34

chlamydia

rickettsia

Question 35

gram negative bacilli

Answer 35

enterics
haemophilus
bordetella
legionella
yersinia
francisella
brucella
pasteurella
gardnerella

Question 36

gram negative spiral

Answer 36

spirochete

-treponema, borrelia, leptospira

Question 37

bacterial DNA

Answer 37

single circle of double strand DNA

Question 38

plasmid

Answer 38

circle of double stranded DNA

-often with antibiotic resistant genes

Question 39

prokaryote

Answer 39

smaller ribosomes

50S and 30S

Question 40

erythromycin

Answer 40

attacks 50S ribosome of bacteria

Question 41

tetracycline

Answer 41

attacks 30S ribosome of bacteria