BACTERIAL GENETIC&PATHOGENESIS

Question 1

prokaryote is haploid while eukaryote is diploid

Answer 1

chromosomes number bcs it is thru binary fission

Question 2

genome of bacteria

Answer 2

two chain of nucleotides , double helix and has backbone of deoxyribose and phophates residues arranged strands,hold together by hydrogen bond

Question 3

components of bacteria

Answer 3

single circular DNA molecule, no intons, histones,
extra chromosomal hv bacteriophage : intracelullar parasites that multiply inside bacteria by making use of host biosynthetic machinery
plasmid : carry gene for antibiotic resistance and enhance pathogenecity, circular DNA molecules found in cytoplasm
transposons : small segments of DNA that inserted within genes of chromosomes

Question 4

what is mutation ?

Answer 4

change in the sequences of nucleic acid of DNA that can be inherited

Question 5

3 principle of mutation

Answer 5

sponteneuos
mutagen-induced - induced by UV rays and chemical
transposones - jumping of foreign DNA into the genome

Question 6

what is mechanism of bacteria acquire drug resistance ?

Answer 6

mutation -modification of target sites
genetic transfer - transformation, transduction,conjugation
several biochemical mechanism -limiting drug uptake, enzymatic inactivation, attaining the alternative pathways

Question 7

what is normal flora ?

Answer 7

permanent residents of body sites and mucous membrane of healthy host not caused disease

Question 8

example of commensals microorganism ?

Answer 8

neisseir meningititis

Question 9

what is primary/true pathogen?

Answer 9

microorganism cause disease in immunocompetent (healthy normal ppl) and immunocompromised that hv virulence factor ex : candida albicans

Question 10

what is oppurtunistic pathogens ?

Answer 10

microorganism cause disease in immnunocompromised people , it dont hv virulence factor

Question 11

lactobacillus is used for ?

Answer 11

protect an prevent growth of yeast by producing hydrogen peroxide so increase lactic acid and decrease pH in vagina

Question 12

streptococcus mutant function in mouth dental plaque?

Answer 12

maintain intracelullar pH

Question 13

normal flora in skin ?

Answer 13

staphylococcus epidermidis tht prevent colonization by pathogens and possible disease thru bacterial interference

Question 14

normal flora in colon and intestine

Answer 14

bacteroides fragilis

e.coli

Question 15

fx of normal flora in GIT

Answer 15

produce polysaccharide A which activate immune response

Question 16

list virulence factor of structural components

Answer 16

protein A -prevents opsonization and protect from host immune system
M protein
polysaccharide capsule -inhibits phagocytosis by neutrophils

Question 17

list virulence factor of enzyme

Answer 17

IgA protease-destroys igA and enter the respiratory tract
coagulase -protect from phagocytosis
streptokinase(fibrinolysin) -activate production of plasmin
hyaluronidase -hydrolyse hylauric acid and enters the tissue

Question 18

list virulence factor of toxin

Answer 18

diptheria toxin
botulinum toxin -blocks Ach
vibrio cholerae -activates adenyl cyclase y ADP-ribosylation

Question 19

state the stages of microbial pathogenesis

Answer 19

1- entry of pathogen according to MOD
2- attachment
3- multiplication
4- invasion
5- evasion of host defense
6- damage of host tissue

Question 20

endotoxin is gram + or gram - bacteria ?

Answer 20

gram - bcs it has outer membrane of lipopolysaccharide lipid A

Question 21

exotoxin can stimulate antibody production and convert to toxoid

Answer 21

yes and it has high toxicity and unstable in temp above 60’c

Question 22

exotoxin or endotoxin cause fever ?

Answer 22

endotoxin bcs it is low toxicity

Question 23

exotoxin are made up of ?

Answer 23

polypeptide

Question 24

which is the true concerning DNA ?

Answer 24

DNA is contained only in nucleus of cell (prokaryote)

Question 25

movement of DNA from one bacteria to another thru pilus is

Answer 25

conjugation

Question 26

CONS is from intact skin it is normal flora

staphylococcus aurens is from abcess in skin it is called ?

Answer 26

pathogen

Question 27

what is carrier ?

Answer 27

person who have the microorganism but dont have symptoms of disease and can spread

Question 28

characteristic of bacterial capsule ?

Answer 28

important mechanism for protection of bacteria against ingestion by neutrophils , it is from polysaccaharide

Question 29

organism that causes endogenous infection in an immununocomprommised patient on antibiotic treatment ?

Answer 29

candida albicans bcs it is normal flora and fungus survive in antibiotic, antibiotic shows treatment for ONLY bacteria

Question 30

what part of LPS responsible for toxic effect

Answer 30

lipid A