quiz 3 Flashcards
starch
example
large carbohydrate polysaccharide.
-glucoses linked by alpha bonds.
amylose
starch hydrolysis
positive and negative
breaks carbohydrates down to short chains
-glucose
starch reacts with iodine: bright blue/black=starch
clear=starch degradation
starch agar: 0.4% soluble starch
dextrose
another name for glucose
lipids
fatty acids. high MW. lipases break lipids down.
lipase test (lipid hydrolysis)
has tributryin (fatty acids 4 C long) and the dye spirit blue. clearing with blue is positive
gelatin hydrolysis test
collagen-connective tissue. if you heat it up, it becomes gelatin.
gelatinases break peptide bonds and release amino acids
theres a clearing zone after adding TCA (trichloroacetic acid, precipitates proteins but not amino acids.)
casein hydrolysis test
casein: protein in milk. when added to media, cloudy appearance.
without adding TCA, a clear zone is observed.
Hydrogen sulfide production test purpose
differentiate sulfur reducing organisms from non reducing organisms
Hydrogen sulfide production test media protocoal enzyme/biochemical basis positive result
- SIM deep (sulfur, indole, motility) has cysteine and thiosulfate
- stab w needle
- cysteine desulfurase- removes S from aa-forms H2S
- thiosulfate reductase- terminal e- acceptor for anerobic respiration-forms H2S.
- cysteine desulfurase- removes S from aa-forms H2S
- black precipitate
h2s indicator is
ferrrous ammonium sulfate
h2s sulfur containing amino acids:
methionine and cysteine.
motility test purpose
detect bacterial motility
motility test media protocoal enzyme/biochemical basis positive result
- 0.4% agar deep (tsa)
- stab w/needle
1. tests for flagella - cloudy-movement away from stab
bile esculin test purpose
identify organisms capable of growing in presence of bile salts.
2 products are formed when organisms hydrolyze the esculin in bile esculin test
glucose (glycolysis)
esculetin
bile esculin test indicator
ferric ammonium citrate
bile esculin test media protocoal enzyme/biochemical basis positive result
-bile esculin agar (slant)
-innoculate with loop (s motion)
1. does it grow in salts?(selective)
2. does it have enzyme to degrade esculin? (differential)
esculetin + glucose—> used by cell. esculetin + ferric —> brown precipitate. (positive)
thiosulfate is reduced to
sulfite and hydrogen sulfide
blood agar
non selective. has nutrients that allows growth of certain organisms. mix of tsa and sheep blood
mannitol salt agar media protocoal enzyme/biochemical basis positive result
- msa
- streak w loop
1. salt (selective bc inhibits growth of organisms that cant grow in 7.5% nacl)
2. pH (differential) —> yellow pos.
mannitol salt agar indicator is
phenol red.
if ph is below 6.8, phenol red turns yellow
if ph is above 8.4, stays pink
hemolysis media protocoal enzyme/biochemical basis positive result
- BAP TSA + sheep blood
- streak
1. Y (gamma, good)-no hemolysis
2. alpha(intermediate)-some hemolysis —> greenish
3. B(bad)- complete hemolysis—> clearing
oxidase media protocoal enzyme/biochemical basis positive result
- tmpd
- drop of __ on paper rub bacteria- toothpick
1. tmpd donates e to terminal cytochrome oxidase (enzyme in membrane bound) - blue
why use toothpick and not metal loop?
bc it’ll take all the electrons, give it false positive.
catalase media protocoal enzyme/biochemical basis positive result
- h202
- drop on petri plate, add bacteria
1. catalase (enzyme cytoplasm) turns h202 into h20+ 02. - bubbles of 02.
DNase media protocoal enzyme/biochemical basis positive result
- tsa plate @ dna added
- streak, add in hcl
1. DNase-exoenzyme degrades large molecule to dNMP’s for transport into cell. - clearing
superoxidate dismutase
02- + 2H+ –> h202
catalase
h202—> h20 + 02
peroxidase
h202 + nadh + h+ —> 2h20 + nad
