Microbio lab Quiz 10
Anaerobic respiration
a form of respiration using electron acceptors other than oxygen. Although oxygen is not used as the final electron acceptor, the process still uses a respiratory electron transport chain; it is respiration without oxygen. (nitrate and sulfur reduction H2S)
The results of the Oxidase Test indicate which type of bacteria?
Oxidase Test (-)-----------------------------------(+) Enterobacteriaceae Pseudomonadaceae
In the 5-5 Oxidase Test (same for 5-4 Catalase Test) what are some ways to get a FALSE NEGATIVE result?
-Use liquid cultures -Junk cultures
In the 5-5 Oxidase Test (same for 5-4 Catalase Test) what are some ways to get a FALSE POSITIVE result?
-Use metal loop -Waiting more than 30 seconds -Use blood agar media
Why is a wooden stick use in the experiment versus a metal loop?
The metal stick has components that can be oxidized
Junk cultures
is bacteria incubated for less than 24 hours, because there will not be enough bacteria for the test.
Aerobic respiration
the process of producing cellular energy involving oxygen. Cells break down food in the mitochondria in a long, multistep process that produces roughly 36 ATP. The first step in is glycolysis, the second is the citric acid cycle and the third is the electron transport system. (Oxygen is the terminal electron acceptor.) Glycolysis--> Kreb's Cycle--> ETC--> Oxygen
5-5 Oxidase Test
1. TSA agar 2. Tetramethyl (-P-phenylenediamine) (TMPD)* in reduced form. chromogenic reducing agent ----> Blue or purple 3. Cytochrome c oxidase 4. Oxidation 5. TMPD in oxidized form 6. TMPD
The results of the Catalase Test indicate which type of bacteria (Divider of Gram-positive cocci)
Catalase Test (+)---------------------------------------(-) Staphylococcus Streptococcus
What do the bubbles indicate for the Catalase test?
Catalase is present. (positive result)
What is the last enzyme in the ETC?
Complex IV and is called cytochrome c oxidase because it makes the final electron transfer of the chain from cytochrome c, residing in the periplasm or attached to the periplasmic side of the cytoplasmic membrane of Gram (-) cells, to oxygen inside the cell.
What are the chain of events that happen in Catalase Test?
ETC----------------------------->O2------------>H2O ^(super oxide radicals form 2O2) superoxide dismutase catalase 2O2 --------------------->H2O2-----------> 2H2O + O2
Cytochrome c oxidase
It is the last enzyme in the respiratory electron transport chain of mitochondria (or bacteria) located in the mitochondrial (or bacterial) membrane. It receives an electron from each of four cytochrome c molecules, and transfers them to one oxygen molecule, converting molecular oxygen to two molecules of water.
What is the 5-4 Catalase looking for?
This test is looking at the ETC for microorganism that are aerobic respiration.
What is 5-5 Oxidase Test application?
This test is used to identify bacteria containing the respiratory enzyme cytochrome c oxidase. (this test looks at ETC for microorganisms that use Aerobic Respiration)
What is the application of the 5-4 Catalase test?
This test is used to identify organisms that produce the enzyme catalase.