Growth and oxygen oncentration

Question 1

What do we add in anaerobes cultures to take off all the oxygen?

Answer 1

A chemical called a reducing agent may be added to such vessels to remove traces of O2

Question 2

what is the reducing agent ?

Answer 2

Thioglycolate

Question 3

What does the thioglycolate?

Answer 3

reduces O2 to H2O

Question 4

reducing O2,creates?

Answer 4

A gradient of oxygen concentration

Question 5

what is present in thioglycolate?

Answer 5

a redox indicator reazurin

Question 6

the redox indicator reazurin is used for?

Answer 6

to differentiate oxic and anoxic zones

Question 7

How does it differentiates oxic from anoxis?

Answer 7

turns pink in the presence of oxigen

Question 8

During aerobic respiration and oxygenic photosynthesis H20 is oxidized to O2, what else is formed?

Answer 8

During theses processes also toxic forms are produced

Question 9

Whats the toxic form?

Answer 9

O2 to O2-

Question 10

Who reduces O2 to O2-

Answer 10

flavoproteins,quinone and iron‐sulfur proteins, present in virtually all cells

Question 11

Whats the problem with the toxic forms of oxygen?

Answer 11

-oxygen oxidize cell components
-stopping key metabolic
pathways
- destroying key structures.

Question 12

c quoi les produits toxic?

Answer 12

• Superoxide
• hydrogen peroxide
• Hydroxyl radical

Question 13

comment les cellules se protegent?

Answer 13

enzymes that destroy these compounds

Question 14

Aerobes and facultative aerobes usually have

Answer 14

catalase and superoxide dismutase

Question 15

comment ils font habituellement?

Answer 15

ils donnent des é ou redonne deux fois un H

Question 16

do anaerobes have the same enzymes?

Answer 16

they may or may not containn such enzymes

Question 17

What if they have the enzyme?

Answer 17

they may be aerotolerant anaerobes