1. Do Halobacteria grow best in the presence or absence of oxygen?

2. Are halobacteria able to grow without oxygen
Are halobacteria able to grow without oxygen? What data supports your conclusion?

3. Halobacteria use bacteriorhodopsin (BR) to produce ATP using light energy
ADP + P

4. Halobacteria use bacteriorhodopsin (BR) to produce ATP using light energy
LIGHT PRESENT
LIGHT
bacteriorhodopsin
(BR)
ATP
ADP P

5. Halobacteria use bacteriorhodopsin (BR) to produce ATP using light energy
LIGHT PRESENT
LIGHT
bacteriorhodopsin
(BR)
ATP
ATP
ADP P

6. Halobacteria use bacteriorhodopsin (BR) to produce ATP using light energy
LIGHT ABSENT
(DARK)
bacteriorhodopsin
(BR)
ADP + P

7. Halobacteria use bacteriorhodopsin (BR) to produce ATP using light energy
ADP
ATP P +
LIGHT
LIGHT PRESENT
LIGHT ABSENT
(DARK)
LIGHT
bacteriorhodopsin
(BR)
ATP
ADP + P

8. Bacteriorhodopsin (BR) is made from bop protein and the molecule retinal
Drawing not to scale and shapes are over simplified!!!

9. Halobacteria change their expression of BR in response to the amount of light in their environment
Halobacterium cell
Drawing definitely not to scale!!!

10. The amount of bR increases when there is more light.
Halobacteria change their expression of BR in response to the amount of light in their environment
The amount of bR increases when there is more light. +
Light bR
Note that the size of nodes in this diagram relates to the amount of light and bR, not the actual size. In other words, the size of bR does not change; a larger node for bR indicates a larger amount of bR.

11. OUR QUESTION:
How do Halobacteria cells change the amount of bR in response to light?