1. How will you know what your experimental data means? Student’s Lab Notebook

2. Making Sense of Your Data What data did you take? What are some things your data requires you to understand?

3. Can difference in color be due to genes?

4. What is known about energy production in Halo?

5. ATP Cells need ATP for nearly all cellular processes that require energy, including growth Therefore, halo must be able to make ATP in the conditions that allow them to grow

6. PPP PPP CHEMICAL ENERGY INPUT ENERGY FOR CELLULAR WORK OUTPUT MORE stored energy ATP ADP P+ LESS stored energy

7. Question #1 What makes halobacterium purple?

8. Halobacterium cell Bacteriorhodopsin (bR) Halo have a purple membrane protein called bacteriorhodopsin (bR)

9. Halobacterium cell Bacteriorhodopsin (bR) Halo have a purple membrane protein called bacteriorhodopsin (bR)

10. Question #2 What is the purple membrane protein made of?

11. Bacteriorhodopsin (bR) Cell membrane Halo have a purple membrane protein called bacteriorhodopsin (bR)

12. Bacteriorhodopsin (bR) Cell membrane Bacteriorhodopsin (bR) is made from a protein called bop and the molecule retinal Bop protein Bop + retinal = bacteriorhodopsin (bR) Retinal

13. Question #3 What is the purpose of the purple membrane protein?

14. BR converts light energy into chemical energy for making ATP Halobacterium cell Bacteriorhodopsin (bR) Note: other proteins are required for this process, but we will simplify and focus on bR LIGHT ATP

15. BR converts light energy into chemical energy for making ATP Halobacterium cell Note: other proteins are required for this process, but we will simplify and focus on BR Bacteriorhodopsin (BR) LIGHT ATP

16. Bacteriorhodopsin (bR) LIGHT ADP P + ATP Cell membrane BR converts light energy into chemical energy for making ATP

17. LIGHT PRESENT Bacteriorhodopsin (bR) LIGHT ADP P + ATP Cell membrane BR converts light energy into chemical energy for making ATP

18. LIGHT PRESENT Halo use bacteriorhodopsin (bR) to produce ATP using light energy LIGHT ABSENT (DARK) Bacteriorhodopsin (bR) ADP P + ATP LIGHT Bacteriorhodopsin (bR) ADP P + ATP LIGHT

19. LIGHT PRESENT Halo use bacteriorhodopsin (bR) to produce ATP using light energy LIGHT ABSENT (DARK) Halobacterium cell LIGHT ATP Halo use bR to produce ATP for growth and metabolism Halobacterium cell LIGHT Halo cannot use bR to produce ATP

20. Question #4 How would amount of light and levels of purple protein be connected?

21. Halobacterium cell Bacteriorhodopsin (bR) Halo change the expression of bR in response to the amount of light in their environment LIGHT

22. Halobacterium cell Bacteriorhodopsin (bR) Halo change the expression of bR in response to the amount of light in their environment LIGHT

23. Halobacterium cell LIGHT PRESENT LIGHT ABSENT (DARK) Halobacterium cell LIGHT When there is more light, halo respond by making more bR LIGHT When there is less light, halo make less bR Halo change the expression of bR in response to the amount of light in their environment

24. OUR QUESTION: How do Halobacterium cells control the amount of bR expressed in response to light? What is the gene and protein network that regulates the expression of bR?