How will you know what your experimental data means?

Student’s Lab Notebook

Making Sense of Your Data

• What data did you take?

• What are some things your data requires you to understand?

Can difference in color be due to genes?

What is known about energy production in Halo?

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

P P P

P P P

CHEMICALENERGY

INPUTENERGY

FOR CELLULARWORK

OUTPUT

MOREstored energy

ATP

ADP P+

LESS

stored energy

Question #1What makes halobacterium

purple?

Halobacterium cell

Bacteriorhodopsin (bR)

Halo have a purple membrane protein called bacteriorhodopsin (bR)

Halobacterium cell

Bacteriorhodopsin (bR)

Halo have a purple membrane protein called bacteriorhodopsin (bR)

Question #2What is the purple membrane

protein made of?

Bacteriorhodopsin(bR)

Cell membrane

Halo have a purple membrane protein called bacteriorhodopsin (bR)

Bacteriorhodopsin(bR)

Cell membrane

Bacteriorhodopsin (bR) is made from a protein called bop and the molecule retinal

Bop protein

Bop + retinal = bacteriorhodopsin (bR)

Retinal

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

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

ATP

ATP

ATP

ATP

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

ATP

ATP

ATP

ATP

Bacteriorhodopsin(bR)

LIGHT

ADP

P+

ATP

Cell membrane

BR converts light energy into chemical energy for making ATP

LIGHT PRESENT

Bacteriorhodopsin(bR)

LIGHT

ADP

P+

ATPATP

Cell membrane

BR converts light energy into chemical energy for making ATP

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

LIGHT PRESENT

Halo use bacteriorhodopsin (bR) to produce ATP using light energy

LIGHT ABSENT(DARK)

Halobacterium cell

LIGHT

ATPATP

ATP

ATPATP

ATP

ATPATPATP

ATP

Halo use bR to produce ATP for growth and metabolism

Halobacterium cell

LIGHT

Halo cannot use bR to produce ATP

Question #4How would amount of light and

levels of purple protein be connected?

Halobacterium cell

Bacteriorhodopsin (bR)

Halo change the expression of bR in response to the amount of light in their environment

LIGHT

Halobacterium cell

Bacteriorhodopsin (bR)

Halo change the expression of bR in response to the amount of light in their environment

LIGHT

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

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?