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How will you know what your
experimental data means?
Student’s Lab Notebook
Making Sense of Your Data
• What data did you
take?
• What other
information would
help you to
understand your
data?
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
MORE
stored energy
P
P
P
ATP
OUTPUT
INPUT
ENERGY
FOR CELLULAR
WORK
CHEMICAL
ENERGY
ADP +
P
P
P
P
LESS
stored energy
Question #1
What makes halobacterium purple?
Halo have a purple membrane
protein called bacteriorhodopsin (bR)
Halobacterium cell
Bacteriorhodopsin (bR)
Halo have a purple membrane
protein called bacteriorhodopsin (bR)
Halobacterium cell
Bacteriorhodopsin (bR)
Question #2
What is the purple membrane
protein made of?
Halo have a purple membrane
protein called bacteriorhodopsin (bR)
Cell membrane
Bacteriorhodopsin
(bR)
Bacteriorhodopsin (bR) is made from a
protein called bop and the molecule retinal
Bop + retinal = bacteriorhodopsin (bR)
Cell membrane
Retinal
Bop protein
Bacteriorhodopsin
(bR)
Question #3
What is the purpose of the
purple membrane protein?
BR converts light energy into
chemical energy for making ATP
LIGHT
ATP
ATP
ATP
Halobacterium cell
ATP ATP
Bacteriorhodopsin (bR)
Note: other proteins are required for this process, but we will simplify and focus on bR
bR converts light energy into
chemical energy for making ATP
LIGHT
ATP
ATP
ATP
Halobacterium cell
ATP ATP
Bacteriorhodopsin (bR)
Note: other proteins are required for this process, but we will simplify and focus on bR
bR converts light energy into
chemical energy for making ATP
Cell membrane
LIGHT
ADP
+
P
ATP
Bacteriorhodopsin
(bR)
bR converts light energy into
chemical energy for making ATP
LIGHT PRESENT
Cell membrane
LIGHT
ADP
+
P
ATP
Bacteriorhodopsin
(bR)
Halo use bacteriorhodopsin (bR) to
produce ATP using light energy
LIGHT PRESENT
LIGHT ABSENT
(DARK)
LIGHT
LIGHT
Bacteriorhodopsin
(bR)
ADP
Bacteriorhodopsin
(bR)
ADP
+
+
P
P
ATP
ATP
Halo use bacteriorhodopsin (bR) to
produce ATP using light energy
LIGHT PRESENT
LIGHT ABSENT
(DARK)
LIGHT
LIGHT
ATP
ATP ATP
ATP
ATP ATP ATP
ATP ATP
ATP
Halobacterium cell
Halo use bR to produce ATP
for growth and metabolism
Halobacterium cell
Halo cannot use bR to produce
ATP
Question #4
How would amount of light and
levels of purple protein be
connected?
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
Bacteriorhodopsin (bR)
Halo change the expression of bR in response
to the amount of light in their environment
LIGHT PRESENT
LIGHT ABSENT
(DARK)
LIGHT
Halobacterium cell
When there is more light, halo
respond by making more bR
LIGHT
Halobacterium cell
When there is less light, halo
make less bR
OUR QUESTIONS:
1. How do Halobacterium cells control
the amount of bR expressed in
response to light?
2. What is the gene and protein network
that regulates the expression of bR?
3. How else can Halo produce energy
and are these genes linked to the
expression of bR?