Getting To Know Photo!!
Photosynthesis That Is.
By now you should have a pretty good
understanding as to what plants are doing during
the process of photosynthesis. If you are still a
little confused, simply break the word down into
its components….
Photo=
Synthesis=
Let’s Review the
PHOTO part of
Photosynthesis
Based on the graph below, what
color is this object:
96%
0%
4%
0%
1.
2.
3.
4.
Red and blue/green
Orange and yellow
Yellow and blue
Blue and violet
Based on the results below, which of the following
pigments is most likely the smallest molecule:
1.
13% 2.
87% 3.
0% 4.
0%
Chlorophyll a
Chlorophyll b
Carotene
Xanthophyll
Carotene
Xanthophyll
Chlorophyll A
Chlorophyll B
How Do You
Know?????
Based on the graph, what colors
are best absorbed by this plant:
0%
100%
0%
0%
1.
2.
3.
4.
Green and orange
Red and violets
Violet and green
Green and reds
9%
0%
17%
0%
74%
Based on the graph below, which color light
is best absorbed by plants for
photosynthesis
1. Red
2. Yellow
3. Green
4. Orange
5. Violet
During our last class, we looked at the
relationship between pH and the rate of
photosynthesis. Before we could discuss
this we needed to review the ph scale. Do
you remember???
The pH range for acids???
The pH range for a base???
The equation for photosynthesis
is as follows….
Carbon Dioxide + Water + Light energy  Oxygen +
CO2
H2O
photons
O
Glucose
(C,H source)
As you can see, carbon dioxide is needed by
plants for photosynthesis to take place.
That’s right. Plants need
carbon dioxide in order to
make sugar!!!
Where do they get the
carbon dioxide they
need???
YOU!
Remember, Bromothymol blue
is blue when the pH is high
(8-14 range)
If the pH is high, BTB is
blue like the sky!!
When carbon dioxide is added to water
or BTB, the pH of that water/BTB:
0%
27%
5%
68%
1.
2.
3.
4.
CO2
Increases and becomes more acidic
Decreases and becomes more basic
Increases and becomes more basic
Decreases and becomes more acidic
pH
If carbon dioxide was added to BLUE
bromothymol blue, this blue solution
would…..
5%
21%
5%
11%
84%
1. Become more acidic
2. Turn Yellow
3. Support photosynthesis if elodea
were added
4. Have a ph range lower than 7 and be
considered an acid
5. All of the above
Remember, if the pH is low (1-6) the BTB
turns yellow like the snow.
What can you conclude about the
levels of carbon dioxide in the
solution?
NOW,
This yellow solution of BTB is loaded with
carbon dioxide and ready for a plant in
order to conduct photosynthesis.
When the plant is added to this
yellow BTB solution, this solution
will…
5%
95%
1. Remain yellow
2. Turn blue
WHY??
Which of the following graphs represents
what will happen to the pH of water high in
CO2 if photosynthesis is occurring:
81%
19%
0%
1. A
2. B
3. None of the graphs
14
14
P
H
P
H
1
A
1
Time
B
Time
WHY?
WHERE IS THIS CARBON
DIOXIDE “GOING?”
Now that we seem to understand the...
•Reactants and products needed for
photosynthesis
•What plants are doing during photosynthesis
•The relationship between pH and rate of
photosynthesis
Let’s look at cellular respiration in greater detail.
I think you will see these
processes go together like peas
and carrots.