This document discusses data logging and the use of gas sensors to measure oxygen and carbon dioxide levels during photosynthesis experiments. It provides background on photosynthesis, cellular respiration, and how they relate to the consumption and production of oxygen and carbon dioxide. The document then outlines the specific procedures to set up gas sensors connected to a computer to measure these gas levels in plant leaves in both light and dark conditions. This allows calculating the rates of photosynthesis and respiration from the sensor readings. Precautions for using the sensors and interpreting the results are also described.
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1. DATA LOGGING
PHOTOSYNTHESIS,OXYGEN
AND CARBON DIOXIDE
Jusman Muktar
(D20101037504)
Nur Fatin Afiqah Kamaruzaman
( D20101037540)
Faiznur Ishak
( D20101037542)
2. WHAT IS DATA LOGGER ?
A data logger is a basic box capable of picking up and
storing signals from sensors. For ease of use they
generally have a minimum number of displays and
controls and their portability enables remote data
logging for example logging data away from the
computer.
Data loggers are either fitted with an internal battery
that is rechargeable or use regular alkaline
batteries. Some may also have external power
supplies. Most data loggers store data in non-
volatile memory, which means the data will not be
lost if the power supply fails.
3. It is important to note that low battery charge may
cause some data loggers to behave erratically. A
cable or docking station is normally provided to
facilitate a connection to a computer or other
hardware. Data loggers can also make use of
Bluetooth or Infra red communication to transfer
data.
4. ENGAGING
Plants make sugar, storing the energy of the sun
into chemical energy, by the process of
photosynthesis.
When they require energy, they can tap the stored
energy in sugar by a process called cellular
respiration.
5. The process of photosynthesis involves the use of
light energy to convert carbon dioxide and water
into sugar, oxygen, and other organic compounds.
This process is often summarized by the following
reaction:
6 H2O + 6 CO2 + light energy → C6H12O6 + 6 O2
6. Cellular respiration refers to the process of
converting the chemical energy of organic
molecules into a form immediately usable by
organisms. Glucose may be oxidized completely if
sufficient oxygen is available by the following
equation:
C6H12O6 + 6 O2 → 6 H2O + 6 CO2 + energy
7. PROBLEM STATEMENT
1. What gas will be released and consumed for
photosynthesis?
2. What is the type of gas sensor that need to be used for
this photosynthesis gas experiment?
3. How to set up and connect the gas sensor to the
computer correctly for this experiment?
4. What is the correct way/procedure to use the sensor in
order to measure the amount of gas that is released
and consumed by a plant during photosynthesis more
accurately.
8. 5. What is the precaution step that need to be taken while using
the sensor?
6. What is the correct and precise method to take the reading
from the sensor?
7. How to calculate the rate of respiration/photosynthesis from
the graph displayed on the monitor?
8. How the application of the gas sensor help you to obtain
result that is more accurate?
9. Can the use of the gas sensor help to reduce the difficulty of
the experiment?
10. Is the use of the sensor burden students and make things
complicated?
9. EMPOWERING
Objectives :
1. To measure the amount of oxygen gas consumed
or produced by plant during respiration and
photosynthesis
2. To measure the amount of carbon dioxide gas
consumed or produced by plant during respiration
and photosynthesis
3. To determine the rate of respiration and
photosynthesis of plant
10. PROCEDURE :
1. Plug the O2 Gas Sensor into
Channel 1 and the CO2 Gas
Sensor into Channel 2 of the
LabPro or CBL 2 interface.
Use the link cable to connect
the TI Graphing Calculator to
the interface. Firmly press in
the cable ends.
2. Turn on the calculator and
start the DATAMATE
program. Press CLEAR to
reset the program.
11. 3. Set up the calculator and interface for an
O2 Gas Sensor and CO2 Gas Sensor.
a) Select SETUP from the main screen.
b) If the calculator displays an O2 Gas
Sensor in CH 1 and a CO2 Gas Sensor in
CH2, proceed directly to Step 4. If it does
not, continue with this step to set up your
sensors manually.
c) Press ENTER to select CH 1.
d) Select OXYGEN GAS from the SELECT
SENSOR menu.
e) Select parts per thousand (PPT) as the
unit.
f) Press once, and then press ENTER to
select CH2.
g) Select CO2 GAS from the SELECT
SENSOR menu.
h) Select parts per thousand (PPT) as the
unit.
12. 4. Set up the data-collection mode.
a) To select MODE, press (the up
arrow key) twice and press
ENTER.
b) Select TIME GRAPH from the
SELECT MODE menu.
c) Select CHANGE TIME
SETTINGS from the TIME
GRAPH SETTINGS menu.
d) Enter “15” as the time between
samples in seconds.
e) Enter “40” as the number of
samples (data will be collected
for 10 minutes).
f) Select OK twice to return to the
main screen.
13. 5. Obtain several leaves
from the resource
table and blot them
dry, if damp, between
two pieces of paper
towel.
6. Place the leaves into
the respiration
chamber, using
forceps if necessary.
Wrap the respiration
chamber in aluminum
foil so that no light
reaches the leaves.
14. 7. Insert the CO2–O2 Tee into the
neck of the respiration chamber.
Place the O2 Gas Sensor into the
CO2–O2 Tee as shown in Figure
1. Insert the sensor snugly into
the Tee. The O2 Gas Sensor
should remain vertical throughout
the experiment. Place the CO2
Gas Sensor into the Tee directly
across from the respiration
chamber as shown in Figure 1.
Gently twist the stopper on the
shaft of the CO2 Gas Sensor into
the chamber opening. Does not
twist the shaft of the CO2 Gas
Sensor or you may damage it.
15. 8. Wait two minutes, and then
select START to begin data
collection. Data will be collected
for 10 minutes.
9. When data collection has
finished, remove the aluminum
foil from around the respiration
chamber.
10. Fill the tissue culture flask
with water and place it between
the lamp and the respiration
chamber. The flask will act as a
heat shield to protect the plant
leaves.
16. 11. Turn the lamp on. Place the lamp as
close to the leaves as reasonable. Do
not let the lamp touch the tissue
culture flask.
12. Press ENTER to view the graph of
O2 GAS VS. TIME. Sketch a copy of
your graph in the Graph section
below. When finished, press ENTER
to return to the graph menu. Press
once, and then press ENTER to view
the graph of CO2 GAS VS. TIME.
Sketch a copy of your graph in the
Graph section below. When
finished, press ENTER to return to
the graph menu. Select MAIN
SCREEN from the graph menu.
17. 13. Perform a linear regression to calculate the rate of
respiration/photosynthesis.
a) Select ANALYZE from the main screen.
b) Select CURVE FIT from the ANALYZE OPTIONS menu.
c) Select LINEAR (CH 1 VS TIME) from the CURVE FIT menu.
d) The linear-regression statistics for these two lists are displayed
for the equation in the form: Y=A∗X+B
e) Enter the value of the slope, A, as the rate of
respiration/photosynthesis in Table 1.
f) Press ENTER to view a graph of the data and the regression
line.
g) Press ENTER to return to the ANALYZE menu.
h) Repeat Steps 13b – 13g to calculate the
respiration/photosynthesis rate using the data from the CO2
Gas Sensor (CH 2 VS TIME).
i) Select RETURN TO MAIN SCREEN from the ANALYZE menu.
18. 14. Repeat Steps 8 – 13 to collect data with the plant
exposed to light.
15. Remove the plant leaves from the respiration
chamber, using forceps if necessary. Clean and dry
the respiration chamber.
19. RESULT :
Leaves O2 rate of CO2 rate of
production/consumpti production/consumpti
on (ppt/s) on (ppt/s)
In the dark - 0.0023 0.00065
In the light 0.0045 - 0.00126
21. DISCUSSION
1. Were either of the rate values for CO2 a positive
number? If so, what is the biological significance of
this?
The CO2 rate value for leaves in the dark was a
positive number. The biological significance of this is
that CO2 is produced during respiration. This causes
the concentration of CO2 to increase, as sugar is
oxidized and broken into CO2, water and energy.
22. 2. Were either of the rate values for O2 a negative number?
If so, what is the biological significance of this?
The O2 rate value for leaves in the dark was a
negative number. The biological significance of this is
that O2 is consumed during cellular respiration. This
causes the concentration of O2 to decrease as glucose
is oxidized for energy.
3. Do you have evidence that cellular respiration occurred
in leaves? Explain.
Yes, cellular respiration occurred in leaves since O2
decreased when leaves were in the dark and
photosynthesis was not possible.
23. 4. Do you have evidence that photosynthesis occurred in leaves?
Explain.
Yes, photosynthesis occurred in leaves since O2 increased
when leaves were exposed to the light.
5. List five factors that might influence the rate of oxygen
production or consumption in leaves. Explain how you think
each will affect the rate?
A greater number of leaves should increase the rate since
there are more chloroplasts to undergo photosynthesis and
more cells to require energy through cellular respiration.
A greater light intensity will increase the rate of
photosynthesis. It may not affect the rate of cellular
respiration.
24. A cooler room may decrease both rates, as cellular
metabolism decreases in cooler weather.
Facing the top of the leaves toward the light should
increase the rate of photosynthesis, since the
chloroplasts are closer to the light source.
If the plants overheat due to the heat from the
lamp, they may wilt and stop functioning. This will
decrease all rates.
If there too many leaves, diffusion may be restricted
and prevent accurate readings. This may apparently
decrease both rates.