Photosynthesis Practical by Megan Cheung https://padlet.com/s2013011311/iaxbpf3afgzq0a9v Chloe, Megan, Suzette, Meredith en-us 2022-01-24 03:19:25 UTC 2025-11-25 17:23:24 UTC hello@padlet.com https://padlet.net/icons/png/1f33f.png s2013011311 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2007880944 Starch test*
1) How does CO2 affect photosythesis (Suzette)
2) how does temperature affect photosyntheis (Chloe)
3) how does light intensity affect photosynthesis (Megan)
4) Is light needed for photosynthesis (Megan) 
5) Is cholrophyll needed for photosynthesis (Meredith)
6) Is CO2 needed for photothesis? \
**add picture**
]]> 2022-01-24 03:24:32 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2007880944 6) Is CO2 needed for photosynthesis? s201301031 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2007881189 Variables:
  • IV: concentration of CO2 (air without CO2 vs with CO2)
  • DV: presence of starch
  • CV: temperature, light intensity, (no) presence of starch to begin with, duration of experiment, plant species etc.
Procedures
  1. Destarch two pots of plants of the same species (see starch test procedures)
  2. Place a pot of soda lime, potassium hydroxide, or sodium hydroxide onto one plant pot (to remove CO2)
  3. Place a pot of sodium hydrogen carbonate solution to the second plant pot (to provide CO2)
  4. Secure clear plastic bags with elastic bands over both pots.
  5. Leave both plants in sunlight for 6 hours.
  6. Conduct a starch test (see starch test procedures)


]]> 2022-01-24 03:24:44 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2007881189 starch test s2013011311 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2007882351 purpose of destarching:
the complete removal of starch by keeping plant away frm any light source lets it undergo respiration only. So starch is used to make glucose. Making the starch level 0 24-48hrs before the experiment. This means that any starch tested after the experiment will be the product of the IV.
procedures:
Test for starch
1. Remove a green leaf from a plant
2. Half-fill a 600 cm3 beaker with tap water. Use a Bunsen burr
heat the water until it boils.
3. Use a forceps to place the leaf in the boiling water and boil
minutes.
4. Turn off the Bunsen burner and prepare a boiling tube half-fi
ethanol.
5. Place the boiling tube with ethanol into the beaker with boile
and transfer the boiled leaf into the boiling tube with a forceps
6. Allow the leaf to remain in the boiling tube until the leaf
decolourises (may take up to 10 minutes).
7. Transfer the leaf from the boiling tube back to the water in t
beaker to wash off the ethanol.
 A Corofuulu opr the leef en e tile fow d ene]]> 2022-01-24 03:25:48 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2007882351 4) Is light needed for photosynthesis s201301137 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010138319 Variables:
IV: exposure to light
DV: presence of starch
CV: duration of experiment, temperature, CO2 watered, distance from light source
Procedures:
1. Cut out a shape from a piece of black paper 
2. Attach the paper to a lead on the potted plant with paper clips
3. Put the plant into a place with light (by a window)
4. water the plant if needed
5. Wait for one day
6. After one day, remove leaf from the plant. Remove black paper from the leaf
7. Test two leaves for starch ]]> 2022-01-25 02:07:42 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010138319 5) Is Chloroplast needed for Photosynthesis? s201301134 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010143528 Variables
- IV: green/non-green area of variegated leaf
- CV: type of plant, test for starch
- DV: presence of starch
Procedure
1. Remove the variegated leaf from the plant.
2. Take note of green and white areas of the leaf.
3. Conduct the STARCH TEST with the entire leaf.
4. Record results of colour change in the leaf after starch test.]]> 2022-01-25 02:11:50 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010143528 2) How does temperature affect photosynthesis? s2013011311 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010165518 2022-01-25 02:28:17 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010165518 3) How does light intensity affect photosynthesis? s2013011311 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010166012 IV: distance between beaker and lamp
DV: rate of photosynthesis (no. of bubbles per minute)
CV: same plant, same duration of experiment, temperature, mass of sodium hydrogen carbonate
Procedures:
1. Using a spatula, measure 5 g of sodium hydrogen carbonate on an electronic balance and transfer the
powder to a 600-mL beaker.
2. Using a 100-mL measuring cylinder, fill the beaker with 500 mL of tap water and stir the mixture with a
glass rod until the solute is completely dissolved.
3. Using scissors, cut a piece of Cabomba at one end and insert the cut end inside a small funnel.
4. Turn the funnel upside down and put it into the beaker. The cut end of Cabomba should face up.
5. Fill a test tube with tap water to the top, carefully turn it upside down and fit it onto the tip of the funnel.
6. With a meter ruler, set the beaker 10 cm away from the LED lamp. Insert a thermometer into the beaker.
Record the initial temperature of the solution in the table of results.
7. Turn on the lamp and start the stopwatch.
8. Immediately count the number of gas bubbles given out by the Cabomba and rising into the test tube in 3
minutes.
9. Turn off the lamp when time is reached. Record the final temperature of the solution.
10. Record the number of gas bubbles in 3 minutes. Calculate and record the rate of photosynthesis.
11. Repeat steps 6 to 10 but change the distance to 40 cm and 70 cm away from lamp.]]> 2022-01-25 02:28:39 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010166012 starch test s201301031 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010176427
Results
Positive: colour changes from orange-brown to blue-black
Negative: colour remains orange-brown

For experiments that require starch test, plants must be destarched-
Purpose of destarching
the complete removal of starch by keeping plant away frm any light source lets it undergo respiration only. So starch is used to make glucose. Making the starch level 0 24-48hrs before the experiment. This means that any starch tested after the experiment will be the product of the IV.

Procedures
  1. Remove a green leaf from a plant
  2. Half-fill a 600 cm3 beaker with tap water. 
  3. Use a Bunsen burner to heat the water until it boils.
  4. Use forceps to place the leaf in the boiling water and boil for 2 minutes. (to rupture the cell membrane and remove the cuticle)
  5. Turn off the Bunsen burner. (as ethanol is highly flammable and boils at around 78 degrees celsius)
  6. Prepare a boiling tube half-filled with ethanol (to remove green pigment from chlorophyll) and place the boiled leaf inside with forceps.
  7. Place the boiling tube with the boiled leaf in the 600 cm3 beaker. 
  8. Allow the leaf to remain in the boiling tube until the leaf decolorizes (may take up to 10 minutes).
  9. Transfer the leaf from the boiling tube back to the water in the 600 cm3 beaker to wash off the ethanol.
  10. Place the leaf on a white tile.
  11.  Use a dropper to drip iodine solution onto the leaf, observe the colour change.

]]> 2022-01-25 02:37:43 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010176427 2. How does temperature affect photosynthesis s201301137 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010188650 Variable:
- IV: temperature
- CV: light intensity, duration of experiment, plant species etc.
- DV: rate of photosynthesis(amount of gas collected)
Procedure:
  1. Set up a gas syringe collection system
  2. Place the pondweed in a beaker and fill it up with water
  3. Place a thermometer on the opposite side of the pondweed to the heater for a more accurate temperature
  4.  Set up the timer to around 2 minutes and turn on the heater until it reaches a certain temperature
  5. After the timer went off, detach the gas syringe collection system and record how much gas has been produced
  6. Repeat step 1-5 for different temperature

]]> 2022-01-25 02:47:38 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010188650 1) How does the concentration of CO2 affect the rate of photosynthesis? (aquatic plants) s201301031 https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010203628 Variables:
  • IV: concentration of CO2
  • DV: rate of photosynthesis (number of O2 bubbles per minute)
  • CV: temperature, light intensity, duration of experiment, plant species (cabomba, elodea etc.)
Procedures
  1. Using a spatula, measure 5g of sodium hydrogen carbonate on an electronic balance and transfer the powder to a 600 mL beaker.
  2. Fill the same beaker with 500mL of tap water.
  3. Stir the mixture with a glass rod until the solute is completely dissolved.
  4. Cut a piece of an aquatic plant (cabomba) and place inside a small funnel.
  5. Turn the funnel upside down and put it into the beaker.
  6. Fill a test tube with tap water, then turn it upside down, covering the tip of the funnel.
  7. Start the timer and count the number of bubbles produced in 3 minutes
  8. Record the rate of photosynthesis using this equation: (no. of bubbles divided by time)
  9. Repeat steps 1-8 but with 0g, 10g, and 15g of sodium hydrogen carbonate.


]]> 2022-01-25 02:59:33 UTC https://padlet.com/s2013011311/iaxbpf3afgzq0a9v/wish/2010203628