what might happen if you were to remove all light from the setup

Photosynthesis Lab

Photosynthesis is i of the most important anabolic chemical reactions that allows life to be on Earth. With water, light energy from the sun, and carbon dioxide from the air, photosynthetic organisms are able to build simple sugars. Organisms that tin brand their own food are called autotrophs, and are at the base of the food chain. The basic reaction is:

6 CO _two + 12 H₂ O + east --> 2 C₆H₁₂ O _{half dozen} + six O ₂

carbon dioxide + water + low-cal energy --> glucose + oxygen

Oxygen molecules are colored to show their fate. Oxygen from CO₂ ends up in glucose. Oxygen from water becomes free O_ii

Photosynthesis has ii stages. Stage 1 requires low-cal. Stage ii can piece of work in the light or in the dark. The energy accumulated in Stage 1 is used to drive Stage 2.

1. The calorie-free reaction is used to convert sunlight into chemical energy stored in ATP and another energy storage molecule called NADP.
2. The low-cal-independent reaction or Calvin Bike takes carbon dioxide and fixes it in three-carbon molecules which volition eventually be synthesized into glucose.

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Experiment: We will deport a simple experiment using spinach leaves to demonstrate that, in the presence of light and carbon dioxide, foliage tissues produce gas bubbles. While nosotros cannot bear witness in this experiment that the bubbles are oxygen without a gas probe, nosotros tin can demonstrate, by use of a control, that the bubbles only form when the leaves are submerged in a sodium bicarbonate solution (which releases CO_ii) and not when they are submerged in pure h2o. We can also demonstrate that the bubbling merely form in the presence of stiff low-cal, by moving the experiment into the nighttime and making further observations. Finally, nosotros could experimentally vary the light intensity to demonstrate the event of light intensity on the process.

When we dissolve baking soda (NaHCO_iii) in water, carbonic acid (H_twoCO₃) and sodium hydroxide (NaOH) are formed. The carbonic acid then breaks downwardly into water and carbon dioxide gas, which is why dissolving baking soda in water causes it to fizz.

NaHCO₃ + H₂O --> H₂CO₃ + NaOH

H₂CO_iii --> H₂O + CO₂ (gas)

Materials:

• Fresh spinach leaves
• Metallic paper hole dial
• x mL or larger plastic syringe (without needle) - get one from your local pharmacy
• Baking soda solution (dissolve some baking soda powder in water)
• Liquid dish soap solution (dissolve five mL in 250 mL of water)
• 3 clear plastic cups or beakers (250 mL to 500 mL)
  • Cup i: Detergent solution
  • Cup two: Baking soda solution (treatment)
  • Cup three: H2o (control)
• Light source (fluorescent is practiced because it produces light without much heat)

Methods:

1. Utilise the metal pigsty punch to cutting out twenty round disks from the fresh spinach leaves, 10 for a control and 10 for a treatment.
2. Carve up the two parts of the syringe, drop x of the spinach disks within, reassemble the syringe.
3. Push the plunger almost to the bottom but don't beat out the disks.
4. Command or treatment
• For the handling, draw up a small amount ~i mL of detergent solution, and so describe the blistering soda solution up to ~iii-5 mL
• For the control, depict upward a small amount ~i mL of detergent solution, and then draw the water up to ~3-v mL
5. Indicate the syringe upward, borer the sides, and then that whatsoever air bubbling ascent, and gently squeeze the syringe until liquid begins to come out.
6. Put a finger on the end of the syringe, and draw the plunger dorsum slightly, creating a fractional vaccum.
7. Repeat until the leaf disks are suspended in the solution. This activity forces the liquid into the interior of the leafage.
8. Watch this video of the process to make sure you're doing it right.
9. Pour the contents of control and treatment syringes into ii labelled articulate plastic cups.
10. Swirl the liquid to attempt to keep the disks from sticking to each other or the sides of the cups and then let them sit.
11. Turn on a bright lite, and monitor the disks every minute. Count how many disks are floating during each of the next 15 minutes.
12. After all (or most) of the disks are floating, put the cups in the dark (a shoebox or a closet) and monitor for the adjacent 15 minutes.
13. Record how many disks remain floating after each minute until all (or most) of them have sunk.

Watch this demonstration to see how to brand the foliage disks sink.

Results:

In the calorie-free, yous should wait to see the disks in the command solution (water) stay on the lesser, but the disks in the handling solution (baking soda) should brainstorm to rise equally they use the CO_ii to undergo photosynthesis and produce oxygen bubbles. The bubbles should cause the disks to float. After you remove the light and place the cups in the dark, the treatment disks should stop undergoing photosynthesis and the disks should begin to sink.

For comparison purposes, each lab group that does this process should report the fourth dimension at which half (5) of the disks is floating. In the case below, that time would be about 11.5 minutes. You can use this Excel spreadsheet to tape your data and it volition motorcar-generate a graph for you.

Some or all of the submerged disks should brainstorm to bladder within about 15 minutes

Questions:

1. How does the suction assist the leaf disks to sink?
2. How does the detergent assist the leafage disks to sink?
3. Why don't the leafage disks soaking in the water (control) bladder?
4. What is the purpose of the baking soda solution?
5. What is the purpose of the light reaction?
6. Why do the leaf disks in the blistering soda solution (handling) brainstorm to float?
7. Why practise the leaves begin to sink again in the nighttime?
8. Why don't the leaves in the blistering soda solution continue to produce oxygen in the night?
9. Why practise we utilise the half-way mark every bit a point of comparison rather than the point at which all the disks are floating?
10. If the low-cal-independent reaction tin run without light, why does oxygen production (and presumably glucose production) stop?

References:

http://media.collegeboard.com/digitalServices/pdf/ap/bio-manual/Bio_Lab5-Photosynthesis.pdf

http://world wide web.biologyjunction.com/5b-photoinleafdiskslesson.pdf

https://www.youtube.com/watch?v=XV9FOWleErA

http://www.berwicksclasses.org/AP%20Biology/Biology%20Assignments/AP%20BIOLOGY%20Lab%204.htm

http://www.kabt.org/2008/09/29/video-on-sinking-disks-for-the-floating-leaf-disk-lab/

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Source: https://www2.nau.edu/lrm22/lessons/photosynthesis/photosynthesis.html

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