Biology 111 Lab: Photosynthesis Post-lab Spring 2018 1. What is the energy sourc
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Question
Biology 111 Lab: Photosynthesis Post-lab Spring 2018 1. What is the energy source for the light independent reactions of photosynthesis? 2. Where did the bubbles in the test tube come from? Light/exposed Tube) 3. Do the light independent reactions occur in the dark? Why or why not? 4. Explain whether or not Photosynthesis is the backwards form of Cellular Respiration (i.e. they occur in the same part of the cell). Equation for cellular respiration: C,H,0. + 6 O:--> 6 CO, +6 HO 5. Define stomata and explain their purpose in plants.
Explanation / Answer
Ans 1-The endergonic light-independent reactions of photosynthesis occur by the use of ATP and NADPH which synthesize at the time of the exergonic light-dependent reactions which provide the energy and help the synthesis of glucose and other organic molecule from inorganic CO2 and H2O.
The light-independent reactions of photosynthesis is the chemical reaction in which change CO2 and other compounds into glucose.
This reaction happen in the stroma,stroma is the fluid-filled area of the chloroplast . These reaction use the product like ATP and NADPH of light-dependent reactions and complete further chemical process on them.
This follow 3 phases to the light-independent reactions, collectively called the Calvin cycle:
1-carbon fixation
2- reduction reactions
3-ribulose 1,5-bisphosphate (RuBP) regeneration.
Ans2- if illuminate a plant, it will yield oxygen. We could put the plant under a funnel and collect the bubbles in an inverted test tube. If the fresh gas is collected, it would relight a shining splint. so if the gas takes 24 hours to collect,or if leave it for many hours before testing it, you might not relight a shining splint, because of the oxygen dissolves in the water and the nitrogen, which is in the water, comes out of solution so that gas collected become almost the same as air.
Ans 3- light independent reaction or Dark Reactions
It is also known as the Calvin Cycle. they do not require sunlight to complete process.
in the first part of photosynthesis when ATP is formed, for living thing to grow, repeat and repair themselve, the inorganic form of CO2 converted into carbohydrate. This happens in the stroma during the Calvin Cycle. And ATP and NADPH associate with CO2 and water for make the end product of glucose. Than the ADP and NADPH+ are recycle to the light-dependent side to over the process.
during hours of darkness, they do cellular respiration in the mitochondria just as all living organisms do.
Ans4- When photosynthesis use energy from the sunlight to build glucose and release O2 from CO2 and H2O, The Cellular respiration combine with O2 and glucose to produce CO2 and H2O
Photosynthesis
6H2O + 6 CO2 + light energy ----------> C6 H12 O6 + 6 O2
Cellular respiration
C6 H12 O6 + 6 O2 ----------> 6H2O +6 CO2 + energy
The formula is exact opposite or reverse to each other.
Ans5-Plants breathe too with the help of tiny openings in leaves called stomata .Stomata open and close to allow the intake of CO2 and the release of O2.
Function
1-The exchange of gas occurs when stomata are open and they facilitate photosynthesis.
2-they also help in the removal of waste product of plants.
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