Question

SI Worksheet Week 7 • Compare the functions of photosystems I and II. • Why do we need oxygen (02) to live? • The Calvin cycle reactions are something called the "dark reactions" to contrast them with the light reactions. Can the Calvin cycle be sustained in a plant that is kept in total darkness for several days? Why or why not? • The chemical that functions as an enzyme-carrying molecule in all organisms is Carbon dioxide Water RuBP • АТР • The main function of the Calvin cycle reactions is to produce Carbon dioxide Sugars NADPH • ATP • The light reactions in photosynthesis require Oxygen Chlorophyll Rubisco . Carbon fixation • Glycolysis occurs in

Answer 1

• Photosystem I (PSI) absorbs the longer wavelength of light at 700nm. Photosystem II (PSII) absorb shorter wavelength of light at 680nm. In PSI photolysis does not take place but takes place in PSII.PSI performs important functions in both cyclic and non-cyclic photophosphorylation but PSII takes part only in cyclic photophosphorylation. PSI receives electrons from PSII and synthesizes NADH, PSII hydrolyzes water and synthesizes ATP.
• We need oxygen mainly because it is required for the living cells to release energy in the form of ATP through Electron Transport Chain in mitochondria. Some biochemical reactions also need oxygen to happen.
• No, Calvin cycle cannot sustain if it is kept in darkness for several hours. This is because it is dependent on the light reactions for ATP and NADPH. NADPH is very unstable molecule so that needs to be utilized instantly after synthesis by the light-dependent reaction.
• The correct answer is - ATP . Enzyme carrying molecule is the co-enzyme of an enzyme and among the given options ATP acts as coenzyme of many enzymes.
• (Not more than 4 questions as per Chegg).