Review Questions
Plants produce oxygen when they photosynthesize. Where does the oxygen come from?
A. splitting water molecules
B. ATP synthesis
C. the electron transport chain
D. chlorophyll
A. splitting water molecules
A. red and blue
B. green
C. red
D. blue
B. green
What is the overall purpose of the light reaction in photosynthesis?
To convert solar energy into chemical energy that cells can use to do work.
What two products result from photosynthesis?
A. water and carbon dioxide
B. water and oxygen
C. glucose and oxygen
D. glucose and carbon dioxide
C. glucose and oxygen
Which molecule absorbs the energy of a photon in photosynthesis?
A. ATP
B. glucose
C. chlorophyll
D. water
C. Chlorophyll
Why are carnivores, such as lions, dependent on photosynthesis to survive?
Because carnivores eat animals that eat plants.
From where does a heterotroph directly obtain its energy?
A. the sun
B. the sun and eating other organisms
C. eating other organisms
D. simple chemicals in the environment
C. eating other organisms
Where in plant cells does the Calvin Cycle take place?
A. thylakoid membrane
B. thylakoid space
C. stroma
D. granum
C. stroma
Which part of the Calvin Cycle would be affected if a cell could not produce the enzyme RuBisCO?
None, because RuBisCO is essential in fixing carbon dioxide. Specifically, RuBisCO catalyzes the reaction between carbon dioxide and RuBP at the start of the cycle.
Which statement about thylakoids in eukaryotes is NOT correct?
A. Thylakoids are assembled into stacks.
B. Thylakoids exists as a maze of folded membranes.
C. The space surrounding thylakoids is called stroma.
D. Thylakoids contain chlorophyll.
B. Thylakoids exists as a maze of folded membranes.
Which statement correctly describes carbon fixation?
A. the conversion of CO2 to an organic compound
B. the use of RUBISCO to form 3-PGA
C. the production of carbohydrate molecules from G3P
D. the formation of RuBP from G3P molecules
E. the use of ATP and NADPH to reduce CO2
A. the conversion of CO2 to an organic compound
Describe the pathway of energy in light-dependent reactions.
The energy is present initially as light. A photon of light hits chlorophyll, causing an electron to be energized. The free electron travels through the electron transport chain, and the energy of the electron is used to pump hydrogen ions into the thylakoid space, transferring the energy into the electrochemical gradient. The energy of the electrochemical gradient is used to power ATP synthase, and the energy is transferred into a bond in the ATP molecule. In addition, energy from another photon can be used to create a high-energy bond in the molecule NADPH.
What is the energy of a photon first used to do in photosynthesis?
A. split a water molecule
B. energize an electron
C. produce ATP
D. synthesize glucose
B. energize an electron
What is the molecule that leaves the Calvin cycle to be converted into glucose?
A. ADP
B. G3P
C. RuBP
D. 3-PGA
B. G3P
Explain the reciprocal nature of the net chemical reactions for photosynthesis and respiration.
Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as a waste product. the reactions of respiration take sugar and consume oxygen to break it down into carbon dioxide and water, releasing energy. Thus, the reactants of photosynthesis are the products of respiration, and vice versa.