Answer:
1. What is required for photosynthesis to occur?
Answer: A. water, sunlight and carbon dioxide
2. What is required for cellular respiration to occur?
C. glucose and oxygen
3. How are the equations (see above) for photosynthesis and cellular respiration related?
D. Products of one are the reactants of the other
4. How do photosynthesis and cellular respiration keep oxygen and carbon dioxide levels stable in the biosphere?
B. Plants give off O2, which animals use for cellular respiration. Animals give off CO2, which plants use for photosynthesis.
Step-by-step explanation:
Photosynthesis is the process of fixing atmospheric CO2 into glucose in the presence of sunlight. It includes the light-dependent phase that forms ATP and NADPH by using the energy of sunlight. The water molecule serves as an electron donor. The light-independent phase uses ATP and NADPH to fix CO2 into glucose. Sunlight is trapped by photosynthetic pigments (mainly chlorophyll) present in the thylakoids of chloroplasts of leaf cells. The atmospheric CO2 enters the leaf cells through stomata. Roots absorb water from the soil.
Cellular respiration is the process of complete oxidation of glucose into CO2 and H2O and requires the presence of molecular oxygen which serves as an ultimate electron donor during oxidative phosphorylation.
Equation for photosynthesis: 6CO2 + 6H2O--> C6H12O6 + 6O2
Equation for cellular respiration: C6H12O6 + 6O2--> 6CO2 + 6H2O
Photosynthesis forms oxygen gas as a by-product during the light-dependent phase which is released into the atmosphere. Animals breathe in oxygen gas from the atmosphere and release CO2 which is a by-product of cellular respiration. The CO2 released into the atmosphere during respiration is used by plants for photosynthesis.