Question

1. in the jar picture to the right, there are only plants present. the jar is sealed but is transparent enough to allow light to enter. predict what will happen to the amount of oxygen and carbon dioxide in the jar, explain your answer. once you have considered that, answer the following question: will the plants die? why or why not.

Explanation:

Plants carry out photosynthesis (using light, carbon dioxide, and water to produce glucose and oxygen) and cellular respiration (using oxygen and glucose to produce carbon dioxide, water, and energy). In a sealed jar:

• Oxygen and Carbon Dioxide Levels: Initially, during the day (when there is light), photosynthesis rate may be higher than respiration rate. So, oxygen levels increase (as a product of photosynthesis) and carbon - dioxide levels decrease (as a reactant in photosynthesis). At night (or when light is insufficient), respiration rate is higher. So, oxygen levels decrease (as a reactant in respiration) and carbon - dioxide levels increase (as a product of respiration). Over time, if the jar is truly sealed (no gas exchange with the outside), a dynamic equilibrium may be reached where the amount of oxygen produced during photosynthesis equals the amount consumed during respiration, and the same for carbon - dioxide (amount consumed in photosynthesis equals amount produced in respiration).
• Plant Survival: If the jar has enough water (for photosynthesis and other plant functions) and the light conditions are suitable (for continuous photosynthesis to meet the energy demands from respiration), the plants may not die immediately. But if there are no nutrient replenishments (plants need minerals from the soil which may be limited in the jar over time) or if there are imbalances (e.g., a pest or disease outbreak with no external intervention), plants may die. Assuming ideal conditions (sufficient light, water, and initial nutrients), in the short - term, due to the gas exchange balance (photosynthesis and respiration balancing each other for gases), plants may survive for a while. But in the long - term, without nutrient replenishment (minerals), plants will die as they cannot sustain growth and repair processes indefinitely.

Answer:

• Oxygen and Carbon Dioxide: Oxygen and carbon - dioxide levels will fluctuate. Oxygen increases during photosynthesis (day/light) and decreases during respiration (night/dark). Carbon - dioxide decreases during photosynthesis and increases during respiration. A dynamic equilibrium may be reached for gas amounts if the system is balanced.
• Plant Death: In the short - term (with sufficient light, water, and initial nutrients), plants may not die immediately due to gas exchange balance. But in the long - term, without nutrient (mineral) replenishment, plants will die.