Photosynthesis is an important process that takes place in plants and other autotrophs, where they convert light energy from the sun into stored chemical energy in the form of glucose. This process primarily occurs in the chloroplasts of plant cells, which contain chlorophyll, the green pigment responsible for capturing light energy.

Question

The overall chemical equation for photosynthesis can be represented as:

6CO2 + 6H2O → C6H12O6 + 6O2

During the photosynthesis process, light energy is absorbed by chlorophyll and used to split water molecules into hydrogen and oxygen. The hydrogen combines with carbon dioxide to form glucose, while the oxygen is released into the atmosphere. This transformation of light energy into chemical energy is essential not only for the survival of plants but also for all living organisms that rely on plants for food and oxygen.

Figure 1: Photosynthesis Diagram

Elodea is a common aquatic plant used to study photosynthesis. This table summarizes how different factors such as light intensity, carbon dioxide concentration, and temperature affected the rate of photosynthesis in Elodea.

Figure 2: Factors Affecting the Rate of Photosynthesis in Elodea Plants


Light Intensity
(lux)
CO2 Concentration
(ppm)
Water Temperature
(°C)

Rate of Photosynthesis
(Oxygen Production, mL/min)

100 lux 300 ppm 20 °C 1.2
200 lux 300 ppm 20 °C 2.5
300 lux 300 ppm 20 °C 4.0
100 lux 400 ppm 20 °C 1.5
200 lux 400 ppm 20 °C 3.0
300 lux 400 ppm 20 °C 5.5
100 lux 300 ppm 30 °C 0.8
200 lux 300 ppm 30 °C 1.9
300 lux 300 ppm 30 °C 3.2
100 lux 400 ppm 30 °C 1.0
200 lux 400 ppm 30 °C 2.2
300 lux 400 ppm 30 °C 4.0


Question
Using the diagram, identify two ways photosynthesis affects the flow of carbon through the carbon cycle.



Responses
A Photosynthesis removes carbon dioxide from the atmosphere.Photosynthesis removes carbon dioxide from the atmosphere.
B Photosynthesis uses glucose in plants to make ATP.Photosynthesis uses glucose in plants to make ATP.
C Photosynthesis releases carbon dioxide into the atmosphere.Photosynthesis releases carbon dioxide into the atmosphere.
D Photosynthesis stores carbon as glucose in plants.

Answer 1

The correct responses to identify two ways photosynthesis affects the flow of carbon through the carbon cycle are:

A: Photosynthesis removes carbon dioxide from the atmosphere.
D: Photosynthesis stores carbon as glucose in plants.

These responses highlight that photosynthesis decreases atmospheric CO2 levels and fixes carbon into a stable form (glucose) that can be used by the plant and other organisms in the food chain. Responses B and C do not accurately reflect the role of photosynthesis regarding carbon flow in the carbon cycle.