Students Conducted an Experiment to Determine the Effect of Light

question 42

Multiple Choice

Students conducted an experiment to determine the effect of light intensity on the rate of photosynthesis. They punched 40 leaf disks from spinach leaves and used a syringe partially filled with water to pull the gases from the leaf disks so that all leaf disks sunk to the bottom of the syringe. Ten leaf disks from the syringe were placed in each of four cups and covered with 50 ml of the solutions as indicated below. All leaf disks were resting on the bottom of the cups when the experiment began. The volume of liquid in each cup and the temperature of the solutions were held constant. All cups were placed 0.5 metres from the designated light source. A large beaker of water was placed between the light and the cups to act as a heat sink to prevent a change in temperature. At the end of 10 minutes, the number of disks floating in each cup was recorded.
$$\begin{array} { | c | c | c | c | } \hline \text { Trial } & \begin{array} { c } \text { Grams of } \\\text { baking soda } \\\text { (CO2 } \text { source) }\end{array} & \begin{array} { c } \text { Wattage of } \\\text { light bulb }\end{array} & \begin{array} { c } \text { Disks floating } \\\text { at 10 minutes }\end{array} \\\hline 1 & 0.5 & 25 & 3 \\\hline 2 & 0.5 & 50 & 5 \\\hline 3 & 0.5 & 75 & 9 \\\hline 4 & 0 & 75 & 0 \\\hline\end{array}$$
Use your knowledge of the mechanism of photosynthesis and the data presented in the chart to determine which of the statements is a correct explanation for the students' data.

• A) Cup 1 had a low rate of photosynthesis because 0.5 grams of baking soda did not provide a sufficient amount of CO?.
• B) Cup 2 had the highest rate of photosynthesis because it had the highest ratio of disks floating to wattage of light.
• C) Cup 3 had the same rate of photosynthesis as Cup 1 because they had the same ratio of disks floating to wattage of light.
• D) Cup 4 had the lowest rate of photosynthesis because it had the least CO?.

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Definitions:

Normal Accidents

A concept from the perspective of complex systems theory, suggesting that in complex technological systems, accidents are inevitable due to the inherent systemic risks and unpredictable interactions within the system.

Risk Society Thesis

The Risk Society Thesis is a sociological theory that suggests modern societies are increasingly preoccupied with the future and managing risks, moving away from wealth distribution towards risk distribution.

Social Goods

Describes goods or services that benefit all members of a community, such as clean air, public parks, and national defense, which are typically provided by the government or nonprofit organizations.

Ulrich Beck

A German sociologist known for his work in refining the theory of reflexive modernization and the concept of the "risk society."