Question

Would you expect the production of sugars by plants in photosynthesis to be an exergonic or endergonic process? Give the reason for your answer.

Short answer

The production of sugars by plants in photosynthesis is an endergonic process because it requires an input of energy from sunlight.

Step-by-step solution

Understand the Concepts

Photosynthesis is the process by which plants convert carbon dioxide and water into glucose and oxygen using sunlight. To determine if this process is exergonic or endergonic, we need to understand these concepts: Exergonic processes release energy, while endergonic processes require an input of energy.

Identify Energy Source

Photosynthesis requires sunlight to drive the chemical reactions. This indicates that energy is being absorbed from the environment.

Analyze Energy Flow

Since sunlight provides the energy needed for plants to convert carbon dioxide and water into glucose, the process is not releasing energy but absorbing it.

Conclusion from Energy Analysis

Since photosynthesis requires an input of energy (sunlight) to produce sugars, it is an endergonic process.

Key concepts

Exergonic vs Endergonic reactions

When studying chemical reactions, it is important to know whether they release or absorb energy.
Exergonic reactions release energy and occur spontaneously. You can think of them as processes that happen naturally with no extra push required. For instance, the breakdown of food molecules in your body releases energy.
In contrast, endergonic reactions require an input of energy to occur. These reactions are like uphill climbs; they need a bit of a boost to get started. A prime example of an endergonic reaction is photosynthesis, where plants absorb sunlight to make glucose.

Photosynthesis

Photosynthesis is the amazing process through which plants turn sunlight, water, and carbon dioxide into glucose and oxygen. This process primarily occurs in the chloroplasts of plant cells.

In general, photosynthesis can be broken down into two stages:

• The Light-Dependent Reactions: These occur in the thylakoid membranes and use sunlight to produce ATP and NADPH.
• The Calvin Cycle: This occurs in the stroma and uses ATP and NADPH from the light reactions to convert carbon dioxide into glucose.

The fact that photosynthesis requires sunlight indicates that it needs energy from the environment, making it an endergonic process.

Energy absorption

Energy absorption is a key aspect of many biological processes, including photosynthesis.
In the context of photosynthesis, plants absorb light energy from the sun. This energy then powers the conversion of water and carbon dioxide into glucose and oxygen.

While it might seem straightforward, the energy absorption in photosynthesis is rather complex. The chlorophyll in plant cells captures light energy, which elevates electrons to a higher energy state.
The excited electrons then move through a series of proteins (known as the electron transport chain) to produce ATP and NADPH.
These energy carriers are crucial for the next stage of photosynthesis, where they help convert carbon dioxide into glucose.