Problem 8 - Biology Concepts and Applications

Question

Carbon is released into the atmosphere by _____________. a. photosynthesis b. aerobic respiration c. burning fossil fuels d. b and c

Step-by-Step Solution

Answer

The correct answer is d: b and c.

Step 1: Understanding Carbon Release

Carbon is released into the atmosphere through various processes. One common way is through breathing or respiration, where humans and animals exhale carbon dioxide. This is termed aerobic respiration.

Step 2: Analyzing Photosynthesis

Photosynthesis is a process used by plants to convert carbon dioxide and sunlight into oxygen and glucose. Instead of releasing carbon, photosynthesis actually absorbs carbon dioxide from the atmosphere.

Step 3: Examining Burning of Fossil Fuels

Burning fossil fuels such as coal, oil, and gas releases a large amount of carbon dioxide and other gases into the atmosphere. This is a major contributor to carbon emissions globally.

Step 4: Identifying the Correct Answer

From the analysis, we can conclude that both aerobic respiration (answer b) and burning fossil fuels (answer c) release carbon into the atmosphere. Therefore, the correct choice is d, which includes both b and c.

Key Concepts

Aerobic Respiration

Aerobic respiration is a vital biological process that occurs in the cells of both plants and animals, including humans. It enables organisms to convert glucose and oxygen into energy. This energy is crucial for cellular functions. The equation for aerobic respiration is: \\[\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{energy} (\text{ATP})\]During this process:

• Glucose (a sugar) is broken down.
• Oxygen acts as a reactant.
• Carbon dioxide and water are produced as byproducts.
• Energy in the form of ATP (adenosine triphosphate) is released.

This carbon dioxide is then expelled into the atmosphere whenever we breathe out. Hence, aerobic respiration is a natural source of atmospheric carbon.

Photosynthesis

Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy, storing it in the bonds of glucose. It is characterized by its pivotal role in reducing carbon dioxide levels in the atmosphere. The basic equation for photosynthesis is:\[6\text{CO}_2 + 6\text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2\]This process involves:

• Carbon dioxide from the atmosphere is absorbed by plants.
• Water is taken up from the soil or surrounding environment.
• Sunlight provides the necessary energy.
• Glucose is synthesized, which plants use as an energy source or store as starch.
• Oxygen, a byproduct, is released into the air.

Through photosynthesis, plants reduce atmospheric carbon dioxide, playing a crucial role in maintaining the balance of the carbon cycle on Earth.

Fossil Fuels

Fossil fuels are natural substances made from decomposed plants and animals, buried beneath the Earth's surface for millions of years. When these fuels, such as coal, oil, and natural gas, are burned for energy, they release significant amounts of carbon dioxide and other greenhouse gases. This contributes to atmospheric carbon levels. The combustion process can be summarized as:\[\text{Fuel} + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} + \text{energy}\]In detail:

• Energy is released when fossil fuels are burned, used for electricity, heating, and powering vehicles.
• Carbon dioxide is produced as a primary byproduct.
• Other pollutants and particulate matter are also emitted.

Burning fossil fuels is one of the largest sources of carbon emissions globally, impacting climate change and environmental health.