Problem 9 - 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

d. b and c

Step 1: Identify the process

First, identify the processes listed in the options that involve the release of carbon into the atmosphere. Photosynthesis doesn't release but rather absorbs carbon dioxide from the atmosphere. Aerobic respiration releases carbon dioxide as a byproduct. Burning fossil fuels releases carbon dioxide when carbon in the fuel reacts with oxygen.

Step 2: Check the correctness of each option

Option a, photosynthesis, is incorrect because it absorbs carbon dioxide. Option b, aerobic respiration, releases carbon and is correct. Option c, burning fossil fuels, also releases carbon and is correct. Option d combines options b and c, both of which release carbon.

Step 3: Determine the most accurate option

Since both aerobic respiration and burning fossil fuels release carbon into the atmosphere, the most accurate choice is option d, which combines these two processes.

Key Concepts

Photosynthesis

Photosynthesis is a crucial biological process that takes place in green plants, algae, and some bacteria. It is the way these organisms convert light energy into chemical energy, stored as glucose. During photosynthesis, plants absorb carbon dioxide (\(CO_2\)) from the atmosphere through their leaves and use water (\(H_2O\)) absorbed by their roots. With the help of sunlight and chlorophyll, they convert these inputs into glucose (\(C_6H_{12}O_6\)) and oxygen (\(O_2\)).

• Energy Source: Sunlight is the primary source of energy in photosynthesis, making it an endothermic process.
• Products: The byproducts are glucose and oxygen, which are vital for plant growth and support life on Earth by providing oxygen.
• Significance: Photosynthesis helps reduce carbon dioxide in the atmosphere, thus playing a significant role in the carbon cycle.

This process is vital for life on Earth as it forms the base of the food chain and maintains oxygen levels in the atmosphere.

Aerobic Respiration

Aerobic respiration is a biological process that occurs in the cells of most living organisms. It is the way cells convert biochemical energy from nutrients into adenosine triphosphate (ATP), and release waste products. In essence, it is the way energy stored in glucose is made available for cellular activities. During this process, glucose and oxygen are used to produce carbon dioxide, water, and ATP.

• Stages: The process occurs in different stages, including glycolysis, Krebs cycle, and the electron transport chain.
• Equation: The overall reaction can be simplified as:\[C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP\]
• Importance: It provides the energy necessary for cellular processes. The carbon dioxide produced as a byproduct is released back into the atmosphere.

Aerobic respiration is essential for the survival of aerobic organisms and contributes to the carbon cycle by returning \(CO_2\) back to the atmosphere.

Burning Fossil Fuels

Burning fossil fuels is a human-induced process that significantly impacts the carbon cycle. Fossil fuels, such as coal, oil, and natural gas, contain high amounts of carbon formed from decomposed plants and animals buried under the earth for millions of years. When these fuels are burned, the carbon stored within them reacts with oxygen to produce carbon dioxide (\(CO_2\)), water vapor (\(H_2O\)), and energy.

• Environmental Impact: The release of carbon dioxide from burning these fuels is one of the major contributors to the greenhouse effect and global warming.
• Processes: Common activities include electricity generation, heating, and powering vehicles.
• Sustainability: Reducing the reliance on fossil fuels and switching to renewable energy sources are crucial for mitigating climate change.

The burning of fossil fuels increases the levels of carbon dioxide in the atmosphere, exacerbating climatic changes and impacting global ecosystems.