The Carbon and Oxygen Cycle

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Questions and Answers

Explain how the carbon and oxygen cycle is essential for sustaining life in an ecosystem.

The carbon and oxygen cycle is the foundation of life on Earth, forming the basis of biological molecules like sugars, fats, proteins, and DNA.

Describe the role of photosynthesis in the carbon cycle and how it affects the amount of carbon dioxide in the Earth's atmosphere.

Photosynthesis converts gaseous carbon in the atmosphere into sugars, utilizing carbon dioxide and decreasing its concentration in the atmosphere.

Explain how cellular respiration is related to the carbon cycle, detailing the inputs, outputs and how it contrasts with photosynthesis.

Cellular respiration converts food (sugar) into energy, releasing carbon dioxide and water. In contrast, photosynthesis uses carbon dioxide and water to produce sugar. It uses oxygen, whereas photosynthesis produces it.

How do decomposers contribute to the carbon cycle?

Decomposers break down dead biomass and release carbon back into the soil and atmosphere. Signup and view all the answers

Based on the image, where is the majority of carbon found in the world?

Based on the image, the majority of carbon is found in gas hydrates. Signup and view all the answers

Why is nitrogen important for living organisms?

Nitrogen is essential for the formation of proteins and DNA/RNA in living organisms. Signup and view all the answers

Explain why plants and animals cannot directly use atmospheric nitrogen (N₂).

Atmospheric nitrogen (N₂) is trapped in a form that plants and animals cannot directly use due to its stable triple bond. Signup and view all the answers

Describe the role of nitrogen-fixing bacteria in the nitrogen cycle and why it is important.

Nitrogen-fixing bacteria convert atmospheric nitrogen (N₂) into a usable form (e.g., ammonia) that plants can absorb through their roots. This conversion makes nitrogen available for incorporation into proteins and DNA/RNA. Signup and view all the answers

What is the first law of thermodynamics, and how does it relate to energy flow in ecosystems?

The First Law of Thermodynamics states that energy is neither created nor destroyed, but only converted. In ecosystems, energy is converted from one form to another as it flows through different trophic levels. Signup and view all the answers

Describe how plants convert sunlight energy into chemical energy, and name the type of sugar that plant bodies are made of.

Plants convert sunlight energy into chemical energy through photosynthesis, producing sugars and other organic compounds. Plant bodies are primarily made of a sugar called cellulose. Signup and view all the answers

How do animals obtain chemical energy from plants, and into what forms of energy do animals convert this chemical energy?

Animals obtain chemical energy from plants by eating them. After ingestion, animals convert this chemical energy (in sugars/fats/proteins) into kinetic energy (movement) and heat. Signup and view all the answers

Explain the role of fossil fuels in the carbon cycle and the general chemical formula for combustion?

Fossil fuels release carbon dioxide and water during combustion, reintroducing carbon from long-term storage back into the atmosphere. The general chemical formula for combustion is: Fossil fuels (containing carbon) + oxygen → CO₂ + H₂O. Signup and view all the answers

Describe what would happen to an ecosystem if there were no decomposers.

If there were no decomposers, dead biomass would not break down, preventing nutrients from being returned to the soil/atmosphere, disrupting nutrient cycles, and hindering the growth of new organisms. Signup and view all the answers

Explain, in terms of the carbon cycle, what happens to the carbon when a living organism dies or is eaten?

When a living organism dies or is eaten, the carbon in its body is transferred to predators or decomposers, which eventually release it back into the atmosphere or soil through respiration or decomposition. Signup and view all the answers

In the context of cellular respiration, how does this process contribute to the carbon cycle, and what is its chemical formula?

Cellular respiration releases carbon dioxide back into the atmosphere as organisms break down sugars to produce energy. The chemical formula is: $C_6H_{12}O_6 + 6 O_2 \rightarrow 6 CO_2 + 6 H_2O$. Signup and view all the answers

How is energy transferred between trophic levels in an ecosystem, and what form does this energy primarily take?

Energy is transferred through the food chain as organisms consume one another, primarily in the form of chemical energy stored in sugars, fats, and proteins within their tissues. Signup and view all the answers

What is the role of root nodules in the nitrogen cycle, and what type of plants are typically associated with them?

Root nodules house nitrogen-fixing bacteria that convert atmospheric nitrogen into ammonia usable by plants. Leguminous plants, like beans and peas, are typically associated with them. Signup and view all the answers

Describe two ways in which human activities have altered the carbon cycle.

Human activities such as burning fossil fuels and deforestation have altered the carbon cycle by increasing atmospheric carbon dioxide levels and reducing carbon sinks. Signup and view all the answers

Explain why the nitrogen cycle is essential for plant growth.

The nitrogen cycle is crucial for plant growth because it facilitates the conversion of atmospheric nitrogen into usable forms, such as ammonia, that plants can absorb and use to synthesize proteins and DNA/RNA. Signup and view all the answers

Describe the role of decomposers in the nitrogen cycle.

Decomposers break down dead organisms and waste products and release nitrogen compounds back into the soil, which can then be converted into other forms by bacteria as part of the nitrogen cycle. Signup and view all the answers

Flashcards

Carbon and Oxygen Cycle

The flow of carbon and oxygen in an ecosystem.

Carbon's Role

The foundation of every living thing; found in all molecules.