Problem 15 - Biology Concepts and Applications

Question

Match each term with its most suitable description. $$ \text {_____ carbon dioxide } \quad \quad\quad\quad\quad \text {a. contains triple bond } $$ $$ \text {_____ bicarbonate} \quad \quad\quad\quad\quad \text {b. nutrient taken up by plant roots} $$ $$ \text {_____ nitrate} \quad \quad\quad\quad\quad \text {c. marine carbon sources } $$ $$ \text {_____ nitrogen gas} \quad \quad\quad\quad\quad \text { d. greenhouse gas} $$

Step-by-Step Solution

Answer

Carbon dioxide - d; Bicarbonate - c; Nitrate - b; Nitrogen gas - a.

Step 1: Match Carbon Dioxide

Carbon dioxide (CO₂) is known as a greenhouse gas because it traps heat in the atmosphere. Therefore, the correct match for carbon dioxide is option 'd'.

Step 2: Match Bicarbonate

Bicarbonate (HCO₃⁻) serves as a marine carbon source and is prevalent in the ocean. Therefore, the correct match for bicarbonate is option 'c'.

Step 3: Match Nitrate

Nitrate (NO₃⁻) is an essential nutrient taken up by plant roots for growth and development. Therefore, the correct match for nitrate is option 'b'.

Step 4: Match Nitrogen Gas

Nitrogen gas (N₂) consists of molecules with a triple bond between nitrogen atoms. Therefore, the correct match for nitrogen gas is option 'a'.

Key Concepts

Greenhouse Gases

Greenhouse gases are crucial to understanding climate change and their effects on the Earth’s temperature. These gases include carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and water vapor, among others. They trap heat in the atmosphere, allowing sunlight to enter but preventing some of the heat from leaving.

• Carbon Dioxide (CO₂): Originates from burning fossil fuels like coal, oil, and natural gas. It is the primary contributor to the greenhouse effect.
• Methane (CH₄): Released by agricultural practices and the decay of organic waste in landfills. It is more effective than CO₂ at trapping heat.
• Nitrous Oxide (N₂O): Comes from fertilizer use and livestock operations. It has a significant warming potential.

Understanding these gases is essential for developing strategies to mitigate climate change and reduce emissions.

Marine Carbon Sources

Marine carbon sources play a vital role in the global carbon cycle. The oceans absorb approximately 25% of the CO₂ emitted into the atmosphere by human activities. This process helps regulate the Earth’s climate.
Bicarbonate (HCO₃⁻) is a key player in this system. Found in seawater, it acts as a buffer, maintaining the ocean's pH balance. When CO₂ is absorbed by the ocean, it reacts with water forming carbonic acid, which then dissociates into bicarbonate and carbonate ions.

• These reactions help modulate the concentration of CO₂ in the atmosphere.
• They also contribute to the formation of shells and skeletons of marine organisms in the form of calcium carbonate.

Marine carbon sources are critical for both carbon sequestration and supporting marine life.

Plant Nutrients

Plant nutrients are the elements essential for plant growth and development. They are typically absorbed by plant roots from the soil.
Nitrate (NO₃⁻) is a primary nitrogen source for plants. Nitrogen is a crucial component of amino acids, proteins, and chlorophyll.

• Without sufficient nitrogen, plants can exhibit poor growth and yellowing of leaves.
• Farmers often use nitrate-based fertilizers to enhance plant growth and improve crop yield.

Other essential nutrients include phosphorus, potassium, magnesium, and sulfur. Each plays a unique role in plant metabolism and health. Effective nutrient management enhances plant productivity and sustainability in agriculture.

Chemical Bonding

Chemical bonding is the force that holds atoms together in molecules. It is fundamental to understanding all chemical reactions and compounds.
Nitrogen gas (N₂) is a classic example, being composed of two nitrogen atoms linked by a strong triple bond. This bond involves three shared pairs of electrons, making N₂ very stable and inert under most conditions.

• Single Bonds: Form when one pair of electrons is shared between two atoms.
• Double Bonds: Occur with two shared pairs of electrons.
• Triple Bonds: Involve three shared pairs of electrons, offering high energy and strength.

Chemical bonds explain the diversity of compounds and materials around us, from simple diatomic molecules to complex polymers. Understanding bonding is key to mastering the intricacies of chemistry.