Food, Energy, and Raw Materials - Summary

Food, Energy, and Raw Materials - Summary

• The human body is composed of atoms that form molecules, which in turn create cells and body structures.
• Food provides raw materials and energy for a variety of purposes, including building and maintaining body structures and driving metabolic processes. It provides the materials needed to form body structures during development and is used to add new molecules to existing ones, replace lost or broken-down molecules, and produce energy to fuel the body's processes.
• The four major biological molecules are carbohydrates, proteins, lipids, and nucleic acids.
• Humans are part of ecosystems and require raw materials, energy, oxygen, and water.
• Photosynthesis and cellular respiration are key processes in ecosystems. Photosynthesis converts light energy into chemical energy, while cellular respiration releases energy from this stored chemical form. Both processes are essential for the flow of energy and materials within ecosystems.
• Ecosystems involve energy flow and chemical cycling. Producers, consumers, and decomposers play distinct roles in these cycles. Producers capture sunlight energy to create sugars. Consumers consume producers for energy. Decomposers get energy from dead producers and consumers, releasing nutrients needed by producers
• Energy and nutrients move through ecosystems via trophic levels, with energy transfer being inefficient. Roughly 90% of energy is lost as heat between levels.
• Nutrients cycle through ecosystems, transferring from producers, through consumers, to decomposers.
• Sunlight is the primary energy source in most ecosystems.
• Energy flows in one direction through ecosystems, from producers (e.g., plants) to consumers (e.g., animals) and then decomposers.
• The Earth is a closed system with regard to matter. Chemical cycles constantly recycle elements like carbon, nitrogen, and phosphorus.
• Biological magnification is the increasing concentration of certain substances (like toxins) in organisms at higher trophic levels of a food chain. This happens because toxins become more concentrated at each level of the food chain.
• Human activities significantly influence ecosystems, particularly through the release of atmospheric carbon dioxide. Deforestation & fossil fuel burning raise CO2 levels.

Important Biological Molecules

• Carbohydrates, proteins, lipids, and nucleic acids are the four key classes of biological molecules.

More Questions (from text)

• Food is necessary to provide energy for metabolic processes and to construct body components during development. The raw materials in food are required to build new structures and replace old ones. The energy from food powers metabolic reactions.
• Different organisms carry out photosynthesis and chemosynthesis for different purposes - they use different energy sources. Photosynthesis uses light energy to produce sugars; chemosynthesis uses chemical energy from inorganic molecules.
• Decomposers 'absorb' nutrients from non-living materials, whereas detritivores 'eat' non-living matter. Decomposers break down dead organisms and return nutrients to the environment. Detritivores consume decaying organic matter.
• There is roughly a 10% energy transfer between different trophic levels. This means that much energy is lost as heat during the transfer between levels.