An energy-rich organic compound needed by organisms is
1. water
2. salt
3. oxygen
4. glucose
The correct answer and explanation is:
Correct Answer: 4. Glucose
Glucose is an energy-rich organic compound that is essential for the survival and functioning of organisms. It is a simple sugar, or monosaccharide, with the molecular formula C₆H₁₂O₆. Glucose serves as a primary source of energy for cells in both plants and animals. During the process of cellular respiration, glucose is broken down in the presence of oxygen to produce carbon dioxide, water, and energy in the form of adenosine triphosphate (ATP). This energy is then used by cells to perform vital functions such as growth, repair, and maintenance.
Unlike water, salt, or oxygen, glucose contains carbon and is considered organic. Water and oxygen are essential for life but do not provide energy. Salt, which is composed of ions like sodium and chloride, also plays an important role in nerve function and fluid balance, but it does not supply energy either. Energy in biological systems comes from the chemical bonds within organic molecules, particularly carbohydrates like glucose.
Plants produce glucose through the process of photosynthesis. In this process, carbon dioxide from the air and water from the soil are converted into glucose and oxygen using energy from sunlight. Animals and humans obtain glucose by consuming carbohydrates found in food such as fruits, vegetables, and grains. Once ingested, these carbohydrates are broken down into glucose during digestion.
The body tightly regulates blood glucose levels to ensure that cells have a constant energy supply. If too little glucose is available, cells cannot function properly. If too much glucose is present, it can lead to health problems such as diabetes. Therefore, glucose is not only a major energy source but also a key compound in maintaining metabolic balance in organisms.