Question

lostantaneous source of energy is (1) proteins (b) fats Id nucleic acids (d) glucose.

Short answer

The instantaneous source of energy for cells is (d) glucose.

Step-by-step solution

Identify the Immediate Source of Energy for Cells

To solve this exercise, we need to identify which of the four options is considered the primary or immediate source of energy for cells. The options include proteins, fats, nucleic acids, and glucose.

Eliminate Incorrect Options

Proteins are primarily used for growth and repair of tissue. Fats are a long-term energy storage molecule. Nucleic acids are not used for energy; they store and transmit genetic information.

Select the Correct Answer

Glucose is a simple sugar that cells can quickly metabolize to produce ATP (adenosine triphosphate), which is the immediate energy currency of the cell. Therefore, the correct answer is glucose.

Key concepts

Cellular Respiration

Cellular respiration is a crucial process that occurs in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. This process takes place in the mitochondria, often referred to as the 'powerhouse of the cell'.

There are several stages of cellular respiration, including glycolysis, the Krebs cycle, and the electron transport chain. During glycolysis, glucose is broken down into pyruvate, which is further processed to generate ATP. The subsequent stages involve intricate biochemical reactions that ultimately result in the production of a substantial amount of ATP from a single molecule of glucose.

• Glycolysis occurs in the cytoplasm and does not require oxygen, making it an anaerobic process.
• The Krebs cycle takes place in the matrix of mitochondria and produces electron carriers that ferry electrons to the next stage.
• The electron transport chain is where the most ATP is generated and is highly dependent on the presence of oxygen.

Understanding cellular respiration is vital because it explains how cells extract energy from food to power biological functions.

ATP (Adenosine Triphosphate)

ATP, or adenosine triphosphate, is often described as the energy currency of the cell. It is a high-energy molecule that stores and supplies the energy needed for various cellular functions. Its structure comprises three phosphate groups linked to an adenosine molecule.

When a cell needs energy, it breaks the bond between the second and third phosphate groups in ATP, releasing energy along with a byproduct called adenosine diphosphate (ADP). The cell can then recharge ADP back into ATP through cellular respiration, closing the cycle.

• ATP provides the energy for muscle contractions, nerve impulses, and chemical syntheses.
• Without ATP, cells would not be able to maintain their structure, grow, or reproduce.

ATP is so fundamental to cellular processes that a constant supply is required for the survival of living organisms, highlighting its significance in the study of cellular biology.

Metabolism of Glucose

The metabolism of glucose is the process by which glucose is utilized by the body to create energy. It begins the moment we ingest food containing carbohydrates.

Enzymes break down complex carbohydrates into glucose, which then enters the bloodstream. Insulin, a hormone produced by the pancreas, aids in the transport of glucose into the cells. Once inside, glucose undergoes glycolysis, which transforms it into pyruvate and generates a small amount of ATP. Pyruvate is then used in the mitochondria for further energy production.

• The Krebs cycle and the electron transport chain complete the glucose metabolism process.
• This metabolic pathway is tightly regulated to ensure balance and efficiency.
• Any disruption in glucose metabolism can lead to metabolic diseases such as diabetes.

Understanding glucose metabolism provides insight into how the body produces and uses energy from food, which is essential for human health and activity.