Which of the following is NOT a function of carbohydrates?
A. Carbohydrates are used in cellular recognition.
B. Carbohydrates are part of DNA and RNA.
C. Carbohydrates are used for long-term energy storage.
D. All of these answers ARE functions of carbohydrates.
E. Carbohydrates are fuels for cells.
The correct answer and explanation is:
The correct answer is C. Carbohydrates are used for long-term energy storage.
Carbohydrates primarily serve as short-term energy sources and are not the main component for long-term energy storage in the body. Long-term energy storage is predominantly handled by fats (lipids), which are stored in adipose tissue. Fats provide a more concentrated source of energy because they have a higher energy density compared to carbohydrates.
Here’s a breakdown of the other options:
- A. Carbohydrates are used in cellular recognition.
Carbohydrates play a crucial role in cellular recognition, especially in the form of glycoproteins and glycolipids. These carbohydrate structures on the cell surface help cells communicate and interact with each other, and they are involved in immune system functions and pathogen recognition. - B. Carbohydrates are part of DNA and RNA.
Carbohydrates are essential components of nucleic acids. In DNA and RNA, the sugar molecule (deoxyribose in DNA and ribose in RNA) forms part of the backbone structure of these molecules, linking with phosphate groups and nitrogenous bases to form the double helix of DNA and the single strand of RNA. - D. All of these answers ARE functions of carbohydrates.
This is incorrect because, as explained earlier, carbohydrates are not primarily involved in long-term energy storage, which is the focus of option C. - E. Carbohydrates are fuels for cells.
Carbohydrates are the primary fuel source for many cells in the body. Glucose, a simple carbohydrate, is metabolized to produce ATP, the energy currency of the cell. Carbohydrates can also be broken down into glycogen for storage in the liver and muscles, but this is still considered short-term energy storage.
Thus, carbohydrates are versatile molecules with many roles, but long-term energy storage is not one of them.