How are protein, nucleic acids, and carbohydrates formed in living organisms?
Proteins, nucleic acids, and carbohydrates are all essential molecules found in living organisms. Let's explore how each of these biomolecules is formed.
1. Proteins:
Proteins are composed of smaller units called amino acids, which are linked together through a process called protein synthesis or translation. Here's how proteins are formed in living organisms:
a) DNA transcription: The first step involves the synthesis of a messenger RNA (mRNA) molecule through a process called transcription. This occurs in the cell nucleus. The DNA molecule serves as a template, and the enzyme RNA polymerase synthesizes the complementary mRNA strand.
b) mRNA processing: The newly synthesized mRNA undergoes several modifications, such as the removal of introns (non-coding regions) and the addition of a cap and poly-A tail. This processed mRNA is then transported out of the nucleus into the cytoplasm.
c) Translation: In the cytoplasm, the mRNA binds to ribosomes, where protein synthesis occurs. Transfer RNA (tRNA) molecules bring the appropriate amino acids and attach them to the growing protein chain based on the mRNA codons. This process continues until a stop codon is reached, resulting in the formation of a complete protein.
2. Nucleic acids:
Nucleic acids, such as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are responsible for storing and transmitting genetic information. Here's how nucleic acids are formed:
a) DNA replication: Prior to cell division, DNA needs to be replicated. Through a process called DNA replication, each strand of the double helix serves as a template for the synthesis of a new complementary strand. Enzymes called DNA polymerases help in this process, leading to the formation of two identical DNA molecules.
b) Transcription (for RNA synthesis): As mentioned earlier, transcription occurs to produce mRNA. RNA polymerase enzyme binds to a specific DNA sequence, called the promoter region, and synthesizes a complementary RNA strand based on the DNA template.
3. Carbohydrates:
Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen atoms. They serve as a primary source of energy for living organisms. Carbohydrates are formed through a process called photosynthesis in plants and by consuming carbohydrate-rich foods in animals. Here's a brief explanation of the two main processes:
a) Photosynthesis: In plants, photosynthesis is the process by which they convert carbon dioxide and water into carbohydrates (glucose) using sunlight. Chlorophyll, found in chloroplasts, captures light energy, and through several enzyme-mediated reactions, glucose is synthesized.
b) Dietary consumption: In animals and humans, carbohydrates are obtained by consuming foods rich in carbohydrates, such as grains, fruits, and vegetables. These complex carbohydrates are broken down through digestion into simpler sugars like glucose, which can then be used as an energy source by cells.
So, proteins are formed through the process of transcription and translation, nucleic acids are formed through DNA replication and transcription, and carbohydrates are formed through photosynthesis in plants or dietary consumption in animals.