Question

Choose the wrong statement in the process of protein synthesis
A. After uncoiling DNA molecules , one strand acts as a template for the formation of mRNA.
B. In the presence of DNA polymerase enzymes,the mRNA is formed based on the triplet codes.
C. The mRNA that leaves nucleus reaches cytoplasm and gets attached with 3os ribosomal subunits
D. The amino acids are transferred from the intracellular amino acid pool to active ribosomes by tRNA.

Answer 1

The mechanism in which cells make proteins is protein synthesis. It takes place in two phases: transcription and translation.

Complete Answer:
- A system that takes place in the cells of all living things: protein synthesis. Protein synthesis is called this process, and it actually consists of two steps, transcription and translation. In eukaryotic cells, in the nucleus, transcription takes place. DNA is used during transcription as a template to make a messenger RNA ( mRNA) molecule.
- The mRNA molecule then leaves the nucleus and goes into the cytoplasm to a ribosome, where translation occurs.In mRNA, the genetic code is read during translation and used to produce a protein.In mRNA, the genetic code is read during translation and used to produce a protein.
- The hydrogen bonds between base pairs are broken by DNA helicase and two DNA strands are thereby separated. In mRNA synthesis, the template strand serves while the other strand is referred to as the coding strand as its base sequence is the same as the newly synthesised mRNA.
- Using the base sequence of template DNA strands, the RNA polymerase enzyme adds ribonucleotides to synthesise RNA. In mRNA, triplet codons are present and act as the protein synthesis template.The enzyme for DNA replication is DNA polymerase.
- During transcription, the primary transcript synthesised undergoes processing to generate a functional RNA and is carried to the cytoplasm. The initiation complex for starting protein synthesis is characterised by the binding of mRNA to 30S ribosomal subunits and initiation factors.
- Each of the 20 amino acids present in the cell pool is covalently bound by aminoacyl-tRNA synthetases to a 3 ' end of specific tRNA using ATP; this charged tRNA carries the connected amino acid to the ribosome.

The correct answer is option (B) In the presence of DNA polymerase enzymes,the mRNA is formed based on the triplet codes.

Note: Transcription is the transmission of genetic instructions in the nucleus from DNA to mRNA. It comprises the initiation, elongation, and termination steps. It carries the instructions to a ribosome in the cytoplasm after the mRNA is processed.
In the ribosome, which consists of rRNA and proteins, translation takes place. The instructions in mRNA are read in translation, and tRNA gives to the ribosome the proper sequence of amino acids. Then rRNA enables the amino acids to form bonds, forming polypeptide chains.