Molecular Biology: DNA to Protein Synthesis

Posted on Jan 30, 2025 in Biology

DNA Replication, Transcription, and Translation

DNA Replication

1. The DNA double helix unwinds.
2. Topoisomerases prevent supercoiling.
3. Single-strand binding proteins (SSB) stabilize the separated DNA strands.
4. Replication forks are bidirectional, with a helicase at each fork.
5. Primase synthesizes an RNA primer, as DNA polymerase cannot initiate synthesis without one.
6. DNA polymerase begins synthesis from the primer in the 5′ to 3′ direction on the leading strand.
7. On the lagging strand, RNA polymerase synthesizes short RNA primers.
8. DNA polymerase III synthesizes Okazaki fragments from these primers.
9. DNA polymerase I removes RNA primers and fills the gaps with DNA.
10. DNA ligase joins the Okazaki fragments. The lagging strand is synthesized discontinuously.

Transcription

1. Transcript: RNA polymerase binds to promoter sequences.
2. Transcription bubbles are opened.
3. A primer is synthesized.
4. RNA polymerase separates from the DNA.
5. Introns are removed, and exons are joined.

Translation

Translation: The process by which the mRNA message is translated into proteins.

1. The mRNA message leaves the nucleus through nuclear pores.
2. mRNA binds to ribosomes, which are responsible for protein synthesis.
3. Ribosomes read the mRNA in triplets (codons).

DNA Replication

1. The DNA double helix unwinds.
2. Topoisomerases prevent supercoiling.
3. Single-strand binding proteins (SSB) stabilize the separated DNA strands.
4. Replication forks are bidirectional, with a helicase at each fork.
5. Primase synthesizes an RNA primer, as DNA polymerase cannot initiate synthesis without one.
6. DNA polymerase begins synthesis from the primer in the 5′ to 3′ direction on the leading strand.
7. On the lagging strand, RNA polymerase synthesizes short RNA primers.
8. DNA polymerase III synthesizes Okazaki fragments from these primers.
9. DNA polymerase I removes RNA primers and fills the gaps with DNA.
10. DNA ligase joins the Okazaki fragments. The lagging strand is synthesized discontinuously.

Transcription

1. Transcript: RNA polymerase binds to promoter sequences.
2. Transcription bubbles are opened.
3. A primer is synthesized.
4. RNA polymerase separates from the DNA.
5. Introns are removed, and exons are joined.

Translation

Translation: The process by which the mRNA message is translated into proteins.

1. The mRNA message leaves the nucleus through nuclear pores.
2. mRNA binds to ribosomes, which are responsible for protein synthesis.
3. Ribosomes read the mRNA in triplets (codons).