3 Main Questions:
- What is transcription?
Transription is the synthesis of RNA under the direction of DNA.
- What is translation?
Translation is the synthesis of a polypeptide, which occurs under the direction of mRNA.
-What is mRNA?
A type of RNA, synthesized using a DNA template, that attaches to ribosomes un the cytoplasm and specifies the primary structure of a protein.
5 Main Facts:
- Genes provide the instruction s for making specific proteins.
- The basic mechanics of transcription and translation are similar for bacteria and eukaryotes, but there is an important difference in the flow of genetic information within the cells.
- Transcription and translation occurs in all organisms.
- In DNA or RNA, the monomers are the four types of nucleotides long, which differ in their nitrogenous bases.
- Genes are typically hundreds or thousands of nucleotides long, each gene having a specific sequence of bases.
Diagram:
As a molecule of mRNA is moved through a ribosome, codons are translated into amino acids, one by one. The interpreters are tRNA molecules, each type with a specific anticodon at one end and a corresponding amino acid at the other end. A tRNA adds its amino acid cargo to a growing polypeptide chain when the anticodon hydrogen-bonds to a complementary codon on the mRNA.
Summary:
Genes provide the instructions for making specific proteins. But a gene does not build a protein directly. The bridge between DNA and a protein synthesis is the nucleic acid RNA. Thus, nucleic acids and proteins contain information written in two different chemical languages.
Getting from DNA to protein requires two major stages: transcription and translation. Transcription is the synthesis of RNA under the direction of DNA. Translation is the synthesis of a polypeptide, which occurs under the direction of mRNA.
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