Module 7 Molecular Genetics

3.7.3 page 4

Lesson Summary

 

This lesson explained the steps involved in producing what our DNA codes for proteins. Transcription of the DNA into mRNA in the nucleus must first occur. The mRNA then travels to the cytoplasm to ribosomes for translation to occur. During translation, the tRNA with complementary anticodons to the mRNA codons are matched up. Each tRNA brings with it an amino acid and with the help of enzymes amino acids are bonded and the coded sequence of amino acids is created. In the next lesson we will be looking at changes in the genetic code and how these changes in DNA can affect the proteins being synthesized.

 

Glossary

 

amino acid: an organic compound consisting of a carboxylic acid group, an amino group and other side groups linked together by peptide bonds to form proteins; the building blocks of proteins

 

anticodon: specialized base triplet located on one lobe of a transfer RNA (tRNA) molecule that recognizes its complementary codon on a messenger RNA (mRNA) molecule

 

anti-sense strand: strand of nucleotides from the double-stranded DNA molecule that is complementary to the sense strand and is not transcribed

 

codon: set of three bases that code for an amino acid or termination signal

 

gene: a specific sequence of DNA that encodes a protein, tRNA, rRNA or regulates the transcription of such a sequence

 

genetic code: the order of base pairs in a DNA molecule

 

messenger RNA (mRNA): strand of RNA that carries genetic information from DNA to the protein synthesis machinery of the cell during transcription

 

promoter region: during transcription, a sequence of nucleotides on the DNA molecule that tells the RNA polymerase complex where to bind

 

protein: organic macromolecule assembled from subunits of amino acids

 

RNA polymerase: main enzyme that catalyzes the formation of RNA from the DNA template

 

sense strand: the one strand of nucleotides from the double-stranded DNA molecule that is transcribed

 

transcription: a strand of messenger RNA (mRNA) is produced that is complementary to a segment of DNA

 

transfer RNA (tRNA): type of RNA that works with messenger RNA (mRNA) to direct the synthesis of a polypeptide in a process known as translation

 

translation: second stage of gene expression, in which the mRNA nucleotide sequence directs the synthesis of a polypeptide with the aid of tRNA