Chapter 14

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34 Cards. Created by Alizabeth ().
RNA Molecules and RNA Processing
 
Term  
Definition

Colineraity

Concept that there is a direct correspondence between the nucleotide sequence of a gene and the continuous sequence of amino acids in a protein.

Exon

Coding region of a spilt gene (a gene that is interrupted by introns). After processing, the exons remain in messenger RNA.

Intron

Intervening sequence in a spilt gene; removed from RNA after transcription.

Group I Intron

Belongs to a class of introns in some ribosomal RNA genes that are capable of self-splicing.

Group II Introns

Belongs to a class of introns in some protein-encoding genes that are capable of self-splicing and are found in mitochondria, cholroplasts, and a few eubacteria.

Nuclear pre-mRNA

Belongs to a class of introns in protein-encoding genes that reside in the nuclei of eukaryotic cells; removed by spliceosomal-mediated splicing.

Transfer RNA Intron

Belongs to a class of introns in tRNA genes. The splicing of thesee genes relies on enzymes.

Codon

Sequence of 3 nucleotides that encodes one amino acid in a protein.

5' Untranslated region (5' UTR)

Sequence of nucleotides at the 5' end of mRNA; does not encode the amino acids of a protein.

Shine-Delgarno Sequence

Consensus sequence found in bacterial 5' untranslated region of mRNA; contains the ribosome-binding site.

Protein-coding Region

The part of mRNA consisting of the nucleotides that specify the amino acid sequence of a protein.

3' Untranslated region (3' UTR)

Sequence of nucleotides at the 3' end of mRNA; does not encode the amino acids of a protein but affects both the stability of the mRNA and its translation.

5' Cap

Modified 5' end of eukaryotic mRNA, consisting of an extra nucleotides; plays a role in the binding of the ribosome to mRNA and affects mRNA stability and the removal of introns.

Poly (A) tail

String of adenine nucleotides added to the 3' end of eukaryotic mRNA after transcription.

RNA Splicing

Process by which introns are removed and exons are joined together.

5' splice site

The 5' end of an intron where cleavage takes place in RNA splicing.

3' Splice site

The 3' end of an intron where cleavage takes place in RNA splicing.

Branch point

Adenine nucleotide in nuclear pre-mRNA introns that lies from 18 to 40 nucleotides upstream of 3' splice site.

Spliceosome

Large complex consisting of several RNAs and many proteins that splices protein-encoding pre-mRNA; contains five small ribonucleoprotein particles (U1, U2, U4, U5, and U6)

Lariat

Looplike structure created in the splicing of nuclear pre-mRNA in which the 5' end of an intron is attached to a branch point in pre-mRNA.