RNA
What is a Codon?
Sequence of three nucleotides in a DNA or messenger RNA molecule that represents the instruction for incorporation of a specific amino acid into a growing polypeptide chain.
What is transcription?
information is copied from DNA to RNA written in essentially the same language = the language of nucleotides. à Both DNA and RNA
Transfer RNA (tRNA)?
Set of small RNA molecules used in protein synthesis as an interface (adaptor) between mRNA and amino acids. Each type of tRNA molecule is covalently linked to a particular amino acid.
RNA splicing
Process in which intron sequences are excised from RNA molecules in the nucleus during the formation of messenger RNA
Where does RNA Polymerase bind in transcription?
The promoter
Ribosome?
Particle composed of ribosomal RNAs and ribosomal proteins that associates with messenger RNA and catalyzes the synthesis of protein.
What is an Intron?
The noncoding region (intervening sequences) of a eukaryotic gene is transcribed into an RNA molecule but is then excised (cut out) by RNA splicing to produce mRNA.
the growing RNA chain is extended by one nucleotide at a time in which direction
5' to 3' direction
Before mRNA can be exported to the cytosol, a eukaryotic RNA must go through several RNA processing steps, which include:
-capping,
-splicing, and
-Polyadenylation (poly-A tail)
What is an Exon?
Coding region of a eukaryotic gene
Øtranscribed into RNA and expressed
ØDetermines the amino acid sequence in a protein.
What enzyme is in charge of making RNA from DNA and how does it work?
RNA Polymerase.
What is the point of Capping and polyadenylation (addition of poly-A tail)?
Øonly on transcripts destined to become mRNA molecules
Øincrease the stability of a eukaryotic mRNA molecule,
Øfacilitate its export from the nucleus to the cytoplasm, and
Øgenerally mark the RNA molecule as an mRNA.
What is the Reading frame?
The set of successive triplets in which a string of nucleotides is translated into protein. An mRNA molecule is read in one of three possible reading frames, depending on the starting point.
is where the polymerase stops and releases both the DNA template and the newly made RNA chain
The Terminator (stop site)
polyribosomes
large cytoplasmic assemblies made up of several ribosomes spaced as close as 80 nucleotides apart along a single mRNA molecule