2C-2D Flashcards
Describe the Genetic Code
The set of rules by which information in encoded in genetic material
Coded information = nucleotide sequences in the DNA template strands
Decoded information = order of amino acids in polypeptides
Describe Transcription
RNA polymerase binds to the promoter region
DNA unwinds
RNA polymerase reads the DNA template strand and uses complementary RNA nucleotides to catalyse the formation of pre-mRNA
Transcription is terminated when the termination sequence is recognised
Describe Translation
mRNA molecule binds to the ribosome
tRNA anticodons complementary to mRNA codons deliver corresponding amino acids to the ribosome
Adjacent amino acids are joined with peptide bonds via a condensation reaction to form a polypeptide
Translation end when a STOP codon is recognised
What is the start and stop codon?
Sequence of 3 nucleotides in mRNA that signals the end of translation respectively
What is the coding reigon?
Portion of DNA or RNA that codes for protein
Alternative splicing
Arranging exons in different patterns
What is the promoter?
The sequence of DNA to which RNA polymerase binds
What is the leader region?
The segment of DNA or mRNA that immediately precedes the coding region (involved in gene regulation)
What is the TATAA box?
A type of promoter region in eukaryotic cells (sequence of bases ‘TATAAA’)
What is an intron?
Non-coding regions of DNA that do not code for proteins. They are spliced out during RNA processing
What is an exon?
Regions of DNA that code for proteins and are not spliced out during RNA processing
Describe the Termination sequence
A sequence of DNA that signals the end of transcription
Describe RNA processing
Addition of a methyl G cap to the 5’end (helps with mRNA recognition by the ribosome)
Addition of poly-A tail to the 3’end (increases stability of the molecule)
Introns removed and exons spliced together
What is the product of Transcription
pre-mRNA from DNA template strand
What is the product of RNA processing
mRNA from pre-mRNA
What is the product of translation
Polypeptide from mRNA
Describe Post-translational modification
Processing events that change the properties of a protein
Further extend possible protein functions by attaching small chemical groups to an amino acid
What is a gene
A segment of DNA
What are genes responsible for?
Code for the production of proteins
Control the actions of other genes
Determine phenotype (physical traits)
They have a region that codoes for an RNA molecule, staring with a promotor and ending in a terminator
