1.3 Gene Expression Flashcards
Processes involved in Gene Expression
Transcription & Translation
Components of RNA (ribonucleic acid)
- a ribose sugar
- a base
- a phosphate
What base replaces Thymine in RNA
Uracil
Types of RNA
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA (rRNA)
mRNA
Carries a copy of the required gene from the nucleus to the ribosome
tRNA
- has a cloverleaf shape
- has an anti codon site and an attachment site for specific amino acids
- each tRNA molecule carriers its specific amino acid to the ribosome
rRNA
Forms the ribosome with the addition of proteins
Protein Synthesis
A process in which instructions are carried from DNA sequences to ribosomes where proteins are synthesised.
Codon
A group of 3 bases that codes for an amino acid
Exons
coding regions of DNA
Introns
non-coding regions of DNA
Splicing
When non-coding introns are edited out so that the coding exons can be turned into protein.
Splicing process
- The gene is copied in full to produce a primary transcript
- introns are removed and exons are joined together to produce a mature transcript
Alternative RNA splicing
- allows one gene to code for a variety of proteins
- different mature mRNA
transcripts are produced from the same
primary transcript depending on which
exons are retained
Transcription
- synthesis of mRNA from a section of DNA
- occurs in the nucleus
Translation
- synthesis of a protein under the direction of mRNA
- occurs in the ribosome
What bonds are amino acids held together by?
Peptide bonds
what are chains of amino acids linked by peptide bonds called?
polypeptide chains
How is the shape of a protein produced?
by the folding of a polypeptide chain
what does the shape of a protein determine?
its function
what are proteins held together by?
- hydrogen bonds
- interactions between amino acids
what is the phenotype of an individual determined by?
proteins that are a result of gene expression
