Genetic Code Flashcards
Gene
a unit of DNA that encodes a specific protein or RNA molecule, and through transcription and translation, that gene can be expressed.
3 types of RNA found in cells
Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA)
Messenger RNA (mRNA)
carries information from DNA by traveling from the nucleus (where it is transcribed) to the cytoplasm (where it is translated)
Transfer RNA (tRNA)
translates nucleic acids to amino acids by pairing its anticodon with mRNA codons; it is charged with an amino acid, where it can be added to the growing peptide
are charged and activated with an amino acid
Ribosomal RNA (rRNA)
forms much of the structural and catalytic component o the ribosome, and acts as a ribozyme to crease peptide bonds between amino acids
Central Dogma
DNA –> RNA –> Proteins
Start codon:
AUG
Stop codon:
UGA, UAA, UAG
Wobble position
Redundancy and wobble (third base in the codon) allows mutations to occur without effects in the protein
protects against mutations
usually found in the 3rd base in the codon
Point mutations can cause:
Silent mutations - with no effect on protein synthesis
Nonsense (truncation) mutations - that produce a premature stop codon (expressed mutation); a mutation were the codon now encodes for a premature stop codon
Missense mutations - that produce a codon that codes for a different amino acid (expressed mutation); a mutation where one amino acid substitutes for another
Frameshift mutations
result from nucleotide addition or deletion, and change the reading frame of subsequent codons
RNA is structurally similar to DNA except:
Substitution of a ribose sugar for deoxyribose
Substitution of uracil for thymine
It is single stranded instead of double stranded
The anticodon sequence allows the tRNA to pair with the codon in the
mRNA
