Chapter 39: The Genetic Code Flashcards
The pathway to protein synthesis is ____
Translation
The language of _____ sequence is translated to the language of an _____ sequence.
Nucleotide
Amino Acid
Process of translation requires a ____
Genetic Code
The __ letter word of DNA (RNA) is translated to the ___ letter alphabet of proteins
4
20
Nucleotides resemble ____
Letters
Codons resemble ____
Words
Genes resemble ____
Sentences
Genome resembles _____
Book
Each codon is a ____ of nucleotides
Triplet
The Genetic Code is a
Collection of codons
For 20 Amino Acids, there should be ____ codons
20
Each codon should have __ nucleotides to impact specificity to each amino acid for a specific codon
3 nucleotides
1 nuc used = 4 combinations
2 nuc = 16 combinations
3 nuc = 64 combinations
What are the 4 characteristics of the Genetic Code?
Specificity, Universal, Redundant, Non-overlapping
What does it mean for the genetic code to be specific?
A specific codon always codes for the same amino acid
e.g. UUU codes for Phenylalanine, it can never code for another AA
What does it mean for the genetic code to be universal?
All living organisms have the same genetic code
There is an exception to the universal rule in _____ codons. AUA codes for methionine instead of isoleucine and UGA codes for tryptophan instead of termination codon
Mitochondrial
____ & ____ code for arginine in the cytoplasm but in the mitochondria they are termination codons
AGA & AGG
Most organisms use the same genetic code because its important for production of
Recombinant proteins
Some organisms have slight modifications - in ciliated protozoa, codons that are ___ signals in most organisms, encode ____
Stop
Amino Acids
______ also use variations of the genetic code
Mitochondria
What does it mean for the genetic code to be redundant?
(degenerate) Although each codon corresponds to a single AA, a single AA can have multiple codons
(e. g. Tryptophan and Methionine have multiple codons)
What does it mean for the genetic code to be non-overlapping?
All codons are independent sets of 3 nucleotides. There is no overlapping. Codon is read from fixed starting point as a continuous sequence of nucleotides, 3 at a time
The starting point it extremely important and is known as the
Reading Frame
Translation of the correct message requires selection of the correct reading frame
The sequence of bases is read sequentially from a fixed starting point until termination in a ___ to ___ direction
5’ to 3’
