Translation Flashcards
Goal of translation is?
To make polypeptides from mRNA sequence
“ORF”
-The codons of an mRNA that are read sequentially to specify amino acids
Open Reading Frame
Characteristics of the genetic code
- Triplet Code
- Continuous
- Nonoverlapping
- Universal
- Redundant/degenerate
- Unambiguous
- Codon bias
- Wobble
Each mRNA codon consists of 3 nucleotides
Triplet Code
The mRNA is read 3 nucleotides at a time without skipping any nucleotides
Continuous
The mRNA is read in successive groups of 3 nucleotides
Nonoverlapping
All known organisms have the same genetic language
Universal
More than 1 codon occurs for each amino acid, 3rd nucleotide might differ
Redundant/degenerate
One codon specifies one amino acid
Unambiguous
Calls for beginning and end of an “ORF”
Start and stop signals
AUG=?
Start codon
Stop codons=?
nonsense codons
The tendency of an organism to use a certain codon for 1 amino acid more than others
Codon bias
Basepairing between tRNA anticodon and mRNA codon doesn’t necessarily follow complementary basepairing ules at the 3rd nucleotide
Wobble
Why is Wobble advantageous?
Because the cell only needs to have 1 tRNA for leucine
-energetically favorable
The genetic code is ________, meaning that an amino acid may be coded by more than one codon.
a. unambiguous
b. degenerate
c. commaless
d. universal
e. nonoverlapping
b. degenerate
Polymers of amino acids that are connected by peptide bonds
Polypeptides
N
Amino end (at 5’)
C
Carboxyl end (at 3’)
Covalent bond between amino acids
Peptide bond
Catalyzes the peptide bond formation by dehydration
Ribosome
_______ along the polypeptide determine how it will fold and thus function.
R groups
Have unique features governed by their R group
Amino acids
Dictates how a protein is folded and thus function
Amino acid sequence
Although some amino acids may look similar, small changes in the amino acid sequence can have darastic effects on protein and phenotype
Amino acid sequence
Nonpolar: Hydrophobic Amino Acids
Alanine, Methionine
Valine, Phenylalanine
Leucine, Tryptophan
Isoleucine, Proline
Polar: Hydrophilic Amino Acids
Glycine, Aspargenine
Serine, Glutamine
Threonine Tyrosine
Cysteine
Polar: (+) charge BASIC
Lysine
Arginine
Histidine
Polar: (-) charge ACIDIC
Aspartic Acid
Glutamic Acid
The sequence of amino acids in a polypeptide chain
Primary structure
The folding and twisting of a single polypeptide chain into a variety of forms (alpha helix, beta-pleated sheet)
Secondary structure
The specific 3D folding of a polypeptide chain
Tertiary structure
The aggregate of polypeptide chains that make up a multisubunit protein
Quaternary structure
Multiple ribosomes translating the same mRNA concurrently,
-In both proks and euks
Polyribosomes (polysomes)
Co-transcription and translation in ________.
Prokaryotes
