Unit 6 - Translation & Genetic Code Flashcards
What is a codon?
A sequence of three consecutive mRNA bases that specifies a particular amino acid
Codons are the basic units of the genetic code.
How many different possible codons exist?
64 different possible codons
Of these, 60 specify amino acids, one specifies methionine and ‘start’, and three signal ‘stop’.
What characteristics define the genetic code?
Nonoverlapping, triplet, universal, and degenerate
This means that the code does not overlap, is read in triplets, applies to all organisms, and allows multiple codons to encode the same amino acid.
What role did synthetic RNAs play in the 1960s?
They were used to decipher the genetic code through experiments
Researchers utilized logic and clever experimental designs during this period.
What components are required for translation?
- tRNA
- Ribosomes
- Energy-storage molecules
- Enzymes
- Protein factors
These components work together to synthesize proteins from mRNA.
What initiates the formation of the initiation complex in translation?
mRNA, a small ribosomal subunit, and a tRNA carrying methionine
The initiation complex is crucial for starting the translation process.
What happens when the ribosome reaches a ‘stop’ codon?
The ribosome falls apart into its two subunits and is released
This process concludes the translation of the polypeptide chain.
What are the possible post-translation modifications of polypeptides?
- Cleavage
- Addition of sugars
- Aggregation
These modifications can determine the protein’s final form and function.
What is the primary structure of a protein?
Its amino acid sequence
This sequence is critical for determining the protein’s overall structure and function.
What forms the secondary structure of a protein?
Attraction between amino acids that are close in the primary structure
Common secondary structures include alpha helices and beta sheets.
What is the tertiary structure of a protein?
The overall three-dimensional shape formed by interactions among widely separated amino acids
This structure is crucial for the protein’s functionality.
What constitutes the quaternary structure of a protein?
When a protein consists of more than one polypeptide
This structure is important in many proteins that function as complexes.
What role do chaperone proteins play in protein folding?
They help with the conformation arising and oversee folding accuracy
Chaperones are essential for ensuring proteins fold correctly.
What is the function of ubiquitin in protein folding?
It attaches to misfolded proteins and escorts them to proteasomes for dismantling
This process is critical for maintaining cellular protein quality.
What diseases are associated with protein misfolding?
Certain diseases are linked to protein misfolding
Examples include Alzheimer’s disease and other neurodegenerative conditions.
