Unit 2, part 5 Flashcards
What is translation in protein synthesis?
A step where genetic information encoded in mRNA is translated into amino acids
It decodes the mRNA to make a protein.
What are the four levels of protein structure?
- Primary
- Secondary
- Tertiary
- Quaternary
What are the basic building blocks of proteins?
Amino acids
Amino acids are the fundamental units that form proteins.
What determines the unique properties of an amino acid?
R side chain
The R side chain is the unique part of each amino acid that gives it distinct characteristics.
What is the primary structure of a protein?
Sequence of amino acids (polypeptide)
The primary structure is the linear sequence of amino acids in a polypeptide chain.
What occurs during the secondary structure of a protein?
Formation of sheets & helices due to H-bonds with R groups
Secondary structure includes alpha helices and beta-pleated sheets.
What is the tertiary structure of a protein?
3D folding due to R-group interactions
The tertiary structure results from interactions among R groups, leading to a specific 3D shape.
What is the quaternary structure of a protein?
Interaction of multiple polypeptides
An example is hemoglobin, which consists of multiple polypeptide chains.
What is the role of mRNA in translation?
It provides the genetic code that is translated into a protein
mRNA is read in codons, with each codon corresponding to a specific amino acid.
What are the four steps of translation?
- Pre-Initiation
- Initiation
- Elongation
- Termination
What is the function of the initiator tRNA?
It carries methionine and starts the translation process
The initiator tRNA is crucial for the beginning of protein synthesis.
What is required for tRNA charging?
Energy (ATP)
Charging tRNA involves attaching the correct amino acid to the tRNA.
What happens during the initiation stage of translation?
Initiation factors bind to mRNA, and the ribosomal subunits assemble
The small ribosomal subunit pairs with initiator tRNA and searches for the start codon.
What are the ribosome sites during translation?
- A-site (Aminoacyl)
- P-site (Peptidyl)
- E-site (Exit)
What occurs during the elongation stage of translation?
The polypeptide chain lengthens as charged tRNAs enter the A-site
Peptide bonds form between amino acids, and uncharged tRNAs exit from the E-site.
What signals termination of translation?
Stop codon
No tRNA binds to stop codons; release factors cut the polypeptide chain.
True or False: The poly-A tail is important for translation.
True
True or False: Elongation does not require energy.
False
What polymerase is responsible for polymerizing the poly-A tail?
RNA Polymerase II
RNA Polymerase II is essential for synthesizing mRNA, including the poly-A tail.
Where is the growing peptide strand located in the ribosome?
P-site
Where do aminoacyl tRNAs enter the ribosome?
A-site
Where are tRNAs without attached amino acids located in the ribosome?
E-site
