TRANSLATION Flashcards
Translation
The synthesis of proteins by the ribosomes
The translation of the mature mRNA made in the nucleus occurs in the
Cytoplasm of eukaryotic cells
Mature mRNA molecules made in the nucleus must move from the nucleus to the
Cytoplasm to be translated by the ribosomes in the cytoplasm
mRNA molecules made in the chloroplast and mitochondrion are
Translated by the ribosomes within these organelles
The ______ is the complex, multi functional, dynamic structure that translates mRNA to make a protein
Ribosome
Each ribosome consists of
One large subunit
One small subunit
Each ribosomal subunit consists of
rRNA and ribosomal proteins
Some antibiotics harm bacteria by
Inhibiting the 70 S ribosome
The ribosome reads the linear sequence of codons in the mRNA to make a
Protein
Each codon is a sequence of
3 consecutive nucleotides
The linear sequence of ______ in mRNA corresponds to the linear sequence of ______ ______ in the protein
Codons; amino acids
How many codons code for amino acids?
61
The start codon codes for
The translation start site and for the amino acid, Methionine
How many stop codons?
3
Three stop codons code for
The translation stop site
What must be delivered to ribosomes during translation?
A continuous supply of the 20 types of amino acids
-tRNAs deliver the amino acids
-One or more tRNAs deliver each type of amino acid
The aminoacyl-tRNA synthetases attach the proper _____ _____ to the proper ______
Amino acid; tRNA
How many aminoacyl-tRNA synthetase enzymes that attach each of the 20 types of amino acids to the correct tRNAs?
20 aminoacyl-tRNAs
The initiation phase ______, _______, and ________ all the components required for the ribosome to begin translation at the start codon
Assembles, aligns, and activates
Initiation phase
-The small ribosomal subunit binds to the 5’ G Cap
-The tRNA that recognizes the start codon binds to start codon
-The large ribosomal subunit binds to form the translation initiation complex that is positioned to begin translation as the start codon
What is required to form the translation initiation complex?
GTP molecule
The initiation factors help
Assemble and align the tRNA, small and large ribosomal subunit at the start codon to form the translation initiation complex
What are initiation factors?
Proteins
Initiation Factors
-One helps the ribosome scan the mRNA to locate the first start codon in mRNA
-One is a helicase enzyme that unwinds the knotted mRNA into a linear form that the ribosome can translate
Each tRNA contains the
Anti Codon that recognizes the corresponding codon in mRNA
The anti codon sequence of each tRNA is
Complementary to the nucleotide sequence of its corresponding codon in mRNA
Elongation cycle
Consists of a precise sequence of events that link the amino acids together in the correct order
-The ribosome reads the linear sequence of codons in mRNA
-GTP supplies the energy
The elongation factors are proteins that -
-Ensure the correct tRNA enters the ribosome
-Reposition the ribosome so it can read the next codon in mRNA
The large ribosomal subunit contains the enzyme that
Joins the amino acids together at a rate of ~3-10 reactions per second
What is the enzyme that links the amino acids together during the elongation cycle?
Peptidyl transferase
The termination phase
Occurs when the release factor enters the ribosome and interacts with the stop codon
-The ribosome contacts the stop codon
-The release factor is the protein that enters the ribosome, interacts with the stop codon, and stops translation
-The newly made protein and the two ribosomal subunits are released
-GTP supplies the energy to disassemble the translation complex
Proteins made by the ribosomes must be delivered to
The cellular location or the extracellular location where their function is required
Proteins contain amino acid sequences called
Signal sequences that direct each protein to its required location
Defective protein sorting causes
Medical problems
Some antibiotics inhibit
The bacteria 70 S ribosome to eliminate protein synthesis
