8.4 Study Guide Flashcards
What is DNA Translation?
The process of using messenger RNA (mRNA) to build proteins.
Define: Codon
a sequence of three nucleotides in a DNA or RNA molecule that codes for a specific amino acid during protein synthesis
Define: Anticodon
Ensures the appropriate Amino Acid is inserted in the polypeptide
a sequence of three nucleotides that matches a codon in messenger RNA (mRNA) during protein synthesis. The anticodon is located on transfer RNA (tRNA).
How does an anticodon work?
- The cell transcribes DNA into a temporary copy of mRNA.
- The mRNA is read by the ribosome, which matches the codons in the mRNA to the anticodons in the tRNA.
- The tRNA delivers the amino acid that corresponds to the codon to the ribosome.
- The amino acid is added to the growing polypeptide.
- The process continues until a stop codon in the mRNA signals the end of protein synthesis.
What is Gene Expression?
The process by which the information encoded in a gene is turned into a function
Define Transcription
The process where a cell copies a specific section of DNA information into a molecule called RNA
Define: Translation
the biological process where the genetic information stored in DNA is converted into a protein by reading the sequence of messenger RNA (mRNA) and assembling amino acids into a polypeptide chain
Changes from nucleic acid language to amino acid language
Define: Start Codon
a sequence of three nucleotides that marks the beginning of protein synthesis in a messenger RNA (mRNA)
Start codon and its amino acid
AUG
Methionine
Define: Stop Codon
a sequence of three nucleotides in DNA or messenger RNA (mRNA) that signals the end of protein synthesis.
What are two alternate names for stop codons?
Termination Codon and Nonsense Codon
Stop Codons (3 total)
UGA
UAA
UAG
What enzyme transcribes the gene?
RNA Polymerase
Can RNA Polymerase work by itself? What else is required to initiate transcription of the gene?
No; it needs a positive transcription factor.
What is a cognate amino acid?
the specific amino acid that is paired with a particular tRNA molecule, meaning it is the exact amino acid that the tRNA is designed to carry and will be incorporated into a growing protein chain during translation
Define: Positive Transcription Factor
a protein that binds to specific DNA sequences near a gene, promoting the transcription of that gene, essentially “turning it on”
Define: Negative Transcription Factor
a protein that reduces or stops the transcription of a gene
Define: Affinity
the strength of the attraction between two biological molecules. It’s a measure of how likely and tightly the molecules will bind to each other.
Define: Mutation
a change in the DNA sequence of an organism (change of A,T,G and C in a molecule of DNA) that can go on to produce an alternate RNA or amino acid sequence
Role of the following in Translation: mRNA (Messenger RNA)
Contains Messages
It acts as the template carrying the genetic information from DNA to the ribosomes, where it is “read” to direct the sequence of amino acids during protein synthesis, dictating the structure of the resulting protein through its codon sequence
Role of the following in Translation: tRNA (Transfer RNA)
Transfers Amino Acids
Contains Anticodons that pair with mRNA Codons to put Amino Acids in the correct order
acts as an adaptor molecule, carrying a specific amino acid to the ribosome and matching it with its corresponding codon on the mRNA molecule, essentially “translating” the genetic code into a growing polypeptide chain
Role of the following in Translation: rRNA (Ribosomal RNA)
Facilitates matching of mRNA and tRNA;
Joins Amino Acids to synthesize a protein
the structural foundation of the ribosome, actively participating in the process of protein synthesis by facilitating the binding of messenger RNA (mRNA) and transfer RNA (tRNA) molecules, ultimately catalyzing the formation of peptide bonds between amino acids to build a polypeptide chain
What is the role of aminoacyl tRNA synthase?
Catalyzes the attachment of a given amino acid to the 3’ end of the cognate tRNA
When does initiation of translation occur?
When the small ribosomal subunit binds with the initiation factors and an initiator tRNA at the start codon of an mRNA, followed by the binding to the initiation complex of the large ribosomal subunit