44 Questions
What is the characteristic of the genetic code where a given amino acid can be specified by more than one triplet codon?
Degenerate
What is the term for the sequence of three ribonucleotide letters that code for an amino acid?
Codon
What is the function of 'stop' signals in the genetic code?
They terminate translation
What is the term for the process where an RNA molecule is intermediate between DNA and proteins?
Messenger RNA
What is the result of a frameshift mutation?
The reading frame is shifted
What is the characteristic of the genetic code where it is read without breaks?
Commaless
Who suggested that an RNA molecule was intermediate between DNA and proteins?
Francois Jacob and Jacques Monod
What is the purpose of polynucleotide phosphorylase in the experiment of Marshall Nirenberg and Heinrich Matthaei?
To degrade RNA
What is the significance of the triplet code in the genetic code?
It is the minimal use of four letters to specify amino acids
What is the characteristic of the genetic code where it is nearly universal across different organisms?
Nearly universal
What is a key difference between RNA polymerase and the enzyme used in the experiment?
The enzyme used in the experiment does not require a DNA template
What determines the probability of the insertion of a specific ribonucleotide in the experiment?
The concentration of the ribonucleotide in the reaction mixture
What is the purpose of using homopolymers in the experiment?
To synthesize RNA with specific codons
What is the result of using a mixed heteropolymer with a ratio of 1A:5C in the experiment?
There is a 1/6 chance for an A and a 5/6 chance for a C
What is the technique used to determine the specific assignments of triplets?
Triple binding assay
What is the result of the triple binding assay experiment?
The genetic code is degenerate but unambiguous
What is the purpose of repeating copolymers in the experiment?
To decipher the genetic code
What is the function of the poly-A tail in eukaryotic mRNA?
It provides stability and protection to mRNA from nuclease attack
What is a characteristic of the genetic code revealed by the experiment?
The genetic code is degenerate but unambiguous
What is the function of the TFIID complex in transcription initiation?
It binds to the TATA box and helps in the recruitment of RNA polymerase II
What is the result of adding a specific ratio of ribonucleotides to the reaction mixture in the experiment?
The probability of the insertion of a specific ribonucleotide is proportional to the availability of that molecule
What is the significance of the experiment in understanding the genetic code?
It deciphered the genetic code
How does transcription termination occur in eukaryotes?
It occurs when RNAP II reaches a polyadenylation signal sequence
What is the function of the 5' cap in eukaryotic mRNA?
It stabilizes and protects the mRNA from nuclease attack
What is the function of RNA polymerase II in eukaryotes?
It transcribes protein-coding genes
What is the difference between prokaryotic and eukaryotic transcription?
Eukaryotic transcription is more complex and regulated
What is the function of the σ factor in RNA polymerase?
To recognize and bind to the promoter sequence
What is the term for the point at which transcription actually begins?
Transcription start site
What is the term for DNA sequences that are homologous in different genes of the same organism?
Consensus sequences
What is the function of the core enzyme in RNA synthesis?
To synthesize RNA using DNA template
What is the term for the process of adding a 5' cap to the mRNA and removing intervening sequences?
Processing
What is the term for the region of the DNA molecule that is unwound to make the template strand accessible to RNA polymerase?
Transcription bubble
What is the term for the sequence-specific cleavage of the transcript required for transcriptional termination?
Cleavage stimulation factor
What is the term for the DNA elements that bind to trans-acting factors to influence gene expression?
Cis-acting elements
What is the term for the complex that binds to the TATA box and determines the transcription start site?
TATA-binding protein
What is the term for the process of unwinding the DNA double helix to make the template strand accessible to RNA polymerase?
Unwinding
What is the significance of the Wobble Hypothesis?
It states that the first two base pairings are more critical.
What is the significance of the ordered nature of the genetic code?
It reduces the effect of mutations on protein function.
What is the function of methionine (AUG) in protein synthesis?
It is the initiator codon for protein synthesis.
What is the result of a mutation that produces a terminator codon (UAG, UAA, or UGA) in a gene?
Only a partial polypeptide is made.
What is the significance of the discovery of exceptions to the universal genetic code?
It reveals that the genetic code is not universal.
What is the role of RNA polymerase in transcription?
It synthesizes RNA from DNA.
What is the result of transcription?
An mRNA molecule is produced.
What is the substrate for the enzyme RNA polymerase?
NTPs
This quiz covers the characteristics of the genetic code, including its linear form, codon structure, and properties such as unambiguity and degeneracy. It also explores the role of start and stop signals in transcription.
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