D1.2 Protein Synthesis Flashcards
(27 cards)
What is transcription?
Transcription is the process where the nucleotide base sequence of a section of DNA is used to synthesize an mRNA molecule using complementary base pairing.
Define mRNA.
mRNA (messenger RNA) is a single-stranded RNA molecule that transfers genetic information from the DNA in the nucleus to the cytoplasm.
What happens during the elongation phase of transcription?
During elongation, RNA polymerase builds the mRNA molecule by bonding RNA nucleotides together.
Define gene expression.
Gene expression is the process by which a gene is ‘switched on’ and undergoes transcription and translation.
What is the role of hydrogen bonds in transcription?
Hydrogen bonds form between RNA nucleotides and their complementary DNA bases during transcription.
What is the function of RNA polymerase?
RNA polymerase is the enzyme responsible for synthesizing mRNA during transcription.
Define complementary base pairing in transcription.
Complementary base pairing in transcription is the process where RNA nucleotides pair with their complementary DNA bases.
What is a polypeptide?
A polypeptide is a chain of amino acids covalently bonded together with peptide bonds.
Define the term codon.
A codon is a sequence of three mRNA bases that codes for a specific amino acid.
What role does tRNA play in translation?
tRNA binds with specific amino acids and brings them to the mRNA on the ribosome.
What is the function of ribosomal RNA (rRNA)?
Ribosomal RNA (rRNA) is part of the ribosome structure and helps catalyse the formation of peptide bonds in proteins.
Define the term anticodon.
An anticodon is a sequence of three bases on the tRNA molecule that are complementary to a codon on mRNA.
What is the stop codon?
A stop codon is a specific sequence of mRNA bases that signals the end of translation.
What happens after the mRNA leaves the nucleus?
After leaving the nucleus, the mRNA attaches to a ribosome in the cytoplasm for translation.
State the role of the ribosome during translation.
The ribosome facilitates the binding of tRNA to mRNA and catalyses the formation of peptide bonds to synthesize a polypeptide.
Define what is meant by the term “triplet code”.
A triplet code is a sequence of three DNA nucleotide bases that codes for one amino acid.
Define the term codon.
A codon is a sequence of three mRNA bases that codes for a specific amino acid.
What does the term “degenerate code” mean?
A degenerate code means that multiple codons can code for the same amino acid.
What is the significance of the start codon (TAC)?
The start codon TAC codes for methionine and signals the beginning of a gene in protein synthesis.
What is the purpose of a stop codon?
A stop codon signals the end of translation, indicating where the polypeptide chain should stop being synthesized.
What is the role of ATP during translation?
ATP provides the energy required for forming peptide bonds between amino acids during translation.
The genetic code is non-overlapping, how does this affect protein synthesis?
The genetic code being non-overlapping means each base is read only once in a single codon, preventing overlap in the sequence interpretation.
Why is it important that the ribosome can bind with more than one tRNA molecule at a time?
Binding with two tRNA molecules at a time allows the formation of a peptide bond between adjacent amino acids to accurately build up the amino acid sequence in the polypeptide chain.
What is a gene mutation?
A gene mutation is a change in the sequence of bases in a DNA molecule that may result in a new allele.
