protein synthesis

• What is a genome?

  The complete set of genes in a cell
• What is a proteome?

  The full range of proteins a cell can produce
• What are the two stages of protein synthesis?

  1. Transcription
  2. Translation

  
• What occurs during transcription?

  Production of mRNA from DNA in the nucleus

  
• What occurs during translation?

  Production of polypeptides from mRNA at ribosomes

  
• Compare and contrast the structures of tRNA and mRNA.

  Similarities:

  • Both are single polynucleotide strands

  
  

  Differences:

  • tRNA is clover leaf shaped; mRNA is linear
  • tRNA has hydrogen bonds; mRNA does not
  • tRNA is shorter; mRNA is longer and variable
  • tRNA has an anticodon; mRNA has codons
  • tRNA has an amino acid binding site; mRNA does not

  
• How is mRNA formed by transcription in eukaryotic cells?

  DNA strands separate, RNA nucleotides align, RNA polymerase joins them

  
• What replaces thymine in RNA?

  Uracil
• What is the difference in mRNA production between eukaryotic and prokaryotic cells?

  Eukaryotes produce pre-mRNA; prokaryotes produce mRNA directly
• Why is splicing necessary in eukaryotic cells?

  To remove introns from pre-mRNA
• What is the first step in translation?

  mRNA attaches to a ribosome at the start codon

  
• What role does tRNA play in translation?

  It brings specific amino acids to the ribosome

  
• How do tRNA anticodons interact with mRNA codons?

  tRNA anticodons bind to complementary mRNA codons

  
• What happens after two tRNAs bring amino acids together?

  A peptide bond forms between the amino acids
• What is the role of ATP in translation?

  It provides energy for peptide bond formation
• Describe the roles of tRNA and ribosomes in translation.

  tRNA:

  • Attaches to specific amino acids
  • Binds to mRNA codons via anticodons

  
  

  Ribosomes:

  • Bind mRNA and facilitate tRNA binding
  • Catalyze peptide bond formation
  • Move along mRNA during translation

  
• How can the base sequence of nucleic acids relate to the amino acid sequence of polypeptides?

  Using a genetic code to identify codons and amino acids

  
• What is the complementary tRNA anticodon for the mRNA codon ACG?

  UGC

  
• How does the sequence of codons on mRNA relate to the DNA template strand?

  They are complementary to the DNA triplet sequence

  
• What replaces thymine in RNA?

  Uracil
• What are common mistakes regarding the genome and proteome?

  • Genome: complete set of genes in a cell
  • Proteome: range of proteins a cell can produce
• What is the specific role of RNA polymerase in transcription?

  It joins adjacent RNA nucleotides to form mRNA

  
• What is a key difference between RNA polymerase and DNA polymerase?

  RNA polymerase joins RNA nucleotides, not DNA
• What type of bonds does RNA polymerase form between nucleotides?

  Phosphodiester bonds via condensation reactions
• What is the function of introns in eukaryotic cells?

  They are removed during mRNA splicing
• What happens to tRNA after it releases its amino acid?

  It is released from the ribosome
• What is the significance of the stop codon in translation?

  It signals the end of polypeptide synthesis

  
• How does the ribosome facilitate translation?

  It catalyzes peptide bond formation and moves along mRNA