Transcription

• What is the main focus of this video lesson?

  Stages of transcription
• What is the role of genes in protein synthesis?

  They encode the primary structure of polypeptides
• What are the two main stages in protein synthesis?

  Transcription and translation
• Where does transcription take place?

  In the nucleus
• What is copied during transcription?

  The base sequence of a gene
• What is the short form of messenger RNA?

  mRNA
• What happens to mRNA after transcription?

  It moves to the cytoplasm
• What is the process called that follows transcription?

  Translation
• What enzyme breaks hydrogen bonds during transcription?

  DNA helicase
• What forms hydrogen bonds with DNA during transcription?

  Complementary RNA nucleotides
• What type of bonds does RNA polymerase form between RNA nucleotides?

  Phosphodiester bonds
• What is the result of transcription?

  A strand of messenger RNA
• How does the base sequence of mRNA compare to the DNA strand?

  It matches the sense strand, replacing thymine with uracil
• What happens to the DNA after mRNA synthesis?

  It returns to its double helix structure
• What is pre-mRNA?

  RNA containing both exons and introns
• What are introns and exons?

  Introns are non-coding regions; exons are coding regions
• What process converts pre-mRNA into functional mRNA?

  Splicing
• Why is splicing not necessary in prokaryotes?

  Introns are uncommon in prokaryotic cells
• What do some genes encode instead of polypeptides?

  Functional RNA molecules
• Name two examples of functional RNA molecules.

  Transfer RNA and ribosomal RNA
• What are the stages of transcription?

  1. DNA helicase breaks hydrogen bonds
  2. RNA nucleotides form hydrogen bonds with DNA
  3. RNA polymerase joins RNA nucleotides
  4. mRNA strand is synthesized
  5. mRNA exits the nucleus through a nuclear pore
• What is the difference between sense and antisense strands of DNA?

  • Sense strand: matches mRNA sequence, thymine replaced by uracil
  • Antisense strand: complementary to mRNA, used as template
• What is the significance of splicing in eukaryotic cells?

  • Removes introns from pre-mRNA
  • Joins exons to form functional mRNA
• What is the role of RNA polymerase in transcription?

  • Synthesizes RNA by forming phosphodiester bonds
  • Moves along DNA to create mRNA strand
• What is the structure of a gene in relation to coding and non-coding regions?

  • Contains coding regions (exons)
  • Contains non-coding regions (introns)