biochem B1L1

• What are the learning outcomes of this lecture?

  Understand DNA structure, replication, transcription, translation
• What distinguishes RNA from DNA at the molecular level?

  RNA has an -OH group on the 2' carbon
• What is the central dogma of molecular biology?

  DNA is transcribed to RNA, which is translated to protein
• Where does transcription occur in eukaryotic cells?

  In the nucleus
• Where does translation occur in eukaryotic cells?

  In the cytosol
• What is the significance of hydrogen bonds in DNA structure?

  They stabilize the double helix structure
• What is a nucleoside?

  A base conjugated to a sugar
• What is a nucleotide?

  A nucleoside conjugated to one or more phosphoryl groups
• What is the structure of DNA?

  Double helical structure with anti-parallel strands
• What is Chargaff's rule?

  A = T and G = C in DNA
• What is the role of DNA ligase?

  Joins short sequences of DNA on the lagging strand
• What is the significance of the S phase in the cell cycle?

  DNA replication occurs during this phase
• What is the function of RNA polymerase during transcription?

  It synthesizes RNA from a DNA template
• What are the three main types of RNA?

  mRNA, rRNA, tRNA
• What is the role of mRNA?

  Template for synthesis of proteins
• What is the role of tRNA?

  Carries activated amino acids to ribosomes
• What are the steps of mRNA synthesis?

  Initiation, elongation, termination
• What occurs during the initiation step of transcription?

  RNA Pol II assembles at promoter sites
• What happens during the elongation step of transcription?

  RNA polymerase synthesizes mRNA in 5’ to 3’ direction
• What is the role of transcription factors?

  Regulate the initiation of transcription
• What are enhancers in gene expression?

  Sequences that influence gene expression from a distance
• What modifications stabilize mRNA after transcription?

  A modified 5’ cap and Poly A tail
• What are the key processes involved in gene expression?

  • DNA replication
  • Transcription
  • Translation
• What are the roles of different types of RNA?

  • mRNA: Template for protein synthesis
  • rRNA: Major component of ribosomes
  • tRNA: Carries amino acids to ribosomes
• What are the steps of transcription?

  1. Initiation: RNA Pol II assembles at promoter
  2. Elongation: RNA synthesis in 5’ to 3’ direction
  3. Termination: RNA Pol II ceases transcription
• What are the roles of transcription factors?

  • Turn gene expression on or off
  • Recognize specific DNA sequences
  • Regulate transcription initiation
• What is the significance of the 5’ cap and Poly A tail in mRNA?

  • Stabilizes mRNA
  • Aids in translation
• What is the importance of DNA replication being error-free?

  • Prevents mutations
  • Preserves genetic integrity
• What is the significance of the anti-parallel nature of DNA strands?

  • Allows proper base pairing
  • Facilitates replication and transcription
• What is the role of DNA polymerase in DNA replication?

  • Synthesizes new DNA strands
  • Has proofreading ability
• What is the function of the replication fork?

  • Site where DNA unwinds for replication
• What is the significance of the CAAT and TATA boxes in transcription?

  • Define transcription initiation points
  • Recruit RNA Pol II
• What is the role of enhancers in gene expression?

  • Influence gene expression from a distance
  • Can be positive or negative regulators
• What is the significance of the 34 Å pitch in DNA structure?

  • Represents the rise per turn of the helix
• What is the role of van der Waals forces in DNA structure?

  • Stabilizes stacked bases at the core
• What is the significance of the 5’ to 3’ direction in DNA synthesis?

  • Ensures correct addition of nucleotides
• What is the role of RNA polymerase II in mRNA synthesis?

  • Catalyzes the synthesis of mRNA
• What is the importance of the stability of mRNA?

  • Essential for effective translation
• What is the role of the replication bubble in DNA replication?

  • Site where DNA strands separate for replication
• What is the significance of the 10 base pairs per turn in DNA structure?

  • Defines the helical structure of DNA