L05- Gene Expression and Epigenetics

• How does the genetic code relate to proteins?


  The genetic code specifies how sequences of nucleotides in DNA and RNA correspond to amino acids in proteins
• What is the role of transcription factors in gene expression?

  Transcription factors regulate the initiation of transcription by binding to specific DNA sequences
• What is the significance of histone modification in transcription regulation?

  Histone modification can affect transcription by altering chromatin structure and accessibility of DNA
• What is the central dogma of molecular biology?


  The central dogma describes the flow of genetic information from DNA to RNA to protein
• What are the differences between RNA and DNA?

  RNA contains ribose and uracil, while DNA contains deoxyribose and thymine
• In which direction is RNA synthesized during transcription?

  RNA is synthesized in a 5' to 3' direction
• What is the role of RNA polymerase in transcription?

  RNA polymerase synthesizes RNA by adding nucleotides complementary to the DNA template
• What is the primary RNA transcript processed into before export?


  The primary RNA transcript is processed into mRNA
• What is the function of the spliceosome in RNA processing?

  The spliceosome removes introns from the primary RNA transcript
• What is the significance of alternative splicing in gene expression?

  Alternative splicing allows for the production of different mRNA and proteins from the same gene
• What are the components of the ribosome involved in translation?

  The ribosome consists of mRNA, rRNA, and tRNA
• What initiates translation in the ribosome?

  Translation starts with an AUG codon and initiator tRNA linked to methionine
• What is a polyribosome or polysome?

  A polyribosome is a complex of multiple ribosomes attached to a single mRNA molecule
• How many possible reading frames does a DNA sequence have?

  A DNA sequence has three possible reading frames
• What is the role of codons in the genetic code?

  Codons are groups of three bases that code for specific amino acids
• How do mutations affect protein sequences?

  Mutations can lead to changes in the amino acid sequence of proteins
• What are the two main types of mutations that can affect protein sequences?

  Deletion/insertion mutations and substitution/point mutations
• What is the predominant level of control for gene expression?

  Control of transcription is the predominant level of control
• What are the components of a gene?

  A gene consists of structural information coding for a protein and regulatory sequences for expression
• How do enhancers affect transcription rates?

  Enhancers are DNA sequences that can increase transcription rates by interacting with transcription factors
• What is the role of transcription factors in regulating gene expression?

  Transcription factors can activate or repress gene expression in response to environmental signals
• What is the significance of X-inactivation in female mammals?


  1. inactivation equalizes gene expression levels between males and females
• What is the 'Histone code'?


  The 'Histone code' refers to the chemical modifications of histone tails that regulate gene expression
• How do environmental factors influence gene expression?

  Environmental factors can impact gene activity through gene-specific transcription factors and epigenetic mechanisms
• What is the relationship between genotype and phenotype?

  Phenotype is determined by both genotype and environmental factors
• What is the role of chromatin remodeling enzymes in transcription?

  Chromatin remodeling enzymes facilitate transcription by altering the association of nucleosomes with DNA
• What is the impact of histone acetylation on gene expression?

  Histone acetylation increases accessibility of DNA for transcription
• What is the significance of dosage compensation in mammals?

  Dosage compensation equalizes gene expression levels between males and females
• What is the effect of X-inactivation on female cells?

  1. inactivation results in one of the two X chromosomes being inactivated in female cells
• How does the environment influence epigenetic mechanisms?

  The environment can influence epigenetic mechanisms, such as histone modifications, affecting gene expression
• What are the key components of the central dogma of molecular biology?

  • DNA is transcribed into RNA
  • RNA is translated into proteins
  • The flow of information is from DNA to RNA to protein
• What are the main types of RNA involved in protein synthesis?

  • Messenger RNA (mRNA)
  • Transfer RNA (tRNA)
  • Ribosomal RNA (rRNA)
• What are the steps involved in the process of transcription?

  1. RNA polymerase binds to the promoter
  2. RNA polymerase synthesizes RNA in a 5' to 3' direction
  3. The primary RNA transcript undergoes processing (capping, polyadenylation, splicing)
  4. The processed mRNA is exported from the nucleus
• What are the steps involved in the process of translation?

  1. The ribosome assembles around the mRNA
  2. tRNA brings amino acids to the ribosome
  3. The ribosome decodes the mRNA in groups of three bases (codons)
  4. Amino acids are linked together to form a protein
  5. Translation terminates at a stop codon
• What are the types of mutations that can affect protein sequences?

  • Deletion or insertion mutations
  • Substitution or point mutations
• What are the roles of transcription factors in gene regulation?

  • Bind to specific DNA sequences
  • Activate or repress transcription
  • Respond to environmental signals
• What are the effects of histone modifications on gene expression?

  • Histone acetylation increases transcription
  • Histone methylation can either activate or repress transcription
  • Modifications can be influenced by environmental factors
• What is the significance of epigenetics in gene expression?

  • Epigenetics involves changes that affect gene activity without altering the DNA sequence
  • It plays a role in development and differentiation
  • It can be influenced by environmental factors
• What is the relationship between genotype, phenotype, and environment?

  • Genotype refers to the genetic makeup
  • Phenotype refers to observable traits
  • Environment influences the expression of genotype into phenotype
• What is the role of chromatin remodeling in transcription regulation?

  • Chromatin remodeling alters the association of nucleosomes with DNA
  • It facilitates access to transcription machinery
  • It is influenced by various factors including environmental signals