Cellular Control

• What do all cells in our body contain?

  The same set of genes
• Why do brain cells differ from muscle cells?

  Different proteins are being made
• What happens to activated genes in a cell?

  They are transcribed into mRNA
• What is the result of proteins formed from activated genes?

  They modify the cell's structure
• What occurs during the differentiation of a stem cell into a red blood cell?

  Certain genes are activated for haemoglobin
• What do transcription factors (TFs) do?

  They activate or deactivate genes
• What are TFs that activate genes called?

  Activators
• What are TFs that deactivate genes called?

  Repressors
• How do activators function?

  They bind to the promoter region
• How do repressors function?

  They block RNA polymerase from binding

  
• What is an operon?

  A section of DNA with controlled genes
• What are the elements of an operon?

  • Structural genes: code for proteins
  • Control elements: promoter and operator regions
  • Regulatory gene: codes for transcription factors

  
• What does the lac operon in E. coli do?

  Controls lactose digestion

  
• When does E. coli produce enzymes to digest lactose?

  When glucose is absent and lactose is present

  
• What happens when lactose is absent in E. coli?

  The lac repressor blocks RNA polymerase

  
• What occurs when lactose is present in E. coli?

  Lactose binds to the repressor, changing its shape

  
• What does lacZ code for?

  Beta-galactosidase enzyme
• What does lacY code for?

  Lactose permease protein
• What is the role of lacA in E. coli?

  Its function is still uncertain
• What is splicing in gene expression?

  Removal of introns from mRNA

  
• In which organisms does splicing occur?

  Only in eukaryotes
• What is the role of cAMP in protein activation?

  It changes protein's 3D structure
• What does cAMP bind to in cell signaling?

  Protein kinase A (PKA)
• What is the function of Hox genes?

  Control the arrangement of body parts
• Why are Hox genes highly conserved?

  Mutations have detrimental effects
• What do Hox proteins do?

  Bind to DNA and regulate gene expression
• How do mitosis and apoptosis contribute to body plan development?

  Mitosis creates cells; apoptosis shapes them
• What is apoptosis?

  Controlled cell death
• What triggers apoptosis?

  Internal and external stimuli
• What is a mutation?

  A change to the base sequence of DNA
• What are the types of mutations?

  • Substitution: one base replaced
  • Insertion: one or more bases added
  • Deletion: one or more bases removed
  • Inversion: sequence of bases reversed

  
• What is a frameshift mutation?

  Change in codons due to insertion or deletion
• What can cause a neutral effect from a mutation?

  Similar amino acids or non-functional sites
• What is an example of a beneficial mutation?

  Antibiotic resistance in bacteria
• What is an example of a harmful mutation?

  Cystic fibrosis or cancer mutations
• A gene mutation is a random change in the genetic material.
• Heritability is the estimate of role of genotype in phenotypic variation

  heritability = VG / VP

  when heritability high much of variation is

  high heritability will result in successful selective breeding
• A 'stop' triplet is the bases that does not code for an amino acid

  A code to stop transcription
• The process by which DNA is transcribed into mRNA is called transcription
• Transcription occurs in the nucleus