gene expression

• What are mutations?

  Changes in the sequence of nucleotides in DNA
• What are the types of mutations?

  • Insertion/deletion mutations
  • Duplication
  • Inversion
  • Translocation
• What happens during insertion/deletion mutations?

  One or more nucleotide pairs are added or removed
• What is a frameshift mutation?

  It alters the sequence after the mutation point
• What occurs during duplication mutations?

  One or more bases are repeated in the sequence
• What is an inversion mutation?

  A group of bases is reversed in order
• What is translocation in mutations?

  A group of bases moves to another chromosome
• What can cause mutations?

  Spontaneous errors and mutagenic agents
• What are chemical mutagens?

  Substances like alcohol and benzene that cause mutations
• What types of radiation can cause mutations?

  Ionising radiation, UV, and X-ray
• What are neutral mutations?

  Mutations that cause no change to the organism
• What are stem cells?

  Undifferentiated cells that can divide into other types
• What are the types of stem cells?

  • Totipotent: Can form any cell type
  • Pluripotent: Can form many cell types, not extra embryonic
  • Multipotent: Limited differentiation, e.g., bone marrow
  • Unipotent: Can only differentiate into one type
• What are totipotent stem cells?

  Cells that can differentiate into any body cell
• Where are totipotent stem cells found?

  In the early embryo called the blastomere
• What causes stem cells to differentiate?

  A change in gene expression
• What is the role of oestrogen in transcription?

  It alters transcription by affecting transcription factors
• How does oestrogen affect transcription factors?

  It alters their shape to bind DNA
• What is small interfering RNA (siRNA)?

  RNA used for short-term gene silencing
• How does siRNA work?

  It binds to mRNA and triggers its breakdown
• What is epigenetics?

  • Heritable changes in gene function
  • No changes to DNA base sequence
  • Environmental factors can influence gene function
• What is DNA methylation?

  Adding methyl groups to DNA to suppress transcription
• What is DNA acetylation?

  Modification that changes DNA structure and gene access
• How does decreased acetylation of histones affect transcription?

  It increases histone binding to DNA, reducing access
• How does cancer arise from mutations?

  Uncontrolled cell division leads to tumor formation
• How does DNA methylation affect gene expression?

  It prevents transcription factors from binding
• What are the types of tumors?

  • Benign: Grow slowly, do not spread
  • Malignant: Grow rapidly, can spread
• What are proto-oncogenes?

  Genes that stimulate cell division
• What are oncogenes?

  Mutated proto-oncogenes that cause uncontrolled division
• What are tumor suppressor genes?

  Genes that control cell division and apoptosis
• What is hyper-methylation?

  Increased methylation affecting tumor suppressor genes
• How can increased oestrogen concentrations affect cancer?

  They can promote cell division and tumor formation
• What are the applications of genome projects?

  • Identify potential antigens for vaccines
  • Determine evolutionary relationships
  • Develop personalized medicine
• What is the proteome?

  All proteins that the genome can code for
• What is the Human Genome Project?

  An international project determining human genome sequence
• What are the potential applications of the Human Genome Project?

  Screening for mutations and genetic disorders
• What are the ethical concerns of the Human Genome Project?

  Discrimination and misuse of genetic information
• What is recombinant DNA technology?

  • Manipulating DNA in various ways
  • Involves reverse transcriptase and restriction endonucleases
  • Used for gene cloning and expression
• What is reverse transcriptase?

  An enzyme that synthesizes DNA from RNA
• What are restriction endonucleases?

  Enzymes that cut DNA at specific sequences