Cyto- gene mutations

• What is a gene mutation?


  A change in the nucleotide sequence of a gene
• What can cause gene mutations?


  Copying errors, chemicals, viruses, etc.
• How do gene mutations affect the gene expression process?


  They may affect the DNA sequence, mRNA sequence, and polypeptide
• What is the antisense strand of DNA?


  The DNA strand that acts as the template for mRNA transcription
• What is a substitution mutation?


  A mutation where one nucleotide is replaced by another
• What is the significance of the genetic code being degenerate?


  A mutation may have no effect on the phenotype
• How can a substitution mutation lead to serious effects like sickle cell anemia?


  It may affect an amino acid essential for the protein's structure and function
• What is an inversion mutation?


  A mutation where a segment of DNA is flipped around backwards
• What is an addition mutation?


  A mutation where one or more nucleotides are added to the DNA sequence
• What is a deletion mutation?


  A mutation where one or more nucleotides are removed from the DNA sequence
• What are the types of gene mutations?


  • Point Mutations
  • Substitutions
  • Insertions
  • Deletions
  • Frameshift
• What is a point mutation?


  A change of a single nucleotide in a gene
• What is a frameshift mutation?


  A mutation that alters the reading frame of the genetic code
• How does a frameshift mutation affect protein synthesis?


  It leads to incorrectly built proteins
• What is the structure of hemoglobin?


  It is a tetramer made of 2 alpha and 2 beta chains
• Where is the beta-chain gene of hemoglobin located?


  On chromosome 11
• What is cDNA?


  Complementary DNA obtained by back-transcribing mRNA
• What is the significance of reverse transcriptase in cDNA synthesis?


  It is the enzyme used to back-transcribe mRNA
• What is the result of a mutation in the hemoglobin gene?


  It can lead to inherited diseases
• What is Down Syndrome caused by?


  Improper separation of chromosome 21 during meiosis
• What is Cri-du-chat syndrome characterized by?


  A deletion of material on the 5th chromosome
• What are the symptoms of Klinefelter’s Syndrome?


  Sterility, small testicles, and breast enlargement
• What is Turner’s Syndrome?


  A condition where female sex organs don't mature at adolescence
• What is the significance of the AIP gene in gigantism?


  Mutations or deletions in this gene are linked to gigantism
• What causes Progeria?


  A single tiny defect in a child's genetic code
• What is congenital terminal hypertrichosis also known as?


  Werewolf Syndrome
• What is Pica?


  An insatiable urge to eat non-food substances
• What is congenital erythropoietic porphyria?


  A condition that causes pain from sunlight exposure
• What is xeroderma pigmentosum?


  A rare autosomal recessive disorder that causes malignant skin tumors when exposed to sunlight
• What are Blaschko's lines?


  Invisible patterns in human DNA that manifest as stripes on the skin
• What is mosaicism?


  A condition where an individual has more than one cell line
• What is a chimera?


  An individual having more than one cell line from two zygotes
• What can result from microchimerism?


  Distinct patchy skin, hair, or eye pigmentation