General Biology 2

• What are letters commonly used to represent in genetics?


  Different versions of genes (alleles)
• What does genotype describe?

  Combinations of alleles in an organism
• What is phenotype?

  Observable characteristics from genotype and environment
• What does homozygous dominant mean?

  Two same capital letter alleles (AA)
• What does heterozygous mean?

  Two different alleles (Aa)
• What does homozygous recessive mean?

  Two lowercase letter alleles (aa)
• What is a dominant allele?

  A version of a gene that is usually expressed
• What is heredity?

  The passing of traits from parents to offspring
• What are hereditary characteristics?

  Traits passed down to the offspring
• What is DNA formed in?

  The nucleolus
• Where are genes found?

  In the nucleolus
• What are chromosomes?

  Thread-like structures containing DNA and proteins
• What is a genome?

  The complete set of DNA instructions in an organism
• What is genetic variation?

  The difference in DNA sequences among individuals
• What is the difference between a gene and an allele?

  • Gene: A portion of DNA that determines a trait
  • Allele: A specific form of a gene
• What are the functions and pairings of genes and alleles?

  • Gene Function: Responsible for trait expression
  • Allele Function: Responsible for trait variations
  • Genes do not occur in pairs; alleles occur in pairs
• Who is Gregor Johann Mendel?

  The father of genetics
• Why did Mendel choose peas for his experiments?

  Due to their many distinct varieties
• What are Mendel's principles of inheritance?

  1. Law of Segregation
  2. Law of Dominance
  3. Law of Independent Assortment
• What does the Law of Segregation state?

  Each parent's alleles split and pass to offspring
• What does the Law of Dominance state?

  Only one parent's trait is expressed in offspring
• What does the Law of Independent Assortment state?

  Different pairs of alleles are inherited independently
• What are the types of non-Mendelian inheritance?

  1. Incomplete Dominance
  2. Codominance
  3. Sex-linkage Trait
• What is incomplete dominance?

  Neither allele completely masks the other
• What is codominance?

  Both alleles are expressed equally
• What is sex-linked inheritance?

  Inheritance patterns of genes on sex chromosomes
• What are the sex chromosomes for males and females?

  Men - XY; Female - XX
• How can females be carriers for X-linked traits?

  They have two X chromosomes
• How do males express X-linked traits?

  They express the trait if they inherit a recessive allele
• What are the types of X-linked inheritance?

  1. X-linked Dominant
  2. X-linked Recessive
• What is X-linked dominant inheritance?

  A dominant allele on X is expressed in both sexes
• What happens to affected fathers in X-linked dominant inheritance?

  They pass the trait to all their daughters
• What is Rett Syndrome?

  A neurological disorder primarily affecting females
• What is Fragile X Syndrome?

  A leading cause of inherited intellectual disability
• What is X-linked hypophosphatemia?

  A form of rickets causing low phosphate levels
• What is X-linked recessive inheritance?

  A recessive allele on X is expressed in males
• What are common X-linked recessive diseases?

  Duchenne Muscular Dystrophy and color blindness
• What is Duchenne Muscular Dystrophy (DMD)?

  A severe muscle-wasting disorder caused by mutations
• What is Becker Muscular Dystrophy (BMD)?

  Similar to DMD but with slower progression
• What is red-green color blindness?

  An inability to distinguish red and green hues