QA3

• What do letters represent in genetics?

  Different versions of genes (alleles)
• What is a genotype?

  Combinations of alleles in an organism
• What does phenotype refer to?

  Observable characteristics from genotype and environment
• What is homozygous dominant represented as?

  [AA]
• What does heterozygous mean?

  Two different alleles
• 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 is homozygous recessive represented as?

  [aa]
• What are hereditary characteristics?

  Traits passed down to offspring
• Where are genes found?

  In the nucleolus
• What is DNA formed 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 are the definitions and functions of genes and alleles?

  • Gene: A portion of DNA that determines a trait
  • Allele: A specific form of a gene
• 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?

  Alleles are passed independently of each other
• What is incomplete dominance?

  Neither allele completely masks the other
• What is codominance?

  Both alleles are expressed equally at the same time
• What is sex-linked inheritance?

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

  Men - XY; Women - XX
• How do females inherit X-linked traits?

  Females can be carriers and express dominant alleles
• How do males inherit X-linked traits?

  Males express the trait if they inherit a recessive allele
• What are the two main types of sex-linked inheritance?

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

  A dominant allele on X is expressed in both sexes
• 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?

  Expressed in males if present; females need two copies
• What is Duchenne Muscular Dystrophy (DMD)?


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

  Similar to DMD but with later onset
• What is red-green color blindness?

  An inability to distinguish red and green hues
• What is G6PD deficiency?

  Leads to episodes of hemolytic anemia
• What is Y-linked inheritance?

  Involves genes located on the Y chromosome
• How are Y-linked traits inherited?

  Passed from father to son only
• What is the central dogma of molecular biology?

  • DNA is converted into RNA
  • RNA is translated into proteins