Chapter 10 Mendel and Inheritance

• Who is considered the father of genetics?

  Gregor Johann Mendel
• What was Mendel's primary occupation while studying genetics?

  He was a friar and taught science.
• Why did Mendel choose to study pea plants?

  They had many simple dichotomous traits.
• What does it mean for a trait to be true breeding?

  It means they always produce offspring that look like the parents.
• What is a monoecious plant?

  A plant that has both male and female reproductive structures in one flower.
• What are some examples of dichotomous traits Mendel studied?

  Flower color, seed shape, and stem length.
• What is Mendel's notation system for generations?

  • P: Parent generation
  • F1: First filial generation
  • F2: Second filial generation
  • F3, F4, F5: Succeeding generations
• What is a backcross in Mendelian genetics?

  A mating of an offspring back to a parent or ancestor.
• What is the result of a formal cross for one trait in Mendelian genetics?

  It shows the inheritance pattern of a single trait.
• What were Mendel's hybridization results for flower color?

  • F1: 100% violet
  • F2: 705 violet, 224 white
  • F2 ratio: 3.15:1
• What were Mendel's hybridization results for plant height?

  • F1: 100% tall
  • F2: 787 tall, 277 dwarf
  • F2 ratio: 2.84:1
• What is a phenotype?

  The observable characteristic version of a trait.
• What are alleles?

  Specific versions of a hereditary particle or gene.
• What is the difference between dominant and recessive alleles?

  Dominant alleles mask others, while recessive alleles are masked.
• What is a genotype?

  The specific combination of alleles carried by an individual.
• What is the significance of Mendel's law of segregation?

  • Heredity is particulate.
  • Each parent carries 2 hereditary particles for each trait.
  • Particles segregate during gamete formation.
• What is a test cross used for?

  To determine if an organism expressing a dominant trait is homozygous or heterozygous.
• What is a pedigree analysis used for?

  • To study the inheritance pattern of human genetic diseases.
  • Useful when test crosses are not feasible or ethical.
• What is alkaptonuria?

  A recessive genetic disorder affecting the metabolism of phenylalanine and tyrosine.
• What is a dihybrid cross?

  • A cross involving parents that differ in two traits.
  • Example: Seed shape and seed color.
• What is incomplete dominance?

  Neither allele is dominant, resulting in a blending of traits.
• What is codominance?

  Two alleles affect the phenotype in separate, distinguishable ways.
• What are multiple alleles?

  Three or more alleles for a gene that exist in a population.
• What is a sex-linked trait?

  A trait associated with a gene located on a sex chromosome.
• What is hemophilia?

  An X-linked recessive disorder affecting blood clotting.
• What are lethal alleles?


  Alleles that can cause the death of the individual inheriting them.
• What is Mendel's law of independent assortment?

  • Alleles for different traits segregate independently during gamete formation.
  • This means the inheritance of one trait does not affect the inheritance of another.
• What is the expected phenotypic ratio from a dihybrid cross?

  1. 3:3:1
• How does Mendel's work contribute to modern genetics?

  It established foundational principles of heredity and genetic inheritance.
• What conclusions can be drawn from Mendel's monohybrid crosses?

  • Blending inheritance is not a viable explanation.
  • Inheritance is particulate.
  • Dominant and recessive traits exist.
• What are the implications of Mendel's law of segregation?

  • Each parent passes only one hereditary particle to gametes.
  • Hereditary particles recombine randomly during fertilization.
• What is the inheritance pattern for hemophilia in females?

  50% carrier, 50% hemophiliac
• What is the inheritance pattern for hemophilia in males?

  50% normal, 50% hemophiliac
• What defines a lethal allele?

  An allele that shortens the average normal lifespan
• What is Huntington's Disease classified as?

  A dominant disorder causing progressive breakdown of neurons
• What does Mendel's Law of Segregation state?

  Each parent passes only one hereditary particle into each gamete
• What are the key points of Mendel's Law of Segregation?

  • Heredity is particulate
  • Each true breeding parent carries 2 hereditary particles for each trait
  • Particles separate during gamete formation
  • Random recombination occurs during fertilization
• What is Mendel's Second Law?

  The Law of Independent Assortment
• How does chromosomal crossover affect gene inheritance?

  It allows genes on the same chromosome to behave independently
• What is epistasis in genetics?

  When one gene affects the expression of another gene