Chapter Five Section One and Two Study Guide – KEY

In order to prepare for the upcoming Heredity Test choose a strategy that best suits your learning style. Some suggestions for answering the questions below are:

  • Create one flash card per question with question on one side and answer on the other
  • Create a “flip book” with questions and answers (see teacher example)
  • Picture dictionary
  • Answer questions on this paper and highlight key words
  • Method of your choice with approval by teacher
  1. Who is considered the “father of heredity?”Gregor Mendel
  1. Mendel concluded that twoset(s) of instructions are present for each characteristic. Each parent donatesoneset(s) of instructions.
  1. When traits are passed down from parents to the next generation, what is this called?heredity
  1. Name the scientist who studied pea plants to determine traits and how they are passed down from generation to generation. Mendel
  1. Why was it important that Mendel use self-pollinating plants in his experiments? By using egg and sperm from the same plant, he was able to create true breeding plants. By creating true breeding (purebred) plants, Mendel guaranteed that all of the offspring of the new plant had the same traits as the parent. The true breeding plants were his control group because he knew what alleles these plants carried.
  1. Why is it important to look at two or more generations of offspring when looking at genetic traits?Because the first generation could carry a recessive trait (hidden) that could show up in the next generation.
  1. What did Mendel call the trait that always showed, if present, in the offspring? dominant
  1. What did Mendel call the trait that always seemed to disappear in the offspring if a dominant trait was present?recessive
  1. The feature that shows up in a population and has different forms, such as hair color, is called what? characteristic
  1. The different forms of the feature, such as red, brown, or blond hair is called what? traits
  1. What percent of dominant and recessive traits did Mendel observe in the first generation of his experiments? Dominant:100%Recessive:0%
  1. In the second generation of Mendel’s experiments, what ratio of dominant to recessive traits did he discover? 3:1
  1. Why is it important to use large quantities of data in an experiment?The results are more accurate
  1. When parents with purebred traits are bred and each parent shows a different trait, such a brown haired father and a blond haired mother, which trait always shows up in the first generation of offspring?dominant
  1. When parents with purebred traits are bred and each parent shows a different trait, such a brown haired father and a blond haired mother, what happens to the recessive trait in the first generation?It is hidden by the dominant trait

What happens to the recessive trait in the second generation?It may show up- 25% chance

  1. What are the instructions for an inherited trait called?genes
  1. The different forms of a gene are called what?alleles
  1. How many alleles are contributed from each parent for a trait?One or more
  1. What are the three different possible combinations of alleles (use the letter B). Label each combination using two of these terms: heterozygous, homozygous dominant, homozygous recessive, purebred dominant, purebred recessive, and hybrid.
    BB– homozygous dominant, purebred dominant;
    bb – homozygous recessive, purebred recessive
    Bb – heterozygous, hybrid
  1. The appearance of a trait, or the physical feature you see, is called thephenotype.
  1. The two alleles of a trait make up the genotype.
  1. If there are two dominant or two recessive alleles, what is the organism called?homozygous
  1. If there are one dominant and one recessive allele, what is the organism called?heterozygous
  1. What is the tool called that scientists use to predictthe chance of different genotypes occurring in offspring?Punnett square
  1. If both parents are heterozygousfor a trait, what is the chance of seeing the dominant trait in the offspring? 75%
  1. What is the mathematical chance that something will happen called?probability
  1. What is it called when two parents bring together different dominant alleles for the trait and the two alleles contribute its own influence to the trait of the offspring (one is not dominant over the other)? An example is when a dominant red flower cross with a dominant white flower and pink offspring are produced. Incomplete dominance
  1. What are four exceptions to Mendel’s principles?Incomplete dominance; one gene many traits; many genes one trait; environmental factors
  1. A male dog is heterozygous and has a long tail (T). A female dog is short tailed. A dog breeder wants to know the chances of the offspring showing the different traits.

What are the chances of having a short tailed offspring? 50% (tt)

What are the chances of having a long tailed homozygous offspring? 0% (TT)

  1. Mom and Dad have no freckles and are both heterozygous (Ff). The couple has 4 children.

-What is the chance of having a child with no freckles? 75% (FF and Ff)

-What is the chance of having a child with freckles? 25% (ff)

-Does this mean that the couple will have 1 child with freckles and 3 children without freckles? No (yes or no).

Explain your answer:

Each child has a 25% (or 1 out of 4) chance of having freckles (ff) and a 75% (or 3 out of 4) chance of having no freckles (FF or Ff). Each child has the same chance as all of the other children of inheriting the freckles.