Chapter 3

• What is the variation of a gene?

  Allele
• What makes up a genotype?

  Allele
• What are two identical copies of alleles?

  Homozygous
• What are two different copies of alleles?

  Heterozygous
• What is a phenotype


  Appearance or manifestation of a characteristic
• Which organism did Gregor Mendel use to discover the basic principles of genetics?

  Pea plant
• What is a cross that occurs between two individuals that differ in two characteristic?

  dihybrid cross
• If an Aa individual is crossed to an aa individual, what will the phenotypic ratio in the offspring be?

  1:1
• A cross between an AABB individual and an aabb individual will produce what type of offspring?

  All will be AaBb
• What is the process of segregation?

  An individual possesses two alleles at a locus and these two alleles separate when gametes are formed, one allele going into each gamete
• What is a shorthand method for predicting outcomes of genetic cross?

  Punnett square
• What is the chi-square test?

  A test showing how well observed results of a genetic cross fit the expected values
• What is degrees of freedom?


  Value that represents the number of ways in which expected classes are free to vary
• What will be the genotypic ratio in the offspring of two Aa parents?

  1:2:1
• In a cross of Hh x Hh, which phenotypic ratio is expected from the offspring?

  3:1
• In coupling configuration, both dominant alleles are on the same chromosome and both recessive alleles are on the other chromosome
• In repulsion configuration, one dominant and one recessive is one chromosome and another dominant and another recessive is on the other chromosome
• What was the molecular/cellular/chemical cause for the rr plant seeds in Mendel’s experiment to be wrinkled?

  The SBE1 gene encodes a protein that converts a linear sugar into a branched form. The normal R allele produces a lot of branched sugars and produces a normal round seed (after dying) but mutation in the gene (r allele) causes the seeds to contain only linear form sugar (no branched form sugar). The excess causes rr seeds to absorb excess water which upon drying makes the seeds wrinkled.
• Which of the following crosses would produce a 3:1 ratio of phenotypes in the next generation?


  Aa x Aa
• A testcross can be used to determine whether an individual is homozygous or heterozygous.
• Low value from chi square test means that the difference is not by chance and that there is a biological difference.
• High value from chi square test means that the difference is due to chance.
• All alleles for any gene will be found on the locus
• The genotype is the set of alleles that an individual organism possesses.
• Two alleles of an individual plant separate with equal probability into the gametes.
• The principle of segregation states that each individual diploid organism possesses two alleles for any particular characteristic, one from each parent
• Multiplication rule can be used to calculate probability of two or more independent events taking place together and usually indicated by and.
• Addition rule can be used to calculate probability of any of two or more mutually exclusive events and usually indicated by or.
• The principle of independent assortment states that alleles at different loci separate independently of one another
• The null hypothesis states that chance alone is responsible for a deviation between observed and expected values