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CHAPTER 3
Concept check questions (in figure legends)
FIGURE 3.2
Concept check: Prior to fertilization, where is the male gamete located?
Answer: The male gamete is found within pollen grains.
FIGURE 3.3
Concept check: In this experiment, which plant, the white- or purple-flowered plant, is
providing the egg cells, and which is providing the sperm cells?
Answer: The white flower is providing the sperm and the purple flower is providing the
eggs.
FIGURE 3.4
Concept check: What do we mean when we say a strain is true-breeding?
Answer: A true-breeding strain maintains the same trait over the course of many
generations.
FIGURE 3.6
Concept check: With regard to the T and t alleles, explain what the word segregation
means?
Answer: Segregation means that the T and t alleles separate from each other so that a
gamete receives one of them, but not both.
FIGURE 3.7
Concept check: According to the linkage hypothesis shown here, what is linked? Are
two different genes linked or are two different alleles of the same gene linked, or both?
Answer: In this hypothesis, two different genes are linked. The alleles of the same gene
are not linked.
FIGURE 3.9
Concept check: Why does independent assortment promote genetic variation?
Answer: Independent assortment allows for new combinations of alleles among different
genes to be found in future generations of offspring.
FIGURE 3.10
Concept check: If a parent is Ttyy, how many different types of gametes can it make?
Answer: Such a parent could make two types of gametes, Ty and ty, in equal proportions.
FIGURE 3.11
Concept check: At which stage are homologous chromosomes separating from each
other?
Answer: Homologous chromosomes separate at anaphase of meiosis I.
FIGURE 3.12
Concept check: Let’s suppose a pea plant is heterozygous for three genes, Tt Yy Rr, and
each gene is on a different chromosome. How many different ways could the three
homologous chromosomes line up during metaphase of meiosis I?
Answer: These chromosomes could line up in four different ways.
FIGURE 3.13
Concept check: What are the two different meanings of horizontal lines in a pedigree?
Answer: Horizontal lines connect two individuals that have offspring together, and they
connect all of the offspring that produced by the same two parents.