BSC 1005 BIO Chapter 7 Study Exam
Questions Correctly Answered.
Put the potential offspring genotypes in order from highest expected frequency to lowest expected
frequency for a cross in which both parents have the RrTt genotype.
a. RrTt rrTt RRtt
b. RrTt RRtt rrTt
c. rrTt RRtt RrTt - CORRECT ANSWER a
Which of the following describe conclusions drawn by Gregor Mendel?
a. Dominant traits are capable of masking the phenotype of recessive traits.
b. An organism's phenotype is determined by genes located on chromosomes.
c. The alleles responsible for a trait are separated and passed down to the following generation.
d. Some traits are complex and controlled by many different genes. - CORRECT ANSWER a, c
Two people of medium skin tone have five children, each with a different skin tone ranging from very
pale to very dark. Most of the children's skin becomes a little bit darker after exposure to the sun.
Judging from this information, skin tone is probably what?
a. influenced by the environment
b. a pleiotropic trait
c. a Mendelian trait
d. a polygenic trait - CORRECT ANSWER a, d
In Labrador dogs, coat color is controlled by the genotypes of two genes. In one gene, the dominant
allele, B, produces black fur, and the recessive allele, b, produces brown fur. However, if a second gene
possesses two recessive alleles, ee, the dog produces yellow fur, regardless of the genotype of the first
,gene. If two dogs that are heterozygous for both genes, BbEe mated, what would be the frequency of
the three phenotypes, black, brown, and yellow? - CORRECT ANSWER yellow: 4/16
black: 9/16
brown: 3/16
BIO cpt2,5 - CORRECT ANSWER starred
Tess's sister is known to carry an allele for a single-gene recessive genetic disorder that is fatal in very
early life. Tess's mother was tested for the allele and found not to carry it. What are the odds that Tess is
a carrier for the allele? - CORRECT ANSWER Since the alleles that are passed on are random, Tess has a
1/2 (or 50%) chance of carrying the allele.
In pea plants, height is controlled by a single gene and the tall allele (T) is dominant to the short allele
(t). You find a tall pea plant in your yard and cross it with a short pea plant. It gives rise to 43 tall
offspring and 35 short offspring. What is the genotype of the tall parent plant?
a. tt
b. TT
c. tT
d. Tt - CORRECT ANSWER d
In modern terms, Mendel's law of segregation states that each gamete formed through meiosis receives
a [single or two] allele of each gene, while the law of independent assortment states that the alleles in
those gametes are chosen at random. - CORRECT ANSWER single
A great deal of the risk of many human diseases, such as coronary heart disease and type 2 diabetes, is
dependent upon lifestyle choices. Which word correctly describes what this indicates about the patterns
of inheritance of these diseases? - CORRECT ANSWER complex
T or F:
A single gene trait with two alleles that show incomplete dominance should possess the same number
of possible genotypes and phenotypes. - CORRECT ANSWER T
, In pea plants, the tall allele (T) is dominant to the short allele (t) and the yellow pea allele (Y) is dominant
to the green pea allele (y). In a cross between a TTYy pea and a ttyy pea, what are the odds that the
offspring will be tall and have green peas?
a. 1/4
b. 1/2
c. 3/4 - CORRECT ANSWER b
In 4 o'clock flowers, flower color is controlled by a single gene with two alleles. The R allele produces red
flower color, and the W allele produces white flower color. These alleles display incomplete dominance,
and when both alleles are present, the flowers appear pink. Remember, when dealing with incomplete
dominance, only capitals are used for the two traits because neither allele exerts dominance over the
other. Match each of the following genotypes to the correct color of flowers.
white flowers
a. RR
b. Rw
c. WW
d. homozygous - CORRECT ANSWER c, d
In 4 o'clock flowers, flower color is controlled by a single gene with two alleles. The R allele produces red
flower color, and the W allele produces white flower color. These alleles display incomplete dominance,
and when both alleles are present, the flowers appear pink. Remember, when dealing with incomplete
dominance, only capitals are used for the two traits because neither allele exerts dominance over the
other. Match each of the following genotypes to the correct color of flowers.
red flowers
a. RR
b. rW
