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Chapter 9 Test : Online

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

The “father” of genetics was
a.
T. A. Knight.
c.
Gregor Mendel.
b.
Hans Krebs.
d.
None of the above
 

 2. 

Mendel obtained his P generation by allowing the plants to
a.
self-pollinate.
c.
assort independently.
b.
cross-pollinate.
d.
segregate.
 

 3. 

What is the probability that the offspring of a homozygous dominant individual and a homozygous recessive individual will exhibit the dominant phenotype?
a.
0.25
c.
0.66
b.
0.5
d.
1.0
 

 4. 

True-breeding pea plants always
a.
are pollinated by hand.
b.
produce offspring each of which can have multiple forms of a trait.
c.
produce offspring each of which can have only one form of a trait.
d.
are heterozygous.
 

 5. 

The first filial (F1) generation is the result of
a.
cross-pollination among parents and the next generation.
b.
crosses between individuals of the parental generation.
c.
crosses between the offspring of a parental cross.
d.
self-fertilization between parental stock.
 

 6. 

Which of the following is the designation for Mendel’s original pure strains of plants?
a.
P
c.
F1
b.
P1
d.
F2
 

 7. 

F2 : F1 ::
a.
P : F1
c.
F1 : P
b.
F1 : F2
d.
dominant trait : recessive trait
 

 8. 

The passing of traits from parents to offspring is called
a.
genetics.
c.
development.
b.
heredity.
d.
maturation.
 

 9. 

A genetic trait that appears in every generation of offspring is called
a.
dominant.
c.
recessive.
b.
phenotypic.
d.
superior.
 

 10. 

homozygous : heterozygous ::
a.
heterozygous : Bb
c.
BB : Bb
b.
probability : predicting chances
d.
homozygous : BB
 

 11. 

Mendel’s finding that the inheritance of one trait had no effect on the inheritance of another became known as the
a.
law of dominance.
b.
law of universal inheritance.
c.
law of separate convenience.
d.
law of independent assortment.
 

 12. 

To describe how traits can disappear and reappear in a certain pattern from generation to generation, Mendel proposed
a.
the law of independent assortment.
b.
the law of segregation.
c.
the law of genotypes.
d.
that the F2 generation will produce only purple flowers.
 

 13. 

The law of segregation explains that
a.
alleles of a gene separate from each other during meiosis.
b.
different alleles of a gene can never be found in the same organism.
c.
each gene of an organism ends up in a different gamete.
d.
each gene is found on a different molecule of DNA.
 

 14. 

The phenotype of an organism
a.
represents its genetic composition.
b.
reflects all the traits that are actually expressed.
c.
occurs only in dominant pure organisms.
d.
cannot be seen.
 

 15. 

If an individual has two recessive alleles for the same trait, the individual is said to be
a.
homozygous for the trait.
b.
haploid for the trait.
c.
heterozygous for the trait.
d.
mutated.
 

 16. 

An individual heterozygous for a trait and an individual homozygous recessive for the trait are crossed and produce many offspring. These offspring are likely to be
a.
all the same genotype.
b.
of two different phenotypes.
c.
of three different phenotypes.
d.
all the same phenotype.
 

 17. 

Tallness (T) is dominant over shortness (t) in pea plants. Which of the following represents the genotype of a pea plant that is heterozygous for tallness?
a.
T
c.
Tt
b.
TT
d.
tt
 
 
In humans, having freckles (F) is dominant over not having freckles (f). The inheritance of these traits can be studied using a Punnett square similar to the one shown below.

nar001-1.jpg
 

 18. 

Refer to the illustration above. The genotype represented in box 1 in the Punnett square would
a.
be homozygous for freckles.
b.
have an extra freckles chromosome.
c.
be heterozygous for freckles.
d.
have freckles chromosomes.
 

 19. 

Refer to the illustration above. The genotype in box 3 of the Punnett square is
a.
FF.
c.
ff.
b.
Ff.
d.
None of the above
 

 20. 

A trait that occurs in 450 individuals out of a total of 1,800 individuals occurs with a probability of
a.
0.04.
c.
0.50.
b.
0.25.
d.
0.75.
 

 21. 

How many different phenotypes can be produced by a pair of codominant alleles?
a.
1
c.
3
b.
2
d.
4
 
 
nar002-1.jpg
 

 22. 

Refer to the illustration above. The phenotype represented by box 1 is
a.
green, inflated.
c.
yellow, inflated.
b.
green, constricted.
d.
yellow, constricted.
 

 23. 

Refer to the illustration above. The genotype represented by box 2 is
a.
GgIi.
c.
GI.
b.
GGIi.
d.
Gi.
 

 24. 

2,000 yellow seeds : 8,000 total seeds ::
a.
1 : 6
c.
1 : 3
b.
1 : 8
d.
1 : 4
 
 
In rabbits, black fur (B) is dominant over brown fur (b). Consider the following cross between two rabbits.

nar003-1.jpg
 

 25. 

Refer to the illustration above. The device shown, which is used to determine the probable outcome of genetic crosses, is called a
a.
Mendelian box.
c.
genetic graph.
b.
Punnett square.
d.
phenotypic paradox.
 

 26. 

Refer to the illustration above. Both of the parents in the cross are
a.
black.
b.
brown.
c.
homozygous dominant.
d.
homozygous recessive.
 

 27. 

Refer to the illustration above. The phenotype of the offspring indicated by box 3 would be
a.
brown.
b.
black.
c.
a mixture of brown and black.
d.
The phenotype cannot be determined.
 

 28. 

Refer to the illustration above. The genotypic ratio of the F1 generation would be
a.
1:1.
c.
1:3.
b.
3:1.
d.
1:2:1.
 

 29. 

What is the expected genotypic ratio resulting from a homozygous dominant ´ heterozygous monohybrid cross?
a.
1:0
c.
1:2:1
b.
1:1
d.
1:3:1
 

 30. 

What fraction of the offspring resulting from a heterozygous ´ heterozygous dihybrid cross are homozygous recessive for both traits?
a.
9/16
c.
3/16
b.
1/4
d.
1/16
 

 31. 

What is the expected genotypic ratio resulting from a heterozygous ´ heterozygous monohybrid cross?
a.
1:2:1
c.
1:2
b.
1:3:1
d.
1:0
 

 32. 

What is the expected phenotypic ratio resulting from a homozygous dominant ´ heterozygous monohybrid cross?
a.
1:3:1
c.
2:1
b.
1:2:1
d.
1:0
 
 
nar004-1.jpg
 

 33. 

Refer to the illustration above. The phenotype represented by box 1 is
a.
round, yellow.
c.
wrinkled, yellow.
b.
round, green.
d.
wrinkled, green.
 

 34. 

Refer to the illustration above. The genotype represented by box 2 is
a.
RRYY.
c.
RrYy.
b.
RrYY.
d.
rrYy.
 

 35. 

Refer to the illustration above. Which of the following boxes represents the same phenotype as box 7?
a.
3
c.
5
b.
4
d.
6
 

 36. 

An organism that has inherited two of the same alleles of a gene from its parents is called
a.
hereditary.
c.
homozygous.
b.
heterozygous.
d.
a mutation.
 

 37. 

In pea plants, yellow seeds are dominant over green seeds. What would be the expected genotype ratio in a cross between a plant with green seeds and a plant that is heterozygous for seed color?
a.
1:3
c.
4:1
b.
1:2:1
d.
1:1
 

 38. 

codominance : both traits are displayed ::
a.
probability : crosses
b.
heterozygous : alleles are the same
c.
homozygous : alleles are the same
d.
Punnett square : chromosomes combine
 

 39. 

The difference between a monohybrid cross and a dihybrid cross is that
a.
monohybrid crosses involve traits for which only one allele exists, while dihybrid traits involve two alleles.
b.
monohybrid crosses involve self-pollination, while dihybrid crosses involve cross-pollination.
c.
monohybrid crosses involve one trait; dihybrid crosses involve two traits.
d.
dihybrid crosses require two Punnett squares; monohybrid crosses need only one.
 

 40. 

What fraction of the offspring resulting from a heterozygous ´ heterozygous dihybrid cross are heterozygous for both traits?
a.
9/16
c.
3/16
b.
1/4
d.
1/16
 

 41. 

A cross of two individuals for a single contrasting trait is called
a.
monohybrid.
c.
dominant.
b.
dihybrid.
d.
codominant.
 

Essay : Choose two...
 

 42. 

How might you go about determining the genotype of a red-flowering plant where red is dominant over white? Write your answer in the space below.
 

 43. 

Describe pollination in pea plants. Write your answer in the space below.
 

 44. 

What are three ways to express the probability of an event that occurs 500 times out of 2,000 total trials? Write your answer in the space below.
 

 45. 

Describe how genotype and phenotype are related, and give an example. Write your answer in the space below.
 

 46. 

Explain what is meant by homozygous and heterozygous, and give an example of each. Write your answer in the space below.
 

 47. 

All of the offspring resulting from a cross between a red snapdragon and a white snapdragon are pink. What is a possible explanation for this? Write your answer in the space below.
 



 
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