BIOLOGY 30
STUDY GUIDE AND REVIEW OF
FUNDAMENTALS OF GENETICS
MULTIPLE CHOICE
(52 marks)
____1. Mendel obtained plants that were pure for particular traits by
a. growing plants from seeds of other plants that showed that trait
b. allowing plants to self-pollinate for several generations
c. discarding plants that showed other traits
d. allowing plants to cross-pollinate for one generation
____2. The appearance of an organism is its
a. genotype b. phenotype c. genotype ratio
d. phenotype ratio
____3. To determine the genotype of an individual that shows the dominant phenotype, you would cross
that individual with one that is
a. heterozygous dominant
c. heterozygous recessive
b. homozygous dominant
d. homozygous recessive
____4. In a dihybrid cross between individual with the genotype RRYY and an individual with the genotype rryy,
all of the offspring with have the genotype
a. RRYY
b. RrYY
c. RrYy
d. rryy
e. RRyy
____5. A segment of DNA that controls a particular hereditary trait is called a(n)
a. genotype
b. heredity
c. allele
d. trait
e. gene
____6. An alternate form of a gene is called a(n)
a. genotype
b. heredity
c. allele
d. trait
e. gene
____7. The genetic makeup of an organism is called its
a. genotype
b. heredity
c. allele
d. trait
e. phenotype
____8. A contrasting form of a hereditary characteristic is called a(n)
a. genotype b. heredity
c. allele
d. trait
e. gene
____9. The transmission of characteristics from parents to offspring is called
a. homozygous dominant b. allele c. heredity d. genotype e. heterozygote
____10. Having two similar, dominant alleles for a trait is called
a. homozygous dominant b. monohybrid cross c. heterozygous d. phenotype e. genotype
____11. An organism having two different alleles for a trait is called
a. heterozygote b. homozygous dominant c. genotype d. monohybrid cross e. phenotype
____12. A cross involving one pair of contrasting traits is called
a. homozygous dominant b. genotype c. heterozygous d. phenotype e. monohybrid cross
____13. A trait is any characteristic that can be passed
a. from plants to animals
c. from one species to another
b. from parent to offspring
d. through a cell membrane
____14. A hybrid is an organism that receives different genetic information from
a. each parent b. different parts on its body
c. only one parent
d. changes in the environment
____15. Each of the seven traits that Mendel studied occurred in
a. one observable form
b. two distinct, observable forms
c. all plants
d. all plants and animals
e. None of the above.
____16. When pure-bred plants are allowed to self-pollinate, they produce
a. only genotypes
c. only phenotypes
b. only offspring with the parental trait
d. offspring with varying traits
____17. Mendel called a trait that did not show in a hybrid a
a. parental trait b. codominant trait c. dominant trait d. recessive trait e. None of the above.
____18. Mendel hypothesized that each trait is controlled by a factor, now called a
a. gene
b. mate
c. hybrid
d. dominance e. None of the above.
____19. What are different versions of a gene for the same trait?
a. alleles b. phenotypes
c. dihybrids
d. true-breeding
____20. The law of segregation states that, during meiosis, each pair of alleles
a. stick together b. is tripled c. separates d. becomes pure-bred e. None of the above.
____21. An allele that expresses itself in a hybrid is a(n)
a. recessive allele b. independent assortment c. allele pair
d. dominant allele
____22. The actual genetic makeup of an organism is called its
a. phenotype
b. homozygous type c. heterozygous type d. genotype
____23. The law of independent assortment states what?
a. Half of an organism's gametes have one allele per pair.
b. One allele is always dominant.
c. Gene pairs sort randomly and independently of each other.
d. Gene pairs sort always in the same manner.
e. None of the above.
____24. An organism in which two alleles for a trait are different is
a. heterozygous b. homozygous c. genotypic d. phenotypic e. None of the above.
____25. In the 1860s, Mendel conducted experiments that established
a. bloodline theory
b. the blending hypothesis
c. codominance theory
d. modern genetics
e. None of the above.
____26. An individual heterozygous for a trait and an individual homozygous recessive for the trait
are crossed and produce offspring that are
a. all the same genotype
c. of two different phenotypes
b. of three different phenotypes
d. all of the same phenotype.
____27. When Mendel crossed pea plants with two contrasting traits, such as flower color and plant height,
a. these experiments led to his law of segregation
b. he found that the inheritance of one trait did not influence the inheritance of the other trait
c. he found that the inheritance of one trait influenced the inheritance of the other trait
d. these experiments were considered failures because the importance of his work was not recognized
____28. A heterozygous individual would have the following genotype.
a. yy
b. GG c. Ww d. Any of the above.
e. None of the above.
____29. A homozygous individual would have the following genotype.
a. Pp b. YY
c. Zz
d. None of the above.
____30. True-breeding pea plants always
a. are pollinated by hand
b. produce offspring with only one form of a trait
c. produce offspring with either form of a trait
d. are heterozygous
____31. 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. the law of phenotypes
e. that the F2 generation will only produce purple flowers
____32. Segregation of alleles occurs during
a. mitosis
b. meiosis
c. fertilization
____33. Punnett squares are grids that show
a. the phenotypes of offspring
b. all possible results of a genetic cross
d. pollination
c. actual results of a genetic cross
d. only dihybrid crosses
____34. In incomplete dominance, there are no
a. genetic crossings
c. dominant or recessive alleles
b. homozygous phenotypes
d. intermediate traits
____35. The scientific study of heredity is called
a. meiosis
b. crossing-over
c. genetics
d. pollination
____36. Mendel obtained his P generation by allowing plants to
a. self-pollinate
b. cross-pollinate c. assort independently
____37. 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
d. segregate
____38. If an individual possesses two recessive alleles for the same trait, the individual is said to be
a. homozygous for the trait
c. haploid for the trait
b. heterozygous for the trait
d. mutated
____39. A genetic trait that appears in every generation of offspring is called
a. phenotypic
b. recessive
c. dominant
d. superior
____40. Mendel's findings 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
e. law of segregation
____41. Tallness (T) is dominant to shortness (t) in pea plants. Which of the following represents a genotype
of a pea plant that is heterozygous for tallness?
a. T
b. TT
c. Tt
d. tt
____42. A 3:1 ratio of tall to short pea plants appearing in the (F2) generation lends support to the principle of
a. recessiveness b. mutation c. segregation
d. crossing-over e. None of the above.
____43. A cross of two individuals for a single contrasting trait is called
a. monohybrid
b. dihybrid
c. dominant
d. codominant
____44. The law of segregation states 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
____45. A trait that occurs in 450 individuals out of a total of 1,800 individuals occurs with a probability of
a. 0.04
b. 0.25
c. 0.50
d. 0.75
e. 1.00
____46. The difference between a monohybrid cross and dihybrid cross is that
a. monohybrid crosses involve traits for which only one allele exists, while dihybrid traits involved two alleles.
b. monohybrid crosses involved self-pollination, while dihybrid crosses involve cross-pollination.
c. monohybrid crosses involve one gene; dihybrid crosses involve two genes.
d. dihybrid crosses require two Punnett squares; monohybrid crosses need only one.
____47. 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 the parental cross
d. self-fertilization between parental stock
____48. Which of the following is the designation for Mendel's original pure strains of plants?
a. P1
b. P
c. F1
d. F2
e. P2
____49. A trait that is not expressed in the F1 generation resulting from the crossbreeding of two genetically
different, true-breeding organisms is called
a. dominant
b. phenotypic
c. recessive
d. genotypic
e. superior
____50. The principle that states that one factor may mask the effect of another factor is the principle of
a. dominance
b. recessiveness
c. phenotypic
d. genotypic
e. None of the above.
____51. How many different phenotypes can be produced by a pair of codominant alleles?
a. 1
b. 2
c. 3
d. 4
e. 5
____52. The likelihood that a specific event will occur is called
a. phenotype
b. probability
c. genotype
d. recessive
TRUE OR FALSE
e. homozygous
(22 marks)
__F__1. Plants in Mendel's P generation were all heterozygous. homozygous
__T__2. Mendel based his principles on his observations of pea plants.
__T__3. The scientific study of heredity is called genetics.
__F__4. In Mendel's experiments with flower color of pea plants, only the parental and F2 generation produced
white flowers.
__T__5. A dominant allele masks the effects of a recessive allele.
__F__6. Offspring of the P1 generation are called F2 generation.
__T__7. The law of segregation states that alleles separate during the formation of gametes.
__F__8. The law of independent assortment states that the alleles for different characteristics are distributed to
gametes in pairs. Independent of other alleles
__F__9. An organism that is homozygous heterozygous for flower color could have the genotype Qq.
__F__10. Codominance Incomplete dominance occurs when both alleles for a gene are expressed in a heterozygous
offspring, such as would
be seen in a pink four o'clock flowers.
__F__11. The allele for a recessive dominant trait is usually represented by a capital letter.
__F__12. Heterozygous individuals have two of the same different alleles for a particular trait.
__F__13. A Punnett square represents the phenotype genotypes of an organism.
__F__14. In heterozygous individuals, only recessive dominant allele achieves expression.
__T__15. Probability is the likelihood that a certain event will occur.
__F__16. The physical appearance of an individual organism, as determined by the genes it has inherited
from its parents, is called its genotype.phenotype
__F__17. The dominant allele for tallness in pea plants is represented by the letter t.T
__F__18. Individuals must may exhibit a trait in order for it to that appear in their offspring.
__F__19. In codominance, two alleles are can be expressed at the same time.
__T__20. All genes have only two alleles.
__F__21. A dihybrid cross involves two pairs of contrasting traits.
__F__22. Crosses involving a study of one gene trait are called monohybrid crosses.
DIRECTIONS: Read Chapter 9, Fundamentals of Genetics, and Answer the questions below as
completely and as thoroughly as possible. Answer the question in essay form (not outline form),
using complete sentences. You may use diagrams or pictures to supplement your answers, but a
diagram or picture alone without appropriate discussion is inadequate. (37 marks)
1. State the two laws of heredity that resulted from Mendel’s work. (4 marks)
Law of Segregation
Each organism contains two factors for each trait; factors segregate, or separate in the
formation of gametes, during meiosis; each gamete contains one factor for each trait
Law of Independent Assortment
Factors for different characteristics are distributed to gametes independently
2. What happens during meiosis that would allow genes located on the same chromosome to
separate independently of one another? (1 mark)
Crossing Over
3. List the steps in Mendel’s experiments on pea plants. Include the P generation, F1 generation,
and F2 generation. (6 marks)
(1) Created a pure strain with self pollination, thus creating a parental (P generation) or P1
and P2 strains
(2) Used cross-pollination between two strains and tracked each trait through the two
generations.
(3) F1 generations were the first generations produced from the cross pollination of the
parental generation
(4) F2 generations were the generations created by the self-pollination of the F1 generations
4. Write the equation for probability. (2 marks)
Probability =
Number of times an event is expected
Number of opportunities for an event to happen
5. Distinguish between codominance and incomplete dominance. Give an example of each type
of inheritance. (6 marks)
Incomplete dominance is when two or more alleles influence the phenotype, resulting in
a phenotype intermediate between the two traits. Example  four o’clock flowers – red
X white creates a pink
Codominance occurs when both alleles for a gene are expressed in a heterozygous
offspring. Example  Blood types – A, B, O or AB
6. Define the terms, dominant and recessive. (2 marks)
Dominant  trait that masks a trait when crossed
Recessive  trait that did not appear in the F1 generation but reappears in the F2
generation, so it is the masked trait
7. Relate the events of meiosis to the law of segregation. (2 marks)
During meiosis, each gamete contains one factor for each trait – in anaphase I the
homologous pairs separate so that each gamete receives one trait
8. Explain the difference between a monohybrid cross and dihybrid cross. Give an example of
each. (4 marks)
Monohybrid involves only one trait being considered at a time. Example – brown hair X
black hair
Dihybrid involves examining two traits at on time. Example – brown hair, green eyes X
black hair, blue eyes
9. Explain how you would use a Punnett square to predict the probable outcome of a monohybrid
cross. Draw a Punnett square to demonstrate your monohybrid cross. (5 marks)
By using the possible gamete combination and utilizing the matrix, the completed matrix
give the probability of the offspring that are created
Bb x Bb
B
B
BB
b
Bb
b
Bb
bb
10. Explain the terms genotype and phenotype. (2 marks)
Genotype is the allele makeup of an organism. Example TT, tt or Tt
Phenotype is the outward appearance as a result of the genotype. Example – tall or short
11. Explain the terms homozygous and heterozygous. (2 marks)
Homozygous is when both alleles are the same. Example TT or tt
Heterozgyous is when the alleles in the pair are different. Example Tt