Modified True/False
Indicate
whether the statement is true or false. If false, change the identified word or phrase to make
the statement true.
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1.
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A mutation in a body cell can be passed to offspring.
_________________________
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2.
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When Mendel crossed purebred short plants with purebred tall plants, all of the
offspring were short. _________________________
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3.
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A Punnett square shows all the possible combinations of alleles resulting
from a cross. _________________________
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4.
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A hybrid is the offspring of parents that have different alleles for a
trait. _________________________
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5.
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An organism’s phenotype is its allele combinations.
_________________________
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6.
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The sex cells produced by meiosis have twice the number of chromosomes as
the parent cells. _________________________
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7.
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Chromosomes carry hormones from parents to offspring.
_________________________
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8.
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A pea plant that is heterozygous for tall stems has the alleles
Tt. _________________________
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Matching
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a. | phenotype | g. | genotype | b. | Heredity | h. | purebred | c. | heterozygous | i. | alleles | d. | Genes | j. | Punnett square | e. | F2
Generation | k. | Recessive
trait | f. | probability | l. | Dominant allele |
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9.
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used to visualize all the possible combinations of alleles
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10.
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passing of traits from parents to offspring
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11.
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physical or behavioral characteristics inherited from parents
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12.
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segments of DNA located on the chromosomes
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13.
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inherited combination of alleles
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14.
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alternative forms of a gene
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15.
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offspring from the F1 Generation
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16.
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more powerful gene form
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17.
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inherits different alleles for a particular trait
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18.
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weaker of two alleles and won’t appear unless two are present
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19.
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The chance of an event or combination of alleles occurring
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20.
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an organism that inherits the same alleles for a trait
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Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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21.
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An organism that has two identical alleles for a trait is
a. | codominant. | b. | tall. | c. | homozygous. | d. | heterozygous. |
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22.
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An organism’s genotype is its
a. | genetic makeup. | b. | feather color. | c. | physical
appearance. | d. | stem height. |
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23.
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Scientists call an organism that has two different alleles for a trait a
a. | hybrid. | b. | trait. | c. | purebred. | d. | factor. |
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24.
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A mutation is harmful to an organism if it
a. | changes the DNA of the organism. | b. | changes the phenotype of the
organism. | c. | reduces the organism’s chances for survival and
reproduction. | d. | makes the organism better able to avoid predators. |
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25.
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What does a Punnett square show?
a. | all the possible outcomes of a genetic cross | b. | only the dominant
alleles in a genetic cross | c. | only the recessive alleles in a genetic
cross | d. | all of Mendel’s discoveries about genetic
crosses |
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26.
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A heterozygous organism has
a. | three different alleles for a trait. | b. | two identical alleles for a
trait. | c. | only one allele for a trait. | d. | two different alleles for a
trait. |
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27.
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What is a mutation?
a. | any change that is harmful to an organism | b. | any change in a gene
or chromosome | c. | any change that is helpful to an organism | d. | any change in the
phenotype of a cell |
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28.
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When sex cells combine to produce offspring, each sex cell will
contribute
a. | one fourth the number of chromosomes in body cells. | b. | half the number of
chromosomes in body cells. | c. | the normal number of chromosomes in body
cells. | d. | twice the number of chromosomes in body cells. |
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29.
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If a homozygous black guinea pig (BB) is crossed with a homozygous white
guinea pig (bb), what is the probability that an offspring will have black fur?
a. | 25 percent | b. | 50 percent | c. | 75
percent | d. | 100 percent |
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30.
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What happens during meiosis?
a. | Two sex cells combine. | b. | Chromosome pairs separate and are distributed
into new sex cells. | c. | Each sex cell copies itself to form four new
chromosomes. | d. | Chromosome pairs remain together when new sex cells are
formed. |
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31.
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What does the notation Aa mean to geneticists?
a. | two dominant alleles | b. | two recessive alleles | c. | homozygous
alleles | d. | one dominant allele and one recessive allele |
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32.
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What is the chromosome theory of inheritance?
a. | Chromosomes are carried from parents to offspring on hybrids. | b. | Genes are carried
from parents to offspring on chromosomes. | c. | Hybrid pairs of chromosomes combine to form
offspring. | d. | Codominant genes combine to form new hybrids. |
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33.
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What is probability?
a. | the actual results from a series of events | b. | a number that
describes how likely it is that an event will occur | c. | the way the results of one event affect the
next event | d. | the number of times a coin lands heads up |
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34.
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What does the notation AA mean to geneticists?
a. | two dominant alleles | b. | heterozygous alleles | c. | at least one
dominant allele | d. | one dominant and one recessive allele |
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35.
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The different forms of a gene are called
a. | alleles. | b. | factors. | c. | masks. | d. | traits. |
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36.
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Walter Sutton discovered that the sex cells of grasshoppers have
a. | 12 times the number of chromosomes found in the body cells. | b. | twice the number of
chromosomes found in the body cells. | c. | the same number of chromosomes found in the
body cells. | d. | half the number of chromosomes found in the body
cells. |
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37.
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An organism’s physical appearance is its
a. | genotype. | b. | phenotype. | c. | codominance. | d. | heterozygous. |
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38.
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Which term refers to physical characteristics that are studied in
genetics?
a. | traits | b. | offspring | c. | generations | d. | hybrids |
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39.
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Which nitrogen base in RNA is NOT part of DNA?
a. | adenine | b. | guanine | c. | cytosine | d. | uracil |
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40.
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Factors that control traits are called
a. | genes. | b. | purebreds. | c. | recessives. | d. | parents. |
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Completion
Complete each
statement.
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41.
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If D represents the dominant allele of a gene, then ____________________
represents the recessive allele.
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42.
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The chromosomes in a pair may each have different ____________________ for each
gene.
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43.
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A chart used to predict results of genetic crosses is known as a(n)
____________________.
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44.
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Genes are carried from parents to their offspring on structures called
____________________.
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45.
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An organism that has two dominant or two recessive alleles is said to be
____________________ for that trait.
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46.
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Mendel used the principles of ____________________ to predict what percent of
offspring would show a particular trait.
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47.
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The process in which a parent cell divides twice to produce sex cells is called
____________________.
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48.
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In pea plants, the tall-stem allele and the short-stem allele are different
forms of the same ____________________.
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Genetics Problems
Write STEP 1, STEP
2, STEP 3, and STEP4 on a piece of notebook paper and complete each step. Then transfer your answers
for STEP 4 into the computer EXAM.
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This is a complete dominance
problem. A tall purebred female plant is crossed with a short male plant. Tall is
dominant.
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49.
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What percent of offspring will be homozygous tall?
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50.
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What percent of offspring will be hybrid tall?
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51.
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What percent of offspring will be heterozygous short?
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52.
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What percent of offspring will be tall?
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This is an incomplete
dominance problem. Neither black nor white alleles are completely dominant. A
gray hybrid male mouse is crossed with a gray hybrid female mouse.
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53.
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What percent of the offspring will be
black?
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54.
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What percent of the offspring will be
white?
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55.
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What percent of the offspring will be
gray?
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56.
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What percent will be purebred?
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THE FOLLOWING (57 - 59) IS FOR HONORS
ONLY.
This is a sex linked, complete dominance problem. A
female carrier of the recessive colorblind gene is crossed with a male with normal vision. Normal
vision is dominant.
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57.
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What percent of the offspring will be females and
carriers?
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58.
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What percent of only the females will be normal and
non-carriers?
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59.
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What percent of the offspring will be
colorblind?
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Short Answer
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ddddagram to answer each question. 
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60.
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In the F2 generation, what percent of the offspring have white
flowers? What are the genotypes of the white-flowered offspring?
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61.
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Suppose one of the parents of the F2 generation had been ww
instead of Ww. What percent of the offspring would have purple flowers? What percent would
have white flowers?
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62.
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Which trait—white flowers or purple flowers—is controlled by a
dominant allele? Which is controlled by a recessive allele? How do you know?
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63.
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In the F1 generation, what is the genotype of the offspring? What is
their phenotype?
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64.
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In which generation are the parents purebred? In which generation are they
hybrids?
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65.
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In the F2 generation, what percent of the offspring have purple
flowers? What is the genotype of the purple-flowered offspring?
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