Download 11 Intro to Genetics Practice Test

11.1-11.3 Introduction to Genetics Practice Test
Completion
Complete each statement.
1. The plants that Gregor Mendel crossed to produce the F1 generation made up the
____________________ generation.
2. The different forms of a gene are called ____________________.
3. If the allele for shortness in pea plants were dominant, all the pea plants in Mendel’s F1 generation would have
been ____________________.
4. If the alleles for traits in pea plants did not segregate during gamete formation, offspring that were recessive for a
trait could be produced only by crossing two plants that were ____________________ for that trait.
5.
____________________ is the likelihood that a particular event will occur.
6. If you flip a coin five times and it comes up heads each time, the probability that it will come up heads the next
time is ____________________.
Tt
T
t
T
TT
Tt
T
TT
Tt
T
=
Tall
t
=
Short
TT
Figure 11–1
7. In the Punnett square shown in Figure 11–1, the genotypes of the offspring are
____________________.
8. Pea plants that are TT, ____________________, or tt have different genotypes.
9. When two heterozygous tall pea plants are crossed, the expected genotype ratio of the offspring is
_________________________.
10. The principle of independent assortment states that ____________________ for different traits can
segregate independently during the formation of gametes.
11. If pea plants that are homozygous for round, yellow seeds (RRYY) were crossed with pea plants that are
heterozygous for round, yellow seeds (RrYy), the expected phenotype(s) of the offspring would be
_________________________.
12. Crossing a pink-flowered four o’clock with a white-flowered four o’clock will produce pink-flowered offspring
and ____________________-flowered offspring.
Short Answer
13. Define genetics.
14. What attributes of the garden pea plant made it an excellent organism for Gregor Mendel’s genetic studies?
15. What might have caused Gregor Mendel NOT to conclude that biological inheritance is determined by factors that
are passed from one generation to the next?
16. How many recessive alleles for a trait must an organism inherit in order to exhibit that trait?
RrYy
RY
Ry
rY
ry
RY
RRYY
RRYy
RrYY
RrYy
Ry
RRYy
RRyy
RrYy
Rryy
RrYy
rY
RrYY
RrYy
rrYY
rrYy
ry
RrYy
Rryy
rrYy
rryy
Seed Shape
R = Round
r = Wrinkled
Seed Color
Y = Yellow
y = Green
Figure 11–2
17. What is the phenotype ratio of the offspring in the Punnett square shown in Figure 11–2?
18. A pea plant heterozygous for height and seed color (TtYy) is crossed with a pea plant heterozygous for height but
homozygous recessive for seed color (Ttyy). If 80 offspring are produced, how many are expected to be
tall and have yellow seeds?
USING SCIENCE SKILLS
Heterozygous male guinea pigs with black, rough hair (BbRr) are crossed with heterozygous female guinea pigs
with black, rough hair (BbRr). The incomplete Punnett square in Figure 11-4 shows the expected results from the
cross.
BbRr
BR
Br
bR
br
BR
BBRR
BBRr
BbRR
BbRr
Br
BBRr
BBrr
BbRr
Bbrr
BbRr
bR
BbRR
BbRr
?
bbRr
br
BbRr
Bbrr
bbRr
bbrr
Hair Color
B = Black
b = White
Hair
Texture
R = Rough
r = Smooth
Figure 11–4
19. Using Tables and Graphs Identify the genotype of the offspring that would be represented by the question mark
in Figure 11–4.
20. Using Tables and Graphs Identify the phenotype of the offspring represented by the question mark in Figure
11–4.
21. Analyzing Data In Figure 11–4, what are the different phenotypes of the offspring?
22. Analyzing Data In Figure 11–4, what are the genotypes of the offspring that have black, rough hair?
23. Calculating What fraction of the offspring in Figure 11–4 would be expected to have white, smooth hair?
Figure 11–5
24. Inferring What do the letters R and I represent in Figure 11–5?
25. Interpreting Graphics In Figure 11–5, what is the genotype of the pink-flowered snapdragons?
26. Inferring Explain whether the alleles in Figure 11–5 show dominance, incomplete dominance, or codominance.
27. Inferring According to Figure 11–5, if red-flowered snapdragons and ivory-flowered snapdragons are crossed,
what percentage of their offspring would be expected to be pink-flowered?
28. Inferring According to Figure 11–5, if two pink-flowered snapdragons are crossed, what percentage of their
offspring would be expected to be pink-flowered?
11.1-11.3 Introduction to Genetics
Answer Section
COMPLETION
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
P
alleles
short
recessive
Probability
1/2
50%
TT and Tt
Tt
1 TT : 2 Tt : 1 tt
genes
round yellow seeds
white
SHORT ANSWER
13. Genetics is the scientific study of heredity.
14. Garden pea plants produce many offspring, they have traits that come in two forms, and crosses between the plants
can be controlled easily.
15. Answers may vary. If the F1 pea plants had had traits of neither parent, Mendel might not have concluded that
factors for traits are passed from one generation to the next.
16. An organism must inherit two recessive alleles for a trait in order to exhibit that trait.
17. The phenotype ratio is 9 round, yellow peas : 3 round, green peas : 3 wrinkled, yellow peas : 1 wrinkled, green pea.
18. Thirty of the offspring are expected to be tall and have yellow seeds.
OTHER
19. The genotype of the offspring is bbRR.
20. The phenotype of the offspring is white, rough hair.
21. The phenotypes of the offspring are black, rough hair; black, smooth hair; white, rough hair; and white, smooth
hair.
22. Offspring with black, rough hair have the genotypes BBRR, BBRr, BbRR, and BbRr.
23. One sixteenth of the offspring would be expected to have white, smooth hair.
24. R represents the allele for red flowers. I represents the allele for ivory flowers.
25. The genotype of the pink-flowered snapdragons is RI.
26. The alleles show incomplete dominance, because a cross between red-flowered snapdragons and ivory-flowered
snapdragons produces snapdragons with an in-between trait—pink flowers.
27. One hundred percent of the offspring would be expected to be pink-flowered.
28. Fifty percent of the offspring would be expected to be pink-flowered.