I can: 9.3
Name: ____________________________________ Date: _____________ Period: ____
1.
A homozygous red flower (RR) is crossed with a homozygous white flower (rr). What is the probability that the resulting flower will be white? Draw a punnett square
Probability of:
RR: ______ %
What is the probability the resulting flower will be white?
______%
Rr: _______ % rr: ________ %
2.
D = light skin, d = dark skin. Johnny’s mother is homozygous dark skin and Johnny’s father is heterozygous light skin. What is the probability that Johnny has dark skin? a.
What is the mother’s genotype? ______ b.
What is the father’s genotype? _______ c.
Probability Johnny has dark skin? _______%
3.
T = tall, t = short. Mendel crossed two pea plants. One pea plant was heterozygous tall and the other was heterozygous short. What are the possible phenotypes (how many tall plants and how many short plants did he get?) Draw a punnett square a.
What is the first pea plant’s genotype? ______ b.
What is the second pea plant’s genotype? _______ c.
What are the two possible phenotypes and their %: i.
__________________: ___/4: ______% ii.
__________________: ___/4: ______%
4.
A homozygous short dog (dd) is crossed with a heterozygous tall dog (Dd). What is the probability that the offspring will be short? _______% You must draw your own punnett square
5.
A heterozygous brown-eyed (Bb) parent and a homozygous brown-eyed parent (BB) have offspring. Which of these genotypes would not occur in their offspring? a.
bb b.
BB c.
Bb

6.
A green flower (GG) is crossed with a white flower (gg). Which combination of alleles is a possible outcome? a.
GG only b.
gg only c.
Gg only
7.
The short stem trait (t) is recessive to the tall stem trait (T). If a homozygous short pea plant is crossed with a heterozygous tall plant, what is the chance that the offspring will be short? a.
One out of four b.
Two out of four c.
Three out of four d.
Four out of four
8.
In a Punnett square, a capital letter stands for a ____ allele. a.
Recessive b.
Dominant c. Homozygous d. Heterozygous
9.
A scientist is studying pea plants. The scientist made this Punnett square to predict the color traits of the offspring of two parent pea plants. Which of these genotypes will complete the punnett square to the right? a.
YY b.
yy c. d.
Yy
Yx
10.
In peas, the color yellow (Y) is dominant to the color green (y). According to the above Punnett
Square, most of the offspring of the two yellow pea plants probably will be: a.
Orange b. Green c. Yellow d. Red
??
11.
In pea plants, the trait for round seeds is dominant over the trait for wrinkled seeds. If a pure dominant (homozygous dominant) plant with round seeds is crossed with a plant with wrinkled seeds, what can be predicted about the offspring plants? [Hint: Create a punnett square].
a.
They will always produce round seeds b.
They will only produce wrinkled seeds c.
Each offspring plant will have some round and some wrinkled seeds d.
Unless the plant with wrinkled seeds was pure recessive, no prediction can be made.
12.
In a certain species of plant, the color purple (P) is dominant to the color white (p). According to the Punnett Square to the right, what is the probability of an offspring being white?
_________%
13.
In a certain species of pine trees, short needles (S) are dominant to long needles (s). According to the Punnett square to the bottom right, what is the probability of an offspring having short needles?
________%
14.
One flower is heterozygous red (Rr) and it is crossed with a homozygous white (rr) plant. Use the Punnett square to determine the probability of one of their offspring having a red color. a.
25% b. 50% c. 75% d. 100%
15.
Complete the tables below:
Fraction Percentage Fraction Percentage
0/4
3/4
_____%
_____%
1/4
__/4
_____%
75%
__/4 25% __/4 100%