Genetics Worksheet
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or
answers the question.
1) For a 100% Tt genotype among a large number of offspring, the parents are
A) both TT.
B) both tt.
C) TT and tt.
D) Tt and tt.
E) tT and Tt.
2) For an offspring tally of 25% TT, 50% Tt and 25% tt, the parents are
A) both TT.
B) both tt.
C) both Tt.
D) Tt and tt.
E) Tt and TT.
3) The number of different kinds of genotype offspring from an Aa vs. Aa cross is
A) 1.
B) 2.
C) 3.
D) 4.
4) Through a PP vs. Pp cross, the chance of producing a dominant appearing offspring in the
firstborn is 100%. The probability for a dominant second born is _____%.
A) 0
B) 25
C) 50
D) 75
E) 100
5) Two different kinds of phenotypes are produced among the offspring from a genetic
cross. The genotypes of the parents are
A) TT and TT.
B) TT and Tt.
C) Tt and tt.
D) Tt and Tt.
E) TT and tt.
6)
In guinea pigs, the allele that produces dark color is dominant to the allele that produces
light color. From a cross between two heterozygous organisms what is the chance of
producing a light colored guinea pig?
A) 4/5
B) 3/4
C) 1/2
D) 1/4
E) 0
7) In pea plants, smooth seeds are dominant over wrinkled seeds. A cross is made between
a wrinkled seed plant and a heterozygote. What is the chance of getting offspring that are
homozygous smooth?
A) 0
B) ¼
C) ½
D) ¾
E) 1/1
8) The expected phenotypic ratio of a cross between two heterozygotes for height in
garden peas is
A) 3 tall: 1 short.
B) 1 TT: 2 Tt: 1 tt
C) all tall.
D) all short.
E) 2 tall: 2 short.
9) Which of the following represents the possible genotype(s) resulting from a cross
between two individuals that are heterozygous for the B gene?
A) BB and Bb
B) BB, Bb and bb
C) BB
D) bb
E) Bb
10) How many genetically different kinds of sex cells can an AaBB organism produce?
A) 1
B) 2
C) 4
D) 6
E) 8
11) A gamete produced by a ttgg plant is
A) tt.
B) gg.
C) ttgg.
D) tg.
12) Four of the five are pure breeding. Select the exception.
A) AABB
B) AaBB
C) AAbb
D) aaBB
E) aabb
1) Answer: C
2) Answer: C
3) Answer: C
4) Answer: E
5) Answer: C
6) Answer: D
7) Answer: A
8) Answer: A
9) Answer: B
10) Answer: B
11) Answer: D
12) Answer: B