2025 BIOL 2153 Genetics COMBINED ALL EXAM 1
QUESTIONS AND ANSWERS (Everything about exam
1) Louisiana State University.
Exam #1 (Grade 1) for Principles of Genetics, Fall Term 2024, Section 7-10.
Bubble in your name and student identification number on SIDE TWO of the
scantron. Also, you need to mark in the grade section whether your exam is Grade 1
or 2. The correct answer for each question will be awarded 3 points (3 x 33 = 99)
and one extra point will be added to make 100 points. Keep this exam booklet and
bring it to your next discussion session, when the exam will be reviewed.
(Q1-4) The following breeding schemes have been used for explaining Mendel’s two
genetic laws during the genetic course.
Scheme 1: Yy x Yy Scheme 2: Rr x rr
Scheme 3: YY x yy Scheme 4: YYRR x yyrr
1. Which scheme is the self-cross at the F1 stage?
a. Scheme 1
b. Scheme 2
c. Scheme 3
d. Scheme 4
e. All of the above
2. Which one is the testcross determining the genotype of the F1 progeny from one pure
breeding line?
a. Scheme 1
b. Scheme 2
c. Scheme 3
d. Scheme 4
e. All of the above
3. Mendel crossed one pure breeding strain of garden pea to discover the segregation law.
Which was this breeding scheme at the beginning?
a. Scheme 1
b. Scheme 2
c. Scheme 3
d. Scheme 4
e. None of the above
4. Mendel also crossed two pure breeding strains of garden pea to discover the
independent assortment law. Which was the breeding scheme at the beginning?
a. Scheme 1
1
,b. Scheme 2
c. Scheme 3
d. Scheme 4
e. None of the above
2
,(Q5-6) We are performing a dihybrid cross experiment as shown below.
P AABB x aabb
F1 AaBb x AaBb
F2
5. How many different genotypes are found among the F2 offspring?
a. two
b. three
c. four
d. nine
e. sixteen
6. What fraction of F2 will be heterozygous for both genes, A and B?
a. 1/2
b. 1/3
c. 1/4
d. 1/6
e. 1/8
7. In the following breeding scheme, what is the probability of obtaining genotype
RRYyTtss in the F2?
P RRYYTTSS x rryyttss
F1 RrYyTtSs x RrYyTtSs
F2
a. 1/8
b. 1/16
c. 1/32
d. 1/64
e. 1/256
8. How many genetically different eggs could be formed by a woman with the following
genotype (AaBBCcDD)?
a. one
b. two
c. four
d. eight
e. sixteen
3
, (Q9-12) We have the following dihybrid crosses. Both genes follow the complete
dominance/recessive inheritance mode
I. AAbb × aaBB II. AaBb × aabb III. AaBb × AaBb
IV. AaBB × aaBB V. AABB × aabb
9. Which crosses will produce a 1:1:1:1 ratio of phenotypes among the progeny?
a. I
b. II
c. III
d. IV
e. V
10. Which crosses will produce a 9:3:3:1 ratio of phenotypes among the progeny?
a. I
b. II
c. III
d. IV
e. V
11. Which crosses will produce a 1:1 ratio of phenotypes among the progeny?
a. I
b. II
c. III
d. IV
e. V
12. Which crosses will produce only one type of phenotypes among the progeny?
a. I and II
b. II and III
c. III and IV
d. IV and V
e. V and I
4
QUESTIONS AND ANSWERS (Everything about exam
1) Louisiana State University.
Exam #1 (Grade 1) for Principles of Genetics, Fall Term 2024, Section 7-10.
Bubble in your name and student identification number on SIDE TWO of the
scantron. Also, you need to mark in the grade section whether your exam is Grade 1
or 2. The correct answer for each question will be awarded 3 points (3 x 33 = 99)
and one extra point will be added to make 100 points. Keep this exam booklet and
bring it to your next discussion session, when the exam will be reviewed.
(Q1-4) The following breeding schemes have been used for explaining Mendel’s two
genetic laws during the genetic course.
Scheme 1: Yy x Yy Scheme 2: Rr x rr
Scheme 3: YY x yy Scheme 4: YYRR x yyrr
1. Which scheme is the self-cross at the F1 stage?
a. Scheme 1
b. Scheme 2
c. Scheme 3
d. Scheme 4
e. All of the above
2. Which one is the testcross determining the genotype of the F1 progeny from one pure
breeding line?
a. Scheme 1
b. Scheme 2
c. Scheme 3
d. Scheme 4
e. All of the above
3. Mendel crossed one pure breeding strain of garden pea to discover the segregation law.
Which was this breeding scheme at the beginning?
a. Scheme 1
b. Scheme 2
c. Scheme 3
d. Scheme 4
e. None of the above
4. Mendel also crossed two pure breeding strains of garden pea to discover the
independent assortment law. Which was the breeding scheme at the beginning?
a. Scheme 1
1
,b. Scheme 2
c. Scheme 3
d. Scheme 4
e. None of the above
2
,(Q5-6) We are performing a dihybrid cross experiment as shown below.
P AABB x aabb
F1 AaBb x AaBb
F2
5. How many different genotypes are found among the F2 offspring?
a. two
b. three
c. four
d. nine
e. sixteen
6. What fraction of F2 will be heterozygous for both genes, A and B?
a. 1/2
b. 1/3
c. 1/4
d. 1/6
e. 1/8
7. In the following breeding scheme, what is the probability of obtaining genotype
RRYyTtss in the F2?
P RRYYTTSS x rryyttss
F1 RrYyTtSs x RrYyTtSs
F2
a. 1/8
b. 1/16
c. 1/32
d. 1/64
e. 1/256
8. How many genetically different eggs could be formed by a woman with the following
genotype (AaBBCcDD)?
a. one
b. two
c. four
d. eight
e. sixteen
3
, (Q9-12) We have the following dihybrid crosses. Both genes follow the complete
dominance/recessive inheritance mode
I. AAbb × aaBB II. AaBb × aabb III. AaBb × AaBb
IV. AaBB × aaBB V. AABB × aabb
9. Which crosses will produce a 1:1:1:1 ratio of phenotypes among the progeny?
a. I
b. II
c. III
d. IV
e. V
10. Which crosses will produce a 9:3:3:1 ratio of phenotypes among the progeny?
a. I
b. II
c. III
d. IV
e. V
11. Which crosses will produce a 1:1 ratio of phenotypes among the progeny?
a. I
b. II
c. III
d. IV
e. V
12. Which crosses will produce only one type of phenotypes among the progeny?
a. I and II
b. II and III
c. III and IV
d. IV and V
e. V and I
4
