1/13/25
Practice Questions 1-10
Apply-Extend 1. January 15-17
1. How many
homologous pairs here?
2. How many replicated
chromosomes?
By the end of section meeting, you should be able to:
• Competently answer questions about number of
homologous pairs, and haploid/diploid
chromosome number relative to mitosis and
meiosis.
• Generate Punnett squares and predict the ratio
of offspring genotypes and phenotypes when
given information about parental phenotypes and
the dominance pattern.
• Enter your correct answers to the eight AE1
questions on the Canvas homework assignment
1
2
5. If the diploid number (2n) for a species is
50, how many homologous pairs are in that
species’ genome, and how many
chromosomes are in a sperm cell of that
species ?
A. 50, 50
B. 50, 25
C. 25, 25
D. 25, 50
• Meiosis is reduction
division.
• What are the products of
meiosis?
3. If a cell with one pair of
chromosomes undergoes
meiosis, how many cells
result, and how many
chromosomes are in each of
the resulting cells?
4. How about a cell with 23
pairs of chromosomes?
3
4
Incomplete dominance –heterozygote
phenotype unlike either homozygote.
Practice Punnett Squares:
6. A man has six fingers on each hand and six toes
on each foot. His wife and their daughter have the
normal number of digits. Having extra digits is a
dominant trait. What fraction of this couple’s
children would be expected to have extra digits?
[question from text, p 238]
Palomino Horses (C1C2)
When two palominos mate, they do not
produce all palomino offspring
• chestnut (homozygous C 1C 1),
• cream (homozygous C 2C 2), or
• palomino (heterozygous C 1C 2)
Draw the Punnett square and answer
7. If you wanted to produce all palomino offspring
(C 1C 2), what two genotypes would you mate?
Answer this too: Tell why it is helpful to know that
this couple has a child with normal number of digits.
[metacognition]
5
6
1
1/13/25
Inheritance of ABO
blood groups. We
use the letter I for
the three different
alleles.
8. In Mendel’s pea plants, the purple flower color allele (F) is
completely dominant over the white flower color allele (f).
Therefore, only homozygous recessive individuals have
white flowers.
If you have a pea plant of unknown genotype with purple
flowers, with which of the following individuals would you
cross it with to determine for sure whether the purple-flower
plant is homozygous (FF) or heterozygous (Ff)? Assume a
cross produces 20 offspring, not hundreds.
Genotype
IAi or IAIA
IBi or IBIB
A. Any purple-flower individual
B. Any white-flower individual
C. A purple-flower individual known to be heterozygous Ff
IAIB
Type AB
ii
Type O
So, how does this demonstrate (a) multiple
alleles and (b) co-dominance?
D. A purple-flower individual known to be homozygous FF
7
8
9. A woman of blood type B marries a man with
blood type A. Both of them have a parent with
type O blood. From the information given,
determine the genotypes of the couple, draw a
Punnett square, and answer what blood types
(phenotypes) are possible in their children?
A. Only blood types A or B.
B. Blood types A or B or O
C. Blood types A or B or AB
D. Blood types A or B or AB or O.
9
10. In 1944 Charlie Chaplin was involved in a
legal battle over the paternity of a child born to a
young starlet. The baby was blood type B, the
mother type A, and Chaplin type O. Based only
on this information, is Chaplin likely to have been
the father of the child?
(Incidentally, at the time of the trial, blood group
evidence was not admissible in California courts,
and Charlie Chaplin was declared responsible for
the child's support.)
10
AE1-Q2. In cats, the allele for short hair (H) is
dominant over the allele for long hair (h). A
female cat shows the short hair trait, but in
previous litters she produced some long-hair
offspring. If this short-hair female is now mated
with a long-hair male, what fraction of their
offspring is expected to have long hair?
A. 0 (none)
B. 1/4
C. 1/2
D. 3/4
E. 1 (all)
AE1 questions 1-8 to answer on Canvas
AE1-Q1. If a cell with genome of 20 pairs of
chromosomes undergoes normal meiosis,
how many cells result, and how many
chromosomes are in each of the resulting
cells?
A. Two cells, each with 20 chromosomes
B. Two cells, each with 40 chromosomes
C. Four cells, each with 10 chromosomes
D. Four cells, each with 20 chromosomes
E. Four cells, each with 40 chromosomes
11
Phenotype
Type A
Type B
12
2
1/13/25
AE1-Q3. In cats, the agouti allele for the “tabby”
coat pattern (A) is dominant over the allele for
solid color (a). (We are ignoring the effect of other
modifier genes for cat coat color.)
AE1-Q4. Sickle-cell anemia is inherited as a simple recessive
traits. Heterozygote carriers do not have sickle-cell anemia.
Neither John nor Maria have the disease sickle cell anemia, but
since it occurs in their families they have been tested and know
they both are heterozygous carriers of the recessive sickle-cell
allele. Draw the Punnett square and answer the two parts:
If two solid black cats (non-tabby) mate, what
proportion of their offspring would be expected to
be solid black?
A. 0 (none)
B. 1/4
(a) What proportion of their offspring are expected to have sickle
cell anemia? (b) What proportion of their offspring are expected
to be heterozygous carriers of the recessive sickle-cell allele?
A. 0 ; 1/4
B. 1/4; 1/4
C. 1/4; 1/2
D. 1/2; 1/2
E. 1/2; 3/4
C. 1/2
D. 3/4
E. 1 (all)
13
Think about this: If only one parent is a carrier, what proportion of
their offspring would be expected to have sickle-cell anemia?
14
AE1 Q6. Which of these sets of parents
(blood type phenotype given) is
probably not correctly matched to their
child (by blood type)
A. Parents A and B, child AB
B. Parents A and O, child AB
C. Parents A and O, child O
D. Parents A and B, child O
E. Parents AB and B, child AB
AE1 Q5. If an infant born to a mother
with blood type O is also type O,
possible types for the father are:
A. AB
B. O or A
C. A or B
D. O only
E. O, A, or B.
15
16
AE1 Q7. Flower color alleles in snapdragons show
incomplete dominance. When pure-bred
homozygous red-flowering snapdragons are
crossed with pure-bred homozygous whiteflowering snapdragons, all the offspring are
heterozygous and have pink flowers. When two
pink snapdragons are crossed, what proportion of
their offspring would be expected to be pink?
A. 0 (none)
B. 0.25
C. 0.50
D. 0.75
E. 1.0 (all)
17
AE1 Q8. Classical albinism results from a
particular recessive allele. Which of the following
are the expected phenotypes of offspring from
an albino woman and a normally pigmented man
who has an albino father? [from an old exam]
A. 3/4 normal pigment, 1/4 albino
B. 3/4 albino, 1/4 normal pigment
C. 1/2 normal pigment, 1/2 albino
D. All normal pigment
E. All albino
18
3