Download B. Monohybrid Crosses—Autosomal Intermediate Inheritance

Mendelian Genetics Test REVIEW
PreAP Biology – Fall 2008
TEST DATE: Fri 12/5
The information below and on the attachments is intended to help guide you through the studying process. It is not a guarantee of
everything that is on the test. You are responsible for preparing for the test based on the handouts, reading assignments, and written
assignments we have completed. Only chapter 8 is on this test.
Vocabulary:
Allele
Autosomal
Blood typing
Carrier
Codominance
Continuous variation (polygenic
inheritance)
Cross-pollinate
Dihybrid
Dominant
F1
F2
Genotype
Genotypic ratio
Heredity
Heterozygous
Homozygous
Incomplete dominance
Mendel’s law of independent
assortment
Mendel’s law of segregation
Monohybrid

Below is the key to the review pages attached. This is
how to use this review:

First, DON’T LOOK AT THE KEY!!!!
 Begin, by working through all of the problems to the
very best of your ability. Look up the things you don’t
know in your notes or book.



P
Phenotype
Phenotypic ratio
Probability
Punnett square
Recessive
Self-pollinate
Sex-linked
Test cross
Finally, the night before the test you should have a
completed, correct review sheet to use as a guide to
reviewing your notes, your book, and your
assignments.
You should have the following:
Genetics Basics – Vocabulary Notes
Genetics Terminology Worksheet (kept as notes)
Genetics Problems Notes & homework worksheet
Other Genetics worksheets and quizzes
Check your work against the key!
Then, work in a group – since you have the key this is
obviously NOT for a grade – and DISCUSS the things
you don’t understand with each other.
Next, COME IN FOR TUTORIALS BEFORE the day
before the test and ask about the things you don’t
understand.
KEY:
Genetics Review 2008
Nearsightedness
1.
to create a tool that can be used to predict the probability of the inheritance of a trait
Vocabulary Review
2.
by looking at their phenotypes, as well as the phenotypes of their parents & offspring
1. E
17. Punnett square
IA
Ee
3.
man =
2. M
18. test cross
IB
Ee
3. J
19. probability
IIA
ee
4. F
20. pedigree
IIB
E-
5. H
21. sex-linked trait
IIC
Ee
6. O
22. polygenic trait
IID
Ee
if you see children with a trait the parents don’t have, it is recessive; if a parent always have the
7. K
23. incomplete dominance
IIIA
ee
trait if a child does, it’s dominant
8. N
24. codominance
IIIB
E-
5.
usually means it’s on the X chromosome
9. G
25. multiple alleles
IIIC
ee
6.
No
10. D
IIID
E-
7.
if a sperm with an X chromosome fertilizes an egg, it’s a female; if a sperm with a Y chromosome fertilizes an egg,
11. L
IVA
Ee
12. A
IVB
Ee
IVC
Ee
woman =
child =
4.
marriage =
or
someone with the disorder =
it’s a male; therefore, it’s the male’s sperm that determines the sex of the child as XX = female and XY = male
8.
½ or 50%
13. P
9.
genetics
14. I
10.
Pisum sativum or commonly called pea plants
15. B
11.
In incomplete dominance, neither allele (gene) is fully expressed, such as in pink snapdragons being produced from
16. C
Individual
Genotype
red and white snapdragons. Codominance is when both alleles (genes) are fully expressed, such as in type AB blood.
Huntington’s Disease
Genetics Problems
Individual
Genotype
6. Hh because K received H from D, D received H
A.1. a. BB x bb
B. 3. a. BB, BY or YY; blue, green or yellow
7. No
D
Hh
b. Bb
b. 25%
8. a. TtBb x TtBb
E
-h
7. H is Hh because he received H from A and passed it
c. 100% Bb
c. 25%
b. omit
G
Hh
on to O. I is H- because she passed H on to O, but
d. black
d. 50%
c. omit
H
Hh
there is not enough information to determine if I is
e. 100% black
4. a. BY or YY
d. tall & blue, tall & white, short & blue, short & white
I
H-
2. a. Bb x Bb
b. 50%
e. 9:3:3:1
J
-h
8. if I is HH, it is 0%; if I is Hh it is 25%
b. BB:Bb:bb
c. 0%
Ear lobes
M
-h
9. A, D, G, H, I, K, L, O
c. 1:2:1
d. 50%
Individua: lA
N
--
10. E, I, J, M, N
d. black:white
5. IAi or IAIA; Ibi or IBIB; IAIB; ii
Genotype: ee Ee
e. 3:1
6. type AB or type B
IB
IIA
IIB
IIIA
IIIB
IIIC
IIID
IIIE
IVA
ee
Ee
E-
ee
Ee
ee
ee
Ee
from A and h from B
HH or Hh.
Genetics Review 2008
1.
Why do genetic counselors use pedigrees?
2. How do you find the genotype of individuals on a pedigree?
3. What represents a man, woman, marriage, child or someone with a disorder?
4. When studying a pedigree, how do scientists determine if a trait is dominant or recessive?
5. What does it mean if a disorder is sex-linked?
6. Can a male be a carrier for a sex-linked disorder?
7. Why does a male determine the sex of the offspring?
8. What is the chance a couple will have a baby boy?
9. What is the study of heredity?
10. What is the scientific name and common name of the specimen that Mendel studied?
11. Differentiate between incomplete dominance and codominance and give an example of each.
Genetics Problems:
A. Monohybrid Crosses—Autosomal Single-Gene Traits:
Given: Black fur (B)is dominant over white (b) fur in rabbits.
1. Cross a homozygous black rabbit with a homozygous white rabbit.
a. What are the genotypes of the mom and dad rabbits? _____ x _____
Show your work with a Punnett square to the right 
b. What are the genotypes of the offspring? _____________
c. What’s the ratio or percentage of each?____________
d. What are the phenotypes of the offspring? _____________
e. What’s the ratio or percentage of each? ____________
2. Cross a heterozygous black rabbit with a heterozygous black rabbit.
a. What are the genotypes of the mom and dad rabbits? _____ x _____
Show your work with a Punnett square to the right 
b. What are the genotypes of the offspring? _____________
c. What’s the ratio or percentage of each?____________
d. What are the phenotypes of the offspring? _____________
e. What’s the ratio or percentage of each? ____________
B. Monohybrid Crosses—Autosomal Intermediate Inheritance: Incomplete Dominance
Sponge Bob and his pal Patrick love to go jellyfishing at Jellyfish Fields! The fields are home to a special
type of green jellyfish known as Goobers and only really great jellyfishermen are lucky enough to
catch some on every trip. Many of the jellyfish are yellow (YY) or blue (BB), but some end up green as
a result of incomplete dominance. Use this information to help you complete each section below.
3. What would happen if SpongeBob and Patrick crossed two “goobers” or green jellyfish? Complete a
Punnett square to the right to help you determine the probability for each color of jellyfish.
(a) Give the possible genotypes and phenotypes for the offspring.
(b) What percentage of the offspring would be yellow? _____%
(c) What percentage would be blue? _____ %
(d) What percentage would be “goobers” (green)? _____ %
4. What would happen if they crossed a yellow jellyfish with a goober? Complete a Punnett square to help
you determine the probability for each color of jellyfish.
(a) Give the possible genotypes and phenotypes for the offspring.
(b) What percentage of the offspring would be yellow? _____%
(c) What percentage would be blue? _____ %
(d) What percentage would be “goobers” (green)? _____ %
C. Monohybrid Crosses—Autosomal Intermediate Inheritance: Multiple Alleles & Codominance
5. Give the genotypes for type A= ____ (Heterozygous) or _____ (homozygous). Type B = ____
(hetero) or _____ (homo); AB = _____; type O = _____.
6. List the possible blood types of offspring if Mom is heterozygous for type A and Dad is
homozygous for type B.
7. If a person has type AB blood and marries a person with type O blood, could they have a child with
type O blood? Prove with a punnett square.
D. Dihybrid Cross.
8. Cross a heterozygous tall,blue flower with a heterozygous tall, blue flower.
The letter for blue is B. The letter for white is b. The letter for tall is T. The letter for
short is t.
a. The genotypes of the parent flowers are _______ x ________
Show your work in a Punnett square:
d. What are the phenotypes of the offspring?
_____________
e. What’s the ratio or percentage of each?
______________
***Study Genetics Vocabulary Notes, Genetics Problems Notes, Pedigrees, and Genetics Problems WS***
Vocabulary Review
© Holt, Rinehart, and Winston
In the space provided, write the letter of the description that best matches the term or phrase.
_____1. heredity
_____2. genetics
_____3. monohybrid cross
_____4. true-breeding
_____5. P generation
_____6. F1 generation
_____7. F2 generation
_____8. alleles
_____9. dominant
_____10. recessive
_____11. homozygous
_____12. heterozygous
_____13. genotype
_____14. phenotype
_____15. law of segregation
_____16. law of independent assortment
A. the alleles of a particular gene are different
B. the two alleles for a trait separate when
gametes are formed
C. the alleles of different genes separate
independently of one another during
gamete formation
D. not expressed when the dominant form of
the trait is present
E. passing of traits from parents to offspring
F. all the offspring display only one form of a
particular trait
G. the expressed form of a trait
H. first two individuals crossed in a breeding
experiment
I. physical appearance of a trait
J. cross that considers one pair of contrasting
traits
K. offspring of the F1 generation
L. when the two alleles of a particular gene
are the same
M. branch of biology that studies heredity
N. different versions of a gene
O. offspring of the P generation
P. set of alleles that an individual has
Write the correct term from the list below in the space next to its definition.
Codominance
Incomplete dominance
Multiple alleles
_______________________ 17.
_______________________ 18.
phenotype of unknown genotype
_______________________ 19.
_______________________ 20.
_______________________ 21.
_______________________ 22.
_______________________ 23.
parents
_______________________ 24.
_______________________ 25.
Pedigree
Polygenic trait
Probability
Punnett square
Sex-linked trait
Test cross
diagram that predicts the outcomes of a genetic cross
cross of a homozygous recessive individual with an individual with a dominant
the likelihood that a specific event will occur
a family history that shows how a trait is inherited
trait whose allele is located on the X chromosome
when several genes influence a trait
when an individual displays a trait that is intermediate between the two
two dominant alleles are expressed at the same time
genes with three or more alleles
Pedigree Practice
B. Huntington disease, a disease of the nervous system, is caused by an autosomal dominant
gene. The pedigree chart below illustrates a family with individuals who have Huntington disease.
Use the chart to answer the questions that follow. HINT: Write the genotypes for each individual in the
pedigree before you start answering the questions.
A
B
hh
Hh
C
D
E
hh
J
F
G
H
I
hh
K
L
M
N
O
Hh
Hh
HH
Key:
H
Female
Male
Huntington Disease
h
Normal Gene
6. What is the probable genotype of individual D? Explain your answer. _________
__________________________________________________________________________________
__________________________________________________________________________________
7. What are the probable genotypes of individuals H and I? Explain your answer. ___
__________________________________________________________________________________
__________________________________________________________________________________
8. What is the probability that N will not have Huntington disease? ________________
9. Which individuals can be determined to have Huntington disease? ______________
10. Identify the individuals whose genotypes cannot be determined without more
information. ______________________________________________________________________
Use the space below to work any Punnett squares you may find necessary to answer
the questions above.
Making and Interpreting Pedigree Studies
Adapted from © 1985 Scott, Foresman and Company
Determining Genotypes from a Pedigree
1. Nearsightedness – or myopia – is a recessive trait. The shaded regions show individuals who
are homozygous recessive for myopia. They exhibit the trait being studied.
Label the generations I., II., III., and IV. Label the individuals in each generation A., B., etc.
Start over with A with each generation. Use the symbols E and e to label each of the individuals in
the pedigree below.
2. Free ear lobes is a dominant trait. Attached ear lobes is a recessive trait. The shaded regions
show individuals who are homozygous recessive for attached ear lobes. They exhibit the trait
being studied. They have attached ear lobes.
Label the generations I., II., III., and IV. Label the individuals in each generation A., B., etc.
Start over with A with each generation. Use the symbols E and e to label each of the individuals in
the pedigree below.