Download Unit 6 Study Guide

NAME:
Genetics Study Guide (Due on Day of Test: Tuesday, 11/22)
Instructions: Read the flip and answer the flop. Answer all questions!
FLIP
FLOP
1. In simple Mendelian Genetics, alleles are either
1. In watermelons, stripes are dominant to no
dominant or recessive. In these types of word
stripes. Cross a homozygous, recessive non-striped
problems, you will see key words such as dominant,
watermelon with a heterozygous striped
recessive, or heterozygous. Remember to set up the
watermelon. What are the genotypes and
genotypes and phenotypes for these word problems
phenotypes of the F1 generation?
BEFORE you attack the problem.
GG – Homozygous Dominant
Gg – Heterozygous
gg – Homozygous Recessive
The first generation produced from the parental
generation is called the F1 generation. If two
offspring from the F1 generation are crossed, the
resulting generation is called the F2 generation.
2. Other types of inheritance patterns are not simple
Mendelian inheritance patterns. The first example of
this is Incomplete Dominance. In this type of
inheritance, neither allele is dominant over the other so
you end up with a blending of traits, which creates the
appearance of a third phenotype.
Example of Symbols:
rr – red
rw – pink
ww – white
Think Incomplete = “In Between”
3. The next type of non-Mendelian inheritance is
Codominance. In codominance both alleles are
equally dominant, so you use two different capital
letters to represent the genotypes. You see both
phenotypes distinctly in the offspring.
Example of Symbols:
BB – black
BY – black and yellow spotted
YY – yellow
Think Codominant = “Both Show”
2. When a blue flower is crossed with a red flower,
all of the offspring created are purple. Cross a
purple flower with a red flower. What is the
phenotypic ratio of the offspring created?
3. In horses, hair color is codominant. Cross an all
brown horse with an all white horse. What would
be the genotypes and phenotypes of the F1
generation? What if you crossed two offspring
from the F1 generation, what would be the results
in the F2 generation?
NAME:
Genetics Study Guide (Due on Day of Test: Tuesday, 11/22)
FLIP
4. Blood types are a specific example multiple alleles
and of codominance. In blood typing, offspring can
have different genotypes and phenotypes from their
parents.
Symbols to use for blood types
Phenotype
A
B
AB
O
FLOP
4. Jane Smith married a man with type B blood. They
had a child with type O blood. Jane must have what
genotype? Explain. Show a Punnett square to support
your answer.
Genotype
IAIA or IAi
IBIB or IBi
IAIB
ii
Think Blood Type = “ABO”
5. John Smith has been taken to court for a paternity
dispute. He is accused of fathering a child out of
wedlock. The child in the case has type AB blood.
John has blood type B. Can John be the child’s
father? Explain. Show a Punnett square to support
your answer.
5. The last type of non-Mendelian inheritance pattern
that we discussed are sex-linked recessive traits.
When you see sex-linked, think “X linked” and
automatically know that you need to use your X and Y
chromosomes as part of the symbols. Also, remember
that males are more likely to have a sex-linked trait
because their Y allele does not carry any genes to
mask the recessive allele that might be on the X
chromosome. Therefore, males only need one
recessive form of a trait to have the condition.
6. Colorblindness is a recessive sex linked trait.
Show the cross between a color-blind female and a
normal vision male.
Example of Symbols
XNXN = normal female
XNXn = carrier female (normal phenotype)
XnXn = diseased female
XNY = normal male
XnY = diseased male
NAME:
Genetics Study Guide (Due on Day of Test: Tuesday, 11/22)
Vocabulary Review
_____ 1. Genetics
_____ 2. Test Cross
_____ 3. Genotype
_____ 4. Phenotype
_____ 5. Gene
_____ 6. Allele
_____ 7. Heterozygous
_____ 8. Homozygous
_____ 9. Dominant
_____ 10. Recessive
_____ 11. Incomplete dominance
_____ 12. Co-dominance
_____ 13. Multiple alleles
_____ 14. Sex-linked inheritance
_____ 15. Pedigree
_____ 16. Karyotype
_____ 17. Carrier
_____ 18. Amniocentesis
_____ 19. Polygenic Traits
A. A picture of an individual’s chromosomes; used to see disorders
B. When both traits are expressed at the same time
C. The study of heredity (passing on traits)
D. This procedure is used to create a karyotype of a fetus.
E. A physical characteristic that is passed on by genes
F. Different forms of a gene
G. The genetic combination that produces a phenotype (ex. Tt)
H. Alleles that are always expressed if present (T)
I. When two alleles are different (Tt)
J. A person does not show a disorder, but has 1 copy of the allele
K. Alleles that are masked or hidden unless there are two (t)
L. The physical expression of a gene; what you see (ex. brown)
M. More than 1 alleles controls the phenotype for 1 trait (blood type)
N. Inheritance when there is a 3rd blending phenotype
O. A graphical family tree showing the inheritance of 1 trait
P. When two alleles are the same (TT or tt)
Q A section of DNA that makes a specific protein and trait
R. When you cross an organism with a homozygous recessive
S. More than 1 gene controls a trait (ex. height, skin color)
Pedigree (Greenhouse Biology, you do NOT have to do the pedigree!)
1. Is this dominant or recessive? How can you tell?
2. What is the genotype of individual I, 1? _____
What is the genotype of individual II, 3? _____
3. Is there any chance of individual III, 2 passing
this on to her offspring? Why or why not?
Karyotypes
1. Is this karyotype from a male or female? How can you tell?
2. Does this karyotype show a normal individual or one with a disorder?
If you see a disorder, which one?
NAME:
Genetics Study Guide (Due on Day of Test: Tuesday, 11/22)
You must show a Punnett square for every problem!
1. A woman names her former boyfriend in a paternity suit. Her child has type O blood. The woman has
type A blood. The accused man has type B blood. What must be the parents genotypes for this to be
his child?
A. Mother: AA and Father: BB
B. Mother: AO and Father: BB
C. Mother: AA and Father: BO
D. Mother: AO and Father: BO
2. Hemophilia is a sex-linked recessive trait. What would be the probability that a male with hemophilia
and a normal female (not a carrier) would have a son with hemophilia?
A. 100%
B. 75%
C. 50%
D. 0%
3. Colorblindness is a sex-linked recessive trait. A mother with normal color-vision and a colorblind father
have a color-blind daughter. Which of the following statements is correct? (Show the cross and Punnett
square to help)
A. All of their daughters will be colorblind
B. The mother is a carrier of the colorblindness gene
C. All of their sons will have normal color vision
D. All of their sons will be colorblind.
4. The red flower gene is incompletely dominant over the white flower gene. When a pure red flower is
crossed with a pure white flower, all of the offspring are pink. When a white flower is crossed with a pink
flower, what are the expected genotypes? (show the cross and Punnett square to help you)
A. 100% RW
B. 50% RW and 50% WW
C. 25% RR, 50% RW and 25% WW
D. 100% WW
5. A white horse is mated with a brown horse and all of their offspring are white and brown. This is known
as codominance. What will be the resulting phenotypes when two of their offspring (two white & brown
horses) are crossed? (Show cross and Punnett square)
A. 25% white, 50% white and brown, 25% brown
B. 100% white and brown
C. 50% white and 50% brown
D. 50% white and brown 50% brown
6. Gregor Mendel, the Father of Genetics, worked with pea plants to study genetics. He saw that yellow
seed color is dominant to green seed color. If Mendel crossed a heterozygous pea plant with a plant
that is recessive for seed color, what is the probability (%) that the offspring will have green seeds?
A. 0%
B. 25%
C. 50%
D. 100%
7. In certain rats, short hair (S) is dominant over long fur (s). A test cross can be used to determine the
genotype of the short hair rat. Draw the Punnett square that represents a test cross that would produce
an offspring including 15 short haired rats and no long haired rats. Go back to your notes to remember
what you use for a test cross! What is the genotype of the parents?
A. SS x SS
B. Ss x SS
C. SS x ss
D. Ss x ss