Name _________________________________ Date__________ Period _____ _
Genetics PRACTICE TEST
MULTIPLE CHOICE: Circle the answer that best completes the sentence.
The different alternatives or choices for a gene (like blue, green, or brown eyes) are called
_____________.
A. generations
B. traits
C. tetrads
D. alleles
Crossing organisms from the F1 generation produces the _____ generation.
A. P2
B. F2
C. P1
D. None of these-you can’t cross F1 organisms with each other!
Crossing organisms from the P1 generation produces the _____ generation.
E. P2
F. F1
G. F2
H. None of these-you can’t cross P1 organisms with each other!
Mendel’s “factors” are now called ___________________.
A. gametes
B. genes
C. cells
D. zygotes
What pattern did Mendel see when crossing pure TALL with pure SHORT pea plants?
A. ALL the F1 offspring were short, but the F2 generation were all tall.
B. ALL the F1 offspring were tall, but the F2 generation were all short.
C. ALL the F1 offspring were short, but 50% the F2 generation were all tall and 50% were short.
D. ALL the F1 offspring were tall, but 25% the F2 generation were short and 75% were tall.
WHICH OF THE FOLLOWING IS TRUE of MENDELIAN INHERITANCE?
A. If a dominant allele is present, the recessive allele won’t be seen.
B. If a recessive allele is present, the dominant allele won’t be seen.
C. Both recessive and dominant alleles show if present
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MATCH THE WORD FROM THE WORD BANK WITH ITS DEFINITION:
GENETICS
HEREDITY
TRAIT
DOMINANT RECESSIVE
____ TRAIT
PURE-BREEDING
ALLELE
FERTILIZATION
___ A characteristic that can be observed such as hair color, seed shape,
flower color, etc
___ FERTILIZATION _____ The joining of a sperm and egg to make a zygote
____ DOMINANT ____ A gene choice that MASKS ANOTHER choice for a trait
_____ RECESSIVE
_____ A gene choice that IS MASKED BY ANOTHER choice for a trait
_____ GENETICS
____ the branch of biology that studies how characteristics are transmitted
from parent to offspring
_____ HEREDITY ______ the passing of characteristics from parent to offspring
_____ ALLELE ______ An alternative choice for a gene (such as brown, green, or blue eyes)
____ PURE-BREEDING
___ An organism that always produces offspring identical to itself if self
pollinated
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PUNNETT SQUARE PRACTICE
Use a Punnett Square to show the possible offspring from the crosses given and answer the
questions:
IN PEAS:
R = round
r=wrinkled
T= tall
t = short
Y = yellow peas
P = purple flowers
y = green peas
p = white
flowers
MAKING MONOHYBRID CROSSES:
What is the genotype of a HOMOZYGOUS YELLOW SEED plant? ______YY________
What is the genotype of A HOMOZYGOUS GREEN SEED plant? _______yy_____________
What is the genotype of a HETEROZYGOUS YELLOW plant? ________Yy_______
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Make a cross between a PURE YELLOW SEED parent and a PURE GREEN SEED
parent.
Genotypes of Parents:
Yy
Yy
Yy
Yy
____YY__ X ___yy___
POSSIBLE OFFSPRING GENOTYPES
___Yy______________________________
POSSIBLE OFFSPRING PHENOTYPES
___Yellow_____________________________________
What is the probability an offspring will show the DOMINANT TRAIT (YELLOW SEEDS)? __100__%
What is the probability an offspring will show the RECESSIVE TRAIT (GREEN SEEDS)? ___0______%
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What is the genotype of a PURE PURPLE FLOWERED plant ? = _PP_____
What is the genotype of a PURE WHITE FLOWERED plant? = ___pp______
What is the genotype of a HYBRID PURPLE FLOWERED plant? = __Pp___
Make a cross between a HOMOZYGOUS PURPLE FLOWERED plant and a
HOMOZYGOUS WHITE FLOWERED plant.
Genotypes of Parents:
Pp
Pp
Pp
Pp
__PP______ X _pp_________
POSSIBLE OFFSPRING GENOTYPES
__________ Pp, ______________________
POSSIBLE OFFSPRING PHENOTYPES
_____purple, _______________________________
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What is the probability an offspring will show the DOMINANT TRAIT (PURPLE FLOWERS)?
__________100_______________%
What is the probability an offspring will show the RECESSIVE TRAIT (WHITE FLOWERS)?
____________0________________%
SEE A PATTERN FOR HOMOZYGOUS (P1) MONOHYBRID CROSSES:
If you cross plants that are PURE DOMINANT for a trait with plants that
are PURE RECESSIVE for that trait, __100______ % of the offspring will
show the DOMINANT trait and the ___recessive________________ trait
will not show at all.
USE THE PATTERN ABOVE TO MAKE PREDICTION ABOUT A CROSS
If you cross a HOMOZYGOUS ROUND SEED plant with a PURE WRINKLED SEED plant
100% will look _____round_____________
0% will look _______wrinkled_____________
The offspring will have a 100% probability of having the __Rr____ genotype.
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MAKE SOME HETEROZYGOUS MONOHYBRID CROSSES
A black coat (B) is DOMINANT in guinea pigs. A brown coat (b) is RECESSIVE.
What is the genotype of a HOMOZYGOUS BLACK guinea pig? = ___BB____
What is the GENOTYPE of a HETEROZYGOUS BLACK guinea pig? =___Bb______
What is the GENOTYPE of a brown guinea pig? =_____bb_____
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Make a cross between TWO HETEROZYGOUS BLACK guinea pigs.
Genotypes of Parents:
BB
Bb
Bb
bb
____Bb______ X ____Bb______
POSSIBLE OFFSPRING GENOTYPES
_____BB, Bb, bb___________________________________
POSSIBLE OFFSPRING PHENOTYPES
____Black, browm__________________________________
What is the probability that a baby will be black? ____75_____ %
What is the probability that a baby will be brown? ____25_____%
What is the probability the baby will be a HYBRID? ____50____%
What is the probability the baby will be HOMOZYGOUS DOMINANT ? ___25______%
What is the probability the baby will be HOMOZYGOUS RECESSIVE? ____25_______%
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Purple fur (P) is DOMINANT in monsters. Yellow fur (p) is RECESSIVE.
What is the genotype of a PURE PURPLE monster? __PP______
What is the GENOTYPE of a HETEROZYGOUS purple monster? __Pp__
What is the GENOTYPE of a YELLOW monster? ____pp____
Make a cross between TWO HETEROZYGOUS PURPLE MONSTERS.
Genotypes of Parents:
PP
Pp
Pp
pp
_____Pp_____ X ___Pp_______
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POSSIBLE OFFSPRING GENOTYPES
____________ PP, Pp, pp_____________
POSSIBLE OFFSPRING PHENOTYPES
____________Purple, yellow_________________________
What is the probability that a baby will be purple? ______75____%
What is the probability that a baby will be yellow? _____25_____%
What is the probability the baby will be a heterozygous? ____50___%
What is the probability the baby will be HOMOZYGOUS DOMINANT ? _25________%
What is the probability the baby will be HOMOZYGOUS RECESSIVE? ____25_______%
SEE A PATTERN FOR HETEROZYGOUS (F1) MONOHYBRID CROSSES:
If you cross 2 parent plants that are BOTH HETEROZYGOUS for a trait the
offspring will show a __3__ : __1__ phenotypic ratio.
_75_______ % of the offspring will show the DOMINANT trait and
___25_____ % of the offspring will show the RECESSIVE trait.
USE DOMINANT OR RECESSIVE TO FILL IN THE BLANKS BELOW:
¼ of the offspring will have two ____dominant______________ alleles, ½ will
be hybrids with one _____ dominant ____ and one
______recessive_________ allele, and
¼ will have two ______ recessive ___________ alleles.
USE THE PATTERN ABOVE TO MAKE PREDICTION ABOUT A CROSS
If you cross two HETEROZYGOUS ROUND SEED plants
75% will look ____round______________
25% will look _______wrinkled___________
The probability is:
¼ will have the genotype __RR____
genotype __rr___
½ will have the genotype __Rr___
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¼ will have the
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Scientists have been investigating the genetic make up of the residents in Bikini Bottom.
Complete the following questions about these inhabitants.
For each genotype below, indicate whether it is HETEROZYGOUS (HE) or HOMOZYGOUS (HO).
TT ___Ho
Bb __He
DD ___ Ho
tt ____ Ho
Ff ____ He
Dd _____ He
ff ____ Ho
bb ____ Ho
BB ____ Ho
FF __ Ho _
Determine the PHENOTYPE for each genotype given. IN SPONGE PEOPLE the allele
for YELLOW BODY COLOR (Y) is DOMINANT to BLUE (y).
YY = ____yellow____
Yy = _____ yellow _____
yy = ___blue_________
IN SPONGEPEOPLE the allele for SQUARE SHAPE (S) is dominant to ROUND (s).
SS = ___square_______ Ss = ____square_______
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ss = _____round_______
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SpongeBob SquarePants recently met SpongeSuzie RoundPants at a dance.
SpongeBob is HETEROZYGOUS for his square pants, but Suzie is ROUND.
Create a Punnett square to show the possibilities that could result if SpongeBob and
SpongeSuzie had children.
Genotypes of Parents:
____Ss______ X _____ss_____
What is SpongBob’s genotype? ___Ss__________
What is SpongeSuzie’s genotype? ____ss_______
What are the chances a child will have a square shape?
__2______ out of 4 OR ___50____%
What are the chances a child will have a round shape?
___2_____ out of 4
OR _50______%
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In SQUID PEOPLE the allele for LIGHT BLUE SKIN (B) is DOMINANT over the
GREEN (b) allele. Everyone in SquidWard’s family has light blue skin. His family
brags that they are a “purebred” line. He recently married a nice girl with light green
skin, which is recessive. Create a Punnett square to show the
possible offspring from this match.
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Genotypes of Parents:
_____BB_____ X ____bb______
POSSIBLE
OFFSPRING GENOTYPES
___Bb_____________________________________
POSSIBLE OFFSPRING PHENOTYPES
__Blue______________________________________
What are the chances of a child with green skin? ___0___%
Would SquidWard’s children still be considered “purebreds”?
YES
NO
EXPLAIN WHY or WHY NOT. ______No, they are heterozygous Bb, not homozygous (pure)
_____________________________________________________________________
_____________________________________________________________________
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INCOMPLETE DOMINANCE:
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In Four O’clock plants RED FLOWERS (FR) are INCOMPLETELY dominant over white (FW)
flowers. Heterozygous plants show a blended intermediate phenotype of PINK flowers.
MAKE A CROSS WITH 2 HETEROZYGOUS FOUR O’CLOCK PLANTS.
Genotypes of Parents:
___ FR FW _______ X ____ FR FW ______
Genotypes____ FR FR ____ FR FW __ FW FW ___
Genotypic Ratio _1:2:1_____________________
Phenotypes __red, pink, white______________
Phenotypic Ratios _1:2:1____________________
IF the red allele in Four-o’clocks WAS COMPLETELY DOMINANT over the white allele, what
would the phenotype be for a plant with Rr genotype? __________red__________
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You are exploring the jungle and find a new species of plant. Some of the plants have red
flowers and some have yellow flowers. You cross a red flowering plant with a yellow flowering
plant and all the offspring have orange flowers. You might assume that the alleles for flower
color in this plant show ____________________.
A. complete dominance
B. incomplete dominance
C. codominance
If the red and yellow alleles in the mystery jungle plant above showed CODOMINANCE
instead, what might you expect a plant with one red allele and one yellow allele to look like?
A.
B.
C.
D.
It would have all red flowers
It would have all blue flowers
It would have red and yellow flowers together on one plant
It wouldn’t make any flowers because it is a mutant.
BLOOD TYPES:
In the ABO blood type system the A and B alleles are dominant to O allele, and A and B are
codominant to each other.
Make a cross between a type A (heterozygous) mom and a type B (heterozygous)
dad.
IAi x IBi
What are the possible genotypes of the offspring?
__IAIB______
___IA_i_____
___IB_i_____ ____ii_____
What is the probability the offspring will have:
A type blood _25___% B type blood __252___% O type blood _25____% AB type blood
___25____%
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Make a cross between a type A (heterozygous) mom and a type B (homozygous)
dad.
IAi x IBIB
What are the possible genotypes of the offspring?
___ IAIB _____
___ IAIB ______
___ IB_i ______ ____ IB_i _____
What is the probability the offspring will have:
A type blood __0___% B type blood ____50__% O type blood ___0__% AB type blood
___50___%
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Make a cross between type A (homozygous) mom and a type O dad.
IAIA x ii
What are the possible genotypes of the offspring?
___IA_i____
___ IA_i ___
__ IA_i ___ ___ IA_i ____
What is the probability the offspring will have:
A type blood ___100_% B type blood ___0__% O type blood ____0_% AB type blood
___0___%
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You are working in the Emergency room and a bleeding patient with type B blood
is brought in. You need to give him blood, but the hospital is all out of type B.
Circle ALL the types of blood could you safely give him instead.
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A
AB
O
EXPLAIN your choices.
__Type B makes anti-a antibodies, so cannot give him blood with A
antigen______________________________________________________
What if the bleeding patient had type AB blood and the hospital was out of AB
blood. Circle ALL the types of blood could you safely give him.
A
B
O
EXPLAIN your choices.
Type AB has A and B antigens and makes no antibodies, so can receive all
JERRY SPRINGER GENETICS:
Wanda tells Jerry Springer that she thinks either Ralph or Fred could be the father of her
baby. Wanda’s genotype is IAi. Wanda’s baby has type O blood. Ralph’s is type AB. Fred’s
genotype is IBi.
Make two crosses to show who could be the father of Wanda’s baby.
Ralph X Wanda
IA
Fred X Wanda
i
IA
i
IA IAIA
IAi
IB
IAIB
IBi
IB IAIB
IBi
I
IAi
ii
Is it possible for Ralph to be the baby’s father?
YES
Is it possible for Fred to be the baby’s father? YES
NO
NO
Does this absolutely PROVE that Fred IS the baby’s father?
EXPLAIN YOUR ANSWER.
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YES
NO
___This just means that Fred has the same blood type as the baby
___________________________________________________________
___________________________________________________________
IF Wanda’s baby has type O blood, what are the possible genotypes for men
who COULD BE the father of Wanda’s baby?
_____IAi, IBi, ii_________________________________________
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IN PEAS:
R = round
T= tall
Y = yellow peas
r = wrinkled
t = short
y = green peas
P = purple flowers
p = white flowers
MAKING HOMOZYGOUS DIHYBRID CROSSES:
Cross a HOMOZYGOUS TALL, HOMOZYGOUS ROUND pea with a SHORT,
WRINKLED pea.
Parent's genotypes
_TTRR_________ X ___ttrr_______
Possible gametes
_TR_ _TR_ _TR_ _TR_
_tr__ _tr_ _tr__ tr__
How many out of 16 will be:
____16___ TALL & ROUND
_____0__ TALL & WRINKLED
_____0__ SHORT & ROUND
_____0__ SHORT & WRINKLED
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SEE A PATTERN FOR HOMOZYGOUS (P1) DIHYBRID CROSSES:
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If you cross plants that are PURE DOMINANT for TWO TRAITS with
plants that are PURE RECESSIVE for TWO TRAITS, ___100_____ % of
the offspring will look DOMINANT for BOTH traits and the
_____recessive___________ traits will not show at all.
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Cross a HETEROZGOUS TALL, HETEROZYGOUS ROUND pea with a PURE
SHORT, WRINKLED pea.
Parent's genotypes
___TtRr_______ X _____ttrr_____
Possible gametes
_TR_ _Tr _tR_ _tr_
_tr_ _tr_ _tr__ _tr_
How many out of 16 will be:
___4____ TALL ROUND
___4____ TALL WRINKLED
___4____ SHORT ROUND
___4___ SHORT WRINKLED
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FIND THE PATTERN FOR HETEROZYGOUS (F1) DIHYBRID CROSSES:
If you cross 2 parent plants that are BOTH HETEROZYGOUS for TWO
TRAITS, the offspring will show a _9___ : __3__ : _3___ : __1__
phenotypic pattern.
Fill in the blanks below with:
DOMINANT
or
RECESSIVE
9/16 of the offspring will show both ____ DOMINANT _______________
traits.
3/16 will look _____ DOMINANT ____________ for trait 1 and
___________ RECESSIVE ______ for trait 2.
3/16 will look _________ RECESSIVE _________ for trait 1 and _____
DOMINANT ____________ for trait 2.
1/16 will look _______ RECESSIVE _____________ for both traits.
USE THIS PATTERN TO TELL THE POSSIBLE OFFSPRING OF A
HETEROZYGOUS DIHYBRID CROSS WITHOUT USING A PUNNETT
SQUARE:
R = round
r=wrinkled
RrTt
T= tall
t = short
X
RrTt
9/16 will look _____round ___________ and _______tall________
3/16 will look _____round___________ and _______short__________
3/16 will look _____wrinkled__________ and ______tall_________
1/16 will look _____wrinkled____________ and ____short______________
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Rhett and Scarlett are expecting a baby. Rhett’s rich uncle has promised them
$1 million if their baby is a blue eyed boy that can carry on the family name.
Brown eyes (B) are dominant over blue eyes (b). Rhett is heterozygous for
brown eyes, while Scarlett has blue eyes. Fill in the Punnett square with Rhett
and Scarlett’s possible gametes.
Rhett’s Genotype: __BbXY___ Scarlett’s Genotype: _bbXX_____
Possible gametes: _BX__ __BY__ __bX__ _bY___
__bX__ _bX_ ___bX_ _bX__
What genotype does a baby need to be a blue eyed boy and get the $1 million?
____bbXY____
Use a Punnett square to show the possible genotypes for their baby.
___4____ Brown eyed boys
__4_____ Brown eyed girls
___4____ Blue eyed girls
___4____ Blue eyed boys
What is the probability they will have a BLUE-EYED BOY and get the $1
million? ____25______%
Why does this cross not follow the 9:3:3:1 pattern for DIHYBRID (2 gene)
crosses? Not 2 parents that are both dihybrid for 2 traits
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LINKAGE
A boy, whose parents and grandparents had normal vision, is color-blind.
What are the genotypes for his mother and his maternal grandparents. Use
XB for the dominant normal condition and Xb for the recessive, color-blind
phenotype.
XBXb
Xb
XBXb
Xb
XbY
The bison herd on Konza Prairie has begun to show a genetic defect. Some
of the males have a condition known as "rabbit hock" in which the knee of
the back leg is malformed slightly. We do not yet know the genes
controlling this trait but for the sake of our question, we shall assume it is
a sex-linked gene and that it is recessive. Now, suppose that the herd bull
(the dominant one which does most of the breeding) who is normal (XN)
mates with a cow that is a carrier for rabbit hock. What are his chances
of producing a normal son?
X NY x X N X n
XN
Xn
XN
XN XN
Xn
Y
XN Y
Xn Y
25% chance
In humans the gene from normal blood clotting, H, is dominate to the gene
for hemophilia, h. This is a sex-linked trait found on the X chromosome. A
woman with normal blood clotting has four children. They are a normal son,
a hemophiliac son, and two normal daughters. The father has normal blood
clotting. What is the probable genotype for each member of the family?
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woman with normal blood clotting XN Xn
father has normal blood clotting XN Y
normal son XN Y
hemophiliac son Xn Y
two normal daughters XN XN or XN Xn
XN
Y
XN
XN XN
XN Y
Xn
XN Xn
Xn Y
10.3.1
Define polygenic inheritance.
10.3.2
Explain that polygenic inheritance can contribute to continuous variation using two examples,
one of which must be human skin colour.
Modified from: http://brookings.k12.sd.us/biology
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