answer key genetics workpacket

CP BIOLOGY

name ______________________________

GENETICS

WORK

PACKET

GENETICS INTRODUCTION QUESTIONS:_____1) Which of the following describes a gene and not allele?

a. blue eyes

c. red hair

b. production of normal hemoglobin

d. size of nose because it does not specify size. ______2) Which of the following is a physical trait?

a. how tall you are

c. amylase production

b. A-type personality

d. migration of butterflies

___________3) Which of the following is considered a form of a trait or an allele? (choose two answers)

a. the loci on the chromosome that codes for length of fingers

b. the nucleotide sequence at the gene that codes for length of fingers

c. the location of a gene that determines your height

d. the code for blue eyes______ 4) Why do genes come in pairs?

a. One is carried on the maternal homolog and one on the paternal homolog.

b. There is a gene on one chromosome (ex. the #1) and another, on a different chromosome (ex. #2 ).

c. There are two genes next to each other on the same chromosome.

d. There are two sister chromatids in every cell.

______ 5) For a specific gene loci

a. the maternal allele may be the same as the paternal allele.

b. the maternal allele may not be the same as the paternal allele.

c. the maternal and paternal alleles will always code for the same trait.

d. all of the above.

#11 6) One of the genes for beta hemoglobin is found on chromosome 11.

The maternal and paternal #11 chromosomes are to the right. Draw a horizontal line across the upper portion of the homologs showing an approximate location of the gene.

Then, draw an imaginary nucleotide sequence to the right and left of the homologs

showing that the chromosomes come from an individual who carries an allele for

normal hemoglobin and one for abnormal sickle cell hemoglobin.

(Hint: Use page 5 in your notes packet and only use about 10 nucleotides to represent

each sequence. You can review your protein synthesis packet for specific ideas.)

______ 7) The alleles in question #6 are

a. homozygous

b. heterozygousChoose from the following two answers to define the next two statements.

a. dominant

b. recessive

___A____ 8) Form of a trait that is expressed (phenotype) when the two alleles are different.

___A, B______ 9) Form of a trait that is expressed when the two alleles are the same (two answers).

Identify the following as a genotype or phenotype.

__Genotype__________________ 10) WW, Ww, or ww.

___Phenotype_________________11) White fur or Black fur.

12) Why cant there be a heterozygous recessive genotype? ____recessive MUST BE homozygous!__No matter what, if alleles are heterozygous (Ww), the dominant trait will ALWAYS be expressed.

__________________________________________

In guinea pigs, black fur (B) is dominant to white fur (b). The gene for black fur is on the #1 chromosome. What are the genotypes of the following animals?__Bb____ 13) Heterozygous or hybrid

__BB____ 14) Homozygous dominant

__bb____ 15) Homozygous recessive

____A, B__________ 16) The Tobiano pattern of coat spotting in horses and ponies shown below is inherited as a simple dominant gene. Which of the following genotypes will express the Tobiano pattern?

a. TT

b. Tt

c. tt

Can you identify the genotype of this Tobiano patterned foal? NO Why or why not?

Could be homozygous dominant or heterozygous dominant!BiologyGenetics Term Sheet/Step ReminderAllele - An alternate or variable form of a gene

Genotype The allele combinations an organism has for a given trait Phenotype - The expression of a pair of allelesHomozygous - Having 2 of the same alleles for a given trait

Heterozygous - Having 2 different alleles for a given traitLaw of Dominance - A type of inheritance pattern where one allele is expressed over another discovered by Mendel

Dominant allele - The allele that is shown in the heterozygous form

Recessive allele - The allele that is hidden or masked in the heterozygous form

Steps to solve a simple genetics problem involving 1 trait

Step 1 Read the problem thoroughlyStep 2 Make a genotype/phenotype key

genotypephenotype

RRRed

RrRed

rrwhite

Step 2 Determine the parental genotypes from the information given in the problem

Ex. A plant heterozygous for red flower color is crossed with a plant producing white flowers. What % of the offspring will have white flower color?

P1Rr Xrr

(heterozygous for red flower color)(white flower color)

Step 3 Use the parental genotypes to set up a Punnet Square

P1R r X r r

Step 4 Use your Punnet square to answer the question(s) in the problem.

What % of the offspring will have white flower color? 50% (2 of the 4)

Bio CP

FA: Understanding Punnett Squares Name ______________________

Answer the following questions using the Punnett Square below for reference:

R=Dominant for red carnation flowers

r= Recessive for white carnation flowers

1) What do the letters across the top (first row) and down the left side of a Punnett square represent?

__Alleles on each of the homologous chromosomes that could POTENTIALLY be inherited from parents if those specific egg and sperm meet. (found in gametes - top and sides are the potential egg and the sperm of the parents - )________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

2) What do the letters inside the rectangles of the Punnett square represent? For example, what do the

letters Rr stand for?

___The genotype of the offspring, or alleles on the homologous chromosomes of the offspring, that would be formed from the fusion of gametes (from parents)(Remember they are only probabilities)_______________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

Bio CP

FA: Genetics Vocabulary Name _____________________________

1) Given the following symbols to represent alleles, circle the allele pairs that are homozygous. Draw a square around the gene pairs that are heterozygous:

DD

Dd

nn

Ww

pp

ss

Tt

CC

Ss

Rr

Yy

2) Given the following symbols and forms of traits, circle those which are genotypes and draw a rectangle

around those which are phenotypes:

blond hairJJ Tt bent little fingerSsfree hanging earlobe

cc

3) A dominant form for a trait is that form which can be identified in an organism that is __________________ (homozygous/ heterozygous) for the trait.

Use the following information to answer questions 4-9. The trait for front hairline in humans is coded for by two different

alleles:

Genotype: Phenotype:

WW = widows peak or a distinct downward point of the

frontal hairline

Ww = as above

ww = straight hairline

4) What are the possible genotypes for individuals who have a widows peak? __WW, Ww__________

5) What is the only genotype for individuals who have a straight hairline? _ww__________________6) What is the phenotype for an individual with the allele pair Ww? __widows peak__________________

7) Which of the above forms or alleles of the trait is dominant? (W, w) __W____________

Define dominant: __allele that is expressed/seen when heterozygous _____________________________________________________________________

______________________________________________________________________________________

8) Which of alleles is recessive? __w______________

Define recessive: __allele that is NOT shown when heterozygous, only visible when homozygous _____________________________________________________________________

______________________________________________________________________________________

9) Using the letters W and w, which of the allele pairs is homozygous dominant? __WW________

homozygous recessive? __ww_______

heterozygous? ____Ww__________

10) If your big toe is longer than your second toe, you are considered homozygous recessive (bb) for big toe

length. If your big toe is shorter than your second toe, you could be either homozygous _dominant _____(BB)

or __Heterozygous______________________ (Bb) for the trait.

In the following questions, you can assume that the dominant allele is represented by a capital letter and the recessive allele is lower case.

11) If attached earlobes in humans is the recessive form of the trait (a) and free-hanging earlobes are dominant (A), fill in the genotypes and phenotypes of the following people:

Genotype:Phenotype:

homozygous dominantAAHanging lobes

homozygous recessiveaaAttached lobes

heterozygousAaHanging lobes

a hybridAaHanging lobes

a purebred (two answers)AA, aaAA = hanging; aa = attached

In the following questions, you can assume that the dominant allele is represented by a capital letter and the recessive allele is lower case.

12) If S = black fur color in guinea pigs and s = white fur color, what is the phenotype of a guinea pig that is

homozygous recessive for coat color? __white_________________

13) If G = green pea pod color and g = yellow pea pod color, what is the allele pair for a pea plant that is

heterozygous for pod color? ____Gg__________

14) If D = dimpled chin and d = smooth chin, what is the phenotype of an individual with the genotype Dd?

_____dimpled_____________________

Enough!! Lets do some Punnett squares. Answer the following questions using either the foil method or the Punnet Square method:

Tt

TTTTt

tTttt

15) Tall cucumber plants (T) are dominant to short (t) cucumber plants.What are the predicted genotypes and phenotypes for the

offspring of two, heterozygous parents?

GENOTYPE: 1 TT: 2 Tt: 1 tt ; 25% TT: 50% Tt : 25% ttPHENOTYPE: 3 tall: 1 short (75% tall and 25% short)Hh

hHhhh

hHhhh

16) Cleft chin is dominant (H) to smooth chin (h).

What are the predicted genotypes and phenotypes for the offspring of a homozygous recessive female and a heterozygous male?

GENOTYPE: 1 Hh: 1 hh; 50% Hh : 50% hhPHENOTYPE: 1 Cleft Chin: 1 smooth chin (50% and 50%)ww

WWwWw

wwwww

17) Mrs. W is very proud that her curly hair (W) is dominant to straight hair. One of Mrs. Ws daughters has curly hair but the other does not.

If Mr. W is homozygous for the trait, what are Mrs. Ws and Mr. Ws genotypes?

Mrs. W: Ww and Mr. W: wwBiology CP

Name_____________________________________________

GENETICS: Check Your Understanding

1. Define allele.

One member of a gene pair. It can have the same or different nucleotide sequences as the allele on the homologous chromosomes. 2. In fruit flies, long wings (L) is dominant over short wings (l).

Write the parents genotypes in the following Punnett Square or use FOIL to determine the genotypic and phenotypic outcomes.

Heterozygous x homozygous recessive. FOIL ____Ll x ll___________________________

Ll

lLlll

lLlll

Genotypes:__Ll and llRatio:______1 : 1, 50% Ll and 50% 11Phenotypes:___Long wings and short wingsRatio:_____1 : 1_________3. In humans, having freckles (F) is dominant over no freckles (f). Therefore, FF is an abbreviation for:

a. homozygous dominantb. heterozygous

c. homozygous recessive

4. What would be the phenotype of the individual in question #3?Freckled!

Matching. Match the word with the statement to the left that describes it.

______5. Homozygous Ca. The form of a trait that is always

expressed if it is present.(in the phenotype)

______6. Pure Breeding Db. The trait that is only expressed when the

individual is homozygous for this gene pair.

______7. Hybrid E (heterozygous)c. Both alleles in a gene pair are identical.

______8. Dominant A d. Another word for being homozygous.

______9. Recessive Be. The two alleles in a gene pair are not

identical.

______10. Allele Ff. One member of a gene pair/one form of a

gene.

THREE RULES FOR ONE-TRAIT CROSSES:

1) If both parents are homozygous for the same form of a trait, all offspring will be identical to the

parents.

2) Any cross in which at least one parent is homozygous dominant, will form offspring with the dominant

phenotype.

3) Any cross in which both parents have at least one recessive allele, will have some offspring that are

homozygous recessive.

It isnt always necessary to use FOIL or a Punnett Square. If you use the three rules of Monohybrid Crosses you can immediately answer the following questions. If you dont believe it, use a Punnett Square or the FOIL method to check your work.

Use the following information to answer questions 1-3.

Mendel studied the trait of pea seed shape. Smooth seeds (S) were dominant over wrinkled seeds (s).

1) Mendel cross pollinated two pea plants and all 250 of the offspring were smooth seeded. Which of the

following crosses most likely represents the genotypes of the parents? (circle one)

a) SS x SS

b) Ss x Ss

c) ss x ss

d) Ss x ss

Which rule(s) did you use? ____2________

2) Mendel counted 98 wrinkled seeds and 102 smooth seeds in the F1 generation. Based on the ratio of the

phenotypes produced, what were the probable allele pairs in the P1 cross?

b) SS x SS

b) Ss x SS

c) ss x ss

d) Ss x ss Which rule did you use? ____3________

3) Mendel conducted another study and found that all the F1 seeds were smooth. Which of the following

genotypes most likely represent the parents? (circle all that apply)

a) SS x SS

b) SS x ss

c) SS x Ss

d) ss x ss

Which rule(s) did you use? ____2________

Going Further: You can also use numbers of offspring to determine what type of cross the parents represent. Punnett squares are only a prediction of what the offspring will look like. The actual numbers will not be exact but should be close.

4) Which of the following would be the approximate number of smooth seeds compared to wrinkled seeds

counted in the offspring of a cross between two pea plants that are heterozygous for seed shape.

a) 97 to 102

b) 103 to 50

c) 297 to 102

d) 103 to 25

CP Biology FA: One-Trait Crosses Name ________________________________

Use the following Punnett squares to help answer the questions. Optional: You may fill in the results of each Punnett square or fill in by the FOIL method, if it will help to answer the questions. You can answer many of the questions simply using the 3 rules of one-trait crosses.

Lack of pigment deposition in the human body is an abnormal recessive trait called albinism. A human with albinism is called an albino. Many mammals display this same recessive trait such as deer, mice and rats. In the Punnett squares below, use A and a to represent the dominant (normal) allele and the recessive (albino) allele, respectively.

AA x aa Aa x Aa

AA x Aa Aa x aa

Aa

aAaaa

aAaaa

AA

AAAAA

aAaAa

AA

aAaAa

aAaAa

Aa

AAAAa

aAaaa

_______1. Which of the following is a cross between two purebred parents?

a. AA x aab. Aa x Aa

c. AA x Aa

d. Aa x aae. none of these

_______2. Which of the following is a hybrid cross?


c. AA x Aa


_______3. Which cross predicts 100% heterozygous offspring?


c. AA x Aa


_______4. Which cross predicts an F1 generation with a phenotypic ratio of 3:1, dominant to recessive?


c. AA x Aa


_______5. Which cross predicts that all offspring would be homozygous recessive?


c. AA x Aa

d. Aa x aae. none of these_______6. Which two crosses predict that some offspring will be albino. (2 answers)


c. AA x Aa


_______7. Which two crosses predict that all offspring will have normal pigment? (2 answers)


c. AA x Aa


_______8. Which cross predicts a genotypic ratio of 1/4 :1/2 : 1/4, homozygous dominant to heterozygous, to

homozygous recessive?


c. AA x Aa


______9. Which cross shows exactly that the parents first child will be albino, and their second will have

normal pigmentation?


c. AA x Aa

d. Aa x aae. none of these______10. Which cross will predict that an offspring has a 50% chance of being albino?


c. AA x Aa


Bio CP

FA: Monster One-Trait Crosses

1) Green spots are dominant to yellow spots in dragon monsters.

Two parents, heterozygous with green spots undergo sexual reproduction with each other.

__G____ __g____ X ___G___ __g____What percent of their offspring are predicted to have green spots? __75%_____________

How many offspring out of 8 babies would be expected to have green spots? _6____________

What is the genotypic ratio for the cross? ___1 GG : 2 Gg : 1 gg _2) A baby monster with yellow spots grows up and mates with a male that is homozygous dominant with green spots.

__g____ __g____ X ___G___ __G____

What is the genotype for all of their children? _Gg________________

What is the phenotype for their children? __Green Spots_____________

3) 2 horns are dominant to 1 horn in the dragon monsters. If a heterozygous male with 2 horns mates with a female with 2 horns and 5 babies are born, all with 2 horns, what is the most likely genotype for the parents?

__H____ __h____ (male) X ___H___ __H____ (femalebut COULD be Hh)4) Forked tongues are dominant to rounded tongues. Two parent monsters with forked tongues have 6 babies. Four have forked tongues and only 2 have rounded tongues. What are the likely genotypes of the parents?

___F___ __f____ X __F____ __f____5) Fire breathing is a recessive trait. The local wizard wishes to breed as many fire breathing monsters as possible. Which of the following crosses will give him the greatest number of fire breathing baby monsters? (circle your answer)

a) a heterozygous cross ___F___ __f____ X ___F___ __f____ - 25% recessiveb) a homozygous dominant crossed with a homozygous recessive __F____ __F____ X ___f___ __f____c) a heterozygous crossed with a homozygous recessive ___F___ ___f___ X ___f___ __f____ - 50% recessiveTechnically ff x ff would be the bestbut its not an option!6) THINK: The background scale color (behind the spots) comes in a dominant, blue form and a recessive, yellow form. If a heterozygous parent that has BLUE spots mates with a homozygous recessive parent that has yellow spots, what color will the babies be? (Choose all that apply)

__B____ ___b___ X ___b___ ___b___

a) blue with green spotsb) blue with yellow spotsc) all yellow in colorIf the parents have 100 babies, how many would you predict to have each of the colors you chose above?

50 Bb Blue ; 50bb yellow7) Wings (w) are special. They are also a recessive trait. Which of the following crosses will produce some babies with wings? (Circle your answer or answers.)

a) WW x ww

c) Ww x Ww

b) Ww x ww

d) WW x Ww

8) Which of the following crosses would produce a 1:2:1 genotypic ratio in the offspring? (Circle your answer.)

a) WW x ww c) Ww x Ww

b) Ww x ww

d) WW x Ww9) Which of the crosses below would show a 50% to 50% outcome in the genotypes and phenotypes of the offspring.

a) WW x ww b) Ww x ww

c) Ww x Ww

d) WW x Ww

10) The wizard needs to conduct a test cross to determine the genotype of a male dragon with the dominant trait of pointed scales instead of the recessive form of round scales. Which of the following females should he cross his male with to determine if the male is homozygous dominant or heterozygous?

a) a female that has pointed scales b) a female with round scalesOnce the wizard has made the cross, he finds, to his surprise, that some of the babies have pointed scales and some have round scales. Based on his findings, what is the genotype of the male parent?

a) WW b) WwWhat were the genotypes of the parents?

Male __W____ __w____ X ___w___ ___w___ FemaleBio CP FA: Two-trait Crosses

Name _________________________________

Use this information for questions #1-3 only. In some breeds of dogs a gene controls the characteristic of barking while tracking an animal. Another gene controls whether the ears are erect or drooping. Barking is dominant (B) to non-barking (b) and erect ears is dominant (E) to drooping ears (e).

______1 Which of the following pairs of alleles would be found in the egg cells of a dog that is homozygous dominant for barking and heterozygous for ear type? BBEe = dogs genotype

a) BE and Be -these are in his gametes

c) BB and Ee this is what he is!!!

b) BE, Be, bE, bed) BB, Bb, EE, Ee

______2 What is the probability that offspring from a homozygous dominant barking, droopy eared male (BBee) and a heterozygous barking, droopy eared female (Bbee), will be non-barking with erect ears?

a) 0%

b) 12.5%c) 25%

d) 50%e) 100%_____3) What is the genotype of a homozygous non-barking/heterozygous erect-eared dog?

a) BBEe

b) bbEE

c) bbEe

d) Bbee

Use the diagram at right for questions 4 & 5 only.

_____4) Given the following two-trait punnett square, what are the GENOTYPES of the parents?

a. FF x EE

b. FfEe x FfEe

c. FEfe x FeFE

d. cannot be determined_____5) What is the probability of an offspring of genotype ffee from the cross shown at right?

a) 1/16b. 9/16c. 4/16 or

d. 0/16_____6) If you were to cross two parents, genotypes GgWw x GgWw, which dihybrid punnett square below is set up properly to illustrate that cross?

Bio CP FA: Two Trait Parakeet Coloring Name ________________________________

Parakeet body and wing colors are genetically controlled. Gene 1 codes for a white body color with blue wings.

There is no recessive allele for this gene. All birds are BB for white body color with blue wings.

Gene 2 codes for an additional coloring across the body and the wings.

This coloring combines with the original coloring to produce a combination of colors.

The dominant allele Y codes for a yellow coloring and the recessive allele y codes for no additional coloring. It produces a non-functional protein.

______ 1) If a female parakeet is BByy, what color will she present on her body and wings?

a) white with blue wingsb) yellow with blue wingsc) yellow with green wings

______ 2) If a female parakeet is BBYy, what color will she present on her body and wings?

a) white with blue wingsb) yellow with blue wingsc) yellow with green wings

___? yy___ 3) Which of the following represents the gametes that could be produced by a white bodied,

blue winged parakeet?

a) BY

b) BB and YYc) BY and byd) By and bY

______ 4) What is the probability that a white bodied, blue winged female and a heterozygous,

yellow bodied male will produce a white bodied, blue winged offspring?

a) 0%

b) 25%c) 50%d) 75%e) 100%

Red fruit (R) and stripes (T) are dominant to yellow fruit (r) and no stripes (t) in watermelon.

__c____ 5) A watermelon plant that is hybrid for fruit color and has no stripes is crossed with a plant

that has yellow fruit and is hybrid for stripes. Which of the following shows the Punnett

square that indicates the alleles in the gametes formed by the parent plants?

a) R t

b) RT Rt c) rT rt

R RT Rt

T

Rt rt

______ 6) What is the probability that the two parent plants in question #5 could produce an offspring

that has yellow fruit without any stripes?

a) 0%

b) 25%c) 50%d) 75%e) 100%

FA: One Trait Crosses Galore

Dimples:

Use the following words or symbols to answer the questions below.

a. 1:2:1

b. 1:1

c. 3:1

d. none of these

e. 0%

f. 25%

g. 50%

h. 75%

i. 100%

__c____ 1) Two hybrid parents show the dominant phenotype: dimples. What is the predicted

phenotypic ratio in their offspring?

__b____ 2) A homozygous dominant male with dimples has children with a heterozygous female. What is the

predicted genotype of their offspring?

___g___ 3) What is the chance that a third child will have dimples, if a male without dimples has 2 dimpled

children with a woman who is hybrid for the trait?

___e___ 4) What percent of babies will show the recessive phenotype if the parents are homozygous dominant

and homozygous recessive.

Achondroplasia: Achondroplasia is one type of dwarfism in humans. It results from a DOMINANT ALLELE that causes a mutation in the fibroblast growth factor receptor gene. This causes an abnormality in cartilage formation which leads to severely shortened bones. Those affected call themselves, achros. Remember that a single, dominant allele causes dwarfism!

Fill in the blanks with a single word in the parenthesis in the following questions.

5) If a male who is normal in size, has a child with a woman who is a homozygous achro, there is a

___________ ( 0, 25, 50, 75 or 100%) chance that the baby will be affected.

6) Two parents can only have children who have the dominant phenotype. The father is heterozygous. The

most likely genotype for the mother is _________________(AA, Aa, aa).

7) 75% of a parents offspring have dwarfism. The parents are both affected. Their genotypes are

______________________ (AA x aa, AA x Aa, Aa x aa, Aa x Aa, aa x aa).

8) If the parent of an affected child does not have dwarfism, and the mother is hybrid, what is the chance that

their next child will be normal? ___________________ ( 0, 25, 50, 75 or 100%).Earwax????? Wet type earwax is a dominant trait. The dry type is recessive. Asians and Native Americans are more likely to have the dry type whereas Caucasians and Africans more likely to have the wet type (honey-brown to dark-brown and moist).9) Two people have a child who has dry type earwax. What do you know about the two parents genotypes?

a) they each have a dominant allele

c) neither is homozygous recessive

b) they are both heterozygous

**** d) they both have at least one recessive allele10) An Inuit male marries a Caucasian female. They have a number of children who have both wet and dry

type earwax. If the Inuit has dry type earwax, what is the genotype of the mother?

a) homozygous recessive

b) homozygous dominant

c) heterozygousIncomplete Dominance:

Merle color in dogs is caused by a gene pair that exhibits incomplete dominance. The merle allele causes white areas in the fur. Homozygous recessive (mm) dogs are normal in color, without white spots. Dogs that are homozygous dominant (MM) are mostly white. Heterozygous (Mm) dogs have random white areas in the coat.

Mm

MMMMm

mMmmm

11) Show a cross between the heterozygous dog to the right and

a female that is colored the same. Show the genotypic and

phenotypic ratios of their offspring.

1: MM: white2: Mm: random white spots (MIXTURE of both phenotypes)1: mm: normal in color, no spotsCodominance: Roan Coloring in Cows and Horses

CRCR

CRCRCRCRCR

CWCR CWCR CW

12)The roan coloring in cows is caused by a gene that produces white hairs intermixed with normal colored hairs. Show a cross between a normal colored red cow (CRCR) and a roan cow (CR CW). Include the

genotypic and phenotypic ratios for the offspring.

1: CRCR : Normal fur

1: CR CW : Roan Fur (showing BOTH red and white)Blood Type:

13) A baby mix-up happened at the hospital!!! Two baby boys lost their wrist tags and the nurses cannot figure out which parents they belong to. The nurses KNOW that each baby belongs to either of two sets of parents. They test the blood of the babies and find that one has type O blood while the other has type AB blood. Which parents to they belong to?

a) Two parents with type A and AB blood, respectively b) Two parents with type A and B blood, respectively

Type O baby belongs to ______B____________ Type AB baby belongs to _______A__________

CP Bio FA One-Trait Crosses-Problem Packet Name ___________________________

Problem 1:

Trait That the Gene Codes For: presence or absence of dimples

Forms of the Trait: DD = dimples present, homozygous dominant

Dd = dimples present, hybrid or heterozygous

dd = dimples not present, homozygous recessive

List the six possible monohybrid crosses that can take place assuming you have male and female parents with each of the above genotypes. The first cross has been done for you.

1) ___DD x dd________ 2) _______________________ 3) ___________________________

4) ___________________ 5) ________________________ 6) ___________________________

Problem 2:

Trait: Earlobe shape

Forms: FF = free hanging, homozygous dominant

Ff = free hanging, hybrid or heterozygous

ff = attached, homozygous recessive

Use the multiplication method (FOIL) or draw a Punnett square to

show the possible genotypes and phenotypes for the offspring

resulting from a cross between two hybrid or heterozygous parents.

Include the ratios for geno- and phenotypes. Show your work.

F1 Genotypes ______________________________

F1 Phenotypes ______________________________

Problem 3:

A tall pea plant is crossed with a short pea plant. All the offspring are tall. What is the genotype of the parents? Show your work.

Genotypes of P1: _____________________

Problem 4

Normal wing shape (N) in fruit flies is dominant to twisted wings (n). Two flies are mated. The female lays 99 eggs which hatch to form 24 flies with twisted wings and 75 with normal wings. What are the probable genotypes of the parents? Show your work.

Genotypes of P1: _______________________Problem 5

Freckles are a dominant trait in humans. A parent who is homozygous for the trait has a child with a parent who is heterozygous or hybrid for the trait. What are the probable genotypes of both parents if all eight (yes, eight) of their children have freckles? Show your work.

Genotypes of Parents: ____________________________

Problem 6

A pea plant with green pods was crossed with a pea plant with yellow pods. Forty of 83 offspring had green pods. If green pod color is dominant, determine the genotypes of the parents. Show your work.

P1 Cross: ______________________

Problem 7

Trait: fur color in mice

Forms: BB = brown fur

Bb = brown fur

bb = white fir

A brown female mouse is mother to 10 baby mice!

The father mouse has white fur but all the babies have brown coats.

What is the probable genotype of the mother mouse? Show your work.

Genotype of mother mouse: ____________________

Problem 8

Long eyelashes are dominant to short lashes. Two parents have the same genotype for eyelash length. Determine their probable genotypes if they have two children, one heterozygous with long lashes and one with short lashes? Show your work.

P1 Genotypes: ______________________

Problem 9

Trait: hairline

Forms: WW = widows peak homozygous dominant

Ww = ws peak hybrid or heterozygous

ww = straight hairline homozygous recessive

A man with a straight hairline marries a woman with a widows peak. Their first two children have a widows peak but the third has a straight hairline. What is the probability of their next child having a widows peak? Show your work.

Probability of next child with Ww: ___________________________

Problem 10

RR

RRRRR

rRrRr

Rough coats (R) in guinea pigs is dominant to smooth coats (r). Two rough-coated guinea pigs were mated and produced offspring that were all rough-coated. Three out of the six offspring were heterozygous. Determine the genotypes of the parents. Show your work.

P1 Cross: __RR x Rr______________Problem 11

Ww

wWwww

wWwww

In squash, white fruit color is dominant to yellow fruit color. If a cross between a white-fruited plant and a yellow-fruited plant yielded 43 white and 39 yellow offspring, what is the white parents genotype? Show your work.

Genotype of white-fruited parent: ___Ww_______________

If there are offspring born with the recessive phenotype, then both parents must have the recessive allele. 1:1 or 50%:50% ratioProblem 12

PP

PPPPP

pPpPp

Chromosome #15 contains a gene which normally codes for an enzyme that breaks down lipids. Without this enzyme, an individual develops Tay-Sachs disease. The disease is characterized by lipid buildup in the brain, severe disability and death by age four. The allele for the normal protein (P) is dominant while the allele for Tay-Sachs (p) is recessive. Determine the chances that a baby born from a homozygous dominant male and a heterozygous female might be born with Tay-Sachs disease. Show your work.

What are the chances that a child from these parents will be born with the disease?

RR

rRrRr

rRrRr

a) 0%

b) 25%c) 50%d) 100%Problem 13

Incomplete Dominance: Squash come in three different shapes, round (RR), long (rr) and bell-shaped (Rr, heterozygous form). Determine the genotypic and phenotypic results of crossing a long squash with a round squash.

Genotypic percent: ___100% Rr_________________

Phenotypic percent: __100% bell-shaped_________________

(mixture of the phenotypes)RW

RRRRW

RRRRW

Problem 14

Codominance: Shorthorn cattle show one of three different hair colors: red, white or roan. Roan is a combination of red and white hairs. This inheritance is symbolized by the following alleles: CR (red), and CW (white). A farmer breeds two adult shorthorns and, over a period of several years, records the following offspring: 4 red cows and 4 roan colored cows. What were the probable genotypes of the parents? Show your work.

P1 Genotypes: ___RW (roan) x RR (red)____________________BO

AABAO

OBOOO

Problem 15

Multiple Alleles and ABO Blood Grouping: Could a man with B type blood father a child with O type blood, if the mother has A type blood? Show your work.

Is it possible? ___YES!!!_If they are BO and AO (not BB and AA)Problem 16

X-Linked genes: A woman who is a carrier for hemophilia marries a normal man. What are the possible phenotypes of their XHXh

XHXH XHXH Xh

YXHYXh Y

children? Show your work.

F1 Phenotypes: Male children-_50% normal: 50% hemophilia (1:1) Female children: 100% normal (50% carrier)Which of the children will be affected? _____ Xh Y ___________

Which of the children will be unaffected? XHY , XH XH, XH Xh Which of the children will be carriers? ______ XH Xh ___________Problem 17

XhXh

XHXH XhXH Xh

YXhYXh Y

X-Linked genes: The gene that causes Duchenne muscular dystrophy (a recessive condition) is carried on the X chromosome. A woman who has the disease marries a normal man. What are the possible phenotypes of their children? Show your work.

F1 Phenotypes: Girls will all be carriers and show normal phenotype. Boys will all have muscular dystrophy.

*** BOYS FROM AFFECTED MOTHER WILL BE AFFECTED!

Across

5. Disorders or conditions caused by X-linked recessive genes are more common in this sex.

6. When writing a dominant gene, we use a __?__ letter.

11. Results which are "predicted"

12. Which genes are found in someone who has blood type O?

14. A type of anemia in which some or all of the red blood cells are shaped like crescents; controlled by incomplete dominance

17. Male reproductive cells which have half the body chromosome number

19. A disorder caused by an X-linked dominant gene, which usually doesn't show its symptoms of damage to the brain until the patient is in his/her 30's/40's.

20. The main purpose of a flower.

21. a gene which is able to hide another form of the gene

22. A disease in which the blood does not clot properly, due to an X-linked recessive gene.

23. Female reproductive cells which have half the body chromsome number

24. A synonym for 'heterozygous'

27. a gene which can be hidden by another form of the gene

28. A synonym for 'homozygous'

Down

1. Along with other techniques, such as ultrasounds and CVS, this technique is useful when looking for chromosomal abnormalities in a fetus.

2. A disease caused by a recessive gene, which results in the production of a large amount of sticky mucus in the lungs, pancreas problems, and salty sweat.

3. A trait which is coded for by more than one pair of genes, such as height or intelligence.

4. A picture which shows the body chromosomes of an individual, arranged in 23 pairs.

7. When writing a recessive gene, we use a __?__ letter.

8. A fertilized egg

9. the "Father of Genetics" who performed basic genetic crosses with pea plants

10. A scientist who discusses genetic diseases with families.

13. Results which are actually seen

15. In a __?__ square, we are able to use the parents' genes to predict the possible genotypes of the offspring.

16. Having two different alleles (copies of the gene) for a particular trait

18. Having two of the same alleles (copies of the gene) for a particular trait

25. A type of inheritance in which neither form of a gene is dominant or able to hide another form of that gene

26. The expected chance of having a boy child is __?__%. (spell out the number)

R

r

rr

rr

Rr

Rr

r

r

Name:

GENETICS

Test Review

Mendel Reproduction

DominantOO

Recessive GeneticCounselor

Zygote CysticFibrosis

Sperm Huntingtons

Eggs Observed

Punnett males

Heterozygous Hemophila

Homozygous SickleCell

Polygenic Expected

Karyotype Lowercase

Purebred Capital

Hybrid Amniocentesis

Fifty IncompleteDominance

EMBED PBrush

C

A

T

T

G

A

A

C

G

G