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Genetics Unit - Test Review

This test will cover genetics, genetic disorders, and chromosomal disorders. First and foremost, study the notes given in class! Second, look over the two quizzes on genetics. Review the worksheets covering incomplete dominance (spongebob), codominance (blood typing), and sex-linked traits. Just because something is not on the review guide does not mean that it will not be on the test.

  1. Describe Mendel’s work. You should know what he worked with and what he discovered.

He worked with pea plants. Discovered patterns of inheritance, dominant and recessive traits

  1. Solve the following types of genetic problems:

1 trait crosses involving a dominant and a recessive gene.

(Tt X Tt)T=Tall t=short

T t

Genotypic Ratio= TT 25% :Tt 50% :tt 25%

T TT Tt

Phenotypic Ratio= Tall 75% :short 25%

t Tt tt

  1. Fill in the missing Dihybrid genotypes: 2 trait crosses involving 2 dominant and 2 recessive genes.

(TtGg X TtGg) T=Tall t=Short

G=Green g=yellow

TG Tg tG tg

TTGG / TTGg / TtGG / TtGg
TTGg / TTgg / TtGg / Ttgg
TtGG / TtGg / ttGG / ttGg
TtGg / Ttgg / ttGg / ttgg

TG

Tg

tG

tg

  1. 1 trait cross that is sex-linked. (in this case, pretend that the disorder is caused by a recessive allele)

(XHXh X XHY)

XH Xh

XH XH XH XH Xh

Y XHY XhY

Describe the possible offspring:

3 “normal” 1 with disorder

1normal male, 1 male w/ disorder, 1 normal female, 1 carrier female

  1. A cross involving 2 genes that are codominant.

Cross a Heterozygous A blood type women with a Heterozygous B blood type man.

A O

List all of the possible genotypes:AB, AO, BO, OO

B AB BO

List all of the possible phenotypes:

O AO OO Type AB Blood, Type A Blood,

Type B Blood, Type O Blood

  1. Pedigrees: Make sure you

put in generation #’s

Which individuals are:

Male:I- 1,3; II- 2, 4, 6; III-1

Female: I- 2, 4; II- 1,3,5; III-2

Carriers:I- 2,4; II- 3

Affected: III- 1

  1. What is a karyotype and identify some of the problems that can be identified by a karyotype.

Karyotype- a picture of a person’s chromosomes. Can be used to check for chromosome abnormalities, like Down Syndrome & shows the sex chromosomes.

8. What is nondisjunction?

Failure of chromosomes to separate during meiosis.

  1. Match the following vocabulary terms:

___ The father of genetics

___ Square diagram used to determine

the outcome of a cross

___ A gene that, when present, is always

expressed or shown

___ A gene that is only shown when the

individual is homozygous

___ Different versions of a gene

___ Actual gene make-up or combination

of alleles

___ Form of a trait that is observed

___ A genetic cross involving only 1 trait

___ Probability

  1. Karyotypes: Answer the following questions:

Is this a male or female: Female

Normal or abnormal karyotype: Abnormal – missing the second sex-chromosome

  1. Incomplete Dominance Punnett Square:

Purple Thingamadoodles are created due to incomplete dominance from Red (R) and
Blue (B) Thingamadoodles. Using a punnett square show all of the possible offspring from a cross between two Purple Thingamadoodles.

RB

RR / RB
RB / BB

R

B

RR