Question 1

If R is dominant to r , the offspring of the cross of RR with rr will ____.

Accepted Answer

A)  have a unique phenotype 
B)  have the same phenotype as the RR parents 
C)  have the same phenotype as the rr parents 
D)  have the same genotype as the RR parents 
E)  have the same genotype as the rr parents

Question 2

If two individuals who are heterozygous for two traits that display incomplete dominance (e.g., AaBb) mate and have offspring, how many different phenotypes are possible?

Accepted Answer

A)  1 
B)  3 
C)  6 
D)  9 
E)  16

Question 3

Red coat is dominant in horses and white coat is recessive. In a cross between a homozygous dominant red-coated horse and a white-coated horse, what genotype(s) would be observed in the offspring?

Accepted Answer

A)  all homozygous recessive 
B)  all homozygous dominant 
C)  half homozygous dominant and half homozygous recessive 
D)  all heterozygous 
E)  half heterozygous and half homozygous dominant

Question 4

If a child has an AB blood type, ____.

Accepted Answer

A)  both parents must have different blood types 
B)  neither parent can have blood type AB 
C)  both parents must have blood type AB 
D)  both parents can be any blood type 
E)  one parent can have blood type O

Question 5

____ is an example of a genetic disorder with little impact on the individual.

Accepted Answer

A)  XXX syndrome 
B)  Turner syndrome 
C)  Hemophilia 
D)  XYY syndrome 
E)  Down syndrome

Question 6

In a Punnett square, the letters on top of the square and on the side of the square represent ____.

Accepted Answer

A)  offspring genotypes 
B)  zygote genotypes 
C)  parental gametes 
D)  offspring phenotypes 
E)  parental phenotypes

Question 7

When genes are located very close together on the same chromosome, ____.

Accepted Answer

A)  gametes usually end up with the same combination of alleles as parental cells 
B)  gametes usually end up with unique combination of alleles 
C)  they are inherited separately 
D)  they often recombine during crossing over 
E)  offspring will look just like one parent

Question 8

When two alleles of the same gene are different, the individual carrying those alleles is said to be ____.

Accepted Answer

A)  recessive 
B)  heterozygous 
C)  phenotypic 
D)  somatic 
E)  homozygous

Question 9

The ABO blood types have ____ different genotypes.

Accepted Answer

A)  4 
B)  6 
C)  8 
D)  12 
E)  16

Question 10

For this problem, you may want to create a Punnett Square on a separate piece of paper. Manuel has cystic fibrosis, a recessive disorder, and sickle-cell anemia, which is also a recessive disorder. Manuel's partner, Lucretia, is normal for both conditions. What is the probability that Manuel and Lucretia will have a normal child without either of the conditions Manuel has?

Accepted Answer

A)  0  percent 
B)  25  percent 
C)  75  percent 
D)  100  percent 
E)  It is not possible to solve this problem with the information provided.

Question 11

The process by which chromosomes fail to separate during meiosis is called ____.

Accepted Answer

A)  aneuploidy 
B)  trisomy 
C)  monosomy 
D)  nondisjunction 
E)  polyploidy

Question 12

Approximately how many gene products are involved in the synthesis of melanin in humans?

Accepted Answer

A)  10 
B)  25 
C)  50 
D)  100 
E)  1000

Question 13

A gene that produces multiple effects is called a(n) ____.

Accepted Answer

A)  codominant gene 
B)  X-linked gene 
C)  epistatic gene 
D)  pleiotropic gene 
E)  incompletely dominant gene

Question 14

Narrative:
Achondroplasia, a hereditary form of dwarfism, is an autosomal dominant disorder; however homozygous dominant individuals either die before birth or very shortly thereafter. The homozygous recessive condition is normal. A dwarf couple decide to have children. Use this information to answer the following question:
Of the children of this couple who survive, what is the probability that they will be normal?

Accepted Answer

A)  0 
B)  ¼ 
C)  1/3 
D)  2/3 
E)  ½

Question 15

Purple flower ( A ) is dominant over white flower ( a ), and tall stem ( B ) is dominant over short stem ( b ). The Punnett square represents a cross between two dihybrids ( AaBb   ´   AaBb ).
In the figure above, how many plants would have the genotype AaBb ?

Accepted Answer

A)  1 
B)  3 
C)  4 
D)  6 
E)  9

Question 16

Purple flower ( A ) is dominant over white flower ( a ), and tall stem ( B ) is dominant over short stem ( b ). The Punnett square represents a cross between two dihybrids ( AaBb   ´   AaBb ).
In the figure above, how many plants would have white flowers and short stems?

Accepted Answer

A)  1 
B)  3 
C)  5 
D)  9 
E)  16

Question 17

Genetic recombination as a result of crossing over occurs more readily between genes that are ____.

Accepted Answer

A)  on the sex chromosomes 
B)  near the centromere 
C)  located close together on the same chromosome 
D)  located far apart on the same chromosome 
E)  located on different chromosomes

Question 18

Males are more commonly affected by X-linked recessive genetic disorders than females because ____.

Accepted Answer

A)  females have two X chromosomes; therefore, they do not inherit recessive alleles 
B)  males have only one X chromosome; therefore, they express all recessive X-linked traits 
C)  males have only one X chromosome; therefore, they have multiple alleles for each X-linked gene 
D)  Y chromosomes cause X-linked gene mutations 
E)  males are genetically weaker than females

Question 19

Human eye color is an example of a trait that varies ____.

Accepted Answer

A)  according to the geographical area 
B)  periodically 
C)  according to humidity 
D)  continuously 
E)  according to seasons

Question 20

In a cross of a DDRR individual with a ddrr individual, the genotype of all offspring will ____.

Accepted Answer

A)  DDRR 
B)  DdRR 
C)  DdRr 
D)  ddRR 
E)  ddRr

Exam 10: Patterns of Inheritance