Question 1

In a genetic cross of Gg with Gg guinea pigs,none of the four offspring were gg.This outcome

Accepted Answer

A)  disproves Mendel's law of independent assortment. 
B)  neither supports nor disproves Mendel's law of independent assortment. 
C)  supports Mendel's law of independent assortment. 
D)  supports Mendel's law of segregation.

Question 2

The following figure shows three generations in one of Mendel's experiments.According to the data in this figure,Mendel's F₂ generation contains many more purple flowers than white flowers.Which of the following is the best explanation of this observation?

Accepted Answer

A)  Three-quarters of the offspring must receive the white allele. 
B)  The chance of an individual offspring receiving a white allele is only 25 percent. 
C)  The probability of any individual offspring receiving at least one copy of the purple allele is 75 percent. 
D)  The white allele is only dominant in about 25 percent of the offspring that inherit it.

Question 3

Many genes contain instructions for building

Accepted Answer

A)  carbohydrates. 
B)  steroids. 
C)  proteins. 
D)  lipids.

Question 4

A pigment in mammals that is responsible for yellow to red hair color is

Accepted Answer

A)  eumelanin. 
B)  pheomelanin. 
C)  tyrosine. 
D)  albinin.

Question 5

Most human genetic traits are

Accepted Answer

A)  controlled by one gene. 
B)  not inherited according to Mendel's laws. 
C)  controlled by more than one gene. 
D)  not heritable.

Question 6

The individuals Mendel observed in the F₁ generations were always

Accepted Answer

A)  homozygous recessive. 
B)  homozygous dominant. 
C)  heterozygous. 
D)  codominant.

Question 7

When a ________ variety of a plant is self-fertilized,all of its offspring have the same phenotype as the parent.

Accepted Answer

The answer of When a ________ variety of a plant...

Question 8

The first generation of phenotypes resulting from a genetic cross between two members of the parental generation would be seen in the ________ generation.

Accepted Answer

The answer of The first generation of phenotypes resulting from...

Question 9

Siamese cats have dark fur on their extremities (paws,nose,ears,and the tail),while the rest of their bodies are covered with lighter hair,despite the fact that only one gene controls their coat color.Why does the coat color differ at different places on a Siamese cat's body?

Accepted Answer

A)  Melanin can be produced in the extremities because they are colder than the rest of the body. 
B)  Melanin can be produced in the extremities because they are warmer than the rest of the body. 
C)  Tyrosinase, which is needed for pigment formation, does not function in the colder extremities. 
D)  Tyrosinase, which is needed for pigment formation, does not function in the warmer extremities.

Question 10

If the D allele is completely dominant over the d allele,what percentage of the offspring will have the dominant phenotype when two heterozygous individuals mate?

Accepted Answer

A)  25 percent 
B)  50 percent 
C)  75 percent 
D)  100 percent

Question 11

An individual with the genotype Aa mates with an individual with the genotype AA.Which of the following is true?

Accepted Answer

A)  These two individuals will have four offspring. 
B)  Half of the offspring will be Aa. 
C)  Twenty-five percent of the offspring will be aa. 
D)  Seventy-five percent of the offspring will be AA.

Question 12

Two genes control fur color in Labrador retrievers.The first gene determines whether the pigment to be deposited in the hair will be black or brown.The second gene determines whether the pigments are put into the dog's hair at all.A dog homozygous for the recessive allele of this second gene will be yellow because no pigment is deposited in its fur.This is an example of

Accepted Answer

A)  epistasis. 
B)  pleiotrophy. 
C)  codominance. 
D)  incomplete dominance.

Question 13

Polygenic inheritance combined with environmental influence typically produces a wide range of phenotypic classes that grade smoothly from one to the next.This type of pattern is known as

Accepted Answer

A)  punctilious variation. 
B)  punctuationism. 
C)  continuous variation. 
D)  epistasis.

Question 14

The first reaction in the chain of enzyme-catalyzed chemical reactions that convert the amino acid tyrosine into eumelanin or pheomelanin is orchestrated by an enzyme encoded by the C gene.Homozygotes for the recessive allele of this gene (cc)exhibit the ________ phenotype.

Accepted Answer

The answer of The first reaction in the chain of...

Question 15

The best way to get accurate results from a probability exercise is to

Accepted Answer

A)  choose an example with incomplete dominance. 
B)  know the answer in advance. 
C)  choose an example that will come out fifty-fifty. 
D)  make a large number of observations.

Question 16

Humans have many genes that contribute to the unique array of proteins found on their red blood cells.Your MN blood type (the letters indicate the presence of M and N proteins on the red blood cells)is determined by the codominant alleles Lᴹ and Lᴺ.Which of the following genotypes could NOT be produced when a man with MN blood and a woman with MN blood mate?

Accepted Answer

A)  LMLM 
B)  LMLN 
C)  LNLN 
D)  LMNLM

Question 17

If the influence of two alleles is fully displayed in the heterozygote without being diminished by the presence of the other allele or being suppressed by a dominant allele,the two alleles are said to be ________.

Accepted Answer

The answer of If the influence of two alleles is...

Question 18

The leaf color of a certain plant is controlled by one gene.For that gene,the allele G = orange and g = green.You have a plant with orange leaves,but do not know whether that plant's genotype is GG or Gg.Which of the following would help you determine the plant's genotype?

Accepted Answer

A)  Cross the plant to another plant with orange leaves. 
B)  Cross the plant to a plant with green leaves. 
C)  Cross two true-breeding, orange-leaved plants to each other and then cross one of their offspring to the plant with the unknown genotype. 
D)  Change the environment in which the plant grows to find the conditions that cause the leaves to produce the orange color.

Question 19

Suppose D were dominant and d were recessive,and you could label the D allele in the P generation with a radioactive substance that could be inherited over several generations.You create hybrids by mating your radioactive DD individuals to dd individuals.Finally,you cross two Dd individuals.In 1,000 offspring,how many do you predict would be radioactive?

Accepted Answer

A)  250 
B)  500 
C)  750 
D)  1,000

Question 20

The genetic makeup of an organism,such as Gg,is its ________.

Accepted Answer

The answer of The genetic makeup of an organism,such as...

Exam 9: Patterns of Inheritance