Question 1

If a healthy young couple are both carriers of cystic fibrosis,the chance that their future child will have this serious illness is
A) 0%.
B) 25%.
C) 75%.
D) 50%.
E) 100%.

Accepted Answer

The probability of inheritance of a single gene trait can be calculated using Mendelian principles. A four square Punnett square can be produced to obtain the answer.

Question 2

Genotype means the
A) number of gametes in an individual.
B) combination of alleles in an individual.
C) number of chromosomes in an individual.
D) observable expression of the genes in an individual.
E) genes an individual has.

Accepted Answer

The genotype of an individual is the set of alleles found for any given gene.

Question 3

Mendel called a trait that is masked
A) homozygous.
B) heterozygous.
C) dominant.
D) recessive.
E) No answer is correct.

Accepted Answer

A recessive allele has effects which are masked or covered by the effects of a dominant allele.

Question 4

Phenotype means the
A) number of gametes in an individual.
B) number of chromosomes in an individual.
C) combination of alleles in an individual.
D) genes an individual has.
E) observable expression of the genes in an individual.

Accepted Answer

Phenotype refers to the observable effect of the genotype, e.g. the color of pea flowers.

Question 5

The pea plant (Pisum sativum)is a good choice for studying heredity because it A) develops slowly. B) produces only a few offspring. C) is easy to control which plants mate with each other. D) has only a few traits that appear in two easily distinguishable forms. E) All answers are correct.

Accepted Answer

Because pea plants have flowers which close over on themselves, it is easy to prevent cross-pollination unless an experimenter wants that to happen.

Question 6

Mendel called a masking trait
A) dominant.
B) recessive.
C) homologous.
D) homozygous.
E) heterozygous.

Accepted Answer

A dominant trait is encoded by a dominant allele, whose effects mask those of a recessive allele.

Question 7

When Mendel crossed short (tt)pea plants with short (tt)pea plants the offspring
A) were all tall.
B) were a mix of tall and short.
C) were nonexistent.
D) were all short.
E) No answer is correct.

Accepted Answer

Crosses between two homozygous recessive individuals always result in homozygous recessive offspring.

Question 8

Of all the people who have studied inheritance,the person who made the most lasting impression on the science of genetics is
A) Charles Darwin.
B) Robert Hooke.
C) King George III.
D) Frederick Griffith.
E) Gregor Mendel.

Accepted Answer

Mendel was an Austrian monk who chose to work on pea plants' heredity.

Question 9

An allele that exerts its effects whenever it is present is
A) recessive.
B) dominant.
C) homologous.
D) homozygous.
E) heterozygous.

Accepted Answer

In a classical Mendelian case, dominant alleles are always expressed.

Question 10

When Mendel crossed tall (Tt)plants with tall (Tt)plants the offspring
A) did not grow and reproduce.
B) were always short.
C) were always tall.
D) were always medium height.
E) were mostly tall individuals and a few short individuals.

Accepted Answer

A Mendelian cross between heterozygous individuals will produce about 3/4 dominant and 1/4 recessive phenotypes.

Question 11

The "P" in "P generation" refers to
A) pure breeding.
B) parental.
C) potential offspring.
D) recessive allele.
E) All answers are correct.

Accepted Answer

Parental generations start out experiments.

Question 12

If the two alleles for a particular gene are identical the gene pair is
A) homozygous.
B) homologous.
C) heterozygous.
D) dominant.
E) recessive.

Accepted Answer

Homozygous individuals always have the same allele on both chromosomes.

Question 13

In humans,alleles for a gene locus on autosomes are inherited from
A) females only (mothers).
B) males only (fathers).
C) males and females (one allele from each parent).
D) males and females (two alleles from each parent).
E) No answer is correct.

Accepted Answer

Mother and father each provide an allele for each gene locus on autosomes.

Question 14

In the study of genetics,the offspring of the P generation are referred to as the
A) wild type generation.
B) F1 generation.
C) genotype.
D) F2 generation.
E) phenotype.

Accepted Answer

"F1" means "first filial," first offspring.

Question 15

Recessive alleles seem to vanish in some generations and reappear in later generations because they
A) cannot be expressed in males.
B) are masked by a dominant allele.
C) cannot be expressed in females.
D) cannot be expressed in successive generations.
E) are lost by mutation.

Accepted Answer

When two recessive alleles are found in an individual, the recessive trait is seen. When one dominant allele is present, the recessive trait seems to "disappear.''

Question 16

If an individual is homozygous for a particular trait
A) each parent contributed a different allele for that trait.
B) one parent contributed two different alleles for that trait.
C) each parent contributed the same allele for that trait.
D) one parent contributed two copies of the same allele for that trait.
E) a mutation must have occurred.

Accepted Answer

Homozygosity is the state in which the alleles of a gene on the two copies of a chromosome are the same.

Question 17

If an individual is heterozygous for a particular trait
A) each parent contributed a different allele for that trait.
B) each parent contributed the same allele for that trait.
C) one parent contributed two different alleles for that trait.
D) one parent contributed two copies of the same allele for that trait.
E) a mutation must have occurred.

Accepted Answer

Heterozygosity is the state in which the alleles of a gene on the two copies of a chromosome are different.

Question 18

A portion of DNA that encodes a specific protein is a
A) gene.
B) chromosome.
C) chromatid.
D) centromere.
E) kinetochore.

Accepted Answer

Protein sequence is derived from gene sequence.

Question 19

The most common allele,genotype,or phenotype in a population is referred to as the
A) wild type.
B) dominant population.
C) recessive population.
D) P generation.
E) F1 generation.

Accepted Answer

A wild type most often survives and reproduces best in nature and is the most common phenotype in nature.

Question 20

If the two alleles for a particular gene are different the gene pair is
A) homologous.
B) heterozygous.
C) homozygous.
D) dominant.
E) recessive.

Accepted Answer

Heterozygous individuals have different alleles for a gene on the two copies of the chromosome containing that gene.

Quiz 10: Patterns of Inheritance

If a healthy young couple are both carriers of cystic fibrosis,the chance that their future child will have this serious illness is

Genotype means the

Mendel called a trait that is masked

Phenotype means the

The pea plant (Pisum sativum) is a good choice for studying heredity because it

Mendel called a masking trait

When Mendel crossed short (tt) pea plants with short (tt) pea plants the offspring

Of all the people who have studied inheritance,the person who made the most lasting impression on the science of genetics is

An allele that exerts its effects whenever it is present is

When Mendel crossed tall (Tt) plants with tall (Tt) plants the offspring

The "P" in "P generation" refers to

If the two alleles for a particular gene are identical the gene pair is

In humans,alleles for a gene locus on autosomes are inherited from

In the study of genetics,the offspring of the P generation are referred to as the

Recessive alleles seem to vanish in some generations and reappear in later generations because they

If an individual is homozygous for a particular trait

If an individual is heterozygous for a particular trait

A portion of DNA that encodes a specific protein is a

The most common allele,genotype,or phenotype in a population is referred to as the

If the two alleles for a particular gene are different the gene pair is