Chapter B2. La genetica dopo Mendel #108784 - Prove ed esercizi Zanichelli

Genes

Traits that are determined by a single gene

A:

occur in single-celled organisms, but not in humans.

B:

are common in humans.

C:

include eye color and skin color.

D:

can have only two alleles.

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Genes

The impact of a single gene on more than one characteristic is called

A:

incomplete dominance.

B:

balanced polymorphism.

C:

pleiotropy.

D:

codominance.

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Genetic sex

The genetic sex of humans is determined by

A:

ploidy, with the male being haploid.

B:

the Y chromosome.

C:

X and Y chromosomes, the male being XX.

D:

the number of X chromosomes, the male being XO.

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Phenotypes

A man of blood group AB and a woman of blood group A, whose father was type 0, have children: what phenotypes could they be?

A:

A only

B:

A, AB, B, and 0

C:

AB only

D:

A, AB, and B

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Genes

Linked genes

A:

have alleles that assort independently of one another.

B:

never show crossing over.

C:

are on the same chromosome.

D:

always have multiple alleles.

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Anemia

An anemic person has a number of problems, including lack of energy, fatigue, rapid pulse, pounding heart, and swollen ankles. This could be an example of

A:

pleiotropy.

B:

sex-linked inheritance.

C:

polygenic inheritance.

D:

codominance.

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The law of segregation

The law of segregation states that

A:

the transmission of genetic diseases within families is always recessive.

B:

gametes cannot be separate and equal.

C:

the number of chromosomes in a cell is always divisible by 2.

D:

each of two alleles for a given trait segregates into different gametes.

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Epistasis

In epistasis

A:

the phenotype does not change from generation to generation.

B:

one gene affects the expression of another.

C:

a portion of a chromosome is deleted.

D:

the behaviour of two genes is entirely independent.

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Genes and traits

Thousands (or even tens of thousands) of different traits make up an individual. For this reason

A:

in a species with 23 different chromosomes, some traits must be coded for by genes on the same chromosome.

B:

the environment must influence more than half of our traits.

C:

all (or nearly all) genes must be pleiotropic.

D:

knowing an individual's phenotype is not sufficient for determining the person's genotype.

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X-linked dominant conditions

Which of the following statements about an X-linked dominant condition in humans is incorrect?

A:

The son of a woman with this desease has just slightly more than a 50% chance of having this condition.

B:

The daughter of a man with this condition has a 100% chance of having this condition.

C:

The son of a woman with this disorder has a 100% chance of having this condition.

D:

Males with this condition almost always have a more severe phenotype, because women usually have at least one normal allele that dilutes the effect of the mutated allele.

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