Ch. 4 Genes and Genetic Diseases

Question 1

Which of the following bases are single-ringed structures in the DNA molecule?
  Cytosine and thymine
  Cytosine and adenine
  Thymine and guanine
  Guanine and adenine

Answer 1

Cytosine and Thymine

Question 2

Which of the following terms best describes the DNA subunit of one deoxyribose molecule, one phosphate group, and one base?
  Polypeptide
  Double helix
  Nucleotide
  Codon

Answer 2

Nucleotide

Question 3

Which of the following statements regarding codons is TRUE?
There are 80 possible codons.
There are 3 codons that signal the end of a gene.
There are 70 codons that specify amino acids.
Each amino acid has 1 codon.

Answer 3

There are 3 codons that signal the end of a gene

Question 4

Which of the following describes the function of DNA polymerase?
  Synthesizes RNA from the DNA template
  Synthesizes a polypeptide
  Performs base pairing in replication
  Splits DNA molecules

Answer 4

Performs base pairing in replication

Question 5

Which of the following best describes a silent mutation?
A change in the DNA but an amino acid change does not occur
Insertion or deletion of one or more base pairs
Increases the number or frequency of mutations
A mutation that occurs in the absence of an exposure

Answer 5

A change in the DNA but an amino acid change does not occur

Question 6

Which of the following statements is TRUE?
Protein synthesis takes place in the cytoplasm.
DNA is replicated in the cytoplasm.
RNA is double stranded.
RNA contains the same bases as DNA.

Answer 6

Protein synthesis takes place in the cytoplasm

Question 7

Which of the following statements is TRUE regarding base pairs?
  Adenine pairs with guanine.
  Guanine pairs with thymine.
  Cytosine pairs with adenine.
  Uracil pairs with adenine.

Answer 7

Uracil pairs with adenine

Question 8

Which of the following terms describes the sequence for the beginning of a gene?
  Intron
  Exon
  Promoter site
  Anticodon

Answer 8

Promoter site

Question 9

Which of the following statements regarding chromosomes is TRUE?
There are three cell types.
The somatic cells contain 46 chromosomes.
Gametes are diploid cells.
Diploid cells are formed through meiosis.

Answer 9

The somatic cells contain 46 chromosomes

Question 10

Which of the following terms describes a cell that does not contain a multiple of 23 chromosomes?
  Aneuploid
  Monosomy
  Trisomy
  Tetraploidy

Answer 10

Aneuploid

Question 11

Which of the following statements regarding Down syndrome is TRUE?
It occurs in 1 in 8000 live births.
Persons with Down syndrome have a normal IQ.
Persons with Down syndrome have a distinctive facial appearance.
Persons with Down syndrome are tall with good muscle tone.

Answer 11

Persons with Down syndrome have a distinctive facial appearance

Question 12

Which of the following syndromes describes a woman born with short stature, webbing of the neck, sparse body hair, and narrowing of the aorta?
  Klinefelter syndrome
  Down syndrome
  Turner syndrome
  Fetal alcohol syndrome

Answer 12

Turner syndrome

Question 13

A person is born with the deletion of the short arm of the chromosome 5. Which of the following syndromes will this child most likely have?
  Down syndrome
  Turner syndrome
  Fragile X syndrome
  Cri du chat syndrome

Answer 13

Cri du chat syndrome

Question 14

.ID: 37590872
Which term best describes an allele with an observable effect?
  Homozygous
  Heterozygous
  Dominant
  Recessive

Answer 14

Dominant

Question 15

Which of the following statements regarding autosomal dominant gene transmission is TRUE?
The affected parent transmits the gene to half of his or her children.
The affected gene is found in males only.
There is skipping of generations for transmission.
Females will transmit the disease more often than males.

Answer 15

The affected parent transmits the gene to half of his or her children

Question 16

Which of the following is a TRUE statement regarding autosomal recessive inheritance?
Parents will always display the trait.
Approximately 50% of children will display the trait.
Males and females are affected equally.
An individual must be heterozygous to display a recessive trait.

Answer 16

Males and Females are affected equally

Question 17

Which of the following is a TRUE statement regarding sex-linked inheritance?
Most sex-linked traits occur on the Y chromosome.
X-linked recessive diseases are more common than X-linked dominant diseases.
Females are more affected by X-linked diseases.
Females are always homozygous for X-linked traits.

Answer 17

X-linked recessive diseases are more common than X-linked dominant diseases

Question 18

Gene products coded by the X chromosome are present in equal amounts in both males and females because:
X inactivation occurs early in embryonic development.
Males have Barr bodies that provide a second copy of the X chromosome.
Females are hemizygous.
Males have two copies of the X chromosome plus a Y chromosome.

Answer 18

X inactivation occurs early in embryonic development