51) Which of the following a major hormonal event at : 1200427.
51) Which of the following is a major hormonal event at the onset of puberty?
A) The hypothalamus decreases its production of GnRH.
B) Circulating levels of FSH decrease rapidly.
C) Ovarian cells become less sensitive to FSH.
D) Testicular cells become less sensitive to LH and FSH.
E) The anterior lobe of the pituitary gland becomes more sensitive to GnRH.
52) Paired chromosomes are called
A) homologous chromosomes.
B) autosomal chromosomes.
C) homozygous chromosomes.
D) heterozygous chromosomes.
E) alleles.
53) In humans, the 22 pairs of chromosomes, which contain most of the genes that affect somatic characteristics such as hair color and skin pigmentation, are called
A) alleles.
B) heterozygous chromosomes.
C) homologous chromosomes.
D) autosomal chromosomes.
E) homozygous chromosomes.
54) If an individual carries a pair of alleles that are the same on both chromosomes, he or she is ________ for the trait.
A) homologous
B) homozygous
C) heterozygous
D) autosomal
E) polygenic
55) If an individual carries two different alleles of the same gene, he or she is ________ for the trait determined by that gene.
A) homologous
B) homozygous
C) heterozygous
D) autosomal
E) polygenic
56) Hemophilia is a(n) ________.
A) example of dominance
B) example of codominance
C) polygenic trait
D) recessive trait
E) sex-linked trait
57) An allele that is ________ will be expressed only if it is present on both chromosomes of a homologous pair.
A) dominant
B) recessive
C) incomplete
D) phenotypic
E) autosomal
58) Polygenic traits include
A) eye color and hair colors other than pure blond or red.
B) albinism and brachydactyly.
C) inability to roll the tongue into a U-shape.
D) curly hair and eye color.
E) blood Rh factor and color blindness.
59) A relatively common inherited autosomal recessive disorder is ________.
A) Duchenne muscular dystrophy
B) cystic fibrosis
C) Huntington’s disease
D) hemophilia
E) Marfan’s syndrome
60) Ova carry
A) one X sex chromosome.
B) XX sex chromosomes.
C) YY sex chromosomes
D) XO sex chromosomes.
E) one Y sex chromosome.
51) Which of the following a major hormonal event at : 1200427
