The heritable disorder fragile X syndrome, a major cause of intellectual disability, is caused by

A) production of enzymes that break the phosphate backbone.
B) UV light.
C) X-rays.
D) the presence of an extra X chromosome in the sperm or egg.
E) the expansion of a region of trinucleotide repeats.


E) the expansion of a region of trinucleotide repeats.

Biology & Microbiology

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Respiration is called aerobic because ________.

A. it happens in the absence of oxygen B. it requires oxygen C. it happens in mitochondria D. it requires carbon dioxide

Biology & Microbiology

The majority of cases of human plague in the United States occur in the northeastern states

Indicate whether the statement is true or false.

Biology & Microbiology

The appearance of the chins at #3 is called the

a. dominant allele. b. genotype. c. offspring. d. recessive gene. e. phenotype.

Biology & Microbiology

What is the diagnostic structure produced by Paracoccidioides brasiliensis?

A. spiny spores visible by brightfield microscopy B. "steering wheel" buds visible in stained tissue samples C. spherules observed in tissue samples D. yeast buds that are not dissolved by KOH E. dimorphism when grown in the lab

Biology & Microbiology