Which purine base forms 3 hydrogen bonds when binding its complementary nucleotide base?
A. guanine
B. cytosine
C. thymine
D. uracil
E. adenine
A. guanine
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Fertilization takes place in the ____________________, and the embryo grows and develops in the ____________________
Fill in the blank(s) with correct word
Shitake mushrooms are decomposers that break down biological molecules from dead organisms. These organisms
belong to the ____ kingdom.
a. Protist b. Animalia c. Bacteria d. Fungi e. Plantae
Many children born with ornithine transcarbamylase deficiency (OTC) die within seventy-two hours of birth. Jesse Gelsinger was not diagnosed with OTC until he was two because ________ and therefore his symptoms were milder.
A) his defective gene was autosomal recessive B) he was a mosaic C) of X-inactivation in males D) of parental imprinting
Mutations in the gene for troponin can result in the production of the troponin protein, which has varying affinities for Ca2+ ions. Suppose that in a muscle cell a mutant troponin is expressed that has such a high affinity for Ca2+ ions that once they
bind to troponin they cannot unbind. What will likely happen in this muscle cell? A) Myosin heads will not bind to actin after action potentials stop being received. B) Myosin heads will bind to actin after action potentials stop being received. C) Tropomyosin will not move to expose myosin binding sites. D) Cross-bridges will form between myosin and tropomyosin.