Which of the following could explain how some (although rare) people can have Down syndrome and have a normal chromosome number?
A. One of the cells during development had
trisomy 21 but then died.
B. A large enough fragment of chromosome
number 21 underwent a duplication event.
C. A large enough fragment of chromosome
number 21 underwent a deletion.
D. Some of the genes in one chromosome
number 21 are mutated.
E. None of the answer options explains this
observation.
B
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One goal of the Human Genome Project was to sequence the ____________________ (number of) chromosomes in the human genome, including all autosomes and the sex chromosomes
Fill in the blank(s) with correct word
A eukaryotic chromosome consists of _____
a. DNA and lipids b. RNA and proteins c. DNA and proteins d. DNA and carbohydrates e. just DNA
The common ancestor that produced the most evolutionary recent derived characters is
A. 12 B. 8 C. 9 D. 6
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.