In the 1940s, proteins were thought to be the more likely molecules to house genetic information. What was the primary reason that DNA was not originally believed to be the genetic material?
(a) DNA has a high density of negative charges.
(b) Nucleotides were known to be a source of chemical energy for the cell.
(c) Both protein and nucleic acids were found to be components of chromosomes.
(d) DNA was found to contain only four different chemical building blocks.
(d)
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The AP-1 transcription factor is a heterodimer of the Fos and Jun proteins. What is the protein-dimerization motif present in these two proteins?
A. basic leucine zipper B. helix-turn-helix C. zinc finger D. homeodomain
Patients with McArdle's Disease lack an enzyme in their livers that catabolizes glycogen. These individuals tire easily during exercise. Which of the following would best explain this symptom?
A. Glycogen is produced from glucose in the blood and then stored in the liver. B. Glycogen synthesis increases the energy available to cells during exercise. C. Glycogen is released from the liver into the blood by the enzyme. D. Glycogen must be broken down to glucose to be used in metabolism.
Piedraia hortae causes ________.
A. black piedra B. white piedra C. tinea versicolor D. All of the choices are correct.
When chemoreceptors detect a slight decrease in pH, this means that ____ concentrations have increased, and the
breathing rate must ____. a. carbon dioxide; increase b. carbon dioxide; decrease c. oxygen; increase d. oxygen; decrease e. chloride; decrease