What types of chromatin remodeling processes have been observed in vitro?
What will be an ideal response?
Ans: There are three changes that have been observed in vitro. First, nucleosomes may slide along the DNA to change the sequence that is exposed. Second, the gap between nucleosomes may be increased or decreased to alter the positions of DNA sequences relative to proteins. Third, the histone octamer may be entirely removed from the DNA to leave a nucleosome-free region.
You might also like to view...
What is a transgenic organism?
What will be an ideal response?
The proper sequence, beginning to end, for the stages of mitosis is
A. prophase-metaphase-anaphase-telophase. B. anaphase-prophase-metaphase-telophase. C. prophase-anaphase-metaphase-telophase. D. telophase-anaphase-metaphase-prophase.
The level of carbon dioxide in the blood is monitored by nerve tissue. If you exercise strenuously, the increase in cellular respiration consumes oxygen from the blood and produces surplus carbon dioxide removed in the blood. Since this physical exertion requires faster breathing to replenish oxygen supplies and carry away carbon dioxide, the carbon dioxide sensors result in signals from the brain to increase breathing rate. After you have rested, and carbon dioxide levels are back to normal, your breathing rate decreases too. This is an example of
A. a positive feedback loop that stimulates a response opposite to the stimulus. B. a response to a sensory impulse that causes a muscle or gland to react. C. the dynamic interplay between events that tend to change the internal environment and events that tend to keep it the same. D. a negative feedback loop that stimulates a response similar to the stimulus. E. the dynamic interplay between events that tend to change the internal environment and events that tend to increase the changes.
Which of the following regulates genes by binding directly to transcription factor proteins?
a. Growth hormone b. Insulin c. Steroid hormones d. Epinephrine