Question: What is the condensed form that DNA exists in to fit into the nucleus? Answer: The condensed form that DNA exists in to fit into the nucleus is chromatin. Question: How does DNA form a nucleosome? Answer: DNA loops twice around a histone octamer to form a nucleosome, also known as “beads on a string. “Question: What is the function of H1 in chromatin structure? Answer: H1 binds to the nucleosome and to “linker DNA,” thereby stabilizing the chromatin fiber. Question: What is the charge of DNA and histones? Answer: DNA has a negative charge from phosphate groups, while histones are large and have positive charge from lysine and arginine. Question: What happens to DNA in mitosis? Answer: In mitosis, DNA condenses to form chromosomes. Question: When does DNA and histone synthesis occur? Answer: DNA and histone synthesis occurs during S phase. Question: Does mitochondria have its own DNA? Answer: Yes, mitochondria have their own DNA, which is circular and does not utilize histones.
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Chromatin Structure: A Question and Answer Review for USMLE Step 1
