DNA Packaging - Nucleosome and Chromatin - Unsolved Practice Set
Chapter: Molecular Basis of Inheritance | Topic: DNA Packaging Nucleosome Chromatin
DNA PACKAGING - NUCLEOSOME AND CHROMATIN - UNSOLVED PRACTICE SET
Topic: DNA Packaging Nucleosome Chromatin
Multiple Choice Questions
Q1. DNA packaging in eukaryotic cells is primarily achieved with the help of:
- Ribosomal RNA
- Histone proteins
- Enzymes like DNase
- Cell membrane proteins
Q2. A nucleosome consists of DNA wrapped around a core of:
- Four histone molecules
- Eight histone molecules (histone octamer)
- Two histone molecules
- No histones at all
Q3. The structure of chromatin, when viewed under an electron microscope, is often described as resembling:
- A single straight rod
- Beads on a string
- A hollow sphere
- A branched tree
Q4. The loosely packed, transcriptionally more active form of chromatin is called:
- Heterochromatin
- Euchromatin
- Nucleosome
- Histone core
Q5. The darkly stained, more densely packed, and transcriptionally less active form of chromatin is called:
- Euchromatin
- Heterochromatin
- Histone
- Nucleoplasm
Short Answer Questions
Q6. Why is DNA packaging necessary in eukaryotic cells, given the length of DNA compared to the size of the nucleus?
Q7. What is a nucleosome? Briefly describe its basic structure.
Q8. Differentiate between euchromatin and heterochromatin.
Q9. Name the core histone proteins that make up the nucleosome.
Long Answer Questions
Q10. Describe, step by step, how DNA is packaged into chromatin and eventually into a fully condensed chromosome in eukaryotic cells.
Q11. Explain the significance of the "beads on a string" structure of chromatin and how it relates to the overall organisation of the genome.
APPLICATION / ANALYSIS
Q12. If a human cell's total DNA, when stretched out, would measure roughly 2 metres in length, but the nucleus is only a few micrometres in diameter, explain, using your understanding of DNA packaging, how such a large molecule fits inside such a tiny space.
Q13. A geneticist examining a stained chromosome under a microscope notices two distinctly different regions - one darkly stained and compact, another lighter and looser. Identify which regions likely correspond to heterochromatin and euchromatin, and explain the functional difference between them.