Nucleus - Structure and Function - UNSOLVED PRACTICE SET
Chapter: The Fundamental Unit of Life | Topic: Nucleus Structure and Function
NUCLEUS - STRUCTURE AND FUNCTION - UNSOLVED PRACTICE SET
Topic: Nucleus Structure and Function
Multiple Choice Questions
Q1. The nucleus is surrounded by a double membrane called:
- Plasma membrane
- Nuclear envelope
- Cell wall
- Nuclear matrix
Q2. The small openings in the nuclear envelope that allow movement of molecules between nucleus and cytoplasm are called:
- Centrioles
- Ribosomes
- Nuclear pores
- Chromosomes
Q3. The dark-staining body within the nucleus that is involved in ribosome synthesis is:
- Chromatin
- Nucleolus
- Nuclear envelope
- Nuclear lamina
Q4. During cell division, chromatin condenses to form:
- Nucleolus
- Nuclear pores
- Chromosomes
- Nuclear envelope
Q5. Which of the following is NOT a component of the nucleus?
- Nuclear envelope
- Nucleolus
- Mitochondria
- Chromatin
Short Answer Questions
Q6. Describe the structure of the nuclear envelope. What is its function?
Q7. What is chromatin? Differentiate between euchromatin and heterochromatin.
Q8. Explain the function of the nucleolus. What would happen to a cell if its nucleolus were destroyed?
Q9. Why is the nucleus called the "control center" of the cell? Give TWO reasons.
Long Answer Questions
Q10. Draw a well-labelled diagram of the nucleus showing the nuclear envelope, nuclear pores, nucleolus, chromatin, and nuclear matrix. Explain the function of each labelled part.
Q11. Describe the structure and functions of chromosomes. How do chromosomes differ from chromatin in terms of structure and visibility?
APPLICATION / ANALYSIS
Q12. In a biology experiment, a researcher removes the nucleus from a frog's egg cell (enucleation) and replaces it with the nucleus from a skin cell of another frog.
(a) What would happen to the egg cell after this procedure? Explain your answer.
(b) This experiment is similar to the technique used to create Dolly the sheep. What does this tell us about the role of the nucleus in determining cell fate?
(c) Why do you think the egg cell's own cytoplasm is necessary for the development of the embryo, even though the nucleus comes from a different cell?
Q13. A patient is diagnosed with progeria, a rare genetic disorder characterised by rapid ageing. Scientists have found that progeria is caused by a defect in a protein called lamin A, which forms part of the nuclear lamina.
(a) What is the nuclear lamina, and where is it located?
(b) How might a defect in the nuclear lamina lead to the symptoms of rapid ageing?
(c) Why do you think defects in nuclear structure can have such severe effects on the entire organism?