Question 1: Define mitosis and describe its role in cell division.

Answer: Mitosis is a type of cell division where a single parent cell divides to form two genetically identical daughter cells, primarily for growth, repair, and asexual reproduction.

Question 2: List the main stages of mitosis in the correct order.

Answer: Prophase, Metaphase, Anaphase, Telophase

Question 3: Explain the importance of spindle fibres during mitosis.

Answer: Spindle fibres attach to chromosomes at the centromeres and help separate sister chromatids during anaphase, ensuring accurate chromosome distribution.

Question 1: A cell takes 24 minutes to complete mitosis. How many cells would complete mitosis in 72 minutes if they all start dividing at the same time?

Answer: 3 cells

Question 2: Using the formula: Number of cells after n cycles = 2^n, how many cells result after 4 cycles of mitosis starting from one cell?

Answer: 16 cells

Question 1: Describe a basic experiment to observe mitosis in onion root tips, including the purpose and safety precautions.

Answer: The experiment involves preparing thin slices of onion root tips, staining them with a dye like acetic orcein, and observing under a microscope to identify stages of mitosis. Safety precautions include wearing gloves and eye protection to handle chemicals, and disposing of waste properly.

Question 1: A sample of 100 cells was examined during mitosis. The following data was recorded: 85 cells in interphase, 10 in prophase, 3 in metaphase, 1 in anaphase, and 1 in telophase. Calculate the approximate percentage of cells in each stage and interpret what this indicates about the duration of each stage.

Answer: Interphase: 85%; Prophase: 10%; Metaphase: 3%; Anaphase: 1%; Telophase: 1%. The high percentage in interphase suggests it is the longest stage, while the very low percentages in later stages indicate they are shorter in duration.

Question 1: Explain how the regulation of mitosis is important for preventing cancer.

Answer: Proper regulation ensures that cells only divide when necessary, preventing uncontrolled growth. Disruption of regulatory mechanisms can lead to uncontrolled cell division, forming tumours and contributing to cancer development.

Question 2: Which phase of mitosis ensures that each daughter cell receives an identical set of chromosomes?

Answer: Metaphase

Question 1: Discuss how understanding mitosis can aid in cancer treatment development.

Answer: Understanding the stages and regulation of mitosis helps scientists develop drugs that can specifically target dividing cancer cells, such as mitotic inhibitors, to prevent tumour growth while sparing normal cells.