Topic 5: Mitotic Cell Cycle Flashcards
Definitions I:
(a) Chromosome
(b) Centromere
(c) Telomere
(a) Chromosome: DNA and histones carrying genes. (1 mark)
(b) Centromere: Region joining sister chromatids. (1 mark)
(c) Telomere: End caps protecting chromosome tips. (1 mark)
Describe the structure of a chromosome in a skin cell. [2 Marks]
DNA wrapped around histones forms chromatids (1 mark); Centromere links sisters, telomeres at ends (1 mark). (2 marks)
Explain the importance of mitosis in a growing plant root. [2 Marks]
Mitosis produces identical cells for root growth (1 mark); Replaces damaged cells, ensures uniformity (1 mark). (2 marks)
Outline the mitotic cell cycle in a human stem cell. [3 Marks]
Interphase: G1 growth, S replication, G2 prep (1 mark); Mitosis: Nuclear division (1 mark); Cytokinesis: Cell splits (1 mark). (3 marks)
State the role of telomeres during DNA replication in a liver cell. [1 Mark]
Telomeres prevent gene loss at chromosome ends. (1 mark)
Outline the role of stem cells in repairing a damaged muscle. [2 Marks]
Stem cells divide by mitosis (1 mark); Differentiate to repair muscle tissue (1 mark). (2 marks)
Explain how uncontrolled cell division forms a tumour in the lung. [2 Marks]
Uncontrolled mitosis forms excess cells (1 mark); Accumulates into a tumour mass (1 mark). (2 marks)
In a root tip, describe chromosome behaviour during prophase of mitosis. [2 Marks]
Chromosomes condense, nuclear envelope breaks (1 mark); Spindle forms, attaches to centromeres (1 mark). (2 marks)
In an animal cell, outline chromosome movement in metaphase and anaphase. [2 Marks]
Metaphase: Chromosomes align at equator (1 mark); Anaphase: Sisters split, move to poles (1 mark). (2 marks)
Describe the role of the spindle and cell membrane in telophase of a plant cell. [2 Marks]
Spindle pulls chromosomes apart (1 mark); Membrane reforms, cytokinesis begins (1 mark). (2 marks)
Interpret a photomicrograph of an onion cell in mitosis and identify the stage. [2 Marks]
Condensed chromosomes aligned = metaphase (1 mark); Scattered or pulled apart = other stages (1 mark). (2 marks)
In a white blood cell, explain chromosome behaviour across all mitotic stages. [4 Marks]
Prophase: Condense, envelope breaks (1 mark); Metaphase: Align (1 mark); Anaphase: Separate (1 mark); Telophase: Re-form nuclei (1 mark). (4 marks)
Analyse the role of mitosis in asexual reproduction of yeast. [3 Marks]
Mitosis duplicates yeast cells (1 mark); Ensures genetic identity (1 mark); Enables budding reproduction (1 mark). (3 marks)
Compare chromosome behaviour in plant and animal cells during mitosis. [4 Marks]
Plant: Wall forms in telophase (1 mark); Animal: Membrane pinches (1 mark); Both: Chromosomes condense, split (1 mark); Spindle acts (1 mark). (4 marks)
