1.6: Cell division
Teaching time: 3 hours . Practical time: 2 hours - root tip squash and calculation of a mitotic index (can use several simulations here) Students use the nuffield practical we can also use prepared slides
key vocabulary
prior learning & retrieval practice
Review topic 1.1 intro to cells
Review topic 1.2 ultrastructure of cells
Mitosis
Essential idea: Cell division is essential but must be controlled.
Exercise 1: Watch this video and connect-extend-challenge.
U1: Mitosis is division of the nucleus into two genetically identical daughter nuclei.
Exercise 2: Define mitosis and explain the events that occur at each stage of PMAT
U2: Chromosomes condense by supercoiling during mitosis.
Exercise 3: What are chromosomes? When do they become visible in the nucleus? What is supercoiling and how does it help chromosomes become visible?
Guidance from the syllabus: The sequence of events in the four phases of mitosis should be known. To avoid confusion in terminology, teachers are encouraged to refer to the two parts of a chromosome as sister chromatids, while they are attached to each other by a centromere in the early stages of mitosis. From anaphase onwards, when sister chromatids have separated to form individual structures, they should be referred to as chromosomes.
Cytokinesis
U3: Cytokinesis occurs after mitosis and is different in plant and animal cells.
Exercise 4: Watch this video and explain what cytokinesis is. Then, using a table, compare and contrast cytokinesis in animal and plant cells
S1: Identification of phases of mitosis in cells viewed with a microscope or in a micrograph.
S2: Determination of a mitotic index from a micrograph.
Exercise 5: Work through this online simulation to learn to identify the stages of the mitosis under the microscope. Online root tip squash with University of Arizona
Interphase
U4: Interphase is a very active phase of the cell cycle with many processes occurring in the nucleus and cytoplasm.
Exercise 6: Outline the cell cycle and describe what happens at each phase including the three stages of interphase.
Cyclins
U5: Cyclins are involved in the control of the cell cycle.
Exercise 7: Watch this video (first 7 mins) and outline the role of cyclins in controlling the cell cycle.
Exercise 8: Play the cell cycle game.
NoS: Serendipity and scientific discoveries—the discovery of cyclins was accidental. (1.4).
Exercise 9: Read about Tim Hunt's discovery of cyclins.
Cell Cycle and Cancer
U6: Mutagens, oncogenes and metastasis are involved in the development of primary and secondary tumours.
Exercise 10: Complete this on Online cell cycle and cancer virtual lab from mhhe
A1: The correlation between smoking and incidence of cancers.
Exercise 11: In pairs prepare a 2-3 minute presentation to the class on either:
Primary Tumours
Secondary Tumours
The correlation between smoking and cancer
Keywords: Apoptosis, Tumour, metastasis, mutations, carcinogen, oncogenes, mutagens
