Cells planning 1.1

Planning sheet for Introduction to Cells 1.1

Desired Results


  • According to cell theory, all living organisms are composed of cells.
  • Organisms consisting of only one cell carry out all functions of life in that cell.
  • Surface area to volume ratio is important in the limitation of cell size.
  • Multicellular organisms have properties that emerge from the interaction of their cellular components.
  • Specialized tissues can develop by cell differentiation in multicellular organisms.
  • Differentiation involves the expression of some genes and not others in a cell.
  • Stem cells can divide and differentiate along different pathways in embryonic development which makes stem cells useful for therapeutic uses.

Essential Questions

  • Are all living things made of cells?
  • Do cells share the same structure?
  • How does 'differentiation' lead to differences in structure?
  • What are the main processes of life which happen in cells?
  • What sort of new properties appear when many cells live collaboratively in multicellular organisms?
  • What are the special properties of stem cells?
  • How can we use this knowledge of cells, to exploit stem cells for medical treatments?

ToK / NOS / IM

When we use microscopes they extend our natural vision but can be believe what we see?

Ethics and the use of stem cells harvested from embryos, umbilical cords and adults.

How science theories can be supported by evidence and how evidence can be used to falsify them, leading to modifications and improvements in the theory.

How scientists from different countries have shared ideas in the development of theories such as cell theory, and germ theory.

Skills students will have

  • Applying cell theory to striated muscle, giant algae, fungal hyphae.
  • Identifying the characteristics of living things ("functions" - Mr H. Gren) Paramecium and Chlorella.
  • Application: Use of stem cells to treat Stargardt’s disease and one other condition.

    From the Genetics SL topic there is this activity:

    Stargardt disease

  • Application: Ethics of therapeutic use of stem cells from embryo umbilical and adult cells
  • Skill: Using a microscope to investigate cells and tissues,
  • Drawing cells. Calculation of the magnification & size. (Practical 1)
Assessment Evidence


  • Completion of worksheets included in the following tasks will give evidence of understanding.
    • Basic concept of cell theory
    • Cell differentiation
    • Stems cells ethics and use.
  • Practical work
    • Skill of using a microscope
    • Drawing cells and estimating their size
    • SA : Volume ratios and cell size
  • Participation in the debate activities about Stem Cells


  • Calculating size and magnification from microscope images.
Learning Activities - Action (attributes will be added to these descriptions)

Using Microscopy to investigate cell theory

Time: 1h A practical Biology lesson that will illustrate the discovery of cells in the history of Biology and teach students how to use microscopes to measure the cell sizes.

Measuring size in Biology

Time: 0.5h How many µm make a mm? This activity gives students clear examples of biological objects to cover sizes from 1mm to 1nm. Students watch a short video clip, investigate a visual biological data base using a slider and make a display which illustrate the huge range of sizes between tiny fleas and the miniscule molecules.

Cell size calculation activities

Time: 1h Student activities to illustrate the sizes of different cell components and to show students how to calculate cell sizes from electron micrographs. The lesson incorporates an online magnification animation and a downloadable worksheet.

Surface area to volume ratio practical

Time: 1h A practical laboratory in which students can visualise diffusion into blocks of different sizes. This will teach students some essential skills for internal assessment, and illustrate the concept of surface area to volume ratio.

Measuring skills, SI units and Uncertainties in Biology

Time: 1h There are some important new skills to learn in IB Biology when it comes to the simple skill of measuring. Professional biologists and IB students are expected to know how precise their measurements are.

This series of short experiments illustrates SI units and the skills a student needs to achieve high grades in data collection and processing.

Being Multicellular

Time: 1h Using video clips this activity explores differentiation, stem cells and emergent properties and gives students an introduction to the concepts together with concrete examples to use in IB examinations.

Critical thinking about stem cells

Time: 1-2hrs This lesson plan contains a range of ides for activities to encourage students to engage with the ethical issues which surround the use of stem cells and therapeutic cloning. Include Stargardt’s disease.

Reflection - considering the effectiveness of the teaching and learning

What worked well (List the content, assessment, planning that were successful)



What didn't work well (Notes, suggestions, or considerations for the future teaching of this unit)



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