Concept-Based Units or Lessons

The examples below outline two areas where concepts could be used to create a unit or a series of lessons.

Example 1: Form and Function - Compartmentalisation

Utilising B2.2, Compartmentalisation in cells is a good starting point for a conceptual sequence of lesions. Compartmentalisation is a concept that falls under the larger concept of Form and Function. A teacher could start with an overview of the cell and the various organelles. The concept of compartmentalisation could then be introduced by encouraging students to find different compartments in the cell, such as the Golgi apparatus, endoplasmic reticulum, and the nucleus. The teacher could then ask how compartmentalisation might be used and guide the students towards the importance of separating different processes, allowing them to occur independently and efficiently.

The teacher could then explore specific examples of compartmentalisation within the cell, such as the role of the nucleus in storing genetic information and regulating gene expression, the role of the mitochondria in producing energy through cellular respiration, or the role of the endoplasmic reticulum in protein synthesis and transport.

If cell respiration and photosynthesis have been covered, then this is an excellent opportunity to explore how the concepts outlined above can be applied to the chloroplast and the mitochondria. As an example, students could be given pictures of each and asked to describe the compartments that are present and the function of those compartments. This can be an excellent way to link the concept of compartmentalisation with the structure and function of chloroplasts and mitochondria. If cell respiration and photosynthesis have not been taught, this would be an excellent opportunity to link them.

Throughout the teaching process, the teacher could provide opportunities for students to apply their understanding of compartmentalisation. For example, the teacher could present a scenario where a particular cellular process is disrupted due to a malfunction in one of the organelles. Students could then be asked to identify which organelle is involved and explain how its dysfunction affects other cellular processes.

The teacher could also explore how disruptions in compartmentalisation can lead to various diseases and disorders. For example, disruptions in lysosomal compartmentalisation can lead to lysosomal storage disorders, and similarly, disruptions in mitochondrial compartmentalisation can lead to various mitochondrial diseases. The formation of many of these compartments, especially the chloroplast and mitochondria, can be explained through the endosymbiotic hypothesis.

Example 2: Form and Function - Gas Exchange in Plants and Animals

This example starts with the big idea of Form and Function and that organisms have evolved ways to maximise gas exchange. Gas exchange is the process by which oxygen is taken in, and carbon dioxide is released. Emphasise that this process is critical for cellular respiration, photosynthesis, and the overall metabolic function of plants and animals.

It is helpful to use analogies and visuals to make connections. For example, you can use the analogy of a sponge to explain how plants take in gases. Just as a sponge absorbs water, a plant absorbs gases through its stomata. Similarly for lungs, you could create models of lungs using balloons, a two-litre bottle and straws. Students could compare the effectiveness of each model and the limitations of each, which helps incorporate 'Nature of Science’, another big concept in the IBDP sciences. You could then introduce the structure of a leaf, including stomata, and compare this to the structure of the lungs. Students could examine both structures, identify the similarities and differences, and discuss why the differences might exist.

Students are required to determine stomata densities and measure breathing rates in humans. This is an excellent chance to connect the two concepts to real-life examples. For example, students could explore how pollution, or some other factor, affects the number and distribution of stomata in plants. Students could also look at the effects of exercise on breathing rate or, for more of a challenge, the impact of training on lung capacity. These activities also provide a good opportunity to develop data literacy and scientific writing skills in preparation for the Internal Assessment.