The Association for Science Education

K2.1 Cells and Cell Functions

Abstract

The emphasis of this article is on the conceptual changes needed by learners (tutors, teachers and their pupils) to come to an understanding of living things. This covers the material useful at KS1-4 and provides access to the key ideas of the topic and provides suggestions for appropriate practical experiences to support learning.

This is one of 17articles whose main aim is to support the processes of teaching/learning between the science education tutor and the trainee science teachers with a focus on “teachers’ knowledge and understanding”. During a primary or secondary BEd, PGCE or GTP we hope that those learning to become science teachers will be able to challenge their own understanding of science and scientific concepts. Unit K0 specifically explores general issues relating to all the knowledge units - to the learning of science.

Standards: This unit specifically addresses Q14 but, appropriately used can contribute to and provide evidence of competence for many others of the standards especially Q4,6,7,8,18, 22 and 25.

Key words: Cells, Living things, Interdependence, Environment.

Contents

1.0 Introduction
2.0 The conceptual barriers to understanding
3.0 Progression in children's ideas
4.0 Giving Practical experiences
5.0 Useful References

1.0 Introduction

A few primary teachers will have completed some post 16 study or even have a degree in biology, and about half of the secondary science teachers will have a degree with some biology content. However that means that a substantial number of trainee teachers of both primary and secondary phases will have an understanding of Biology equivalent only to a grade C at GCSE. The aim of these five ‘biology’ units is to provide support for these trainees (via their tutors) so that they can either teach to GCSE level, or acquire an understanding at that level so they have the confidence to teach at primary school. The emphasis is on the conceptual changes needed by learners (tutors, teachers and their pupils) to come to an understanding of living things.

Primarily younger children need to interact with science at the level of their senses, which provide concrete experiences to support scientific understanding of the world. This is the basis of all KS1 science activity. However, at KS2 it is appropriate to introduce them to macroscopic perspectives of the universe through the topic ‘Earth and Space’, whilst they will be also interested in microscopic perspectives through early introduction to use of microscopes (note that younger KS1 children will also be fascinated to look into the world of the very small through informal introduction to microscopes by looking at everyday objects). This introduces them to the concept that the universe is far greater than their senses perceive and that instruments such as microscopes and telescopes can extend our senses to show us features of the universe that we couldn’t know about without them. These ideas are refined and developed through KS3 and 4, where perspectives of scale can be developed further, and within this context, investigations of cells and cell functions provide an important perspective to understanding how whole organisms function.

The National Curriculum Programmes for Study for Sc2 ‘Life Processes and Living Things’ refer to cells and cell functions at KS3 and 4, while KS1 and 2 refers to life processes of living things. This acknowledges that younger primary children need to develop understanding of the features and properties of living things, whilst microscopic features of life processes are most appropriate for secondary pupils.

Download K2.1_1.0a 'National Curriculum Programmes for Study for Sc2 Life Processes and Living Things, section 1'
For the full document see http://www.nc.uk.net/webdav/

2.0 The conceptual barriers to understanding

All topics in science are intrinsically fascinating, and can lead us into understanding features of the universe that may not be accessible through immediate sensory experience; within this particular topic this leads us into an appreciation of the awesome beauty, intricate elegance and interdependence of life through detailed microstructure of living things and life processes. However, it is most important that we match pupils’ levels of thinking and experience with the concepts of science in a way that engages and interests them. These ideas may be fascinating, but they can be taught in a way that makes them very uninteresting and seemingly irrelevant. We need to hold at the forefront of our minds that as children mature and become adults their capacity to deal with abstract ideas and features that are not immediately accessible to direct sense experience increases, hence we need to find ways of making ideas accessible at all levels.

At KS1 direct experiences and observations are most relevant to introduce children to ideas of life processes, and at KS2 these can be developed more systematically through the mnemonic MRS GREN as a particularly useful way into investigating how organisms are adapted to environments (Movement, Respiration, Sensitivity to environment, Growth, Reproduction, Excretion and Nutrition). The topic of cells and cell functions is most applicable to KS3 and 4, though it is useful at KS2 to introduce the concept of living things being made of cells and how the properties of living things are fulfilled by cells in the context of organs and organ systems. At all stages we need to help pupils make connections between the features and properties of living things and how cells function to their own observations of animals, plants and themselves. We need to help pupils make connections between the ideas about how cells work to provide insight about their own bodies and to inform health and lifestyle choices. Also, this topic shows how all living things share similar processes, which provides insight into evolutionary relationships and the idea of ‘the family of life’. This sense of interconnectedness with other living organisms may foster a sense of empathy, which is essential to environmental education and environmental action to conserve the environment, which must be a primary focus for education in a world that is suffering increasing environmental damage.

There are many practical activities that link the concepts to observations of living things. In every case, the ideas need to be linked closely to observations and applied to a wide range of living things so that the concepts make sense. The ideas of science are powerful when they nest in hierarchies and the big ideas at the highest level are the most useful. The problem is that detailed information is often needed to understand the big ideas and it is all too easy to get lost in the detail and miss out on the connections. The challenge for science educators is to introduce learners to the big ideas through appropriate detail without ‘obscuring the forest through too close attention to the trees’. Many students will have negative experiences of science through uninspired or uninformed teaching and have failed to see the significance of scientific ideas. Primarily, we need to encourage a sense of significance in teaching science for appreciation of the beauty, deep interdependence of all living things and elegance in life processes. The details of cell functions nest into this perspective and, if the big ideas are communicated well, this should provide a motivation for learners to be interested in and investigate a topic that gives us insight into the very nature of life through understanding its processes.

3.0 Progression in children's ideas

A significant aspect of the big picture for the topic on cells and cells function lies within developing a sense of place and scale. KS1 children will find it difficult to appreciate micro and macro perspectives, but can be introduced to concepts of very small through topics such as ‘minibeasts’ where they can look at small invertebrates through hand lenses or stereo microscopes to show details that are not obvious to the naked eye. They will also be fascinated to look at everyday objects under a microscope to see more details that not visible to normal vision. Similarly, KS2 children will be fascinated to look at a range of objects through microscopes, including cells, so that they can start to appreciate that organisms are built of these tiny structures and that they can take on many forms and functions. (A sense of scale and place in the universe can be promoted by children drawing examples of cells, in an organ, within a person, in a house, in a street, in a town, in a county, in a continent, on planet Earth, in the Solar System, in the Milky Way Galaxy, in the Universe (showing many galaxies). This approach makes a very effective classroom display, which can be complemented by a time line running around the room of events since the formation of the Earth showing how the Earth and living things have changed in time.)

At KS1 and 2 the main focus of section one of SC2 of the National Curriculum is to develop understanding of living and non-living things and to understand the common properties of living things. At KS3 and 4 the focus of this section is the topic of cells and their functions. It is important for students to appreciate this perspective of scale and sense of place, and many teachers miss this aspect when addressing topics about the micro (as cells, made up of chemicals built from atoms) and the macro (as Earth in Space), failing to recognise this as part of a continuum of science that embraces all aspects of the universe. A good way to emphasise this for students is to show that living things are organised into a number of levels which interact with each other. Branches of science are related to one or a number of these levels. Students can be invited to link branches of science with appropriate levels of biological organisation.

Download K2.1_3.0a 'Levels of organisation and associated branches of science'
Download K2.1_3.0b 'Key ideas within the topic'

Download 3.0b introduces approaches to key ideas within the topic including

  • All living things are made of cells
  • Plant and animal cells
  • Cell structure and function
  • Chemicals of cells
  • Movement of materials in and out of cells
  • Growth and respiration
  • Photosynthesis
  • Cell division and reproduction

4. Giving Practical experiences

Download 4 provides examples of practical activities to develop the main ideas associated with cells and cell functions
Download K2.1_4.0a 'Examples of practical activities'

5. Useful References

Section Developed by: Michael Littledyke, University of Gloucestershire

Published: 23 Aug 2006, Last Updated: 12 Sep 2008