Topic 2
Cell structure and organisation
Coursebook section 2.1 Teaching ideas ◆
Ascertain how familiar students are with the structure of animal and plant cells. If they already have good knowledge of them you may be able to move quickly through this topic. ◆ Project a large image of some cells onto a screen. Ask students what they are. Ask them to try to identify the different parts. Ask them how big they think cells really are. Tell them that a large cell may be about 0.1 mm long, and ask them to look at a ruler and imagine 10 cells side by side between two of the millimetre marks. ◆ Revise the concept of magnification. Coursebook questions 2.3 to 2.5 could be done as a class discussion, or as group work. ◆ Students could make model cells, using a plastic bag (cell membrane), water or jelly (cytoplasm) and a small rubber ball (nucleus). Put the whole thing inside a cardboard box to represent the cell wall of a plant cell. Challenge students to suggest how they could add chloroplasts and vacuole to the plant cell model. ◆ Discuss and explain the structure of animal cells. Students could carry out Activity 2.2 Looking at animal cells. They could exchange their drawings with one another, and mark them using the self-assessment check list for drawing (on the student CD-ROM). Discuss any difficulties that students had with this activity, and how they solved them. ◆ Use a similar approach to deal with the structure of plant cells. You could perhaps begin by drawing a rectangle on the board, and asking pupils to come to the front and complete the diagram to show the structures in a plant cell. Activity 2.3 Looking at plant cells, could be carried out. (You will need to demonstrate how to obtain and mount the piece of onion epidermis.) ◆ Students should now have enough information to be able to construct their own comparison of features found in animal cells and plant cells. This could possibly be done as a class or group activity. ◆ Coursebook questions 2.6 to 2.19 can now be answered. Common misunderstandings and misconceptions ◆
Students frequently confuse cell membrane and cell wall.
Homework ideas ◆ ◆ ◆ ◆ ◆
Worksheet 2.2 Cell structure Worksheet 2.3 Magnification calculations Workbook exercise 2.1 Animal and plant cells Workbook exercise 2.2 Drawing cells and calculating magnification Workbook exercise 2.3 Organelles
Topic 3
Cells and organisms
Coursebook section 2.2
Original material © Cambridge University Press 2014 © Cambridge University Press 2014
IGCSE Biology
Chapter 2: Teaching ideas
2