Introduction

The biology of cells and the interaction of molecules within them show remarkable similarities across species and so this makes the study of cell and molecular biology fundamental to all aspects of biology. The features and ultrastructure of prokaryotic and eukaryotic cells are compared and the cell cycle in eukaryotic cells, differentiation of cells into tissues and organs and cell and tissue culture are explored. The chemistry of the cell molecules is studied to help candidates understand how molecules interact and how this is important to the functioning of the cell as a whole. Membrane structure and function is further developed from Higher level study to help candidates come to an understanding of membranes as dynamic structures that have many functions which can be attributed to the many types of proteins found as components of the cell membrane. Candidates’ understanding of cell ultrastructure and function is further developed by study of the cytoskeleton. The theme of molecular interactions in cell biology is developed by a study of three of the molecular interactions found in cells: the importance of enzymes in the control of cell metabolism is introduced as an example of an interaction found in the cytosol, the sodiumpotassium pump as an interaction associated with membranes, and cell signalling as a communication interaction. Finally, the great advances made in DNA technology are explored and legal, social, moral and ethical issues raised in the many applications of the technology are discussed.

Candidates undertaking this unit should have a clear understanding of the topics covered in the units: Cell Biology (H) or Cell Function and Inheritance (H).