Microvilli and cilia are cell structures. Describe how cilia differ structurally from the microvilli shown in Fig. 2.1 and Fig. 2.2.
A scientist measured the length and the diameter of some of the microvilli shown in Fig. 2.1 in order to estimate the total surface area of the microvilli on the epithelial cell surface. The scientist assumed that each microvillus had a cylindrical shape. Suggest one further measurement needed to estimate the total surface area of the epithelial cell's microvilli.
Identify the organelle labelled Z in Fig. 2.1 and explain why epithelial cells of the small intestine contain a large number of these organelles.
Bacteria are found attached to epithelial cells in the intestines of mammals. Describe how the organisation and distribution of DNA in epithelial cells differs from that in bacterial cells.