BIOLOGY IN FOCUS

PATTERNS IN NATURE
REVISION QUESTIONS
SR
Table 1.6
TR
1. (a) Clarify what is meant by a scientifi c theory.
(b) Describe how you would go about validating a scientifi c theory.
(c) State the cell theory.
2. Before the development of the cell theory, it was commonly believed that living organisms could
arise by spontaneous generation.
(a) Outline the theory of spontaneous generation.
(b) Describe experimental evidence that was used to discount this theory.
(c) Explain the role that the invention of the microscope played in the dismissal of the theory of
spontaneous generation.
3. Describe the contributions of Robert Hooke and Robert Brown in the development of the cell
theory. (Find a reliable way of remembering which ‘Robert’ did what!)
4. Discuss why biologists have continued to use light microscopes since the invention of the
electron microscope.
5. Put the following words into order of size, from smallest to largest: organelles, molecules, cells,
atoms and organisms.
6. Compare the detail seen with a light microscope in plant and animal cells when viewed under
a light microscope. As a guide use the table below. (Copy out a larger version or print it from
the Student Resource CD.)
Table 1.6 Parts of cells visible under a light microscope
Part of cell Plant cell Animal cell
Boundary
Organelles
Cell shape
Vacuoles
7. State whether the each of the following photographs was viewed under a light or an electron
microscope and whether it shows plant or animal cells. Justify your answers.
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SAMPLE CHAPTER ONLY