1. Cell Structure and Function

2. Cell Structure and Function • The discovery and the basic theory of cells. • Cell size and number. • The two major kinds of cells. • Plant cells and animal cells. • Cell me mbrane (plasma membrane). • Cytoplasm. • Nucleus. • Ribosomes.

3. Endoplasmic reticulum (rough ER and smooth ER). • Golgi complex (body). • Lysosomes. • Peroxisomes. • Mitochondria. • Chloroplasts. • Cytoskeleton. • Vacuoles.

4. The Discovery and Basic Theoryof Cells

5. Robert Hooke • About 1663, Hooke directed an instrument maker to improve his own microscope.

6. Robert Hooke Discovered and NamedCells • Hooke began to focus his new instrument on everyday objects. • When Hooke peered at a thin slice of cork, he saw what he called “pores” or “cells”.

7. Anton Van Leeuwenhoek

8. Leeuwenhoek’s small, simple,hand-held microscope

9. Leeuwenhoek had far greater success at seeing living cells such as Euglena. • He discovered bacteria and called them “animalcules”.

10. Matthias Schleiden • In 1838, Schleiden drew an important conclusion based on years studying plant tissues. • All plants, he said, are made up of cells.

11. Theodor Schwann • In 1839, Schwann drew an important conclusion based on years studying animal tissues. • All animals, he said, are made up of cells.

12. Schleiden and Schwann • 1n 1839, both together published the even broader conclusion that: • All living things are composed of cells.

13. Rudolph Virchow • 20 years later, Virchow stated that living cells arise only from preexisting cells.

14. The Modern Cell Theory • 1. All living things are made up of one or more cells. • 2. Cells are the basic living units within organism, and the chemical reactions of life take place within cells. • 3. All cells arise from preexisting cells.

15. Cell Size • Not all cells have the same size. • We use the micrometer to measure the sizes of cells. • There are 1,000 millimeters in 1 meter. • There are 1,000,000 micrometers in 1 meter.

17. Surface-to-Volume Ratio • The life of a cell dependsonexchanges of materials with the environment. • Movement of of all these materials takes place through the cell’s surface. • The larger a cell’s volume, the greater the amount of material to be exchanged. • Since this exchange depends on the cell’s surface area, the surface-to-volume ratio imposes limits on cell size.

18. Surface-to-Volume Ratio • Surface: 6x4= 24 cm2 Surface: 8x6= 48 cm2 • Volume: 2x2x2= 8 cm3 Volume: 8x1= 8 cm3 • Surface-to-volume: 24/8= 3 Surface-to-volume: 48/8= 6 • Small size increases surface-to-volume ratio

19. Question 1 • Four of the five answers listed below are portions of a well-known theory. Select the exception: • A. cells are the structural and functional components of living things. • B. cells arise from preexisting cells. • C. all organisms are made up of cells. • D. all cells have a nucleus.

20. Question 2 • Select the correct statement: • A. as a cell increases in size, its surface-to-volume ratio increases. • B. as a cell decreases in size, its surface-to-volume ratio increases. • C. as a cell increases in size, its surface-to-volume ratio stays the same.

21. Question 3 • The fingerlike extensions of the outer membrane of the cells lining the intestine serve to: • A. increase the cells’ cytoplasm. • B. decrease the cells’ cytoplasm. • C. increase the cells’ surface-to-volume ratio. • D. decrease the cells’ surface-to-volume ratio.

22. Answers • Question 1: D • Question 2: B • Question 3: C