This document provides an overview of cell structure and function. It begins by outlining learning objectives related to describing cell components, comparing cell types across domains of life, and explaining key aspects of cell membranes and organelles. Specific topics covered include why cells are typically small, distinguishing features of bacterial, archaeal and eukaryotic cells, the composition of cell membranes from phospholipids and proteins, and how membranes form bilayers and achieve selective permeability. Organelle functions are also briefly mentioned for eukaryotic cells.

1. Section 3.1 Amoeba © Wim van Egmond/Visuals Unlimited
Unit 2 - Cells

2. Learning Objectives
• Describe the properties of a cell.
• Identify the components common to all cells.
• Compare and contrast the cells that characterize the three domains of
life.
• Explain how the chemical structure of phospholipids enables them to
form a bilayer in water.
• Explain why a biological membrane has selective permeability.
• Identify different functions of membrane proteins.
• Identify the functions of the organelles in eukaryotic cells.
• Describe how organelles interact in carrying out a cell’s function.
• Compare and contrast the structure and function of cytoskeletal
proteins.
• Compare and contrast different cell junctions in animal cells.
• Explain the function of plasmodesmata in plant cells.

3. Cell theory explains the prevalence and
commonalities of cells.
Section 3.1 Table 3.1Filamentous cyanobacteria and green alga © McGraw-Hill Education/Don Rubbelke, photographer

4. Most cells are too small to see without a
microscope
Section 3.1 Figure 3.2

5. Similarities among all cells
Section 3.1
Regardless of size, all cells have
Figure 3.31

6. What do you observe?
Radius = 1 cm Radius = 4 cm
Surface area = 12.6 cm2 Surface area = 201.1 cm2
Volume = 4.2 cm3 Volume = 268.1 cm3
Heat Gain Heat LossSurface-to volume ratio
Thermo-
How?
Why are cells so
small?

7. Why Are Cells So Small?
Section 3.1 Figure 3.4
Smaller cells have more
_____________relative
to their _________.
High surface area allows
the cell to

8. Different Cell Types Characterize
Life’s Three Domains
Section 3.2 Figure 3.5
Unique features distinguish the
Bacteria, Archaea, and Eukarya.

9. The Anatomy of a Bacterium
Section 3.2 Figure 3.6
Bacteria are

10. The Anatomy of an Animal Cell
Section 3.2 Figure 3.8
Animal cells are

11. The Anatomy of a Plant Cell
Section 3.2 Figure 3.9
Plant cells are

12. A Membrane Surrounds Each Cell
Section 3.3 Figure 3.10
Cell membranes are
composed of

13. Section 3.3
A phospholipid has two
regions:
Structure of a phospholipid
Figure 3.10

14. Section 3.3
Phospholipids spontaneously form
bilayers in water
Figure 3.11

15. Section 3.3 Figure 3.12
Besides phospholipids, cell
membranes also contain
proteins:
Fluid mosaic:
A Membrane Surrounds Each Cell

16. 3.3 Mastering Concepts
How does the chemical structure of
phospholipids enable them to form a bilayer
in water?
© The Columbian, Janet L. Mathews/ AP Images