1. Miller and Levine biology 7.1 – 7.2
Introduction to Cells
Miller and Levine biology 7.1 – 7.2

2. How do we know cells exist?
In 1665 Robert Hooke used an early microscope to examine a piece of cork (plant material).
At the same time, Anton van Leeuwenhoek used a single lens microscope to examine pond water.
Where did the term cells come from?

4. Cell Theory
Following the discovery of cells, scientists agreed that both plants and animals are made of cells and are the smallest units of life. This lead to a cornerstone of biology known as “Cell Theory”.
Cell Theory states:
All living things are made up of cells.
Cells are the basic unit of structure and function of living things.
New cells are produced from existing cells.

5. How do we study cells?
Light microscopes

6. How do we study cells?
Electron microscopes

7. Two major cell categories
Prokaryotic
Bacteria
Eukaryotic
Animal cells
Plant cells

8. What are the differences?
Prokaryotes Eukaryotes
Generally smaller and simpler Generally larger and more complex
DO NOT separate genetic material DO separate their nucleus genetic material
in the nucleus

9. Eukaryotic

10. Prokaryotic

12. Exocrine secretory epithelial cells
Salivary gland mucous cell (polysaccharide-rich secretion)
Salivary gland number 1 (glycoprotein enzyme-rich secretion)
Von Ebner's gland cell in tongue (washes taste buds)
Mammary gland cell (milk secretion)
Lacrimal gland cell (tear secretion)
Ceruminous gland cell in ear (earwax secretion)
Eccrine sweat gland dark cell (glycoprotein secretion)
Eccrine sweat gland clear cell (small molecule secretion)
Apocrine sweat gland cell (odoriferous secretion, sex-hormone sensitive)
Gland of Moll cell in eyelid (specialized sweat gland)
Sebaceous gland cell (lipid-rich sebum secretion)
Bowman's gland cell in nose (washes olfactory epithelium)
Brunner's gland cell in duodenum (enzymes and alkaline mucus)
Seminal vesicle cell (secretes seminal fluid components, including fructose for swimming sperm)

13. Why are cells small?

14. How are cells organized?
Cell membrane/wall
Cytoplasm
Within the cell are various organelles
which you will read about in chapter 7.2
(Pg. 196)
Nucleus