1. Topic 2
CELLS
Nerve cell

2. Assignment: 2.1 Cell Theory Vocabulary Assignment
Biozone-- page 57-60, 62-65, 80, 81, 96, 256, 266 (be prepared for a quiz)
Chapter readings-- pages 4, 5, 9, 52-54, 212, 218, 219 (be prepared for a quiz)
Essay Topic-- Investigate and report on one therapeutic use of stem cells (typed, edited, 1-2 pages) due Friday September 2nd

3. 2.1.1 Outline the Cell Theory
All living organisms are composed of cells, and the products of cells (ex. hair and scales)
Cells are the smallest units of life
Cells only come from pre-existing cells
Advances in technology (particularly the electron microscope) greatly increased our knowledge of cells and allowed us to study the ultrastructures in detail

4. Hooke, Schleiden and Schwann

5. Characteristics of Cells

6. Characteristics of Cells (functions of living things)
Metabolism- all the chemical reactions that occur within an organism
Response- to stimuli which is also known as sensitivity
Growth- includes both in cell size and number
Reproduction- whether sexual or asexual (passing heredity molecules to offspring)
Homeostasis- which means maintaining relatively stable conditions inside the body
Nutrition- which means the source of food for nutrients and energy

7. 2.1.2 Discuss the Evidence for the Cell Theory
A series of steps led to the discovery of cells (mostly related to advances in technology)
1590- Dutch optician Zacharias Jansen invents the compound microscope (compound means 2 or more lenses which provides greater magnification)
1665- Englishman Robert Hooke studies cork and coins the term “cells”
1675- Dutchman Antonie van Leeuwenhoek discovers unicellular organisms
1838- German Mathias Schleiden suggests all plants are made of cells

8. Evidence (cont.)
1839- German Theodor Schwann suggests all animals are made from cells
1840- Czech Jan Evangelista Purkinje names the cells contents “protoplasm”
1855- German Rudolf Virchow suggests that all cells come from other cells (biogenesis)
1860s- scientists disproved the theory of spontaneous generation (ex. Louis Pasteur)

9. Evidence for the Cell Theory
Inductive reasoning
Using verifiable observations and measurements to draw conclusions
General principles from a large number of specific observations
ex. All living things are made of cells
Deductive reasoning
Inquiry – questions, hypotheses, testing
Predictions tested through experiments
If then type of logic from general to specific
ex. Humans are made of cells

10. What is Protoplasm?

11. The Cell Theory

12. 2.1.3 State that unicellular organisms carry out all the functions of life
Organisms such as paramecium, euglena, chlamydomonas and amoeba have only one cell and this single cell has to carry out all the functions of life (metabolism, response, homeostasis, growth, reproduction and nutrition)

13. Viruses vs. Unicellular Organisms
Viruses- have no cytoplasm or organelles, no metabolism, depend on host cells for metabolism and reproduction (NOT considered living)
Unicellular organisms
Bacteria = prokaryotic
Protista = eukaryotic (ex. amoeba, euglena, paramecium, chlamydomonas)
Carry out all the functions of life
Flashcard- draw and label each protista above as well as describe (autotroph, heterotroph, location, size????)

14. Compare the relative sizes of molecules, cell membrane thickness, viruses, bacteria, organelles and cells using appropriate SI units
SI stands for International System of Units
(from French: Système International)
100 cm = 1 m
10 mm = 1 cm
1000 mm = 1 m
1000 μm = 1 mm
1000 nm = 1 μm or nm = 1 mm

15. Table of Relative Sizes
Most useful units for measuring the sizes of cells and structures within them are micrometers (μm) and nanometers (nm)
Biological Structure
Typical Size
Molecules (e.g. DNA double helix is 2 nm in diameter and a hydrogen atom is 0.1 nm)
0.1 – 2 nm
Cell Membrane Thickness
7.5 – 10 nm
Viruses (sizes vary)
HIV is 100 nm
Bacteria (sizes vary)
1-4 μm or nm
Mitochondrion
0.5-5 μm
Chloroplast Organelles
2-10 μm
Nucleus
10-20 μm
Prokaryotic Cell
1-5 μm
Eukaryotic Cell μm

16. Sizes of Cells and Organelles Vary
Animal cells are often smaller than plant cells
The yolk of an egg is one cell
Each sap filled vesicle of an orange is one cell
The largest known bacterium (Epulopiscium) was found in fish in the tropical waters surrounding Lizard Island, Australia is over 1 mm in length