1. Cells
In this section we will examine in depth many aspects of the fundemental structure for life, THE CELL

2. Topics on Cells Introduction and History of Cell Theory
Basic Cell Structure
General Shared Characteristics
Similarities and Differences between Prokaryote and Eurayote cells
Principle organelles and their functions
Processes of Cellular Control
Enzymes
Review Genetic Material
Structure and Function of DNA and RNA
Control of Transcription and Translation

3. Topics on Cells Proteins Cellular Reproduction
Duplication and Synthesis
Transcription and Translation
Cellular Reproduction
Cell Cycle
Mitosis
Meiosis

4. Topics on Cells Cellular Energy Cellular Transportation ATP
Aerobic v. Anaerobic respiration
Alcohol and Lactic Acid Fermentation
Photosynthesis
Cellular Transportation
Osmosis
Simple Diffusion
Facilitated Diffusion

5. Introduction and History of Cell Theory
Predictions were made early about cells that have become the basis for modern cell theory.
Rudolf Virchow wrote “Every animal appears as a sume of vital units, each of which bears in itself the complete characteristics of life” he went on to say “All cells come from cells”

6. Introduction and History of Cell Theory
Modern cell theory has three principles
Every living organism is made up of one or more cells.
The smallest living organism are single cells, and cells are the functional units of multicellular organisms.
All cells arise from preexisting cells.

7. Introduction and History of Cell Theory
Though cells vary dramatically in their structure and function, from the simple Streptococcus bacteria cell to the trillions of cells that exist in your body right now there are common characteristics between them.

8. General Shared Characteristics
Molecular Components
Proteins
Amino acids
Lipids
Carbohydrates
Sugars
Nucleotides
DNA
RNA

9. General Shared Characteristics
Structural Components
Plasma membrane
Cytoplasm
Ribosomes

10. General Shared Characteristics
Metabolism
Extracts evergy and nutrients from the environment
Uses energy and nutrients to build, repair and replace cellular parts

11. General Shared Characteristics
Plasma Membrane
It isolates the cell’s contents from the external environment.
It regulates the flow of materials into and out of the cell, for example, acquiring nutrients and expelling wastes.
It allows interaction with other cells

12. General Shared Characteristics
DNA is used as Hereditary Blueprint
Each cell has genetic material
The genetic material is deoxyribonucleic acid (DNA)
In eukaryotic cells (plants, animals, fungi, and protists) this DNA is contained within a separate membrane-bound structure called the nucleus.
In prokaryotic cells (bacteria and archaeans) the DNA although localized to a particular region within the cell is not separated by membranes from the rest of the cell’s interior

13. General Shared Characteristics
All Cells contain Cytoplasm
Cytoplasm consists of all the material inside the plasma membrane and outside the DNA-containing region
It contains water, salts, and an assortment of organic molecules
Most metabolic activities occur here

14. General Shared Characteristics
All Cells Obtain Energy and Nutrients from their environment
Due to their complexity cells must continously acquire and expend energy
At some point this energy has come from the sun

15. General Shared Characteristics
Cell Function Limits Cell Size
Cells are small, between 1 and 100 micrometer (millionths fo a meter)
Since Hooke first identified cells in 1665 technology has allowed us to learn more and more
Why do you think cells are so small?
Why are large organisms made up of small units rather than one giant cell?

16. Cell Size Comparison
Just to emphasis how small a cell is think of this.
I am 1.91m tall my cells are m in diameter.
If you increase each of our sizes equally till the cell was my size I would be between 19.1 and 1910 Km tall.
That is half way across the United States.

17. General Shared Characteristics
Now back to why cells are so small.
The answer to this relates to diffusion or movement of molecules into and out of the cell
The larger the cell is the longer nutrients take to get to the center.
In a 20 cm cell it would take 200 days for oxygen to get to the center.
Secondly as cells get larger their volume increases faster than their surface area.
Triple a cells radius and it becomes 27 times greater involume but 9 times greater in surface area (remember pie?)
Thus more need for exchange but less space to do it in