Cells

Cell Theory

All living organisms are composed of cells. They may be unicellular or multicellular.

The cell is the basic unit of life.

Cells arise from pre-existing cells.

Modern Cell Theory

1. all known living things are made up of a cell or cells.

2. the cell is structural & functional unit of all living things.

3. cells come from pre-existing cells by division.

4. Most cells contains hereditary information which is passed from cell to cell during cell division.

5. All cells are basically the same in chemical composition.

6. all energy flow (metabolism & biochemistry) of life occurs within cells.

Two Basic Types of Cells

Prokaryotic (Bacterial cells)

Eukaryotic (EVERYTHING else!!)

Prokaryotic Cells

Bacteria

Simple

Usually 1 chromosome

May have Plasmid (Circular, double stranded DNA)

No membrane-bound organelles

DNA Nucleoid region

Have ribosomes

E. coli - Gram-negative, strains undergoing conjugation. E. coli can cause urinary tract infections, traveler's diarrhea and nosocomial infections.

Bacteria

E.coli at 1000x (Our scope)

E. coli At 10 000X (a little better)

Although Not Living, Here are Viruses (Bacteriophages) Attacking a Bacterium

Eukaryotic

Membrane-bound organelles

Mitochondria Cellular Respiration takes place to produce energy (ATP molecule)

May be autotrophic (undergo photosynthesis that requires light or chemosynthesis that does not use sunlight but uses other “chemicals” such as CO2 or methane

May be heterotrophic (consumes their food)

True nucleus

Plants have cell wall

Many are multi-cellular; some are single-celled

Genes on chromosomes, some of which code for proteins

And no Algae are NOT plants……they are protists!

“Typical” Plant Cell

“Typical” Animal Cell Micrograph

“Typical “ Animal Cell

Cells are Specialized A Few Examples

Red blood cells are in abundance and carry oxygen (O2) to your cells

White blood cells fight infection

Nerve cells send impulses (electric and chemical signals)

Sperm cells Male gametes that carry genetic information

Ovum Female gamete that carries genetic information

Eukaryotic Cells - Plant

Central Vacuole

Chloroplast

Nucleus

Mitochondria

Cell Wall

Cell/Plasma Membrane

Nucleolus

Eukaryotic

Includes everything EXCEPT bacteria……even this guy (yes, he’s real!)

the hydrothermal worm lives around thermal vents at the bottom of the ocean……really tiny (568/1000 of a millimeter)

More Tiny Critters!

A dust mite about half a million times amplification…….these dudes live in your mattress, pillow…….

The house dust mite, D. pteronyssinus