cells. cell theory all living organisms are composed of cells. they may be unicellular or...
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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.
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.
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!
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)