Cells & Classification Study Guide
 Cells were first observed during the 1600’s by Robert Hooke. They were dead cork cells.
Most cells are microscopic and can only be seen with a microscope.
 The Cell Theory States:
o All living organisms are composed of cells. They may be unicellular or multicellular.
o The cell is the basic unit of life.
o All cells come from pre-existing cells.
 Some
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basic characteristics of living organisms are:
made of cells (and have DNA)
grow and develop
reproduce
obtain energy by breaking break down nutrients
- either autotrophic or heterotrophic
 get rid of wastes
 respond to internal and external stimuli (homeostasis)
 Animals, plants, fungi, protists and bacteria are all living organisms – viruses are NOT
living because they need a host cell to reproduce.
 There are two types of cells:
o Prokaryotic – no nucleus, no membrane-bound organelles. Thought to be the first
living organisms. Able to withstand the Earth’s early harsh environment. Includes all
bacteria (Archaebacteria & Eubacteria)
o Eukaryotic – “True Nucleus”. Contains a well-defined nucleus and membrane-bound
organelles (examples include - mitochondria, vacuoles, golgi body, chloroplasts, cell
wall, lysosomes, ER, Cell membranes - are selectively permeable, meaning only certain
material is allowed to enter and leave the cell.
 Scientific names must be either underlined or italicized. Humans – Homo sapiens
 There are Seven Levels of Classification:
o Kingdom – broadest or contains the largest number of organisms
o Phylum
o Class
o Order
o Family
o Genus
o Species – narrowest – contains only ONE type of organism
 There are three Domains – Eukarya, Archaea, & Bacteria
 There are six kingdoms:
1. Animalia
2. Plantae
3. Fungi
Domain Eukarya (hint: all made of eukaryotic cells…)
4. Protista
5. Eubacteria (still a prokaryotic cell)
Domain Bacteria
6. Archaebacteria
Domain Archaebacteria
Characteristics of the Six Kingdom System:
Animalia –
Eukaryotes, multicellular, Heterotrophic
Example: human, worm, fish
PlantaeEukaryotes, multicellular, Autotrophic (rarely heterotrophic)
Example: pumpkin, apple tree, moss
FungiEukaryotes, both unicellular/multicellular, Heterotrophic
Example: mushroom, mold, yeast
ProtistaEukaryotes, both unicellular/multicellular, both Autotrophic/Heterotrophic
Example: algae, amoeba, diatoms
Eubacteria – Prokaryotes, unicellular, both Autotrophic/Heterotrophic
Example: E. coli (lives in our intestines), Streptococcus pyogenes (causes strep
throat)
Archaebacteria - Prokaryotes, unicellular, both Autotrophic/Heterotrophic
Example: Methanogen, Halophile, Thermophile