Welcome to the Wonderful World of the Cell!
The way the world works: atoms-cells-tissues-organs-organ
systems-organisms-populations-ecosystem
Cell Theory:
1. All organisms are made of one or more cells.
2. The cell is the basic unit of organization of organisms.
3. All cells come from pre-existing cells.
Variety makes the world go round…
Red blood cell: 8 m
Nerve cell: 1m
Largest single cell is an egg: average diameter of 8cm
Most cells: 2-200 m
3 Types of Cells: viruses, prokaryotic, eukaryotic
1. Virus:
a. Examples: small pox, HIV, rabies
b. Virus-from the Greek word meaning “poison”
c. Constructed of compounds associated with living
organisms BUT ARE NOT living organisms
i. WHY???
1. NO nucleus
2. NO cytoplasm
3. NO organelles
4. NO cell membrane
d. not able to replicate themselves-they need a host to use
their enzymes and organelles
 VIRAL STRUCTURE
o ALL viruses have:
 Nucleic acid (DNA/RNA-can be helical, loop,
varied shapes)
 Protein coat surrounding the nucleic acid (capsid)
o Some viruses have an envelope outside the capsid taken
from the host’s cell membrane during replication
o On the surface of the envelope are glycoproteins
(projections that the virus uses to attach to the host cell)
2. Prokaryotic:
a. Examples: bacteria
b. Pro-before
c. Karyo-kernel (nucleus)
d. ALL PROKARYOTES HAVE
i. Cell wall
ii. Cell membrane
iii. Cytoplasm
iv. Ribosomes (to make proteins)
v. DNA/RNA
e. NONE HAVE
i. Membrane-bound organelles (mitochondria,
endoplasmic reticulum, lysosomes, etc.)
ii. Membrane-bound nucleus
3. Eukaryotic:
a. Examples: plants, animals, fungi (amoeba, kelp),
protists (mushrooms, mildew, mold)
b. Eu-true
c. Karyo-kernel (nucleus)
d. ALL EUKARYOTES HAVE
i. Membrane-bound organelles
ii. Membrane-bound nucleus