Download Notes: Some Tid-Bits About the Cell

A Bit of “Extras” About Cells
 Essential Questions: What are the differences between
prokaryotic and Eukaryotic cells? How are they the same?
Are viruses living cells? What is cell specialization?
 Cell Theory:
1. Cells are the building blocks of life.
2. All organisms are made of one or more cells.
3. All cells arise from pre-existing cells.
 A comparison:
Examples
Nucleus
DNA
Cell Membrane
Cell Wall
Ribosomes (not
membrane bound
Complex
organelles
(membrane
bound)
Virus
Flu, Cold,
HIV, Ebola
No
Yes – little
pieces
Prokaryotes
Eukaryotes
Bacteria
Plant, Animal, Fungus
No
Yes – small
amount in
circular
shape
No (protein Yes
coat)
No
Some
Yes
Yes – lots in the form
of a double helix
Yes
No
Yes
Yes ~ Plant = cellulose
No ~ animal
Yes
No
No
Yes
 Cell Types in Animals:
1. Autosomes (Somatic cells) = body cells
Ex. skin, liver, bone, blood, muscle, etc.
2. Gametes = sex cells
Ex. sperm, egg
 Cell Specialization:
 Sperm + Egg = Zygote (1 cell)?
- Embryo = more than one cell,…until the full baby is formed
 How does this one cell become a cell with a certain job when
every cell has the same DNA?
- At specific stages of the embryo, certain sections of the
DNA get “turned off”.
- The only DNA expressed (“left turned on”) is the DNA
specific to that cell type.