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Chapter 3
Cells Under the Microscope
Anton van Leeuwenhoek (16321723) - First to see “animalcules” in
pond water
The Cell Theory

1. Made of 1 or more cells.

2. Cells are the basic unit.

3. All cells come from other cells.
All Cells Have

Cell Membrane: Surrounds
Cell

Cytoplasm: Water-like inside

DNA: Genetic material

Ribosomes: Make Proteins
Cell Size

Smalls cells
 More efficient
Two Basic Cell Types
Prokaryote
Eukaryote
Size
Small
Large
DNA
No nucleus
Within nucleus
Organelles
No organelles
Membrane-bound
organelles
Body Type
Unicellular
Unicellular or
Multicellular
Prokaryote

Bacteria

Smallest simplest
cells

Cell Wall: Surrounds
cell membrane &
provides structural
support

Flagellum: Long
threadlike structures
that enable movement
Organelle

Membrane-bound structures that carries
out specific activities in the cell.

“Little organs”
They Both Have
Nucleus

Contain DNA

Nucleolus: Where
ribosomes are
made
Endoplasmic Reticulum (ER)

Membrane bound

Rough ER:
 Has Ribosomes
 Makes Proteins

Smooth ER:
 Makes Lipids
Golgi Apparatus

Golgi processes &
packages into
vesicles (small sac
used for moving
things around the
cell)

Distributes vesicles
for use inside cell or
exported outside cell
Mitochondria

Makes ATP (energy)
from breaking down
food

Surrounded by
membranes, contain
DNA & ribosomes

Came from prokaryotes
(endosymbiosis)
Lysosomes

Contains special
enzymes for
digestion in the cell.
Animal Cells Can Also Have

Hair-like structures
used for cell
movement

Flagella: Like those
found in bacteria
Plant Cells
Cell Wall
Surrounds & supports cell
 Maintains cell shape
 Protects
 Connects to other cells

Chloroplasts

Uses sunlight to make
sugar.

Provide energy for
cell.

Surrounded by double
membrane, contains
DNA.

Came from
prokaryotes
(endosymbiosis)
Vacuole
Large sac that stores water & other
substances
 Full makes cell rigid

Cell Analogy