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Cells and
Microorganisms
Organisms
All living things are organisms.
Organisms
NOT Organisms
History of the Cell
You’ve
probably seen cork
stoppers in bottles or cork on
bulletin boards. Cork comes
from the bark of an oak
tree, an organism.
In 1665, Robert Hooke, an
English scientist, observed a
thin layer of cork though a
microscope. Because
Hooke thought the
structures he saw looked like
tiny rooms, he named them
cells.
History of the Cell
 Hooke’s
description of cells made scientists want
to know more about them. Using microscopes,
they learned that all living things are made of
cells.
 A cell is the basic unit of structure and function in
living things.
 Cells are microscopic, meaning that they cannot
be seen with the naked eye.
Plant & Animal Cells
 There
are 2 types of cells:Plants and animals have
different types of cells, each with its own job.
 The different cells work together to carry out life
functions that keep an organism alive and healthy.
 For example, your body has cells that help you break
down food. It has cells that carry oxygen to other
cells. It also has cells that carry away waste
materials.
 To perform its own functions, each cell contains
structures called organelles. Each type of organelle
has a certain function that helps keep the cell alive.
Animal Cells
ALL animals contain animal cells.
Remember:
Humans are
considered
animals, too!
Animal Cell: Organelles (Parts)
Nucleus
Cytoplasm
Cell Membrane
*Animal cells
are round in
shape.
What’s Their Function?
 Cell
Membrane: Holds a the cell together and
separates it from its surroundings. Allows nutrients and
water to pass in and out of the cell.
 Nucleus: Directs and controls ALL cell activities.
 Cytoplasm: A jelly like fluid containing chemicals
that keep the cell healthy.
Plant Cells
ALL plants contain plant cells.
Plant Cell: Organelles (Parts)
Nucleus
Cell Membrane
Cell Wall
Chloroplast
Cytoplasm
*Plant cells are
rectangular in
shape.
What’s Their Function?
 Cell
Wall: Supports and protects the outside of the
 Cell
Membrane: Holds a the cell together and
plant cell.
separates it from its surroundings. Allows nutrients and
water to pass in and out of the cell.
 Nucleus: Directs and controls ALL cell activities.
 Chloroplasts: Makes food for the plant cell.
 Cytoplasm: A jelly-like fluid containing
chemicals that keep the cell healthy.
Let’s Review Cells
Animal Cells
Both
Nucleus
Cytoplasm
Cell Membrane
Plant Cells
Cell Wall
Chloroplasts
Single-Celled
Organisms
Bacteria
Virus
Protozoa
Multi-Celled
Organisms
Flower
Cat
Bee
Tree
What’s the Difference?
Single Celled Organisms
The entire
organism
contains 1 cell
Usually
microscopic
Multi Celled Organisms
Both have cell
parts: nucleus,
cell membrane,
cytoplasm, etc.
The organisms
have more
than one cell