Cell Structure and Function
• It wasn’t until the
1600s that
scientists were
able to use
microscopes to
observe living
things.
Cells
• In 1665, Robert
Hooke observed
cork cells under
the microscope. He
called them cells.
• This is a drawing he
made of the cork
cells.
• Here is what cork
cells look like in a
modern microscope
with special
lighting.
Leeuwenhoek’s Microscope
• Anton Van
Leeuwenhoek used a
single-lens
microscope to view
pond water and other
things.
• Here is his
microscope.
Cell Theory
The Cell Theory States
• It wasn’t long
before scientists 1. All living things are
made of cells.
realized that all
living things were 2. Cells are the basic units
made up of cells.
of structure and
This discovery
function in living
brought about the
things.
formulation of the
3. New cells are produced
cell theory.
from existing cells.
Types of Cells
• Cells are classified as
prokaryotic or
eukaryotic.
• Prokaryotic cells have
genetic material that is
not inside a nucleus. No
nucleus.
• Eukaryotic cells have
genetic materials in a
nucleus. (“true” nucleus)
Cell Structures
• Cells contain small
structures called
organelles. Each
organelle has a
specific job it
performs in the
cell.
1.The Nucleus
• This is a membranebound structure that
contains the DNA.
DNA is the genetic
material that is the
code for making
proteins.
EX: Chief Executive
Officer (CEO)
2. Chromatin
• The DNA and surrounding protein.
EX: blueprints to factory product
• Ribosomes are
protein assembly
organelles.
• Ribosomes can be
“free” in the
cytoplasm or on the
endoplasmic
reticulum.
• EX: Workers in the
assembly line
• The endoplasmic
reticulum is the site
where lipids of the cell
membrane are
assembled, along with
proteins and other
materials.
• It can contain ribosomes
and be Rough ER or have
no ribosomes and be
Smooth ER
EX: Assembly line (where
workers do their work)
• The golgi apparatus
modifies, sorts, and
packages proteins
and other materials
from the ER.
EX: Finishing /
packaging department
6. Lysosomes
• Lysosomes are small
organelles that contain
enzymes.
• These enzymes breakdown
lipids, carbohydrates, and
proteins into small
molecules that can be used
by the cell.
• Lysosomes also remove
“junk and clutter” in
the cell.
EX: Maintenance crew
7. Vacuoles
• Vacuoles are storage
organelles.They store
water, salts, proteins,
etc.
• Plants have a large
vacuole that helps plants
support leaves and
stems.
• EX: storage/supply
room
8. Mitochondria
• The mitochondria is
the organelle that
converts chemical
energy from food
into ATP to power
cell processes.
EX: Power plant
• Chloroplasts are
organelles that
capture sunlight
energy and convert it
into chemical energy
in a process known as
photosynthesis.
EX: Power plant
10. Cell Membrane
• The cell or plasma
membrane surrounds
the cell and
regulates what
enters and exits
the cell.
• Ex: shipping
receiving
and
department of a
factory.
11. Cytoplasm
• The cytoplasm
(cytosol) is the fluid
outside the nucleus. It
contains the
organelles.
• EX: factory floor
where most of the
products are
assembled, finished,
and shipped.
12. Centrioles
• Centrioles are
cylindrical bundles of
microtubules that
function in cell
reproduction.
Division of Labor
• In multicellular organisms, each cell has a
specialized task to keep the organism alive.
• Specialized cells include blood, muscle,
heart cells, etc.
• Living things are organized into the
following hierarchy.
1. Cells
2. Tissues
3. Organs
4. Organ Systems
5. Organisms
Levels of Organization
1. Macromolecules
2. Organelles
3. Cells
4. Tissues
5. Organs
6. Organisms
7. Populations
8. Communities
9. Ecosystems
10. Biosphere
• This chart
shows the
increasing
complexity of
organization
from tiny
molecules to
the whole
biosphere.