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Cell Theory
Robert Hooke
observed compartments
in a thin slice of
cork. He named them
cells.
Cell Theory
1.
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
All living things are
composed of cells
Cells are the basic unit of
structure and function in
living things.
Cells come from preexisting
cells.
10 Trillion Cells make up
the human Body
 There are 210 Types of
cells found in the human
body.
Nucleus

Houses the cell’s genetic
material in the form of
DNA. Control Center
of cell!
Cytoplasm
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The entire region of the cell between the nucleus
and the plasma membrane is called the
cytoplasm.
Is a gel-like fluid that is composed of water,
salts, and organic molecules.
Holds all cell organelles in place!
Eukaryotic vs. Prokaryotic

Bacteria and archeabacteria are prokaryotic.
They lack a nucleus.

Plants, animals, fungi, protists all contain
eukaryotic cells which contain a nucleus.
Cell Wall
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Protects the plant cell
and maintains its shape.
Animal cells do not have
cell walls!
Provides the cell with
structural support, and
protection.
In plants, the cell wall is
constructed primarily
from a carbohydrate
polymer called cellulose!
Cell Membrane
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Plasma Membrane- both
plant and animal cells
have a thin outer
covering which defines
the boundary of the cell
and regulates the traffic
of chemicals between the
cell and its surroundings.
You would have to stack
8,000 cell membranes to
reach the thickness of a
piece of paper.
Membranes
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Regulate the transport of substances across the
boundary, allowing only certain substances to
pass.
They are mainly composed of proteins and lipids
called phospholipids.
Since lipids are hydrophobic, they create a
boundary between the cell’s aqueous cytoplasm
and the aqueous environment surrounding the
cell.
Phospholipid Bilayer
(Proteins can be considered icebergs floating
in a sea of phospholipids).
Membrane Proteins

Proteins perform most
of the membrane’s
specific functions.

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Helping molecules cross
the membrane.
Cellular signaling.
Passive Transport

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Diffusion across a
membrane is called
passive transport b/c no
energy is used by the cell.
In facilitated diffusion,
proteins help move
molecules across the
membrane.
Active Transport

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When a cell expends
energy to move
molecules or ions across
a membrane the process
is known as active
transport.
Usually opposes
diffusion.
Active = ATP
Osmosis

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Diffusion of water!
1. In a saline solution.
Percentage of water is
less on the outside of the
cell, so water moves out.
2. Equilibrium.
Each green dot represents oxygen
molecules.


Will oxygen
molecules move into
or out of the cell?
When will diffusion
stop?
Vesicles
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Small membrane sacs that
specialize in moving products
into and out of the cell.
Vesicles store, transport, or
digest cellular products and
waste.
Endocytosis- taking
substances in!
Exocytosis- Removing
substances.
Ribosome's

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Proteins are constructed
in a cell by ribosome's.
(Protein Synthesis).
Ribosome's build
proteins from the genetic
instructions held within a
messenger RNA.
mRNA travels from
nucleus.
Endoplasmic Reticulum
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E.R. is responsible for
folding, and transport of
proteins and other molecules
to be used in the cell.
Rough and Smooth are
physically connected, but
differ in structure and
function.
Rough E.R. contains
ribosome's, smooth does not.
Salivary cells contain a lot of
Rough E.R. Why?
Smooth E.R. produces lipids!
Golgi apparatus

An organelle that
modifies, stores, and
routes protein and other
chemical products to
their destinations.
Vacuoles

Storage of undigested
nutrients.
Lysosmes

Membrane bound sacs
called lysosmes contain
digestive enzymes that
can break down
macromolecules.
Mitochondria

Sites where cellular
respiration occurs. This
process releases energy
from sugars and certain
other organic molecules
and then uses it in the
formation of another
organic molecule called
ATP (Energy).
Chloroplasts
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Chloroplasts are organelles
found in plant cells and
eukaryotic algae that conduct
photosynthesis.
Chloroplasts absorb sunlight
and use it in conjunction with
water and carbon dioxide to
produce sugars, the raw
material for energy and
biomass production in all
green plants and the animals
that depend on them, directly
or indirectly, for food