Cell Theory
• All organisms are
made up of one or
more cells
• The cell is the basic
unit of structure and
the function of all
living things
• All cells arise from
previously existing
cells
Levels of Organization
Cells; What are they Good For?
•
•
•
•
•
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Getting food
Using food for Energy
Transportation
Growing
Reproducing
Elimination of Waste
2 Types of Cells
Prokaryotic
Eukaryotic
• No Nucleus
• Circular DNA
• No membrane bound
organelles
• Nucleus
• Linear DNA
• Membrane bound
organelles
Animal vs. Plant Cells
Animal Cells
Plant Cells
Cell Structure
The Cell Membrane
• Controls the movement of materials
in and out of the cell
All cells have a
cell membrane
The Cell Wall provides structure and
support.
All cells EXCEPT
animals have a
cell wall
The Nucleus holds the DNA
• What does DNA do?
All cells EXCEPT
bacteria have a
nucleus
The Nucleolus is a region of the
nucleus where ribosomes are
made
All cells EXCEPT
bacteria have a
nucleolus
The Rough Endoplasmic Reticulum
(RER)
• Is studded with ribosomes.
• Helps fold proteins for export or transport
• Packages proteins in vesicles to send to the
Golgi Apparatus
All cells EXCEPT
bacteria have a
rough
endoplasmic
reticulum
The Smooth Endoplasmic Reticulum
(SER)
• Processes and packages polysaccharides
and lipids in vesicles.
All cells EXCEPT
bacteria have a
smooth
endoplasmic
reticulum
Ribosomes are where proteins are
formed.
•They consist of two sub-units (large
& small)
All cells have
ribosomes
The Golgi Apparatus
• Receives proteins in vesicles from the
RER
• Adds tags to proteins to mark them for
delivery and then sends them out for
shipment.
All cells EXCEPT
bacteria have a
golgi apparatus
The Mitochondria is the site of
cellular respiration
• Where sugar is turned into ATP, and
energy is released
All cells EXCEPT
bacteria have
mitochondria
The Chloroplast is the site of
photosynthesis
• Where sunlight is transformed into
sugar
Only plant cells
have chloroplasts
The Cytoskeleton creates internal
structure and allows for movement
internally and externally.
Lysosomes are specialized vesicles
made from the golgi
•They break down old organelles,
foreign materials, bacteria and viruses
All cells EXCEPT
bacteria have
lysosomes
Vacuole
• Membrane-bound
sacs that aid in…
– Digestion
– Water pressure
– Waste release
• All cells have
vacuoles, however,
their function is
dependent on the
type of cell
Inner Life of the Cell
by: Harvard University
Narrated Version – Click Here
Cellular Transportation
The Cell Membrane
• All cells have a cell membrane
– It is a thin, flexible barrier surrounding the
cell
•
–
provides protection and support.
Has the ability to change shape.
•
Why would this be important?
Cell Membrane
• It is selectively permeable
– It controls what enters and leaves the cell.
Parts of the Cell Membrane
• The cell membrane is made up of lipids
(AKA fats).
– Containing two different parts
•
•
water-loving head (hydrophilic)
2 water-hating tails (hydrophobic)
Parts of the Cell Membrane
• These lipids join together as a lipid
bilayer (i.e. 2 layers) in water.
– These layers form an asymmetrical, closed
circle.
Parts of the Cell Membrane
• What do you think would happen if
there was a tear in the bilayer?
• How do you think temperature (too
hot; too cold) might affect the bilayer?
Parts of the Cell Membrane
• The bilayer is also made up of different
membrane proteins.
– They aid in the transport of molecules across
the membrane (transmembrane proteins)
Parts of the Cell Membrane
• Some have carbohydrate chains
– They help protect the membrane surface
– They play an important role in cell-cell
recognition.
– What are some examples of cell to cell
recognition?
Membrane Functions
• Diffusion
– This is the movement molecules from regions
of higher concentration to regions of lower
concentration
Brining your Chicken
• What is “Brining”?
– The brining process
forces water into the
muscle tissues of the
meat
– What science process is
occurring here?
• Why would we want to
do this with chicken?
– The resulting water in the
muscle tissues will make
the meat more moist and
tender.
Membrane Functions (cont.)
• Osmosis
– The diffusion of water through a membrane.
– Movement of water from a region of high
water concentration to a region of lower water
concentration through a semi permeable
membrane.
Osmosis
Membrane Functions (cont.)
• Passive transport
– Diffusion occurs across a
membrane without the
use of energy.
1. Simple Diffusion
a)
b)
Occurs through channel
proteins or pores
Dissolves into bilayer and
diffuses across membrane
2. Facilitated Diffusion
a)
Needs help of a carrier
protein
Membrane Functions (cont.)
• Active transport
– Movement of molecules
across a membrane with
the use of energy.
– Molecules are going
against normal tendencies.
– This occurs with the help of
a carrier protein.
Membrane Functions (cont.)
Membrane Functions (cont.)
Activity time
The Hungry Cell
•How do cells receive large molecules?
–Such as proteins, food, etc…
•Work in pairs
•Materials:
–plastic shopping bag (the cell),
–a pair of scissors,
–a piece of string,
–several pieces of “food” (chickpeas).
“Hungry Cell” Rules
You must get the food into the cell, BUT you must follow
these rules:
• The food must enter through a solid part of the bag
– you can’t just drop it into the bag
• The inside of the bag may NOT be directly open to the
outside environment
– In other words, you can’t work with the bag turned insideout, because neither can cells.
• When the food enters the “cell” all the pieces MUST
stay together and must be able to move around
together inside the cell.
• You ARE allowed to work with your hands inside the
“cell”.
Endocytosis
• Cells take in macromolecules
– What are some examples?
Exocytosis
• Materials leave cell
– vesicles fuse with cell membrane and release
material