Transcript Chapter 7 – Cell Structure and Function

Chapter 7 – Cell Structure and
Function
Section 7-1:
Life is Cellular
cell is the common structure
The _____
that makes up every living thing
______________
Microscopes were essential to
the discovery of the cell,
without them were are not able
to see cells with the naked eye
Around the same time _______
Anton
van
Leeuwenhoek (Dutch)
___________________
water under a
observed pond
____________
microscope and observed
living microorganisms
Robert Hooke (English)
In 1665, ________________
examined cork
_____ and termed the
little chambers he saw as cells
Matthias Schleiden (German)
In 1838 ____________________
concluded all plants
______ are made of cells
In 1839 Theodor
___________________
Schwann (German)
stated that all _________
animals are made of cells
In 1855 Rudolf
_________________(German)
Virchow
new cells only come
concluded that __________
from the division of existing cells
All of these observations with the microscope
led to the cell theory! It states:
1. All living things are composed of cells
2. Cells are the basic units of structure
and function in living things
3. New cells are produced from existing
cells
______________________________________
Transmission electron microscopes (TEMs) allow
us to view cell structures
The electrons can only pass
thin
through _____specimens,
so have
thin (___________)
nonliving
to be sliced very _____
________________________________
Scanning
electron microscopes (SEMs) produce a
3D
image of the cell by scanning the surface
__________
Electrons scatter in air, so the
samples have to be viewed in a
vacuum (__________)
nonliving
_________
Ant
Moth Eye
Table Salt
Mold
Burdock
Cancer Cell
Pollen Grains
Cells come in a variety of shapes/sizes
______________ and can be
categorized in different ways
5-50 micrometers but some do
Typical cells range from ___________________,
fall out of that range
All cells have 2 characteristics; a
cell membrane and
barrier called a ________________,
at some point they contain DNA
Cells fall into 2 broad categories based on
whether they have a _________
nucleus or not;
Eukaryotes and Prokaryotes
_________= a large membraneNucleus
enclosed structure that contains
material in the
a cell’s genetic
_________________
form of DNA
Eukaryotes
____________ have a nucleus (their DNA is separated
___________)
larger and more __________
complex than prokaryotic cells
Usually _______
internal structures and membranes
Generally contain many ____________________
structures act like specialized organs
Many of the internal
___________________
_______ 
they are known as organelles
Some live as single-celled organisms, many form large
multicellular organisms (plants, animals, fungi, and protists)
Prokaryotes
_____________ do not have a nucleus
(their DNA is not
______________)
contained
Usually _________
smaller and less
complex
_________ than eukaryotic cells
Some may contain a few
internal
membranes but
_____________________,
they aren’t usually complex
_________are
Bacteria
considered to be prokaryotes
Section 7-3:
Cell Boundaries
Cell boundaries are important and include
cell membranes & cell walls
membrane regulates what
The cell
________________
enters and leaves the cell
The membrane is made up of a
double layered sheet = lipid bilayer
flexible structure yet is a
The membrane gives the cell a ___________________,
barrier to the outside world
strong ________
cell wall is to provide
The main function of the __________
_________________________
support and protection for the cell (a tough outer coating)
The wall lies outside
________ the membrane
replace
(that means the wall doesn’t
_______________
the membrane, it is in addition too)
One of the most important functions of the cell
the movement of
membrane is to regulate
________________________
dissolved molecules from side to side
_____________________
Concentration plays a big role in which way
________________
molecules through the membrane
Concentration of a solution = ______
mass
volume of
of the solute in a given _________
mass/volume
solution (_______________)
high
Particles tend to move from ______concentration

_____concentration
low
This is known as diffusion and does not require energy
Equilibrium
_____________ = when concentration of the
solute is the
_________
same throughout the system
Not every substance can diffuse across the cell membrane
If the substance can diffuse, the
permeable to it
membrane is ____________
If the substance cannot diffuse, the
impermeable to it
membrane is ______________
Most membranes are
selectively permeable  they
_______________________
only let certain things through
__________= diffusion of water
Osmosis
through a selectively
permeable membrane
Water moves from high
_____ concentration  low
____ concentration
When the two solutions on either side of the membrane are
the same, they are __________
isotonic (_______________)
same strength
The same
concentrations
on each side!
A ______
more concentrated
solution is hypertonic
____________
above strength
(_______________)
Higher
concentration
outside the cell!
A _____
less concentrated
hypotonic
solution is _____________
below strength
(_________________)
Lower
concentration
outside the cell!
Osmosis can create __________
pressure on cells
solution
If a cell is in a hypertonic
_____________________,
water leaves
_______ the cell to try to even
out the concentrations  this
causes the cell to shrink
If a cell is in a ____________________,
hypotonic solution
enters the cell to try to
water ________
even out the concentrations  this
causes the cell to swell up
Cell
walls help prevent the cell
___________
in a hypotonic solution from
swelling and bursting, even
with high osmotic pressure
Some larger molecules seem to pass through the
membrane easily because of protein channels
_____________________
Facilitated
diffusion = when
protein channels help molecules
diffuse across the membrane
Sometimes cells need to use _________________
active transport to move cells
against the concentration difference
across the membrane ________
Active transport requires
________________
energy
and is usually carried out by
transport proteins or “pumps”
Larger molecules may be transported
by movements of the cell membrane
_____________ = the process of taking
Endocytosis
into the cell
material ______
Phagocytosis
eating
______________ = “cell _______”
Pinocytosis
drinking
_____________ = “cell __________”
Exocytosis
____________ = the process of releasing
__________
large amounts of material from the cell
Cells are _____________
specialized to perform certain tasks and
the way cells associate with other cells
Red blood cells,
platelets, T
lymphocytes
Sometimes a single cell is the organism
= _______________________
unicellular organism
Unicellular organism do everything
grow respond,
a living thing does; _______,
transform
energy reproduce
__________________,
There are lots of these unicellular
organisms on Earth
Multicellular
organism = an organism made of many cells
________________________
There is a great diversity of
multicellular organisms
___________________
Cell
specialization = when cells through
the organism develop in different ways
to perform different tasks
Animal
________ cells are specialized in many ways
Red blood cells are specialized
oxygen  they
to transport _________
protein that binds to the
have a ________
_________
oxygen to move it
The pancreas produces enzymes needed for digestion
Since enzymes are proteins, pancreatic cells are packed with
ribosomes
______________
Muscle cells are specialized to
help organisms move  they
have very overdeveloped
_______________
cytoskeletons to help us move
Plant cells are also specialized
______
There are levels of organization to make it easier to describe
cells ________,
tissues ________,
organs
cells in a multicellular organism; _____,
organ systems
and _______________
Cells are the first level of organization
________
Tissue = a group of similar cells
that perform a particular function
Most animals have 4 main types
muscle ___________,
epithelial
of tissues; _________,
nervous and ____________
connective
_________,
Organs
________ = many groups of tissues that work together to help
perform tasks
Ex. Each muscle in our body is
an organ  it has more than
just muscle tissue, it also has
connective and nervous tissues
The tissues within an organ
all perform essential tasks
Organ
system = a group of organs that work together to
_______________
perform a specific function
Ex. Digestive system or
respiratory system
This organization is very
important as it divides up
labor
______ between cells and makes
multicellular life possible