Biology/Chapter 7 notes-CELL STRUCTURE & FUNCTION
I.
Life is Cellular
A. The Discovery of the Cell
It was not until the ______________
that scientists began to use
microscopes to observe organisms.
In 1665 ____________________used an
early compound microscope to see tiny
chambers in cork. He called these
chambers cells after the tiny rooms
in monasteries….we know these not to
be empty now.
About the same time in
Holland______________________________
used a single-lens microscope to look
@ pond water,
Cell Theory
 In 1838 Mathew Schleiden
concluded plants were made of
cells
 1839 Theodore Schwann said all
animals were made of cells
 1855-Virchow said cells could
only come from existing ones.
 These 3 things
compile_________________
1. All living things composed
of ___________
2. Cells are the basic units
of
___________________________
of living things
3. New cell are produced from
__________________________.
B. Exploring the Cell
Florescent labels and
light microscopy have
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been used to follow
molecules through the
cell.
_______________________
,which scans cells w/a
laser beam can make 3-d
images of cells
Video technology make
it possible to watch
cell growth, division
and development
Light makes it
difficult to visualize
tiny structures because
it
scatters/______________
____________allow
things like proteins be
visualized (things as
much as 1000 x smaller
can be visualized….TEMS
allow you to see
specimens cut into
ultra thin slices
W/ a
______________specimens
do not have to be cut
to see 3-D images….Both
must be placed into a
vacuum so air molecules
do not scatter
electrons
1990’s_______________________
have revolutionized
visualization of
surfaces and atoms have
been observed…can be
used in ordinary air
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and can show DNA
structure
C .Prokaryotes and Eukaryotes
Cells typically range
from
_______________micrometers,but some
bacteria are .2 and
some amoeba are 1000
micrometers
All cells have 2
things in common:
1. cell membrane-a
barrier
2. @ some point they
contain_______
2 broad categories:
1. _____________________________genetic material is NOT contained
in a nucleus/generally less
complicated than other cells/carry
out all cell activities…present
day members are
_______________________.
2. _____________________________contain a nucleus w/ genetic
material,generally larger,much
diversity.
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Chapt, 7 II. EUKARYOTIC CELL STRUCTURE
• Organelles=Specialized structure that performs
important functions within an eukaryotic cell.
• 2 major parts of eukaryotic cells-nucleus &
cytoplasm--Cytoplasm is material inside
membrane and outside nucleus
Figure 7-5 Plant and Animal Cells
Section 7-2
Smooth ER
Ribosome
(free)
Vacuole
Chloroplast
Ribosome
(attached)
Cell
Membrane
Nuclear
envelope
Cell wall
Nucleolus
Golgi
apparat
Mitochondrian
us
Nucleus
Rough ER
Plant Cell
Go to
Section:
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Figure 7-5 Plant and Animal Cells
Section 7-2
Nucleolus
Nucleus
Nuclear
envelope
Ribosome
(attached) Ribosome
(freeCell
)
Membrane
Mitochondrian
Smooth
endoplasmic
reticulum
Rough
endoplasmic
reticulum
Centrioles
Golgi
apparatus
Animal Cell
Go to
Section:
____The Nucleus
• Contains nearly all the cell’s DNA
• Codes for instructions to make proteins and
other molecules
• Surrounded by nuclear envelope---has many pores
to allow material in and out
• Contains chromatin—has DNA bound to
protein,usually spread throughout nucleus,but
condenses during cell division to make
CHROMOSOMES,containing genetic info
• Usually contain Nucleolus—assembly of ribosomes
begin here.
____Ribosomes
• Proteins are assembled here
• Made out of small particles of RNA and protein
• Found throughout cytoplasm
• Coded instructions from nucleus tell how to
make proteins
• Cells active in protein synthesis have a lot of
ribosomes
---Endoplasmic Reticulum
• Site where lipid components of cell membrane
are assembled,along w/ proteins and other
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materials exported from cell(those proteins are
made there)
• Rough ER is involved in protein
synthesis,because ribosomes are on it
• Newly made proteins leave ribosomes and insert
on rough ER ,where they may be modified
• If cell makes a lot of protein ,there is much
ER
• Smooth ER may contain many specialized enzymes
----Lysosomes
• Small organelles filled w/enzymes
• May digest or break down lipids,carbs,and
proteins into small molecules that can be used
by the rest of the cell
• Lysosomes remove “junk”,or used up organelles…very important that this aspect / function
occurs
--Vacuoles
• Sac like structures that store water ,salts
,proteins, and carbs
• Plants may have a single large water filled
vacuole
• Contractile vacuoles control water in
paramecium
==Mitochondria and Chloroplasts
• Most all eukaryotic cells contain mitochondria
that convert chemical energy stored in food
into compounds convenient for cell to use
• Mitochondria have an outer and inner membranes
• In humans,nearly all mitochondria comes from
ovum(egg cell)
-Chloroplasts
• Capture energy from sunlight and convert into
chemical energy in photosynthesis
• Contain 2 membranes and chlorophyll
--Organelle DNA
• In chloroplasts and mitochondria
• Small DNA molecules
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• Maybe descendants of early prokaryotes
• ----Endosymbiotic theory says these prokaryoic
ancestors developed a symbiotic relationship w/
early eukaryotes and resided within---evolving
into mitochondria
==Cytoskeleton
• Network of protein filaments that help cell
maintain shape
• Also involved in movement
• MICROFILAMENTS are threadlike structures made
of a protein-actin….make a major network and a
tough framework///allows amoebas and such to
move
• MICROTUBULES-hallow structures made of proteins
called tubulins—important in holding a cell’s
shape----form a mitotic spindle in cell
division/which helps separate chromosomes
• CENTRIOLES are microtubules near nucleus in
animals and help organize cell division
• Microtubules also help make projections like
cilia or flagella
Chapter 7 Notes cont’d
III. Cell Boundaries
 All cells have a
_____________________________and some have a
cell wall.
A.Cell Membrane
 Regulates what enters and leaves the cell and
also provides
__________________________________________.
 Almost all cell membranes are made of a double
layered sheet called a
______________________________________flexible,yet strong barrier
 Cell membranes usually have a protein molecule
imbedded in the bilayer w/ carbohydrate
molecules attached
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 Called a _________________model
 Some of the proteins form channels or pumps to
move material across the membranes
 Some of the carbs act as
____________________tags
Figure 7-15 The Structure of the
Cell Membrane
Section 7-3
Outside
of cell
Proteins
Carbohydrate
chains
Cell
membrane
Inside
of cell
(cytoplasm)
Protein
channel
Lipid bilayer
Go to
Section:
B. Cell Walls
 In plants,algae,fungi, and many prokaryotes
 Lie ________________the cell membrane
 Usually porous enough to let water,O2,CO2 and
certain other substances to pass through
easily
 Main function is support and protection
 Usually made of fibers of
_____________________________________produced in cell and secreted to surface
 Mostly _____________________-tough carb
fibers
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C.Diffusion Through Cell Boundaries
 Every cell is in a liquid
environment
 Cell membrane regulates the
movement of cell materials from
one side to the other
1. Measuring concentration
 Cytoplasm is a solution of various
substances in water
 ___________________________of a solution
is the mass of solute in given volume of
solution---ie. Mass/volume…..If you have
15 g salt in 3 L water,what is the
concentration?-----____________________________….If you
have 24 g salt in 2L water you would
have 12 g/mL salt….Which solution is
more concentrated?______________
2. Diffusion
o In a solution the particles move
constantly,spreading out
randomly….tending to move where more
concentrated to an area less
concentrated…This is called
__________________.
o ________________________________=
concentration of a solute is the same
throughout a system
o does not require energy because random
movement
o if equilibrium is reached,particles
keep moving across the membrane,still
balancing concentration

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D. Osmosis
o Some molecules are too large or too
strongly charged to make it across
the lipid bilayer----thus impermeable
to it
o Most membranes are selectively
permeable
o _____________________is the diffusion
of water across a selectively
permeable membrane
o water moves easily and will move to
balance the concentration of a
solute,water moving from area of
higher to lesser conc…..ie For the
WATER
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o ____________________-same strength of
a solute on both sides of a solute
o more concentrated side of solute is
____________________
o less concentrated side
is____________________________
o Osmosis exerts a pressure known as
______________________________________
on the hypertonic side of a
membrane….This could results in a cell
bursting
o Bursting not so much a problem in
larger organisms…-tend to be in
isotonic environments
o Osmotic pressure may not allow a plant
or bacterial cell to burst,but could
weaken the cell wall
o
See p.186
E. Facilitated Diffusion
 Some molecules,like
glucose ,diffuse quickly
across due to
________________________
 These allow only certain
molecules to pass
 Since it is diffusion it
does not require energy
and still goes from area
of higher to lower
concentration
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F. Active Transport---Movement
_____________________________
_____________________________
_____________________
 Requires much energy
 Usually carried out by
proteins or pumps found
in the membrane
1. Molecular Transport
 Small molecules and ions carried by
proteins that act like energy requiring
pumps
 Ca ,K,and Na ions are carried
2. Endocytosis and Exocytosis
 Transports larger molecules and
even clumps of matter
 __________________________________
is the process of taking material
inward by enfolding,or pockets
 In endocytosis ,the pocket breaks
loose from the cell membrane and
forms a vacuole…large
molecules,food and even whole
cells can be taken in this way
 2 examples of endocytosis are
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1. ______________________________________extensions of cytoplasm surround a
particle and package it in a food
vacuole,then the cell engulfs it ---This
is how amoebas eat-----is a form of active
transport
2. __________________________________________
-Cells use this to take up liquids in the
environment—tiny pockets filled w/ liquid
form along the cell membrane and pinch off
to form vacuoles
3. ______________________________________-releases large amounts from the cell by
pinching off or a contractile vacuole as
in paramecium---also active transport
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IV.The diversity of cellular life
Take your own notes here,using book and/or
powerpoint
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