Download Cell Structures and Functions Notes Jan 2003

Microscope Notes
Name:
One of the major developments in the field of biology was the invention
of the _____________________. This device provides an ____________
image of a small object, an object otherwise too small to be seen
with an unaided eye. One of the first microscopes was made by ____
______________________________. This microscope only had one lens
mounted to a metal support and is known as a _____________________
microscope. Its total magnification was about 300X.
A short time later, scientists began using the ______________________
microscope, which is composed of ________ lenses. The strongest of
the compound microscopes is about ___________________ times. The
limitation of the compound microscope is its _____________________
power. The resolving power is the ability of an instrument to separate
and distinguish two objects. Example: Look at the two lines on the side
of your notes. When you are close to them, you can easily tell that they
are separate. When you are far from them, they appear to be one line. At
this point, your eye can no longer resolve the two lines.
The problem of the resolving power of the compound microscope was
solved in the 1940’s when the _____________________ microscope was
invented. This method uses a beam of electrons rather than light. The
limitation of microscope is that it cannot be used to study living
specimens. The organisms must be sliced very thinly and fixed with
toxic chemicals.
The most recently developed microscope is the __________________
________________ microscope. Specimens do not have to be sliced
thin for viewing so living organisms may be observed. In the images
below, the first is a virus viewed with an electron microscope. The
second is a tick’s mouth parts taken with a scanning electron
microscope.
The diagram above illustrates the capabilities and limitations of these
microscopes.
Below is a diagram of a compound microscope similar to those that we
will be using in class.
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Modern Cell Theory
All living things are made up of _____________.
Organisms containing only one cell are called __________, while
organisms that are made up of many cells are called
_________________. You are _______________ because you
are made up of _____________ of cells.
Cells were first examined by __________________ in 1665 when he observed cork
under a microscope.
Understanding of the cell increased with the discoveries of the following scientists:
_______________________:discovered the nucleus (1831).
______________________ :stated that the cell is the unit of structure in plants (1838).
________________________:cell is the unit of structure in animals (1839).
________________________:all cells come from preexisting cells (1859).
The Modern Cell Theory: *know this*
1.
2.
3.
Cell Structures and Functions Notes
Cells differ in
1. _____________________________________
2. _____________________________________
3. _____________________________________
Internal Organization
_______________: contains _______ which directs the activity of the cell
________________: a cell component that performs specific functions in the cell
_________________: cells that contain a nucleus and membrane-bound
organelles
_________________: cells that lack nuclei and membrane-bound organelles
Eukaryotes (______________, _____________, ___________, ____________) and
prokaryotes (______________) differ greatly in structure.
Prokaryotes
Eukaryotes
1 - 10 μm
10 - 50 μm
billion years ago
billion years ago
nucleus?
membrane-bound
organelles?
size
when evolved?
cytoplasm?
cell membrane?
cell wall?
Some Do
ribosomes?
DNA?
examples
Circular
Free Floating
Cells can differ greatly from one another in size and shape. In multicellular
organisms, there is tremendous diversity among cells because they are
specialized to perform certain functions. There is a strong correlation between
shape and function. Cells are built a certain way in order to perform their
particular function more efficiently. The organelles inside a cell dictate what the
job of the cell will be.
Each living cell carries out the tasks of __________________, transforming food
into ____________, getting rid of _____________, and ____________________.
Cell Part or Organelle
Description and functions
the outermost living ___________ of animal cells.
______________ the exchange of substances
between the __________ and its environment.
a ______________, non-.living, rigid structure that
is produced by some cells; found outside of the
cell membrane; ________________ and
___________________ the cell; not present in
____________________.
thick __________ filling cell’s interior; location of
most metabolic activity; contains the
____________________
a network of __________ constructed of
microtubules and microfilaments; __________ cell
and maintains _______________.
membrane-bound; controls _______ activities such
as _____________.
outer boundary of _______________; consists of
double membrane containing ___________.
the ___________ material of the cell; in nondividing cells they appear as thin, threadlike
strands called _______________________.
spherical structure involved in the synthesis and
assembly of _______________; one or more may
appear in nucleus
the fluid-filled interior of the _______
in which the other parts are suspended
a system of membranous tubules that penetrates
through out the cytoplasm & is continuous with the
nuclear envelope. Intercellular highway (a path
along which molecules move from one part of the
cell to another)
has ___________ attached to it; helps to store and
transport _______
lacks _______________; functions in metabolic
processes including synthesis, storage, and
transport of ______ and carbohydrates w/in cell.
tiny particles floating freely in cytoplasm or
attached to ER; NOT
membrane-bound; aggregates of protein and RNA
molecules; location of
___________________synthesis;
bacteria cell
_________________
human liver cell _______________
stacks of flattened membranous sacs surrounded
by transport vesicles; receives proteins from the
rER and distributes them to other organelles or out
of the cell
(receiving, processing, packaging, and shipping)
large oval organelles; double membrane; inner
membrane is _______________ which is folded to
provide increased surface area; involved in
production of ________ as cell ______________
occurs here.
membrane-bound vesicles; formed by pinching off
Golgi apparatus;
contain _______________ enzymes;
digests _______ molecules, invading objects, or
worn out cell ________
________________ cells only
use ___________ to break down fats (these
molecules then go to the mitochondria as fuel for
respiration);
when in the liver, they detoxify alcohol and other
harmful cmpds; Degrade hydrogen peroxide, a
toxic compound that can be produced during
metabolism, into __________.
large membrane sacs used as _____________
chambers within the cytoplasm;
contain ________ molecules the cell has engulfed
or stored molecules such as lipids, pigments, or
wastes;
Animal cells: they are ___________ and small
Plant cells: ________________: one single large
vacuole taking up to _____% available space;
contains mostly ________ & provides internal
support
paired cylinders of microtubules @ ____________
angles;
usually near the ______________;
involved in cell division in ___________________
cells
found in _______; contain pigments
colorless plastid; store __________
contain ________________ pigments that give
_____________, flowers, and autumn leaves their
hues
green organelles found in plants & other
photosynthetic organisms;
double membrane; interior contains
______________ membranes where the pigment
____________ is found;
chlorophyll is essential for photosynthesis
hair-like organelles that extend from the
surface of cells
–When they are present in large numbers on a
cell they are called _________ ex:
___________________
–When they are less numerous and longer they
are called ___________ex. __________ & algae
for cell motility & to move ____________over
surface
Animal cells are very similar to plant cells except for the following major
differences:
–Animal cells do not contain _____________________
–Animal cells are not surrounded by _______________________
–The vacuoles in ______________ are much larger than those of
_________________
Animal cell
Plant Cell
Aerobic Respiration / Photosynthesis
Comparison Chart
Aerobic Respiration
Where it
happens in
the cell
Explanation
of Process
Chemical
Equation
Photosynthesis
Molecule movement and Cells
_______________________:
All organisms encounter great fluctuations in their environments (change in
______________, ______________, ________________, etc) that cause
them to struggle continuously to maintain a steady state. The process of
maintaining a relatively constant internal environment despite changing external
conditions is called __________________________.
If a cell is to maintain its identity and remain alive, it must maintain an internal
environment that is __________________ from its surroundings. The
__________ __________________ separates the chemicals in the cell from
those in its environment. The plasma membrane can be described according to its
________________________________:
1. __________________________: the membrane is impermeable when a
substance cannot pass through.
2. __________________________: the membrane is permeable when a
substance can pass through.
3. __________________________ (semi-permeable): the membrane
allows some substances through while others cannot.
Moving Materials Into and Out of Cells:
Particles move into or out of a cell by passing through the cell’s _________
_________________. _______________ transport is the movement of a
substance through a cell’s membrane ______________ the cell using any
______________. There are several different types of passive transport:
1. ______________________: A net movement of particles from an area
of _____________ concentration to an area of _______________
concentration. In the example below, a drop of ink diffuses until it fills the volume
uniformly. At this point the system can be described as being in
______________________. Equilibrium means that the _______________ of
a substance is the same throughout a __________.
Equilibrium
Key terms:
a) ___________: a substance that _______________ in another. Examples: sugars, amino
acids, and ions are solutes in cells.
b) _____________: the more plentiful substance that dissolves the solute; in cells, the
solvent is ________________.
c) ______________: the mixture of solutes and solvent.
d) ______________________________: the difference in concentration of a substance
across a space.
2. The second type of passive transport is __________. Osmosis is simply the diffusion of
water molecules through a ___________ from an area of __________ concentration to an area of
________ concentration.
We are comparing the concentrations of two solutions. ___________ is how the concentrations of
solutes in two solutions compare; determines movement of water into or out of cells. The
comparisons fall into one of three categories:
A. _______________ solution = solute concentration inside and outside cells is _________.
There is ___ net movement of water into or out of cell.
___% water in cell : ___% water out of cell
B. ______________ (low) solution = low in solutes (high in water molecules). Therefore water
moves _______ cell.
______% water in cell (______): _______% water outside cell (________)
C. ________________ (high) solution = high in solutes (low in water molecules). Therefore water
moves ________ cell.
_______% water in cell (_______): ____% water outside cell (________)
In the example below, side B has a higher concentration of water molecules to side A (side B is
hypotonic, side A is hypertonic). Water will move from side B to side A.
Before
After
Above is an example of a human blood cell in the 3 types of solution. Note the cell is maintaining
homeostasis in the isotonic solution. The cell gains water in the _____________ solution until it
has __________ or ruptured. The cell __________ in the ____________ solution because it
loses water.
This second example demonstrates the effect of osmosis on plant cells. In the first picture, plant
cells have been placed in a ___________ solution so that water has entered the cells. The
_____________ keep the cells from rupturing. The pressure within the cell (_________
_________) is great and the cell is said to be ___________. The second picture illustrates a
plant cell in _____________ solution. _____________ has occurred and the plant is
___________ (low _______________ pressure).
3. The third type of passive transport is ______________ diffusion. In this type of transport,
some molecules such as _____________ is transported across the membrane from _________
conc. to __________ conc. by a _________________. The protein is specific in the molecule it
can carry.
__________________: ________________ is required to move a material across the cell
membrane ________________ a concentration difference (low to high concentration).
These are the types of active transport:
1) _______________ pumps: cause the production of ____________ molecules (the form of
energy used by a cell); these pumps transport protons through the internal plasma membranes of
the mitochondria and chloroplasts.
2) ____________________ Pumps and couple channels: Uses the energy of ___________ to
power the active transport of sodium (Na+) ions out through a cell’s membrane and potassium (K) in.
This is the most important energy-using process in your body!!!!! More than 1/3 of all the energy
used by a human cell (that is not dividing) is used to transport sodium ions.
Why? 1) This is how nerve cells send impulses (more later)... and....
2) They help to transport _________ particles and a variety of other particles into your
cells by two different kinds of channels. One is the sodium-potassium pump. The other channels
are coupled channels.
How?
1. Active transport of Na+ out of the cell increases the Na+ concentration outside
the cell (as many as 300 per sec). This increase leads to step 2.
2. Na+ move back into the cell by the coupled channels that also carry sugar
molecules. The coupled channel contains two passageways through the membrane. The force of the
Na+ is so great that it pulls sugar molecules into the cell too.
How Molecules Cross the Membrane
Active/passive
Molecules
that move
Diffusion
direction
Energy
needed
Protein
needed
Osmosis
Facilitated
diffusion
Active
transport
Sometimes food particles are too large to enter through protein channels. In this case, the cell
engulfs the particle by means of ______________. If the material is liquid and contains dissolved
molecules, the endocytosis is called _______________. Human egg cells receive nourishment via
__________________. If the material brought into the cell is another cell or other fragment of
organic matter, the process is called ________________________. Ex: white blood cells,
Amoebas.
phagocytosis
pinocytosis
Phagocytosis &
the Amoeba
_________________ is the opposite of endocytosis. This is when the cell
___________________________ waste materials out of the cell.
The Cell Membrane Notes
Cell Membrane Structure
The _________________________________________________ of the cell membrane shows
that it is composed of proteins that are similar to shifting tiles. The spaces between the tiles are
filled with fluid-like ________________________________.
Phospholipids consist of ___________________________ (water-loving) heads, which point
towards the outside environment and the cytoplasm. The
_____________________________________________ repel the water and point in.
Extracellular fluid (watery environment)
Phospholipid
bilayer
Hydrophobic tails
Hydrophilic heads
cytoplasm (watery environment)
This causes the phospholipids to form a double layer (bilayer) that acts like a barrier between the
cell and the environment. The ___________________________________ also contains
_____________________________, which makes it stronger, more flexible and more
permeable.
Memorize Fig.
7-12 on p. 182
of textbook!!!
The purpose of the membrane is to control what goes in and out of the cell!