Download III. Membrane Transport (Active and Passive)

Biology Test #3 Notes: Cell Structures, Functions, and Membrane Transport
I. Cell Theory (data gathered over a 200 year period by several scientists)

All living things are made up of at least one cell.

The cell is the basic/smallest unit of structure and function in living things (the bricks of buildings).

_____________________________________________________________________________

In 1665, Robert Hooke was the 1st to see and name the cell from cork found in plants using a ______________.

In 1676 Anton Von Leeuwenhoek was the 1 st to view a _______________ _____________.

Robert Brown in 1831 was the 1st to see and name the _______________ of a cell.
Why did it take more than 160 years for Brown to view the nucleus after Leeuwenhoek’s discovery?
II. Parts of a Cell and Their Generalized Functions (3 general areas – cell membrane, cytoplasm w/organelles, and
the nucleus)
1.
Cell Membrane – A bilipid structure that is the outermost portion of the cell
Functions include:
(a) A boundary between the cell’s contents and the
environment which regulates what enters and exits
the cell.
(b) Communicates with other cells within an organism or
unicellular organisms.
(c) Contains proteins that identify the cell.
(d) It serves as an attachment site for some organelles and near-by cells
2. Cytoplasm and it’s Organelles- Cytoplasm may also be called the Intra-Cellular Fluid/ICF or Cytosol.
a) Cytoplasm is a viscous fluid made up of water, minerals, organic molecules, and organelles. It is located
between the cell membrane and the nuclear membrane.
b) Organelles, or “little organs”, perform specific functions for the cell (division of labor).

Ribosomes – Site of _____________ ________________ (where protein macromolecules are made
using directions from DNA).
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
Endoplasmic Reticulum
- Rough ER (endoplasmic reticulum) hold ribosomes (protein maker) on their membranes.
- Smooth ER makes new membranes for organelles and the cell using lipids, carb’s, &
proteins.
- Both ER’s are pathways/tunnels for molecules to travel through cytoplasm or out of the cell.

Golgi Apparatus/Body – Golgi combine small glucose molecules into larger starch or glycogen molecules.
They attach these carbohydrates with lipids to proteins which now packaged
to the correct size and shape and ready to be used or stored by the cell.

Mitochondria – ___________________________________________________________________
___________________________________________________________________
Mitochondria have their own ___________.

Lysosomes – Hold digestive enzymes that breakdown old cell parts, nutrients, & foreign substances
(toxins/bacteria).

Cytoskeleton – An arrangement of proteins (microtubules & microfilaments) that support and give the
cell its shape.
The cytoskeleton disassembles near the end of a cell’s life cycle allowing a cell to split into 2 new cells.
The disassembled cytoskeleton will reform into the spindle apparatus, a temporary cell part that
ensures that each of the 2 new cells will get the same # of chromosomes. After chromosomes evenly
divide, the cell splits w/each new cell getting a portion of the spindle apparatus which will become
their new cytoskeleton. This will give each new cell support and a specific shape.


Microfilaments – Long, thin fibers that give a cell its shape and enables the movement of organelles
within the cell.

Microtubules – Hollow tubes that move chromosomes (spindle apparatus), they also make up
centrioles.
Centrioles – Pairs of bundled microtubules located in the cytoplasm that assemble the spindle apparatus
(has its own DNA).
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
Cilia – ________, numerous microtubules on cell membranes functioning in movement of the cell or
substances near cell.

Flagella – ____________, usually singular microtubule from the cell membrane that functions to move a
cell (sperm tail).
Organelles primarily in plant cells
 Cell Wall – A tough, supportive and protective covering of plants (of cellulose), fungi (of chitin), most
bacteria, and some protists. The cell wall is located outside the cell membrane and allows
most molecules to pass.

Vacuoles – Large sac’s that store proteins, lipids, carbo’s, water, & waste. Can give a cell structural
support (turgor).

Plastids – Storage sac’s holding macromolecules & pigments. Pigments allow photosynthesizers to absorb
light energy .

Chloroplasts – Green pigmented plastid (filled w/chlorophyl) that absorbs light. Have their own
DNA.
Chromoplasts – Yellow, orange, and red plastids that absorbs light.

Leucoplasts – Nonpigmented plastids that store starch (carbohydrate), proteins, and lipids.

3. Nucleus – The nucleus is surrounded by the ______________ ______________, which envelops nucleoplasm
that protects ______.
DNA makes RNA (3 types), RNA then travels to the cytoplasm to make _______________.
Proteins determine an organisms ______________.
The nucleus also contains the nucleolous which makes the ribosomes. Ribosomes (made up mostly of
RNA) then travel to the cytoplasm where most will attach themselves to __________________ ER.
III. Cell Shape & Function, Size Limitations, and Cell Types

The cell is the smallest living portion of any organism, unicellular (one-celled) or multicellular (many-celled). In a
multicelled organism, like a human, there can be over 200 different types of cells, trillions in all.

3 characteristics determine a cell’s function:
a)

b)
c)
In multi-celled organisms, individual cells may specialize. Specialized cells perform a limited amount of jobs.
Advantage of Cell Specialization – Increased ________________________________________.
Disadvantage of Cell Specialization – Increased _________________________________________.
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Cell Size Limitations:

If a cell gets too large, the distance between the nucleus (containing DNA which controls protein synthesis) and
other organelles becomes too great for effective control and communication.

As a cell grows, its surface area (cell membrane) grows at a slower rate than its volume (organelles, cytoplasm, &
nucleus).
Why does this limit cell size?
a) Prokaryote Cells - Kingdoms:
b) Eukaryote Cells –
- Kingdoms:
IV. Microscopy (The Microscope)
Properties of Light Microscopes
Magnification – An increase in the size of an image.
Resolving/Resolution Power – How clear the magnified specimen appears.
Field of View – How much of the image is seen through ocular. 40x =
100x =
400x =
Depth of View – How resolute/clear images appear at different distances from the ocular/eyepiece.
 Increasing the magnification will decrease resolving power, field of view, and depth of view.
Data Table Contrasting Light vs. Electron Microscopes
Microscope Characteristics
Light Microscope
Electron Microscope
Light – Air
Electron beam – Vacuum
Colored specimen’s, stain’s, & dye’s can be seen
No light = no color
Highest practical magnification
Radiation source & medium of travel
Radiation focussing mechanism
Specimen image
Specimen type (dead or alive)
Size & Cost
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Structures and Functions of a Common Light Microscope
 Color each microscope part by its color as indicated in the data table, below left. Be sure to color in the
word in the data table and on the picture of the light microscope, below right.
Microscope Part Function
Microscope Part
Arm & Base
(light blue, dark blue)
The 2 parts held while carrying a scope
Ocular/Eyepiece
(red)
Holds a 10x lens for magnification and where
the specimen is viewed
Ocular Tube
(light green)
Creates a distance between ocular lens and
objective lens for correct magnification
Revolving Nosepiece
/Objective Turret
(pink)
Moves objectives w/different magnifying
powers to be rotated above specimen
Objective Lens
4, 10, 40, & 100x
(dark green)
Carries the 2nd lens for magnification
Stage w/clip
(black)
Holds slide/specimen in place for viewing
Stage Aperture
(not seen in this view)
Hole in the stage allowing light through
Iris Diaphragm
(orange)
Controls light passing through specimen
Light Source
(yellow)
Provides light needed to produce an image
Course and Fine
Objective Knobs
(dark & light brown)
Moves the stage up and down to focus or
improve resolution of the image
Condenser
and Knob
Condenses/focuses light before it passes
through the specimen
Light Intensity Knob
(gray)
Regulates light intensity from the source
Slide Adjustment
(not seen in this view)
Moves slide/specimen (forward, left, right,
backword) w/o you touching the slide
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III. Membrane Transport (Active and Passive)
HEY!?!?! How do cells get… amino acids to build proteins? Nucleotides to build DNA & RNA? Carbon dioxide
and water for photosynthesis? Water, minerals, vitamins, etc.?
Plants acquire carbon dioxide from the air via their leaves and water from the soil via their roots.
Animals acquire water and nutrients from plants and other animals via their mouths.
 What gets across a cell’s membrane? How do molecules get in? How does the cell rid itself of waste? Is
energy needed for membrane transport (the movement of molecules across a cell’s membrane)?
Homeostasis – Homeostasis is an organisms way of maintaining normal function.
Examples include: _____________________________________________________________
- Homeostasis is maintained by negative and positive feedback mechanisms (see test #1 notes).
- Because cells are the basic unit of structure and function, if they die, the tissues they comprise may
die. If tissues die, organs may fail. If organs fail, the organism can die.
Maintaining the cells internal environment (the fluid that surround cells – ECF/Extra Cellular Fluid)
so the cell has all the raw materials needed to live and function properly is vital to the organism’s
survival.
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Homeostasis must be maintained even under times of stress.
-
Stress includes: ________________, malnutrition, physical exertion, pathogen ____________
(bacteria, viruses, etc.), and temperature ____________________.
- The ________________of molecules (hormones to be transported to other cells, excess water,
and waste products) from the ICF/IntraCellular Fluid (or Cytoplasm) to the ECF (outside the
cell) is as essential to maintaining homeostasis as the entrance into the cell of molecules
that provide the raw materials and energy needed for biochemical processes.
- The cell’s membrane structure allows it to be semi- or selectively _____________________,
allowing some, but not all molecules through.
Permeability fluctuates according to the ever changing needs of the cell. For example, if the
cell needs more glucose (sugar), the cell membrane will be more permeable to sugar, allowing
more sugar to enter the cell.
1. Passive Transport – The movement of molecules (H20 or solutes) across a cell’s membrane (in or out) w/o the use
of ___________ to achieve equilibrium. Equilibrium is an equal concentration of a particular
molecule in the ECF and ICF.
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a) Simple Diffusion – The movement of molecules or _____________
(small molecules dissolved by water to form a
solution) from an area of greater concentration
to an area of lesser concentration. The cell’s
membrane acts as a _______________________
or boundary between areas of differing concentrations.
b) Facilitated Diffusion – The movement of molecules that move through
specific channels/holes via proteins embedded in the
cell membrane. Molecules may enter or exit, but only
traveling down a gradient, or area of high to low
concentrations. As with simple diffusion, facilitated
diffusion occurs with no energy being used. Each molecule that enters or leaves must do so
through a specific protein channel (100’s in all).
c) Osmosis – The movement of ___________ molecules across
a cell’s membrane from an area of higher to lower
concentration w/o the use of energy.
As the amount of water increases in the ICF/cytoplasm,
so does the pressure is exerts on the cell membrane.
The force of water on the cell membrane is termed
________________ (or osmotic) pressure.
When turgor/osmotic pressure is too low the cell wilts (plasmolysis) and when turgor/osmotic
pressure is too high the cell bursts (cytolysis).
Type of Transport
Diffusion
Osmosis
Facillated Diffusion
Active Transport
Materials Moved
(example:water,
minerals)
Direction of
movement(example, High
conc. to Low conc.)
Energy Requirements
* Terminology associated with the movement of molecules across a cell’s membrane *
Hypertonic– The area (ICF or ECF) that possesses a higher concentration of a solute and a lower concentration of
water.
Hypotonic – The area (ICF or ECF) that possesses a lower concentration of a solute and higher concentration of
water.
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Isotonic– A condition in which the ICF and the ECF are in equilibrium, or an equal molecule concentration.
_________tonic
_________tonic
ECF =
42% solute
ECF = 42% solute
_________tonic
ECF =
42% solute
ECF = 42% solute
ECF = 42% solute
Indicate, using red arrows, the direction solute molecules are moving (diffusion) in each of the cells above.
Indicate, using blue arrows, the direction water molecules are moving (osmosis) in each of the cells above.
2. Active Transport – The movement of molecules from an
area of lower concentration to an area
of higher concentration. To move
molecules against the concentration
gradient, cellular energy is needed (ATP).
a) Endocytosis – The movement of substances into a cell by
being surrounded/engulfed by the cell’s
membrane.
 Phagocytosis – Endocytosis of a large molecule
or small unicellular organism.
 Pinocytosis – Endocytosis of large quantities
of fluids or dissolved substances.
b) Exocytosis – Movement of large molecules or quantities
of fluids/dissolved substances out of the cell.
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Biology Test #3 Format: Cell Structures & Functions, and Cell Membrane Transport
1-15 = Multiple Choice (will cover anything not asked in matching or completion questions)
16-25 = Matching cell part/organelle to its description (answers may be used once, more than once, or not at all)
26-32 = Complete with the best possible answer

Discuss in sentence format, a positive and negative aspect of “Cell Specialization”.
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Be able to discuss which organelles are found exclusively in plant cells and which can be found in both plant and animal cells.
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Draw and label a segment of a cell/plasma membrane that contains the following:
protein channel
hydrophobic tail
hydrophilic head
ECF
ICF
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Do all cells have the same number of individual organelles? Explain.
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Describe what is occurring during an experiment regarding diffusion or osmosis.

What organelle produces glucose?
What organelle converts glucose into a different form of energy?
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