Download PROKARYOTIC and EUKARYOTIC CELLS

Biology CP
Name________________________________
Unit 3 Cellular Biology
Part 3C Structure and Function
(NOTE: Included in this unit: History of the Microscope and Cells and Microscope Use)
The Cell Theory states:
Textbook p. 190
1. All living things are made up of cells.
2. Cells are the basic unit of structure and function in living cells.
3. New cells are produced from existing cells
Even with the wide variety of cellular size, shape and function, the structure of all cells is remarkably
similar.
Despite their differences, all cells, at some point, contain *___DNA_______ the molecule that carries
biological information. In addition all cells are surrounded by a thin, flexible barrier called a *cell
membrane.
PROKARYOTIC and EUKARYOTIC CELLS
Textbook p. 193
Cells fall into two broad categories depending on whether they contain a *nucleus________.
The nucleus (plural-nuclei) can be described as a large membrane enclosed structure that contains
genetic material in the form of DNA and cntrols many of the cell’s activities.
Eukaryotes are cells that *___enclose their DNA in nuclei____________.
Prokaryotes are cells that *____ do not enclose their DNA in nuclei ____________.
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Prokaryotic cells are generally *______smaller______________ and *_____simpler___________
than eukaryotic cells. Despite their simplicity, prokaryotes carry out every activity associated with
living things. The organisms we call ________bacteria_________ are prokaryotes.
Eukaryotic cells are generally *________larger______________ and *____more
complex_________________ than prokaryotic cells. Eukaryotes display great variety. Some, like the
protists, live solitary lives as *_____unicellular______ organisms. Others form large
_________multicellular_________ organisms (ex. Plants, animals and fungi).
*Differences and Similarities Between Prokaryotic and Eukaryotic Cell Types
*to fill this table in, see pages 206-207. (+ present, -- absent)
Cell Characteristic
Prokaryotic Cell
Eukaryotic Cell
outer cell membrane
+
+
cytoplasm-cellular fluid
+
+
ribosomes-structures which form proteins
+ smaller
+ larger
nucleus
-
+
chromosomes (DNA or RNA)
+
+
membrane bound organelles
-
+
cells carry out life processes
+
+
average size of cells
1-10 m
2-1,000m
time of evolution
3.5 billion years ago
1.5 billion years ago
Found in these Domains
Archaea and Bacteria
Eukarya
general shape of the cell
spherical, rod
shaped, spiral
wide variety of shapes
depending on function
Let’s explore the size and scale of cells:
http://learn.genetics.utah.edu/content/begin/cells/scale/
http://learn.genetics.utah.edu/content/cells/scale/
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CELL ORGANIZATION:
Textbook Lesson 7.2 p.196-207
It’s easy to divide the Eukaryotic cell into two major parts: the * ___nucleus________ and the
*__cytoplasm______. The *__cytoplasm______ is the portion of the cell outside the nucleus.
___Prokaryotic____cells have cytoplasm, too, even though they do not have a nucleus.
The cytoplasm contains an aqueous (water-based) solution (also called the Cytosol).
The Cytoplasm looks just like “empty space” in diagrams, but it’s not!
The cytoplasm is a dynamic and active part of the cell. The cell’s metabolism (the sum of all
chemical reactions in the cell), transport of materials throughout the cell and the activities
associated with each organelle all occur in the cytoplasm.
We will consider each major structures of eukaryotic plant and animal cells (some of which are
found in prokaryotic cells) one by one.
Because these structures act like specialized organs, they are called *__organelles___________,
literally “little organs”.
ANALOGY: In some respects the living cell can be compared to a modern factory. Organelles of the
cell can be compared to the specialized machines and assembly lines of the factory. Cells, like
factories follow instructions and produce products. This analogy works so well, we can use it to help
us understand how cells work. As you learn about the cell, think about the comparisons.
A. NUCLEUS
Like the main office in a factory, the nucleus is the
_______control center________ of the cell.
Structure of the Nucleus:
1. The nucleus contains: *_nearly all the cell’s DNA and, with it , the coded instructions for
making proteins and other important molecules____________.
Note: Prokaryotic cells lack a nucleus, but they do have *_______DNA__________ that
contains the same kinds of instructions.
2. The nucleus is surrounded by a double membrane that is also called the nuclear
envelope. The nuclear envelope is semi permeable:
a) Covered with small nuclear pores (openings).
b) the nuclear pores keep DNA within the nucleus but allow smaller molecules
like RNA and proteins out.
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3. *__Chromosomes____, which carry the cell’s genetic information, are also found in the
nucleus. Most of the time, it is spread throughout the nucleus in the form of *_chromatin____
(a complex of DNA bound to proteins), but when a cell divides this condenses into
*__chromosomes___ which can be seen under a microscope.
3. The nucleus usually contains one or more nucleoli (nucleolus is singular) which are areas
composed of sections of condensed DNA and proteins (they look dark when viewed through
the microscope). The nucleolus is where *________the assembly of ribosomes
begins_____________________.
B. VACUOLES, VESICLES, LYSOSOMES, AND THE CYTOSKELETON
These organelles represent the cellular factory’s _storage space__, __cleanup crew__,
and_support structures___.
VACUOLES and VESICLES
Vacuoles and vesicles are places for the cell to store things!
Vacuoles and vesicles are both found in cytoplasm of all eukaryotic cells. They are sac-like
membrane-enclosed structures (compartments).
The function of vacuoles is to: *store materials like water, salts, proteins, and carbohydrates
Plant cells typically have one large central
vacuole filled with *_liquid__. The pressure of
the central vacuole in these cells increases
their *__rigidity____, making it possible for
plants to support heavy structures, such as
*____leaves____ and flowers.
Vacuoles are also found in some unicellular organisms and some animals.
For example,
paramecium (a freshwater protist) contains a specialized vacuole called a *_______contractile
vacuole____________ that contracts rhythmically to pumps excess water out of the cell.
Some
organisms form “food vacuoles” through endocytosis or release waste particles by exocytosis.
Nearly
all
eukaryotic
cells
contain
smaller
membrane-enclosed
structures
called
*_____vesicles______ which store and move materials between cell organelles, as well as to and
from the cell surface.
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LYSOSOMES
Lysosomes are the ______clean up crew___________, they take care of “junk” removal!
Lysosomes are small organelles (membrane-bound sacs) filled with *____enzymes_______.
They are found in the cytoplasm of all animal cells, but are rare in plant cells. (Plant cells store
their digestive enzymes in the large, central water vacuole instead).
Lysosomes break down *
lipids, carbohydrates, and proteins into small molecules that can be
used by the rest of the cell
_____
Lysosomes are also involved in breaking down *
organelles that have outlived their
usefulness
***Lysosomes form compartments that maintain the
-----lysosome
correct pH for the enzymes of hydrolysis, while at the
same time protecting the cell from the digestive
enzymes that might break down necessary cell parts.***
Lysosomes are formed by the Golgi apparatus.
.
CYTOSKELETON
The cytoskeleton provides movement and support. It is
like the __steel______ or cement beams and
__columns____ that hold up the factory walls and roof.
Eukaryotic cells are given their shape and internal organization
by a network of *__protein_____ filaments known as the
*__cytoskeleton_______.
Certain parts of the cytoskeleton also help *____transport____
materials between different parts of the cell, much like the
*___conveyor belts____ that carry materials from one part of a
factory to another.
Some cytoskeletal components may also be involved in moving the entire cell as in *_cell flagella___
and *____cilia_____.
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The cytoskeleton helps*
the cell maintain its shape and is also involved in movement
The cytoskeleton is mostly made up of two different types of protein filaments:
1. Microfilaments are *
threadlike structures made up of a protein called actin
Form a tough flexible framework that supports the cell and help cells move.
2. Microtubules are * hollow structures made up of proteins called tubulins
In many cells, microtubules play critical roles in maintaining
cell shape. They are also important in cell division.
In animal cells, organelles called *___centrioles____ (which
help organize cell division) are also formed from tubulins.
Microtubules also help build projections from the cell surface:
*_cilia (plural) _- (shorter, more numerous)
cilium (singular)
*_flagella (plural)_- (longer, fewer)
flagellum (singular)
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C. ORGANELLES THAT BUILD PROTEINS: RIBOSOMES,
ENDOPLASMIC RETICULUM, AND the GOLGI APPARATUS
RIBOSOMES
Each ribosome is like a _small machine_____ in a factory, turning out proteins on orders that
come from its DNA “___boss____”!
Ribosomes are found in both prokaryotic and eukaryotic cells, though in prokaryotic cells the
ribosomes are smaller and simpler.
Ribosomes are: * small particles of RNA and protein
Ribosomes produce *
proteins by following coded instructions that come from DNA
Ribosomes are made by the NUCLEOLUS.
Ribosomes can be found attached to the rough ER or or floating free in cytoplasm.
ENDOPLASMIC RETICULUM
The endoplasmic reticulum is like the _conveyor__ ___belt_______ on an assembly line!
The Endoplasmic Reticulum (ER) is where * lipid components of the cell membrane are
assembled, along with proteins and other materials that are exported from the cell
The ER is found in the cytoplasm of all eukaryotic cells.
Rough Endoplasmic Reticulum: The portion of the ER involved in the
synthesis of proteins is called the *rough Endoplasmic Reticulum. It is
given this name because of the *___ribosomes_____ found on its surface.
Newly made proteins leave these ribosomes and are inserted into the
rough ER, where they may be chemically *_modified___.
Proteins made on the rough ER include those that will be released, or *________secreted____ , from
the cell as well as many *_________membrane_____ proteins and proteins destined for
*___lysosomes_____and other specialized locations within the cell. Cells which produce large
amounts of protein for export have large amounts of Rough ER.
Other cellular proteins are made on “*
membranes.
free
“ ribosomes, which are not attached to
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Smooth Endoplasmic Reticulum: Ribosomes *___are not______ found on the
surface of the smooth ER. In many cells, the smooth ER contains collections of
*____enzymes_____ that perform specialized tasks, including the synthesis of
*________membrane lipids____ and the *_detoxification_______ of drugs.
*___Liver_____cells, which play a key role in detoxifying drugs, often contain
large amounts of smooth ER.
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GOLGI BODIES OR GOLGI APPARATUS
The Golgi apparatus directs customization and packaging/shipping!
In eukaryotic cells, proteins produced in the rough ER move next into an organelle called the Golgi
apparatus which appears like a stack of *____flattened membranes_________.
As proteins leave the rough ER, molecular “*_________address tags____” get them to the right
destination as they are bundled into tiny *____vesicles______ that bud from the ER and carry
them to the Golgi.
The Golgi apparatus *_modifies, sorts and packages proteins and
other materials from the endoplasmic reticulumfor storage in the cellor
release outside the cell.
From the Golgi, proteins are “shipped” to their final destination
inside or outside the cell.
D. ORGANELLES THAT CAPTURE AND RELEASE ENERGY
CHLOROPLAST
Chloroplasts are the biological equivalent of _solar_ _power__plants; site of Photosynthesis!
Chloroplasts are located in the cytoplasm of eukaryotic autotrophs such as plants and some
other organisms.
***Each chloroplast contains its own unique DNA, proteins and ribosomes; can self-replicate.***
Function: Chloroplasts capture*energy from sunlight and convert it into food that contains chemical
energy in a process called photosynthesis.
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Read pages 230-233 (Lesson 8.2 in the text) for information on chloroplasts and
photosynthesis.
Plants gather the sun’s energy with light-absorbing molecules called *_pigments____.
Plants’ principal pigment is *____chlorophyll_ which appears green to our eyes because it does not
absorb light well in the green region of the spectrum.
The chloroplast contains saclike photosynthetic membranes called *____thylakoids______ which are
interconnected and arranged in stacks known as *grana_________ (singular: granum). Pigments
such as chlorophyll are located in the thylakoid membranes. The fluid portion of the chloroplast,
outside of the thylakoids, is known as the *____stroma___.
Photosynthesis uses the energy of sunlight to:* convert water and carbon dioxide (reactants) into
high-energy sugars and oxygen
Plants then use the sugars to produce complex carbohydrates such as *_starches___, and to provide
energy for the synthesis of other compounds, including *_proteins____ and *___lipids_____.
Write the overall equation for photosynthesis :
light
In symbols:* 6 CO2 + 6H2O __
C6H12O6 + 6O2
light
In words:*
Carbon dioxide + water
sugar + oxygen
Although the equation for photosynthesis looks simple, there are many steps to get from the reactants
to the final products. In fact, photosynthesis actually involves two sets of reactions which work
together to capture the energy of sunlight and transform it into energy-rich compounds such as
carbohydrates.:
*_Light-dependent_ reactions (Calvin cycle) require the direct involvement of light and lightabsorbing pigments. These reactions take place within the thylakoid membranes. Uses water and
produces oxygen.
*__ Light-independent __ reactions use carbon dioxide but do not need light and complete the
process of photosynthesis by producing carbon-containing sugars and other carbohydrates. These
reactions take place outside the thylakoids in the stroma.
*Think about it:
Do you think all plant parts contain chlorophyll? Explain. *__No, only those cells that receive sunlight
produce chlorophyll, it would not be efficient to produce chlorophyll in other cells__________
Some prokaryotic bacteria are photosynthetic. Do they contain chloroplasts?*______No, they do not
have membrane-bound organells.
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MITOCHONDRIA
Textbook Lesson 7.2 p. 202
Mitochondria are like the _____power____ __plants__________ of the cell!
Mitochondria are located in the cytoplasm of all eukaryotic cells
(In humans, nearly all of our mitochondria come from the cytoplasm of the egg cell (mother)).
Function: Mitochondria convert *
more convenient for the cell to use.
the chemical energy stored in food into compounds that are
Structure:
Each mitochondrion contains its own unique DNA, proteins and ribosomes; can self-replicate.
Has an outer membrane which encloses a fluid (“matrix”) and a highly folded inner membrane
(“cristae”).
**Mitochondria convert chemical energy stored in food into a form that can be used easily by
the cell. This form is called ATP.**
*Think about it:
Which do you think would contain more mitochondria- a heart
muscle cell or a skin cell?
Why?*
a heart muscle cell. There is constant need for
availability of energy in the form of ATP
_____________________________________________
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Read pages 226-227 (Lesson 8.1in the text) for information on ATP.
What does ATP stand for?*
adenosine triphosphate_____
ATP is a nucleotide which contains the following three parts: *
and three phosphate groups ________________
adenine, ribose (5-carbon sugar),
ATP can easily release and store energy by *_____breaking _____ and *___reforming_______ the
bonds between its phosphate groups, making it exceptionally useful as a basic energy source for
all cells.
Since cells can regenerate ATP as needed by using the energy in foods like glucose, cells usually
only store a *____small___ amount of ATP.
Read pages 250-251 for information on cellular respiration.
Food provides living things with the chemical building blocks they need to grow and reproduce.
Food molecules contain chemical energy that is released when their chemical bonds are
*___broken___. Rather than burning food and releasing all of its energy as *_heat___,
cells instead break down food molecules gradually, capturing a little bit of chemical energy
at key steps. This enables cells to use the energy stored in the chemical bonds of foods
like glucose to produce compounds such as *_______ATP____ that directly power the
activities of the cell.
If cellular respiration took place in just one step, all of the energy from glucose would be
released at once, and most of it would be lost in the form of *___light____ and
*___heat_____.
If oxygen is available, organisms can obtain energy from food by a process called aerobic
cellular respiration which involves the mitochondria. [If oxygen is not available, cells must
undergo a less efficient anaerobic process called fermentation (occurs in the cytoplasm).]
Write the overall equation for aerobic cellular respiration :
light
In symbols:*
C6H12O6 + 6O2
6 CO2 + 6H2O + energy
light
In words:*
Glucose + oxygen
carbon dioxide + water + energy
There are three main stages of cellular respiration:
1. Glycolysis – occurs in the *_____cytoplasm______ of the cell.
Produces a small amount of ATP.
2. Krebs cycle – takes place inside the *___mitochondrian____ (in the matrix).
Produces a small amount of ATP.
3. Electron transport Chain – takes place inside the *__ mitochondrian ________ (on
the cristae membranes).
Produces a large amount of ATP.
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E. CELLULAR BOUNDARIES
The cell, like a factory needs _____walls____ and __a roof_______to protect it from the
environment outside, and also to serve as a barrier that keeps its products safe and secure
until they are ready to be shipped.
CELL WALL
Don’t confuse a cell wall with the cell membrane. The cell wall is located outside the cell
membrane and is only present in certain organisms:
Main functions:* ___support, shape, and protect the cell___________
Found in some organisms: * most prokaryotes and many eukaryotes_____
Not found in other organisms: * _not found in animal cells________________
Location in the cell:* ___outside the cell membrane_____________
Structure:
1. Is inflexible without breaking. Not found in animals because we need to be more flexible
for movement.
2. Is composed of multiple layers of carbohydrates (cellulose) and other molecules.
3. Most are porous with openings that allow substances like water, oxygen, carbon dioxide to
pass through.
4. Bacteria, Fungi, Protists, Plants – each group has a slightly different makeup of cell wall
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CELL MEMBRANE (PLASMA MEMBRANE)
Let’s review…
Fluid Mosaic Model-The cell membrane is
made of 2 layers. The membrane is actually
more like a fluid than a solid. Proteins “bob” like
floats within the phospholipid bilayer.
The cell membrane is made of three different
macromolecules: * ____lipids_________,
____proteins____, and _carbohydrates__.
Some of the proteins form* _channels____
and* _____pumps___ that help move material across the cell membrane. Other proteins attach
directly to the *__cytoskeleton____, enabling cells to respond to their environment by using their
membranes to help *________move____ and *_____change shape_____. Many of the carbohydrate
molecules act like *___chemical identification cards_______, allowing individual cells to recognize
one another.
Functions of the plasma membrane:
1. Boundary between the cell and the ______environment_________________
2. Selectively permeable: _____some substances can pass through and others
cannot__________________________________
3. Helps cell to maintain ___homeostasis________ so the correct amounts of solutes and
solvents are available within the cell.
For a review of all the structures of cells, explore:
http://learn.genetics.utah.edu/content/begin/cells/insideacell/
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*Write the names of each lettered structure using the diagram above.
A mitochondria_ - powerhouse of the cell cell respiration takes place here, ATP production
B
chloroplast- site of photosynthesis in plants; not found in animal cells
C
cell membrane-selectively permeable barrier; allows certain molecules into and out of the cell
D ____cytoplasm-material between cell membrane and nuclear envelope; site of most metabolic reactions
E
ribosomes-site of protein synthesis –are found on ER and free floating in cytoplasm
AB
cell wall-in plant cells only, outside of cell membrane for support and protection
AC
vacuole-holds water, food and waste products; large central one in plants, smaller ones in animals
AD
nucleus(DNA) – not an organelle; regulates all cellular activity through protein synthesis
AE
nucleolus – not an organelle; area of densely packed DNA and proteins; site of ribosome production
BC
smooth ER– lipids made here; detoxification of alcohol and drugs like sedatives
BD
golgi apparatus –matures; packages and exports proteins from the cell
BE
lysosomes –contain hydrolytic enzymes for digestion
CE
centrioles –only in animal cells; important in cell division
Which cell – the one on the right or the left – is the Animal cell?__right_ Plant cell?___left____
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FORM LEADS TO FUNCTION
Cells of complex organisms display a wide diversity of structural formations. Each different
structure is directly related to the functioning of the cell.
Pick any two cell types from the previous diagram – compare and contrast their specialized structure,
and relate this to the cells’ function in the body.
Answers will vary
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