2.3 Eukaryotic Cells
09/09/2010 05:22:00
Topic 2 - Cells
2.3 Eukaryotic Cells
Orange book  pg. 22
Green book  pg. 15-17
2.3.1 Draw and label a diagram of the ultrastructure of a liver cell as an
example of an animal cell. (23, 17)
2.3.2 Annotate the diagram of an animal cell with the functions of each named
structure (23, 17-19)
2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells. (17,
18)
2.3.4 Compare prokaryotic and eukaryotic cells (22-23, 20)
2.3.5 State three differences between plant and animal cells (20)
2.3.6 Outline two roles of extracellular components (20, 20)
2.3.1 Animal Cell
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2.3.1 Draw and label a diagram of the ultrastructure of a liver cell as an example
of an animal cell.
Drawing should show free ribosomes, rough endoplasmic reticulum, lysosome,
Golgi apparatus, mitochondria and nucleus.
Orange book  pg. 23
Green book  pg. 17
To do:
 Colour in the handout of the animal cell
Visit the two websites:
Typical Animal Cell
http://www.wisc-online.com/objects/index_tj.asp?objID=AP11403
Animal Cell Animation
http://www.cellsalive.com/cells/3dcell.htm
Typical Animal Cell
Whereas prokaryotic cells occur in the bacteria, eukaryotic cells occur in
organisms such as algae, protozoa, fungi, plants and animals.
Eukaryotic cells range in diameter from 5 to 100 m. Also, usually noticeable is
the nucleus in the cytoplasm. Other organelles may be visible in the cell if you
have a microscope with high enough magnification and resolution. Organelles are
non-cellular structures that carry out specific functions (abit like organs in
multicellular organisms). Different types of cell often have different organelles.
These structures bring about compartmentalization in eukaryotic cells. This is
not a characteristic of prokaryotic cells. Compartmentalization allows chemical
reactions to be separated. This is especially important when the adjacent
chemical reactions are incompatible. It also allows chemicals for specific
reactions to be isolated. This isolation results in increased efficiency.
2.3.2 Structure & Function
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2.3.2 Annotate the diagram of an animal cell with the functions of each named
structure
Orange book  pg. 23
Green book  pg. 17-19
To do:
You have many organelles to learn. The best way to do this is to use all the
resources and tackle one organelle at a time.
 Visit the websites:
Animal Cell Organelles
http://www.wisc-online.com/objects/index_tj.asp?objID=AP11604
Cell Animation
http://www.cellsalive.com/cells/3dcell.htm
Cell Structure and Processes
http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/cells.htm
 Use the notes below to label and annotate the handout of a eukaryotic cell
 Complete the handout “2.3.2 The Organelles of a Eukaryotic Cell Summary
Table”
Summary  Complete the “Organelle Quiz” on the following website:
http://www.zerobio.com/target_practice_quiz/target_practice_quiz_cells.htm
Organelles of Eukaryotic Cells
 Endoplasmic reticulum
 Ribosomes
 Lysosomes (not usually in plant cells)
 Golgi apparatus
 Mitochondria




Nucleus
Chloroplasts (plant and algae)
Centrosomes (all eukaryotes but centrioles not found in higher plants)
Vacuoles
Rough Endoplasm
The endoplasmic reticulum (ER) is an extensive network of tubules or channels
that extend almost everywhere in the cell from the nucleus to the plasma
membrane. Its structure enables it function which is the transportation of
materials throughout the internal region of the cell. RER is studded with
numerous ribosomes, which give it its rough appearance. The ribosomes
synthesise proteins, which are processed in the RER (e.g. by enzymatically
modifying the polypeptide chain, or adding carbohydrates), before being
exported from the cell via the Golgi Body. These proteins may become parts of
membranes, enzymes, or even messengers between cells.
Ribosomes
These are the smallest and most numerous of the cell organelles (however, they
do not have an exterior membrane) and are the sites of protein synthesis. They
are composed of protein and RNA, and are manufactured in the nucleolus of the
nucleus. Ribosomes are either found free in the cytoplasm, where they make
proteins for the cell's own use, or they are found attached to the rough
endoplasmic reticulum, where they make proteins for export from the cell.
They are often found in groups called polysomes. All eukaryotic ribosomes are
of the larger, "80S", type. (Prokaryotic ribosomes are the “70S” type).
Lysosomes
Lysosomes are intracellular digestive centres that arise from the Golgi
apparatus. The lysosome lacks any internal structures. They are sacs bounded
by a single membrane that contain many different enzymes. The enzymes are all
hydrolytic and catalyse the breakdown of protein, nucleic acids, lipids and
carbohydrates. Lysosomes fuse with old or damaged organelles from within the
cell to break them down so that recycling of the components may occur. Also,
lysosomes are involved with the breakdown of materials that may be brought
into the cell by phagocytosis. The interior of a functioning lysosome is acidic.
This acidic condition is necessary for the enzymes to hydrolyse large molecules.
Golgi Apparatus
Another series of flattened membrane vesicles, formed from the endoplasmic
reticulum. This organelle functions in the collection, packaging, modification and
distribution of materials synthesised in the cell. It often involves transporting
proteins from the RER to the cell membrane for export. Parts of the RER
containing proteins fuse with one side of the Golgi body membranes, while at
the other side small vesicles bud off and move towards the cell membrane,
where they fuse, releasing their contents by exocytosis. This organelle is found
in high numbers in glandular cells such as those in the pancreas, which
manufacture and secrete substances.
Mitochondria
This is a sausage-shaped organelle (8µm long – close to the size of a prokaryotic
cell), and is where aerobic respiration takes place in all eukaryotic cells.
Mitochondria are surrounded by a double membrane: the outer membrane is
simple and quite permeable, while the inner membrane is highly folded into
cristae, which give it a large surface area. The inner membrane is studded with
stalked particles, which are the site of ATP synthesis. An area called the inner
membrane space lies between the two membranes. The space enclosed by the
inner membrane is called the mitochondrial matrix, and contains small circular
strands of DNA. It also contains ribosomes.
Nucleus and Nuclear Envelope
This is the largest organelle. Surrounded by a nuclear envelope, which is a
double membrane allowing compartmentalization of the eukaryotic DNA, thus
providing an area where DNA can carry out its functions and not be affected by
processes occurring in other parts of the cell. The nuclear membrane does not
provide complete isolation as it has numerous pores - large holes containing
proteins that control the exit of substances such as RNA and ribosomes from
the nucleus. The interior is called the nucleoplasm, which is full of chromatin - a
DNA/protein complex containing the genes. During cell division the chromatin
becomes condensed into discrete observable chromosomes. The nucleolus is a
dark region of chromatin, involved in making ribosomes.
The following are not specifically listed on your syllabus but are worth having
knowledge of.
Cytoplasm or Cytosol
This is the solution within the cell membrane. It contains enzymes for
glycolysis (part of respiration) and other metabolic reactions together with
sugars, salts, amino acids, nucleotides and everything else needed for the cell to
function.
Vacuoles
These are membrane-bound sacs containing water or dilute solutions of salts
and other solutes. Most cells can have small vacuoles that are formed as
required, but plant cells usually have one very large permanent vacuole that fills
most of the cell, so that the cytoplasm (and everything else) forms a thin layer
round the outside. Plant cell vacuoles are filled with cell sap, and are very
important in keeping the cell rigid, or turgid. Some unicellular protoctists have
feeding vacuoles for digesting food, or contractile vacuoles for expelling water.
Microvilli
These are small finger-like extensions of the cell membrane found in certain
cells such as in the epithelial cells of the intestine and kidney, where they
increase the surface area for absorption of materials. They are just visible
under the light microscope as a brush border.
2.3.3 Liver cells
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2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells.
Orange book  pg. 23
Green book  pg. 17-18
To do:
Carefully examine the false-colour TEM of part of a liver cell. Locate as many of
the structures of an animal cell as you can. List these below the diagram.
On the handout of the same TEM of part of a liver cell, label and annotate the
structures you can identify.
2.3.4 Comparison Prokaryotic vs Eukaryotic09/09/2010 05:22:00
2.3.4 Compare prokaryotic and eukaryotic cells
Orange book  pg. 22-23
Green book  pg. 20
To do:
Not much choice but to LEARN it 
 Visit each of the websites:
Cell Animation
http://www.cellsalive.com/cells/3dcell.htm
Comparison of Cells
http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_stru
cture/cell_structure.htm
Prokaryotic vs. Eukaryotic
http://www.biology.ualberta.ca/facilities/multimedia/index.php?Page=253
You should be able to complete the following animations:
Comparing Prokaryotic and Eukaryotic Cells
Study the table below
Summary  Complete the handout: “Eukaryote vs Prokaryote Worksheet”
Summary of Differences between Prokaryotic and Eukaryotic Cells
If you are asked to state the similarities between the two types of cells, you
should be certain to include the following:



both types of cell have some sort of outside boundary that always involves a
plasma membrane
both types of cells carry out all the functions of life
DNA is present in both cell types
2.3.5 Plant vs Animal
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2.3.5 State three differences between plant and animal cells
Orange book  pg. not covered
Green book  pg. 20
To do:
Not much choice but to LEARN it 
 Visit each of the websites:
Typical Animal Cell
http://www.wisc-online.com/objects/index_tj.asp?objID=AP11403
Animal Cell Animation
http://www.cellsalive.com/cells/3dcell.htm
Plant Cell Animation
http://www.cellsalive.com/cells/3dcell.htm
Study the tables below
Summary  construct a table in your green exercise books to make a
comparison of plant and animal cells – use KEY words only in your comparison
Complete the questions at the end of the document in your green exercise
books.
Comparison of Plant and Animal Cells
Plant Cells
Animal Cells
Exterior of cell includes an outer cell
wall with a plasma membrane just
inside
Exterior of cell includes only a plasma
membrane. There is no cell wall.
Chloroplasts are present in the
There are no chloroplasts
cytoplasm
Possess large centrally located
vacuoles
Vacuoles are usually not present or are
small
Store carbohydrates as starch
Store carbohydrates as glycogen
Do not contain centrioles within a
centrosome area
Contain centrioles within a centrosome
area
Because a rigid cell wall is present, this Without a cell wall, this cell is flexible
cell type has a fixed, often angular,
and more likely to be a rounded shape
shape
Most cellular organelles are present in both plant and animal cells. When an
organelle is present in both types of cell, it usually has the same structure and
function. For example, both cell types contain mitochondria that possess
cristae, matrix and the double membrane. Also, in both cell types, the
mitochondria function in the production of ATP for use by the cell.
The outermost region of various cell types is often unique, as shown in the
following table:
Cell
Components of Outer Layer
Bacteria
Cell wall of peptidoglycan
Capsule of polysaccharides
Plants
Cellulose cell wall
Animals
NO cell wall
Plasma membrane secretes a mixture of sugar and proteins
called glycoproteins that forms the extracellular matrix
Typical Animal Cell
Typical Plant Cell
Questions
1. The diagram below shows the structure of a liver cell as seen using an
electron microscope.
a. Name parts labeled A, B, C and D. (4)
b. Give the function of each part you have labeled. (4)
2. Copy and complete the following passage about the palisade cells of a leaf
and write on the dotted lines the most appropriate word or words to
complete the passage. (5)
The palisade cell is typical of plant cells in that it has three structures,
.......................................................... , ................................................................. and
......................................................, none of which is present in animal cells. In
common with animal cells, plant cells (such as palisade cells) have membranebound organelles which are not present in.............................................. cells. In a
leaf, palisade cells are grouped together as a layer just below the epidermis
forming a ....................................................., the function of which is to carry out
photosynthesis.
3. Some cells were broken up and the organelles that they contained were
separated by ultracentrifugation. The drawing shows three of the types of
organelle which were obtained.
a. The cells were all the same type. Which of the cells A to D listed below
might they have been? (1)
A
bacterial cells
B
red blood cells
C
D
cells from a plant leaf
epithelial cells from the lung
b. Explain why only organelle X appeared in the sediment when the broken
up cells were centrifuged at the lowest speed. (1)
c. Give the function of: (20
i.
organelle Y;
ii.
organelle Z
4. The diagram represents the structure of an animal cell as it would appear
when seen with an electron microscope.
a. Name one structure:
i. that is present in this cell but would not be in a bacterial cell; (1)
ii. that is not present in this cell but may be present in a bacterial
cell. (1)
b. Describe one function of the organelle labelled X. (1)
5. The drawing shows part of an animal cell.
a. Name feature X.(1)
b. Describe the function of organelle Y. (1)
c. Describe one way in which the function of organelle Z is related to the
function of organelle Y. (2)
6. The diagram shows part of a cell that secretes enzymes.
a. Give one piece of evidence, visible in the diagram, which shows that this
cell is a eukaryotic cell. (1)
b. Name the process which is occurring at point X on the diagram. (1)
2.3.6 Extracellular Components
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2.3.6 Outline two roles of extracellular components
Orange book  pg. 20
Green book  pg. 20
To do:
Short one 
Read the relevant information below and in the green book.
Very brief summary in green exercise books
The extracellular matrix (ECM) of many animal cells is composed of collagen
fibres plus a combination of sugars and proteins called glycoproteins. These
form fibre-like structures that anchor the matrix to the plasma membrane.
This strengthens the plasma membrane and allows attachment between adjacent
cells. The ECM allows for cell-to-cell interaction, possibly altering gene
expression and bringing about coordination of cell action within the tissue. Many
researchers think the ECM is involved in directing stem cells to differentiate.
Cell migration and movement also appear to be, at least partially, the result of
interactions in this area.