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Title: Specialized Cells (on page 43 in your notebook)
Generalized Cells – cells that contain all parts of the cell.
A generalized cell is a drawing that contains all parts of the cell. In reality, there are many cells that lack
one or more parts. A red blood cell, for example, contains cytoplasm and a cell membrane but other parts
are missing.
Specialized Cells- contain only structures directly connected to its
function.
In a specialized cell, the structure of the cell is directly connected to its function.
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(The following information is taken from the above site.)
Animal Cells
All animals are made up of cells.
This diagram represents an animal cell. Most cells have:
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A nucleus that controls the activities of the cell
Cytoplasm, where most of the chemical reactions take
place. The reactions are controlled by enzymes
A cell membrane that controls what enters and leaves the
cell
Mitochondria in the cytoplasm where respiration takes
place to release energy
Plant Cells
This diagram represents a plant cell. Plant cells also have:
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A cell wall made of cellulose, which strengthens the cell
and provides support
They often have:
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Chloroplasts which contain the green pigment chlorophyll.
This absorbs light energy for photosynthesis
A permanent vacuole filled with cell sap, which provides
support
Specialized Cells
Different types of cells look different because they are adapted to their function. They are said to be
specialized.
Similar cells that carry out the same function are grouped together in tissues.
Different tissues work together in organs.
Different organs are combined together to form organ systems.
For example, muscle cells form muscle tissue. The heart contains muscle tissue, nervous tissue and
connective tissue. The heart is part of the circulatory system.
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http://www.livingscience.co.uk/year7/cells/cells.htm
(The following information is taken from the above site.)
Cells
All plant and animal cells have the following:
A Cell Membrane. This controls what goes in and out of the cell
Cytoplasm. This has the thickness of wallpaper paste. It is where the chemical reactions take place.
A nucleus. This is the 'brain' of the cell. It contains the genetic material (DNA) and tells the cell what
to do.
Only plant cells contain:
A Cell Wall. It support the plant cell and is very strong. It is made out of a substance called cellulose.
A Vacuole. This is filled with a liquid called cell sap. It helps the cell to maintain its shape.
Chloroplasts. These are green discs that allow the plant to make food by photosynthesis. They
contain a chemical called chlorophyll. Plant tissues which contain them appear green.
Some cells are adapted to do certain jobs. Examples of these are shown below:
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Red Blood Cells
Red blood cells are adapted to carry oxygen around the body in blood vessels. A red blood cell has a
small size to enable it to fit through capillaries and a biconcave shape (see the picture below - it looks
a bit like a Werther's Original sweet). Red blood cells are flexible and contain the chemical
hemoglobin which binds to oxygen to carry it around the body.
The shape of the red blood cell provides a large surface area to help it take in oxygen and release it
rapidly. The flexible shape helps it to fit through narrow capillaries.
In the lungs hemoglobin in the red blood cells combines with oxygen to form oxyhemoglobin
Oxygen + Hemoglobin
Oxyhemoglobin
When the red blood cells reach tissues oxyhemoglobin breaks down to release oxygen:
Oxyhemoglobin
Oxygen + Hemoglobin
White Blood Cells
White blood cells are bigger than red blood cells and have a flexible shape. White blood cells help to
protect our body against disease. The diagrams below show how white blood cells can 'eat' bacteria
cells which have entered the body.
Palisade Cells
Palisade cells contain lots of chloroplasts and are found near to the top surface of the leaf. The
chloroplasts absorb light energy and make food (glucose) for the plant using photosynthesis. The
chloroplasts give plants their green color. The diagram below shows cells in a plant leaf. The palisade
cells can be seen just below the top surface of the leaf.
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(The following information was taken from the above site.)
Specialized cells
Animal and plants cells in multi-celluar organisms often become specialized to carry out particular jobs. In this
way they can carry these functions out much more efficiently. Here are some examples:
The cells of fungi are similar to plant cells. They have a nucleus, cytoplasm, ribosomes and
mitochondria. While fungi do have a cell wall, it is made of chitin, a different type of carbohydrate from
cellulose. They are however not green – they don’t photosynthesize and so don’t contain chloroplasts. Fungi
need to feed on other organisms to obtain their energy source. Fungi are involved in decomposition - recycling
nutrients from dead organisms back into the ecosystem. Humans have made great use of fungi, e.g. yeast are
fungi and are used to make wine, beer and bread.
The primary function of hemoglobin (Hb) is to transport oxygen. Since oxygen is not very soluble in water (the major constituent of
blood), an oxygen transport protein must be used to allow oxygen to be 'soluble'. Hemoglobin (Hb) is the oxygen transport protein
used in the blood of vertebrates. Below is a wireframe diagram of a hemoglobin molecule. It is composed of 4 polypeptide chains
(represented in this diagram by different colors. Each chain contains one heme group (colored orange), each of which contains one
iron ion (not shown). The iron is the site of oxygen binding; each iron can bind one O2 molecule thus each hemoglobin molecule is
capable of binding a total to four (4) O2 molecules.
Specialized Cells Chart
Cell Name
root hair cell
Structure Description
large surface area
Function
to absorb water,
Found?
roots of plants
minerals
palisade
xylem
transport water,
hollow tube-like
phloem
minerals
stems, leaves
transport food,
of plants
nutrients
Drawing