CELL ORGANELLES

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CELL ORGANELLES

• AP BIOLOGY PERIOD 5

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Centrioles Dmitri Zohaib

• Found only in animal cells.
• Paired organelles that are found near the
  nucleus, located at right angles to each other.
• Each centriole is made of nine sets of triplet
  microtubules.
• Function compression-resisting girders of the
  cytoskeleton. They also have a role in building
  cilia and flagella.

http//meteo.ids.pl/komorka/struktury/centriole.ht
m
http//www.funhousefilms.com/sciencpg.htm
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Centrosome

• Contains centrioles
• Serves to order microtubules
• Microtubules make up spindle apparatus used in
  cell division.
• Centrosomes in plants lack centrioles
• For more information on Centrosomes and
  Centrioles go tohttp//www.cellsalive.com/cells/c
  entriol.htm

http//imiloa.wcc.hawaii.edu/krupp/BIOL101/present
/celllect/img022.jpg Campbell Biology textbook
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Extracellular Matrix
Most of the cells in multicellular organisms are
surrounded by a substance called the
extracellular matrix (ECM).

• Extracellular matrices are composed of tough
  fibrous proteins in a polysaccharide base
• The molecular composition of and structure of
  the ECM varies from cell to cell-
• Collagen, the most abundant protein found in the
  ECM of animal cells, forms strong fibers outside
  the cell.
• - Proteoglycans and fibronectins are also
  glycoproteins that can exist in the ECM,
  connecting the cell to the ECM. (Fibronectins
  bind to receptor proteins called integrins)
• These glycoproteins (proteins with a covalently
  bonded carbohydrate) are secreted by the cell

Brendan
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ECM Functions

• Although animal cells lack cell walls, they are
  surrounded by an extracellular matrix
• The ECM fills the spaces between cells and binds
  cells and tissues together
• Current research shows that the ECM can regulate
  a cells behavior by communicating with the cell
  through integrins

• The ECM can also influence the activity of genes
  in the nucleus by mechanical and chemical
  pathways
• The ECM of a particular tissue could help
  coordinate the behavior of all the cells within
  that tissue
• http//web.indstate.edu/thcme/mwking/extracellular
  matrix.html
• http//users.rcn.com/jkimball.ma.ultranet/BiologyP
  ages/E/ECM.html

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Lysosomes Structure

• The structures vary in size from 0.2 to 2
  micrometers in diameter.
• Contain around 40 enzymes for intracellular
  digestion
• The lysosome membrane helps to contain and
  protect the enzymes.
• The membrane of the lysosome is a lipid bilayer
  and has a hydrogen to pump H into the lysosome
  to maintain a low pH.

http//www.carolguze.com/text/102-8eukaryoticcells
.shtml
http//www.cbc.umn.edu/mwd/cell_www/chapter2/per-
lys.html
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Lysosomes Functions

• Lysosomes are the cells' garbage disposal system.
  
• They degrade the products of injestion, and worn
  out organelles such as mitochondria.
• They also handle the products of
  receptor-mediated endocytosis.
• Waste product get enclosed in a vacuole, vesicles
  containing lysosomal enzymes then fuse with it to
  digest the waste.
• The pH becomes acidic and this activates the
  enzymes which degrades the waste.

http//cellbio.utmb.edu/cellbio/lysosome.htm
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Peroxisomes - Structure

• Contain oxidative enzymes, such as D-amino acid
  oxidase, ureate oxidase, and catalase.
• They resemble a lysosome.
• Peroxisomes are distinguished by a crystalline
  structure.
• They also enlarge and bud to produce new
  peroxisomes.

http//www.cytochemistry.net/Cell-biology/lysosome
.htm
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Peroxisomes - Functions

• Peroxisomes function to rid the body of toxic
  substances like hydrogen peroxide, or other
  metabolites.
• They are a major site of oxygen utilization and
  are numerous in the liver where toxic byproducts
  are going to accumulate.

http//www.cytochemistry.net/Cell-biology/lysosome
.htm
http//micro.magnet.fsu.edu/cells/plants/images/pe
roxisome.jpg
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Vacuoles
Stephanie and Tony

• A single layer of membrane enclosing fluid in a
  sack
• In plant cells, there is usually one central
  vacuole called a tonoplast which can occupy up to
  90 of the cell.
• http//www.tvdsb.on.ca/westmin/science/sbi3a1/Cell
  s/vacuole.htm
• Animal cells have multiple smaller vacuoles
• Vacuoles contain a liquid called cell sap which
  is mostly water.

Vacuole is number 2 Picture from
http//www.cyberenet.net/aedmills/biorefweb/cells
.html
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Function of Vacuoles

• There are several different kinds of vacuoles
• Food, transport, storage, central, contractile
  vacuoles.
• capture food
• contain waste products
• storage of organic compounds, proteins (in
  seeds), and inorganic ions(e.g., K and Cl-) and
  salts (e.g., salts of calcium).
• enable a cell to elongate rapidly
• storage of pigments, and harmful toxins
• In plant cells, the vacuole can expand so that it
  is pressing against the cell wall, creating
  turgor pressure and maintaining cell rigidity.
• http//en.wikipedia.org/wiki/Vacuole

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Intercellular Junctions
Laura Chris

• provides physical contact between cells
• In animals
• Desmosomes disk-shaped protein attachments with
  fibers extending out of cell
• Tight junctions seams that encircle the whole
  cell
• Gap junctions tunnels between cells made of
  protein (connexon)
• In plants
• Plasmodesmata cytoplasmic connections

Photo from Campbell Website Biology, 6th Edition
http//occawlonline.pearsoned.com/bookbind/pubbook
s/campbell6e_awl/chapter0/deluxe.html
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• Intercellular junctions connect separate cells
  and integrate them so they can function together
  and exchange resources.
• Plant cells
• - plasmodesmata
• - unifies all the cells
• - resources are transported through
  cytoplasm.
• In animals, there are three types
• Tight junctions
• - membranes of neighboring cells are fused
  together
• - prevents leakage among cells (digestive
  tract)
• Desmosomes (anchoring junctions)
• - fastens cells into fused, strong, sheets
• - found in stressed tissues in skin or the
  heart
• Gap junctions (communicating junctions)
• - provide channels/tunnels between neighboring
  cells
• - transports sugars, salt ions, amino acids,
  etc.
• - prevents separate cells from exchanging
  cytoplasms, but allows the transport of
  essential materials.

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MITOCHONDRIA

• BY
• Justine Dimitra

http//www.cellsalive.com/cells/mitochon.htm
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Function and Structure

• Mitochondria are the power centers of the cell.
  The energy needed for the cell to move, divide,
  produce products, and contract is provided for by
  the Mitochondria.
• Mitochondria are about the size of bacteria and
  differ in shape, which depends on the cell type.
• Mitochondria include a double membrane. The
  inner membrane is very complex and forms folds
  called cristae. Sugar and oxygen combine to
  produce ATP in the inner membrane. The outer
  membrane is smooth and less complex.
• ATP is the primary energy source for the cell.
• CO2 H2O Heat are the waste products

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Cell WallStructure

• Plant cells have thin primary walls thicker
  secondary walls
• The middle lamella glues the adjacent cells
  together
• Thickness of the walls vary from .1mm to several
  micrometers
• Chemical composition of wall vary. Cellulose is
  the primary material
• Fungi utilize chitin in their cell wall
• Microfibrils of cellulose are embedded in a
  matrix of other polysaccharides and proteins

Found on campbellbiology.com
Christine and Sarah, Per. 5
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Cell WallFunction
The cell wall is one of the features of plant
cells that distinguishes them from animal cells.

• protects the plant cell
• maintains its shape
• prevents excessive uptake of water
• the strong walls of specialized cells hold the
  plant up against the force of gravity.
• Secondary walls present in woody plants

Found on campbellbiology.com
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Golgi Apparatus Jennie Nicole Function

• Package materials for export from the cell
  process proteins synthesized in the endoplasmic
  reticulum.
• Receive vesicles pinched off from the surface of
  the endoplasmic reticulum carrying proteins,
  soluble proteins awaiting processing, and
  processing enzymes
• Sugar adds to proteins to create glycoprotein's.
• Blebs off vesicle of finished product.
• Using signals, the Golgi separates the products
  from the processing enzymes that made them and
  returns the enzymes back to the endoplasmic
  reticulum.
• - sends packaged products to cytoplasm for use
  or export.

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Structure
http//ntri.tamuk.edu/cell/golgi.htm http//www.wi
nterwren.com/apbio/cellorganelles/golgi.html http
//personal.tmlp.com/Jimr57/tour/cell/cell_golgi1.h
tm

• The Golgi apparatus is a cell structure mainly
  devoted to processing the proteins synthesized in
  the endoplasmic reticulum.
• Golgi apparatus consists of sacs ,with a single
  membrane, which are stacked like pancakes
• The Golgi consists of a stack of membrane-bounded
  cisternae located between the endoplasmic
  reticulum and the cell surface
• Golgi apparatus is also known as the Golgi body.
  
• Closely associated with the edges of the
  flattened sacs there are vesicles that are
  pinched off from the Golgi.
• They are continuous with E.R. and nuclear envelope

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Endoplasmic Reticulum (ER) Structure

• It has a series of sacs called cisternae and
  tubules.
• Smooth ER-Lacks ribosome.
• Rough ER- Ribosome cover its surface which gives
  a rough appearance.
• Network (labyrinth)
• Consists of flattened sheets of cisternae that
  have bridges which connect the individual sheets
• Continuous with nuclear envelope and plasma
  membrane

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Function

• Rough ER
• synthesizes and secretes proteins
• Aids in the production of the membrane by placing
  the proteins in it.
• Examples
• Secretes protein insulin into the pancreas to
  help control blood sugar.
• Most of the proteins it secretes are
  glycoproteins, which are proteins that are
  covalently bonded to carbohydrates.

• Smooth ER aids in metabolic processes such as
• Synthesis of lipids
• Metabolizes carbohydrates
• Detoxifies drugs and poisons
• Production of steroids
• Storage and production of glycogen

-http//cellbio.utmb.edu/cellbio/rer1.htm -Campbel
l biology e-book, chap. 7.11
Nehal and Jesse
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Chloroplast
By Katlin And Karen

• Structure
• Chloroplasts are disk shaped organelles
  surrounded by a double membrane.
• Components
• The inner membrane surrounds the fluid-filled
  region called the stroma.
• The stroma holds enzymes responsible for the
  light-independent reactions of photosynthesis.
• Thylakoids are disk-like sacs containing
  photosynthetic machinery and pigments.
• Each individual stack of thylakoids are called
  granum.

Chloroplast Info
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Functions

• The main function of chloroplast is to carry out
  photosynthesis in eukaryotic cells.
• Chloroplasts contain the green pigment
  chlorophyll, along with enzymes and other
  molecules that function in the photosynthetic
  production of sugar.
• Light reactions take place on the membranes of
  the grana.
• The dark reactions take place in the stroma.

More info on chloroplast function.....
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Plasma Membrane (Cell Membrane)by Max and Kevin

• The membrane is a barrier, separating a cell from
  external environment.
• Double phospholipid bilayer with hydrophililic
  end facing outside and hydrophobic end inward.
• Intrinsic proteins are embedded in the membrane.
• Glycoproteins are usually present in the aqueous
  layers of the cell.
• Cholesterol is present in animal cell membranes
  to maintain fluidity.

micro.magnet.fsu.edu/cells/animals/plasmamembrane.
htmlh282w347sz39tbnidSazAKEh1suwJ
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Plasma Membrane (Cell Membrane)Function

• Keeps the whole cell together.
• Controls the transportation of essential
  nutrients into the cell (food, oxygen).
• Controls the rate of chemical exchange with
  outside environment, lets wastes out.
• Provides an active site for metabolism to occur.

www.smuhsd.k12.ca.us/bhs/science-dept/vaughn/mvaug
hn/Student2520Projects/Jennifer2520Lee2520262
520Jisoo2520Membrane/cem3s1_1.jpgimgrefurlhttp
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Structure of Nucleus
Adeline and Anna

• A long spherical structure
• Contains most of the genes
• Contains proteins and chromatin which is made of
  DNA, organized into chromosomes
• Contains proteins called histones
• Chromatin is DNA protein
• Nuclear envelop consists of a double layer
  nuclear membrane that contains numerous pores
• Pores transport large macromolecules and
  ribosomal subunits to the cytoplasm
• The nuclear envelope separates the nucleus
  contents from the cytoplasm.
• Contains one or more nucleoli
• Nuclear lamina

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Function of Nucleus

• Serves as a site for replication and mitosis
• Storage system for genetic information
• Stores genes on chromosomes
• Organizes genes into chromosomes to allow cell
  division.
• Transports regulatory factors gene products via
  nuclear pores
• Produces messages (messenger Ribonucleic acid or
  mRNA) that code for proteins
• Produces ribosome's in the nucleolus
• Organizes the uncoiling of DNA to replicate  key
  genes
• Links for more information http//cellbio.utmb.ed
  u/cellbio/nuclear_envelope.htm http//occawlonline
  .pearsoned.com/bookbind/pubbooks/campbell6e_awl/ch
  apter7/deluxe.html

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Structure of Ribosomes!!!

• Structure-
• Spherical
• Consists of RNA molecules and Proteins
• Produced by Nucleolus
• Made of large and small subunits
• -some are free floating and some are
  in the cytoplasm.
• -Some are attached to the E.R. to create
  rough E.R.

Nicole and Natalie
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RIBOSOMES

• FUNCTION
• Ribosomes are the protein synthesizing machines
  of the cell.
• They translate information encoded in mRNA into a
  polypeptide.

http//users.rcn.com/jkimball.ma.ultranet/BiologyP
ages/R/Ribosomes.html