cells

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Compendium 2
How do cells do what they
do?
Lecture 1 of 4 - The cell and
its organelles
HUMB1000 Human Structure & Function
Dr Ajanthy Arulpragasam
Building 308, room 208
9266 3358
hsf100@curtin.edu.au
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Compendium 2 learning outcomes
• List the major cell organelles and briefly describe their functions.
• Distinguish between the cytoplasm, cytosol, and cytoskeleton.
• Describe the structure of the cell (plasma) membrane.
• Define the four different types of primary tissues.
• Define the main characteristics of epithelial tissue.
• Describe the different cell shapes of epithelia.
• Define simple, stratified, pseudostratified and transitional epithelia
and give an example where each is found including an understanding
of why (functionally) it is found in this location.
The cell
• Structural and functional unit of all living things, including humans
http://www.sebiology.org/cell/Physical_cell.html http://www.cfne.unimelb.edu.au/research-laboratories/stem-cells/ http://www.umassmed.edu/cemf/services/

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Functional characteristics of cells
1. Cell metabolism and energy use
2. Synthesis of molecules
3. Communication
4. Reproduction and inheritance
Human cell
• Plasma membrane
• Cytoplasm
• Cytoskeleton
• Nucleus
• Ribosomes
• Golgi apparatus
• Lysosomes
• Mitochondria
• Centrioles
• Cilia
• Microvilli

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Plasma membrane 1
• Also known as the cell membrane
Function:
• Encloses and supports cellular contents
• Controls what goes into the cell and
what comes out
• Role in inter-cellular (cell-to-cell)
communication
Plasma membrane 2
Structure:
• Lipid bilayer (phospholipids
bilayer and cholesterol)
(45-50%)
• Provides flexibility
to the cell
• Carbohydrates (4-8%)
• Proteins (45-50%)

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Plasma membrane 3
Structure:
• Glycocalyx (outer surface of cell membrane)
• Glycoproteins (carbohydrates and proteins)
• Glycolipids (carbohydrates and lipids)
• Carbohydrates
Cytoplasm
• Cellular fluid material outside the nucleus but within the boundaries
of the plasma membrane
• Organelles (“little organs”)
• Cytosol
Cytoplasm
Cytosol
Organelles

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Cytosol
• Fluid portion of the cytoplasm (ions and proteins in water)
• Cytoplasmic inclusions – aggregates of chemicals
• Cytoskeleton – supports the cell and its organelles. Responsible
for changes to the shape of the cell and movement of its organelles
Cytoplasm
Cytosol
Organelles
Cytoplasmic inclusion
Cytoskeleton
Plasma membrane
Mitochondrion
Ribosomes
Nucleus
Tubulin subunits
Actin subunits
10 nm
8 nm
25 nm
Endoplasmic
reticulum
Intermediate filaments are
protein fibers 10 nm in diameter.
Microtubules are composed
of tubulin protein subunits.
Microtubules are 25 nm in
diameter with walls
5 nm thick.
Protein subunits
5 nm
• Supports the cell and its organelles. Responsible for changes to
the shape of the cell and movement of its organelles
• Microtubules
• Microfilaments
• Intermediate filaments
Cytoskeleton
Cytoplasm
Cytosol
Organelles
Cytoplasmic inclusion
Cytoskeleton
Microtubules,Microfilaments
and Intermediatefilaments

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Nucleus
Function:
• “Control centre” of the cell
• Deoxyribonucleic (dee-ox-ee-rye-bow-new-clay-ick) acid (DNA) in the
nucleus determines the structural and functional characteristics of
the cell
Structure:
• Nuclear envelope - a bilayer membrane surrounding the nucleus
envelope. Porous
• Nucleoplasm (new-cleo-plas-sem)
• Nucleolus (new-cleo-less) – primarily produces ribosomes
http://www.sebiology.org/cell/Physical_cell.htmlhttp://www.umassmed.edu/cemf/services/
Nucleoplasm
Nucleolus
Ribosomes
Function:
• Sites of protein synthesis
• Nucleolus, nucleus and cytoplasm
Structure:
• Composed of 2 subunits: large and small
• Free ribosomes and membrane-bound ribosomes

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Endoplasmic reticulum 1
Structure:
• Fattened, interconnecting sacs and tubules
• Rough endoplasmic reticulum – with
ribosomes
• Smooth ER – without ribosomes Nuclear pore
Ribosomes
Nucleus
Smooth
endoplasmic
reticulum
Cisternae
Rough
endoplasmic
reticulum
Outer membrane
of nuclear envelope
Endoplasmic reticulum 2
Function:
• Rough endoplasmic reticulum
• Synthesis and modification of proteins
• Smooth ER
• Site of lipid, steroid and carbohydrate synthesis
• Detoxification of harmful substances (e.g. drugs)
• Breakdown of glycogen to glucose

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Transportvesicle
Cisternae
Secretory
vesicles
Golgi apparatus
• Golgi spelt with a capital ‘G’ (1898, Camillo Golgi)
Structure:
• Flattened membranous sacs, with cisternae
• Secretory vesicles
Function:
• “Traffic director” for cellular proteins
• Modifies, packages and distributes proteins
and lipids that are made in the rough
endoplasmic reticulum
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Cytoplasm
1
2
3 4
5
Plasma membrane
Vesicle forming
by endocytosis
Vesicle taken
into the cell
Fusion of vesicle
with lysosome
Lysosome
Golgi
apparatus
Lysosomes
Structure:
• Membrane-bound vesicles that
form at the Golgi apparatus
• Contain enzymes within them
Function:
• Cell’s “demolition crew”
• Digestion of molecules (nucleic
acids, proteins, lipids,
carbohydrates, etc) that are no
longer needed by the cell

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Enzymes
(a)
Crista
DNA
Outer membrane
Inter membrane space
Inner membrane
Matrix
Mitochondria 1
Structure:
• Outer membrane
• Intermembrane space
• Inner membrane
• Matrix
• Change shape continuously
• Has its own genetic material  reproduce itself
Mitochondria 2
Function:
• “Power plants of a cell”
• ATP (adenosine triphosphate) production and supply
• ATP is the unit of currency for energy

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Centrioles (and the centrosome)
Structure:
• Barrel-shaped organelles oriented at right angles to each other
• Wall of centrioles is composed of microtubules
• Two centrioles can be found in the centrosome (cell’s centre)
Function:
• Cell division
Cytoplasm
Cytosol
Organelles
Cytoplasmic inclusion
Cytoskeleton
Microtubules, Microfilaments
and Intermediatefilaments
Cilia
Structure:
• Whip-like, motile cellular extensions which
project from the outer surfaces of certain cells
Function:
• Movement of substances across the surface of
cells
• E.g. cilia lining the respiratory tract which move
mucus out of the lungs
• E.g. cilia in the fallopian tubes of the female
reproductive system which moves the egg from the
ovary to the uterus http://en.wikipedia.org/wiki/Cilium

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Flagella
Structure:
• Similar to cilia but longer
• Found in humans on sperm cells only (one flagellum per sperm)
• Unlike cilia which moves substances across the cell surface, flagella
move the actual cell itself i.e. sperm cell
Function:
• Motility
http://commons.wikimedia.org/wiki/Main_Page
Microvilli
Structure:
• Extensions of the plasma membrane
• Each cell has many microvilli usually
• 1/10-1/20 size of cilia, hence micro
• Non-motile
Function:
• Increases the cell’s surface area
• E.g. absorptive cells of intestine or kidney tubules

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Plasma membrane Fluid portion of the cytoplasm
Cytoskeleton Site of steroid, carbohydrateand lipid synthesis
Nucleus Cell’s demolition crew
Ribosomes Encloses and supports cellular contents
Golgi apparatus Control centre of the cell
Lysosomes Supports the cell and its organelles
Mitochondria Cell’s centre where centrioles can be found
Centrosome Modifies, packages and distributes proteins
Flagella Increases the cell’s surface area
Microvilli Power plant of a cell
Cytosol Site of protein production
Endoplasmic reticulum Action of this structure moves the actual cell itself
Test your knowledge: the cell’s organelles
Plasma membrane Encloses and supports cellular contents
Cytoskeleton Supports the cell and its organelles
Nucleus Control centre of the cell
Ribosomes Site of protein production
Golgi apparatus Modifies, packages and distributes proteins
Lysosomes Cell’s demolition crew
Mitochondria Power plant of a cell
Centrosome Cell’s centre where centrioles can be found
Flagella Action of this structure moves the actual cell itself
Microvilli Increases the cell’s surface area
Cytosol Fluid portion of the cytoplasm
Smooth endoplasmic reticulum Site of steroid, carbohydrateand lipid synthesis
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Test your knowledge: the cell’s organelles

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Compendium 2 questions
• What makes up the environment of a cell?
• What are the main organelles inside a cell and what is their function?
• What happens to a cell if an organelle stops working?
• Are all cells in the body the same?
• What are the four primary tissue types?
• What are the general characteristics and functions of epithelia?
• Where are epithelial tissues found?
• What are the types of cell surface modifications found in epithelia and what functions do these have?
• What are the 3 types of simple epithelia? Give an example of where they are found and how are they adapted for their specificfunctions?
• What are the two main types of stratified squamous epithelia? Give an example of where they are found and how are they adapted for
their specific functions?
• What are the general characteristics of connective tissue?
• How do the general characteristics of connective tissues compare with those for epithelia?
• Name the 3 types of muscle found in the body and briefly describe their functions?
• What are the general characteristics of nervous tissue?