Transcript Human Physiology: Cell Structure and Function

Human Physiology:
Cell Structure and
Function
BY
DR BOOMINATHAN Ph.D.
M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGS, Israel), Ph.D (NUS, SINGAPORE)
PONDICHERRY UNIVERSITY
I Lecture
31/July/2012
Source: Collected from different sources on the internet-http://koning.ecsu.ctstateu.edu/cell/cell.html
Collected from different sources, modified and presented by Dr Boominathan Ph.D.
Anatomy, physiology, …
 Anatomy
is the science of the structure
 Physiology is the science of the function
 Anatomy and physiology are closely
linked, in particular physiology cannot be
understood without anatomy
 In many respects, both are ‘closed
sciences’
Physiology




Some important moments:
17th century: William Harvey first describes the
closed circulation
19th century: Claude Bernard formulates the modern
version of homeostasis – the constancy of the
internal milieu
19th century: Johannes Muller formulates the ‘law of
specific nerve energy’
Physiology





Some important moments:
17th century: William Harvey first describes the
closed circulation
19th century: Claude Bernard formulates the modern
version of homeostasis – the constancy of the
internal milieu
19th century: Johannes Muller formulates the ‘law of
specific nerve energy’
In general, a slow development of our modern view
of the function of the body
Physiology:
Missing from the scheme:
Structure and motion:
 Skeletal system
 Muscles
Integratory systems:
 Nervous system
 Hormones
Cell Structure
& Function
Source: http://koning.ecsu.ctstateu.edu/cell/cell.html
Unit-I Outline
Levels of Cellular Organization & functionOrganelles, tissues, organs & systems.
 Cell theory
 Properties common to all cells
 Cell size and shape – why are cells so small?


Prokaryotic cells
 Eukaryotic cells



Organelles and structure in all eukaryotic cell
Organelles in plant cells but not animal
Cell junctions
History of Cell Theory
 mid

Improved microscope, observed many living cells
 mid

1600s – Anton van Leeuwenhoek
1600s – Robert Hooke
Observed many cells
 1850

– Rudolf Virchow
Proposed that all cells come from existing
cells
Cell Theory
Cells were discovered in 1665 by Robert
Hooke.
Early studies of cells were conducted by
- Mathias Schleiden (1838)
- Theodor Schwann (1839)
Schleiden and Schwann proposed the Cell
Theory.
9
Cell Theory
1.
2.
3.
All organisms consist of 1 or more
cells.
Cell is the smallest unit of life.
All cells come from pre-existing
cells.
Cell Theory
 All
living things are made up of cells.
 Cells are the smallest working units of all
living things.
 All cells come from preexisting cells
through cell division.
Cell Theory
Cell Theory
1. All organisms are composed of cells.
2. Cells are the smallest living things.
3. Cells arise only from pre-existing cells.
All cells today represent a continuous line of
descent from the first living cells.
12
Cell Theory
Cell size is limited.
-As cell size increases, it takes longer for
material to diffuse from the cell
membrane to the interior of the cell.
Surface area-to-volume ratio:
as a cell increases in size, the volume
increases 10x faster than the surface
area
13
Cell Theory
14
Cell Theory
Microscopes are required to visualize cells.
Light microscopes can resolve structures
that are 200nm apart.
Electron microscopes can resolve
structures that are 0.2nm apart.
15
Cell Theory
All cells have certain structures in common.
1. genetic material – in a nucleoid or nucleus
2. cytoplasm – a semifluid matrix
3. plasma membrane – a phospholipid bilayer
16
Definition of Cell
A cell is the smallest unit that is
capable of performing life
functions.
Observing Cells (4.1)
 Light microscope
 Can observe living cells in true color
 Magnification of up to ~1000x
 Resolution ~ 0.2 microns – 0.5 microns
Observing Cells (4.1)
 Electron Microscopes
 Images are black and white – may be
colorized
 Magnifcation up to ~100,000
• Transmission electron microscope (TEM)

2-D image
• Scanning electron microscope (SEM)

3-D image
SEM
TEM
Examples of Cells
Amoeba Proteus
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
Two Types of Cells
•Prokaryotic
•Eukaryotic
Prokaryotic
 Do
not have
structures
surrounded by
membranes
 Few internal
structures
 One-celled
organisms,
Bacteria
http://library.thinkquest.org/C004535/prokaryotic_cells.html
Prokaryotic Cells
Prokaryotic cells lack a membrane-bound
nucleus.
-genetic material is present in the
nucleoid
Two types of prokaryotes:
-archaea
-bacteria
24
Prokaryotic Cells
Prokaryotic cells possess
-genetic material in the nucleoid
-cytoplasm
-plasma membrane
-cell wall
-ribosomes
-no membrane-bound organelles
25
Prokaryotic Cells
26
Prokaryotic Cells
Prokaryotic cell walls
-protect the cell and maintain cell shape
Bacterial cell walls
-may be composed of peptidoglycan
-may be Gram positive or Gram negative
Archaean cell walls lack peptidoglycan.
27
Prokaryotic Cells
Flagella
-present in some prokaryotic cells
-used for locomotion
-rotary motion propels the cell
28
Prokaryotic Cell Structure
 Prokaryotic
Cells are smaller and
simpler in structure than eukaryotic
cells.


Typical prokaryotic cell is __________
Prokaryotic cells do NOT have:
• Nucleus
• Membrane bound organelles
Prokaryotic Cell
TEM Prokaryotic Cell
Eukaryotic

Contain organelles surrounded by membranes
 Most living organisms
Plant
http://library.thinkquest.org/C004535/eukaryotic_cells.html
Animal
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
Plant Cell
http://waynesword.palomar.edu/images/plant3.gif
Eukaryotic Cells
Eukaryotic cells
-possess a membrane-bound nucleus
-are more complex than prokaryotic cells
-compartmentalize many cellular functions
within organelles and the
endomembrane system
-possess a cytoskeleton for support and
to maintain cellular structure
36
Eukaryotic Cells
37
Eukaryotic Cells
38
Eukaryotic Cells
Nucleus
-stores the genetic material of the cell in
the form of multiple, linear chromosomes
-surrounded by a nuclear envelope
composed of 2 phospholipid bilayers
-in chromosomes – DNA is organized with
proteins to form chromatin
39
Eukaryotic Cells
40
Eukaryotic Cells
Ribosomes
-the site of protein synthesis in the cell
-composed of ribosomal RNA and
proteins
-found within the cytosol of the cytoplasm
and attached to internal membranes
41
Cell Structure
 All
Cells have:
 an outermost plasma membrane
 genetic material in the form of DNA
 cytoplasm with ribosomes
Cell Parts
Organelles
Surrounding the Cell
Cell Membrane

Outer membrane of cell
that controls movement
in and out of the cell
 Double layer
http://library.thinkquest.org/12413/structures.html
Cell Wall

Most commonly found
in plant cells &
bacteria
 Supports & protects
cells
http://library.thinkquest.org/12413/structures.html
Inside the Cell
Nucleus
 Directs
cell activities
 Separated from cytoplasm by nuclear
membrane
 Contains genetic material - DNA
Nuclear Membrane

Surrounds nucleus
 Made of two layers
 Openings allow
material to enter and
leave nucleus
http://library.thinkquest.org/12413/structures.html
Chromosomes

In nucleus
 Made of DNA
 Contain instructions
for traits &
characteristics
http://library.thinkquest.org/12413/structures.html
Nucleolus

Inside nucleus
 Contains RNA to build
proteins
http://library.thinkquest.org/12413/structures.html
Cytoplasm
 Gel-like
mixture
 Surrounded by cell membrane
 Contains hereditary material
Endoplasmic Reticulum

Moves materials around
in cell
 Smooth type: lacks
ribosomes
 Rough type (pictured):
ribosomes embedded in
surface
http://library.thinkquest.org/12413/structures.html
Ribosomes

Each cell contains
thousands
 Make proteins
 Found on ribosomes
& floating throughout
the cell
http://library.thinkquest.org/12413/structures.html
Mitochondria

Produces energy through
chemical reactions –
breaking down fats &
carbohydrates
 Controls level of water and
other materials in cell
 Recycles and decomposes
proteins, fats, and
carbohydrates
http://library.thinkquest.org/12413/structures.html
Golgi Bodies

Protein 'packaging
plant'
 Move materials within
the cell
 Move materials out of
the cell
http://library.thinkquest.org/12413/structures.html
Lysosome

Digestive 'plant' for proteins,
fats, and carbohydrates
 Transports undigested
material to cell membrane
for removal
 Cell breaks down if
lysosome structure
is disrupted.
http://library.thinkquest.org/12413/structures.html
Vacuoles

Membrane-bound
sacs for storage,
digestion, and waste
removal
 Contains water
solution
 Help plants maintain
shape
http://library.thinkquest.org/12413/structures.html
Chloroplast

Usually found in plant
cells
 Contains green
chlorophyll
 Where
photosynthesis takes
place
http://library.thinkquest.org/12413/structures.html
1. Plasma Membrane
• All membranes are phospholipid
bilayers with embedded proteins
• The outer plasma membrane
isolates cell contents
 controls what gets in and out of the cell
 receives signals

2. Genetic material in the
form of DNA


Prokaryotes – no membrane
around the DNA (no nucleus)
Eukaryotes – DNA is within a
membrane (there is nucleus)
3. Cytoplasm with ribosomes


Cytoplasm – fluid area inside outer
plasma membrane and outside
DNA region
Ribosomes – make proteins
Cell Structure
 All
Cells have:
 an outermost plasma membrane
 genetic material in the form of DNA
 cytoplasm with ribosomes
Why Are Cells So Small? (4.2)
 Cells
need sufficient surface area to allow
adequate transport of nutrients in and
wastes out.
 As cell volume increases, so does the
need for the transporting of nutrients and
wastes.
Why Are Cells So Small?
 However,
as cell volume increases the
surface area of the cell does not expand
as quickly.

If the cell’s volume gets too large it cannot
transport enough wastes out or nutrients in.
 Thus,
surface area limits cell volume/size.
Why Are Cells So Small?
 Strategies
for increasing surface
area, so cell can be larger:


“Frilly” edged…….
Long and narrow…..
 Round
cells will always be small.
Eukaryotic Cells
 Structures



in all eukaryotic cells
Nucleus
Ribosomes
Endomembrane System
• Endoplasmic reticulum – smooth and rough
• Golgi apparatus
• Vesicles


Mitochondria
Cytoskeleton
NUCLEUS
CYTOSKELETON
RIBOSOMES
ROUGH ER
MITOCHONDRION
CYTOPLASM
SMOOTH ER
CENTRIOLES
GOLGI BODY
PLASMA
MEMBRANE
LYSOSOME
VESICLE
Fig. 4-15b, p.59
Nucleus (4.5)
– isolates the cell’s genetic
material, DNA
 Function

DNA directs/controls the activities of the cell
• DNA determines which types of RNA are made
• The RNA leaves the nucleus and directs the
synthesis of proteins in the cytoplasm at a
______________
Nucleus
 Structure

Nuclear envelope
• Two Phospholipid bilayers with protein
lined pores


Each pore is a ring of 8 proteins with an
opening in the center of the ring
Nucleoplasm – fluid of the nucleus
Nuclear pore
bilayer facing cytoplasm
Nuclear envelope
bilayer facing
nucleoplasm
Fig. 4-17, p.61
Nucleus
 DNA


is arranged in chromosomes
Chromosome – fiber of DNA with
proteins attached
Chromatin – all of the cell’s DNA and
the associated proteins
Nucleus
 Structure, continued

Nucleolus
• Area of condensed DNA
• Where ribosomal subunits are made

Subunits exit the nucleus via nuclear pores
ADD
THE
LABELS
Endomembrane System (4.6 – 4.9)
 Series




of organelles responsible for:
Modifying protein chains into their final
form
Synthesizing of lipids
Packaging of fully modified proteins and
lipids into vesicles for export or use in
the cell
And more that we will not cover!
Structures of the
Endomembrane System
 Endoplasmic


Reticulum (ER)
Continuous with the outer membrane of
the nuclear envelope
Two forms - smooth and rough
 Transport
vesicles
 Golgi apparatus
Endoplasmic Reticulum (ER)


The ER is continuous with the outer
membrane of the nuclear envelope
There are 2 types of ER:
• Rough ER – has ribosomes attached
• Smooth ER – no ribosomes attached
Endoplasmic Reticulum
 Rough
Endoplasmic Reticulum (RER)
• Network of flattened membrane sacs create
a “maze”

RER contains enzymes that recognize and
modify proteins
• Ribosomes are attached to the outside of
the RER and make it appear rough
Endoplasmic Reticulum
 Function
RER
• Proteins are modified as they move through
the RER
• Once modified, the proteins are packaged
in transport vesicles for transport to the
Golgi body
Endomembrane System
 Smooth



ER (SER)
Tubular membrane structure
Continuous with RER
No ribosomes attached
 Function

SER
Lipids are made inside the SER
• fatty acids, phospholipids, sterols..

Lipids are packaged in transport vesicles and
sent to the Golgi
Endomembrane System
Vacuoles
-membrane-bound structures with various
functions depending on the cell type
There are different types of vacuoles:
-central vacuole in plant cells
-contractile vacuole of some protists
-vacuoles for storage
82
Endomembrane System
Endomembrane system
-a series of membranes throughout the
cytoplasm
-divides cell into compartments where
different cellular functions occur
1. endoplasmic reticulum
2. Golgi apparatus
3. lysosomes
83
Endomembrane System
Rough endoplasmic reticulum (RER)
-membranes that create a network of
channels throughout the cytoplasm
-attachment of ribosomes to the
membrane gives a rough appearance
-synthesis of proteins to be secreted, sent
to lysosomes or plasma membrane
84
Endomembrane System
Smooth endoplasmic reticulum (SER)
-relatively few ribosomes attached
-functions:
-synthesis of membrane lipids
-calcium storage
-detoxification of foreign substances
85
Endomembrane System
Endomembrane System
Golgi apparatus
-flattened stacks of interconnected
membranes
-packaging and distribution of materials to
different parts of the cell
-synthesis of cell wall components
87
88
Endomembrane System
Lysosomes
-membrane bound vesicles containing
digestive enzymes to break down
macromolecules
-destroy cells or foreign matter that the cell
has engulfed by phagocytosis
89
90
Endomembrane System
Microbodies
-membrane bound vesicles
-contain enzymes
-not part of the endomembrane system
-glyoxysomes in plants contain enzymes
for converting fats to carbohydrates
-peroxisomes contain oxidative enzymes
and catalase
91
Golgi Apparatus
 Golgi

Apparatus
Stack of flattened membrane sacs
 Function


Golgi apparatus
Completes the processing substances
received from the ER
Sorts, tags and packages fully processed
proteins and lipids in vesicles
Golgi Apparatus
 Golgi
apparatus receives transport
vesicles from the ER on one side of the
organelle

Vesicle binds to the first layer of the Golgi and
its contents enter the Golgi
Golgi Apparatus


The proteins and lipids are modified as they
pass through layers of the Golgi
Molecular tags are added to the fully modified
substances
• These tags allow the substances to be sorted and
packaged appropriately.
• Tags also indicate where the substance is to be
shipped.
Golgi Apparatus
Transport Vesicles
 Transport


Vesicles
Vesicle = small membrane bound sac
Transport modified proteins and lipids from
the ER to the Golgi apparatus (and from Golgi
to final destination)
Endomembrane System
 Putting

it all together
DNA directs RNA synthesis  RNA
exits nucleus through a nuclear pore 
ribosome  protein is made  proteins
with proper code enter RER  proteins
are modified in RER and lipids are made
in SER  vesicles containing the
proteins and lipids bud off from the ER
Endomembrane System
 Putting
it all together
ER vesicles merge with Golgi body 
proteins and lipids enter Golgi  each is
fully modified as it passes through
layers of Golgi  modified products are
tagged, sorted and bud off in Golgi
vesicles  …
Endomembrane System
 Putting
it all together
 Golgi vesicles either merge with the
plasma membrane and release their
contents OR remain in the cell and
serve a purpose
Vesicles
 Vesicles

- small membrane bound sacs
Examples
• Golgi and ER transport vesicles
• Peroxisome


Where fatty acids are metabolized
Where hydrogen peroxide is detoxified
• Lysosome


contains digestive enzymes
Digests unwanted cell parts and other wastes
Lysosomes (4.10)
 The
lysosome is an example of an
organelle made at the Golgi apparatus.

Golgi packages digestive enzymes in a
vesicle. The vesicle remains in the cell and:
• Digests unwanted or damaged cell parts
• Merges with food vacuoles and digest the contents
• Figure 4.10A
Lysosomes (4.11)
 Tay-Sachs
disease occurs when the
lysosome is missing the enzyme needed
to digest a lipid found in nerve cells.

As a result the lipid accumulates and nerve
cells are damaged as the lysosome swells
with undigested lipid.
Mitochondria (4.15)
Function – synthesis of ATP


3 major pathways involved in ATP
production
1. Glycolysis
2. Krebs Cycle
3. Electron transport system (ETS)
Mitochondria
 Structure:


~1-5 microns
Two membranes
• Outer membrane
• Inner membrane - Highly folded



Folds called cristae
Intermembrane space (or outer compartment)
Matrix
• DNA and ribosomes in matrix
Mitochondria
Mitochondria (4.15)
Function – synthesis of ATP


3 major pathways involved in ATP
production
1. Glycolysis - cytoplasm
2. Krebs Cycle - matrix
3. Electron transport system (ETS) intermembrane space
Mitochondria
TEM
Human Physiology:
Cell Structure and
Function
BY
DR BOOMINATHAN Ph.D.
M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGSWI, Israel), Ph.D (NUS, SINGAPORE)
PONDICHERRY UNIVERSITY
II Lecture
6/August/2012
Source: Collected from different sources on the internet-http://koning.ecsu.ctstateu.edu/cell/cell.html
Mitochondria
Mitochondria perform 2
functions within the cell
1.They are the primary sites for ATP
synthesis in the cell
2.They have a key role in apoptosis programmed cell death
Mitochondria are actively transported
along microtubules in some cells
Mitochondria are anchored near sites of high
ATP consumption in other cells
Mitochondria are dynamic organelles
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
Relative contributions of nuclear and
mitochondrial genes to protein composition
Mitochondria are organized
into 4 distinct compartments
Mitochondria are organized
into 4 distinct compartments
QuickTime™ and a
MPEG-4 Video decompressor
are needed to see this picture.
Compartments of a mitochondrion
compared with a bacterium
Mitochondria are organized
into 4 distinct compartments



Outer membrane:
Perforated with large
channels (porins) that
allow entry of molecules <
5000 kD
Enzymes involved in
mitochondrial lipid
synthesis
Mitochondria are organized
into 4 distinct compartments



Intermembrane space:
Enzymes that use newlymade ATP to
phosphorylate other
nucleotides
Compartment into which
H+ is pumped
Mitochondria are organized
into 4 distinct compartments





Inner membrane:
Folded into christae to
maximize surface area
Proteins that carry out
redox reactions of the
electron transport chain
Proteins that synthesize
ATP
Transport proteins that
move molecules into and
out of the matrix
Mitochondria are organized
into 4 distinct compartments



Matrix:
Internal space containing
enzymes for Krebs cycle
Contains mitochondrial
DNA, special ribosomes,
tRNAs, and enzymes
required for gene
expression
Mitochondria catalyze a major
conversion of energy by
oxidative phosphorylation
Text
Mitochondria use pyruvate or
fatty acids to make energy
Pyruvate from sugars, fatty acids from
fats
High energy electrons are generated
via the citric acid (Krebs) cycle
Protons are pumped across the inner
mitochondrial membrane
The electron transport chain consists
of 3 enzyme complexes
The electrochemical gradient of H+
across the inner membrane has 2
components:
The proton gradient drives ATP synthesis
Text
ATP sythase is a protein complex
embedded in the inner mitochondrial
membrane
ATP synthase acts as a rotary motor
ATP synthase acts as a rotary motor
QuickTime™ and a
Sorenson Video decompressor
are needed to see this picture.
ATP synthase is a motor



Motor complex
attached to glass and
bound to fluorescent
actin filament
ATP added and the
complex is imaged by
fluorescent
microscopy
Actin filament is spun
like a propeller
QuickTime™ and a
YUV4 20 code c d eco mpres sor
are nee ded to s ee this picture.
The proton gradient also drives
coupled transport
IN
IN
OUT
IN
Mitochondria
Summary: Mitochondria
-organelles present in all types of
eukaryotic cells
-contain oxidative metabolism enzymes for
transferring the energy within
macromolecules to ATP
-found in all types of eukaryotic cells
-Self-replicative
- No. 100 to 1000, depending on the
energy requirement
136
Mitochondria
Summary: Mitochondria
-surrounded by 2 membranes
-smooth outer membrane
-folded inner membrane with layers
called cristae
-matrix is within the inner membrane
-intermembrane space is located
between the two membranes
-contain their own DNA
137
Mitochondria
138
Chloroplasts
Chloroplasts
-organelles present in cells of plants and
some other eukaryotes
-contain chlorophyll for photosynthesis
-surrounded by 2 membranes
-thylakoids are membranous sacs within
the inner membrane
-grana are stacks of thylakoids
139
Chloroplasts
140
Mitochondria & Chloroplasts
Endosymbiosis
-proposal that eukaryotic organelles
evolved through a symbiotic relationship
- one cell engulfed a second cell and a
symbiotic relationship developed
-mitochondria and chloroplasts are thought
to have evolved this way
141
Mitochondria & Chloroplasts
Much evidence supports this
endosymbiosis theory:
Mitochondria and chloroplasts:
-have 2 membranes
-possess DNA and ribosomes
-are about the size of a prokaryotic cell
-divide by a process similar to bacteria
142
Mitochondria & Chloroplasts: Origin
143
Vacuoles (4.12)
 Vacuoles
are membrane sacs that are
generally larger than vesicles.

Examples:
• Food vacuole - formed when protists bring food
into the cell by endocytosis
• Contractile vacuole – collect and pump excess
water out of some freshwater protists
• Central vacuole – covered later
Cytoskeleton (4.16, 4.17)
 Function

gives cells internal organization, shape, and
ability to move
 Structure





Interconnected system of
microtubules,
microfilaments,
and intermediate filaments (animal only)
All are proteins
Cytoskeleton
Microfilaments

Thinnest cytoskeletal elements (rodlike)

Composed of the globular protein actin

Enable cells to change shape and move
Intermediate Filaments
 Intermediate


filaments
Present only in animal cells of
certain tissues
Fibrous proteins join to form a
rope-like structure
• Provide internal structure
• Anchor organelles in place.
Microtubules
– long hollow
tubes made of tubulin proteins
(globular)
 Microtubules




Anchor organelles
act as tracks for organelle
movement
Move chromosomes around
during cell division
Used to make cilia and flagella
Cilia and flagella (structures for cell motility)


Move whole cells or materials across the cell surface
Microtubules wrapped in an extension of the plasma
membrane (9 + 2 arrangement of MT)
Cytoskeleton
Cytoskeleton
-network of protein fibers found in all
eukaryotic cells
-supports the shape of the cell
-keeps organelles in fixed locations
-helps move materials within the cell
151
Cytoskeleton
Cytoskeleton fibers include
* Actin filaments – responsible for cellular
contractions, crawling..
* Microtubules – provide organization to
the cell and move materials within the cell
* Intermediate filaments – provide
structural stability
152
Cytoskeleton
153
Cell Movement
Cell movement takes different forms:
- Crawling is accomplished via actin
filaments and the protein myosin.
- Flagella undulate to move a cell.
- Cilia can be arranged in rows on the
surface of a eukaryotic cell to propel a
cell forward.
154
Cell Movement
The cilia and flagella of eukaryotic cells have
a similar structure:
9+2 structure: 9 pairs of microtubules
surrounded by a 2 central microtubules
Cilia are usually more numerous than
flagella on a cell. Cillia > Flagella
155
Cell Movement
156
Plants
Plant Cell Structures
 Structures
found in plant, but not animal
cells




Chloroplasts
Central vacuole
Other plastids/vacuoles – chromoplast,
amyloplast
Cell wall
Chloroplasts (4.14)
 Function
– site of photosynthesis
 Structure


2 outer membranes
Thylakoid membrane system
• Stacked membrane sacs called granum


Chlorophyll in granum
Stroma
• Fluid part of chloroplast
Origin of Mitochondria and
Chloroplasts
 Both
organelles are believed to have once
been free-living bacteria that were
engulfed by a larger cell.
Proposed Origin of Mitochondria
and Chloroplasts
 Evidence:





Each have their own DNA
Their ribosomes resemble bacterial
ribosomes
Each can divide on its own
Mitochondria are same size as bacteria
Each have more than one membrane
Plastids/Vacuoles in Plants
 Chromoplasts
– contain colored
pigments
• Pigments called carotenoids
 Amyloplasts
– store starch
Central Vacuole
– storage area for water,
sugars, ions, amino acids, and wastes
 Function

Some central vacuoles serve specialized
functions in plant cells.
• May contain poisons to protect against predators
Central Vacuole
 Structure



Large membrane bound sac
Occupies the majority of the volume of the
plant cell
Increases cell’s surface area for transport of
substances  cells can be larger
Cell surfaces
protect, support, and join cells


Cells interact with their environments and
each other via their surfaces
Many cells are protected by more than the
plasma membrane
Cell Wall

Function – provides structure and protection



Never found in animal cells
Present in plant, bacterial, fungus, and some protists
Structure



Wraps around the plasma membrane
Made of cellulose and other polysaccharides
Connect by plasmodesmata (channels through the walls)
Plant Cell TEM
Typical Plant Cell
Typical Plant Cell –add the labels
Cell Junctions
Plasma membrane proteins connect
neighboring cells - called cell junctions


Plant cells – plasmodesmata provide
channels between cells
Cell Junctions

3 types of cell junctions in animal cells
Tight junctions; Anchoring junctions & Gap
junctions
Cell Junctions
Tight junctions – membrane proteins
seal neighboring cells so that water
soluble substances cannot cross
between them
1.
•
Example, between stomach cells
Cell Junctions
Anchoring junctions – cytoskeleton
fibers join cells in tissues that need to
stretch
2.
•
See between heart, skin, and muscle cells
Gap junctions – membrane proteins on
neighboring cells link to form channels
3.
•
This links the cytoplasm of adjoining cells
membrane proteins seal
neighboring cells so that
water soluble substances
cannot cross
1
1. Tight junction
2
3
2. Anchoring
junction
cytoskeleton fibers join
cells in tissues that need to
stretch
3. Gap junction
membrane proteins on
neighboring cells link to
form channels
Plant Cell Junctions
 Plasmodesmata
form channels between
neighboring plant cells
Walls
of two
adjacent
plant cells
Vacuole
Plasmodesmata
Plant cell 1
Layers
of one plant
cell wall
Cytoplasm
Plasma membrane
Plant cell 2
Extracellular Structures
Extracellular structures include:
-cell walls of plants, fungi, some protists
-extracellular matrix surrounding animal
cells
178
Extracellular Structures
Cell walls
-present surrounding the cells of plants,
fungi, and some protists
-the carbohydrates present in the cell wall
vary depending on the cell type:
-plant and protist cell walls - cellulose
-fungal cell walls – chitin
-the entire outside surface of the cell often
has a loose carbohydrate coat called the
glycocalyx.
179
Extracellular Structures
Extracellular matrix (ECM)
-surrounds animal cells
-composed of glycoproteins and fibrous
proteins such as collagen
-may be connected to the cytoplasm via
integrin proteins present in the plasma
membrane
180
Extracellular Structures
181
182
183
Levels Of Organization and
Function-Organelles, tissues,
organs and systems
Levels Of Organization
7.3.1 Summarize the levels of
organization within the human
body (including cells, tissues,
organs, and systems).
The levels of organization from
simplest to most complex are:
 Cells
 Tissues
 Organs
 System
 Organism
Cells
 The
basic unit of structure and
function in the human body
 Though all cells perform the processes
that keep humans alive, they also
have specialized functions as well.
 Examples may be nerve cells
(neurons), blood cells, and bone cells.
Tissues


A group of specialized cells
that work together to perform
the same function.
There are four basic types of
tissue in the human body:
Tissues




Nerve Tissue
Muscle Tissue
Epithelial Tissue
Connective Tissue
Tissues
1.
Nerve tissue – carries
impulses back and forth to
the brain from the body
Three types of muscle tissue
tissue – (cardiac, smooth, skeletal)
contract and shorten, making body parts move
 Skeletal
 Muscle
 Cardiac
 Smooth
3. Epithelial tissue – covers the surfaces of
the body, inside (as lining and /or covering
of internal organs) and outside (as layer of
skin)
4. Connective tissue – connects all parts of
the body and provides support (for
example tendons, ligaments, cartilage).
Organs
A
group of two or more different types
of tissue that work together to perform
a specific function.
 The task is generally more complex
than that of the tissue.
 For example, the heart is made of
muscle and connective tissues which
functions to pump blood throughout
the body.
Systems
A
group of two or more organs that work
together to perform a specific function.
 Each organ system has its own function but
the systems work together and depend on
one another.
 There are eleven different organ systems in
the human body: circulatory, digestive,
endocrine, excretory (urinary), immune,
integumentary, muscular, nervous,
reproductive, respiratory, and skeletal.
Human Physiology:
Levels Of Organization and FunctionOrganelles, tissues, organs and
systems
BY
DR BOOMINATHAN Ph.D.
M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGSWI, Israel), Ph.D (NUS, SINGAPORE)
PONDICHERRY UNIVERSITY
II Lecture
7/August/2012
Source: Collected from different sources on the internet-http://koning.ecsu.ctstateu.edu/cell/cell.html
Collected and modified by Dr Boominathan Ph.D.
Human Physiology:
Cell Membrane transport across
cell, membrane and Intercellular
communication
BY
DR BOOMINATHAN Ph.D.
M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGSWI, Israel), Ph.D (NUS, SINGAPORE)
PONDICHERRY UNIVERSITY
II Lecture
9/August/2012
Source: Collected from different sources on the internet-http://koning.ecsu.ctstateu.edu/cell/cell.html
Collected, and modified by Dr Boominathan Ph.D.
Human Physiology:
Regulation of cell multiplication
and Musculo-skeletal system
BY
DR BOOMINATHAN Ph.D.
M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGSWI, Israel), Ph.D (NUS, SINGAPORE)
PONDICHERRY UNIVERSITY
II Lecture
13/August/2012
Source: Collected from different sources on the internet-http://koning.ecsu.ctstateu.edu/cell/cell.html
Collected, and modified by Dr Boominathan Ph.D.
Human Physiology:
Musculo-skeletal system:
Structure and function of bone,
cartilage and connective tissue.
Disorders of the skeletal system.
Types of muscles structure and
function
BY
DR BOOMINATHAN Ph.D.
M.Sc.,(Med. Bio, JIPMER), M.Sc.,(FGSWI, Israel), Ph.D (NUS, SINGAPORE)
PONDICHERRY UNIVERSITY
II Lecture
14/August/2012
Source: Collected from different sources on the internet-http://koning.ecsu.ctstateu.edu/cell/cell.html
Collected, and modified by Dr Boominathan Ph.D.