1. Cell Biology.pptx

Cell Discovery
Cell Theory and
Introduction to CELL BIOLOGY
Presented by: Dr.T.Ugandhar

History
• The study of cells started about three
hundred years ago.
• With the help of one powerful instrument
the cell was begin to be known to humans.

Cell Discovery
• The scientist who have contributed to
the discovery of the cell:
 Hans and Zacharias Jansen
Robert Hooke
Matthias Schleiden
Theodor Schwann
Robert Brown

Anton van
Leeuwenhoek
Rudolph Virchow

1595
• Hans and Zacharias
Jansen
Credited for the
production of lenses.

1665
• Robert Hooke
English Scientist.
Coined the term
“CELL”
He found it in a cork.
Inventor of the
compound
microscope.

1674
.
• Anton van Leeuwenhoek
Dutch Businessman.
Described cells in a drop of pond water that he
called “animalcules”
“Father of Ancient
Microbiology”

1833
• Robert Brown
English botanist,
discovered the
nucleus in plant
cells(orchid).

1838
• Matthias Jakob
Schleiden
German
botanist, conclud
ed the all plant
tissues are
composed of
cells.

1839
•Theodor Schwann
German zoologist,
concluded that all
animal tissues are
composed of cells.
Proposed the cell
theory

1858
• Rudolph Virchow
Completed the cell theory by expounding
his famous conclusion “omnis cellula e
cellula” or cells develop from pre- existing
cells.

Cell Theory According to Schwann
1) The cell is the unit of structure,
physiology, and organization in living
things.
2) The cell retains a dual existence as
a distinct entity and a building block
in the construction of organisms.

Continued…
3) Cells form by free-cell formation,
similar to the formation of crystals
(spontaneous generation).

Spontaneous Generation
The hypothetical process by which living
organisms develop from nonliving matter.

Revised Cell Theory
1. All known living things are made up of cells.
2. The cell is structural & functional unit of all living
things.
3. All cells come from pre-existing cells by division.
(Spontaneous Generation does not occur).

1
CELL BIOLOGY
HCB 11103
INTRODUCTION TO
CELL BIOLOGY

LEARNING OBJECTIVES
• To understand basic science CELL
BIOLOGY
• Comprehend the way in which molecules
of a cell cooperate to create a system
that feeds, moves, grows, divides and
respond to stimuli
• Be acquainted with the core concepts of
cell biology in considerable depth

14
BIOLOGY?
Biology (from Greek βιολογία - βίος, bios, "life"; -λογία, -logia, study of) is
the science that studies living organisms
Living things
structure
function
origin
evolution
distribution
classification
principles
Cell theory
Evolution
Genes
Homeostasis
Energy
Microbiology
Molecular
biology
biochemistry
Zoology
Botany
Cellular
biology
Cell physiology
Ecology

15
CELL BIOLOGY?
• Cell biology (formerly cytology, from the
Greek kytos, "container").
Cell properties/ physiology
Structure
Organelles
Interaction with the
environments

Cell is structural and functional
unit of all living organism

18
The cell is the structural unit of life.
All organism is make up of cells.

1.1 The Discovery of Cells (1)
• The discovery of cells
followed form the invention
of the microscope by Robert
Hooke, and its refinement by
Anton Leewenhoek.

The Discovery of Cells
• Cell theory was articulated in the mid-1800s
by Schleiden, Schwann and Virchow.
– All organisms are composed or one or more cell.
– The cell is the structural unit of life.
– Cells arise from pre-existing cells by division.

Basic Properties of Cells
• Life is the most basic
property of cells.
• Cells can grow and
reproduce in culture for
extended periods.
– HeLa cells are cultured
tumor cells isolated form
a cancer patient
(Henrietta Lacks) by
George Gey in 1951.
– Cultured cells are an
essential tool for cell
biologists.

• Cells Are Highly Complex and
Organized
–Cellular processes are highly regulated.
–Cells from different species share similar
structure, composition and metabolic
features that have been conserved
throughout evolution.

• Cells Posses a Genetic Program and
the Means to Use It
–Genes encode information to build
each cell, ad the organism.
–Genes encode information
for cellular reproduction,
activity, and structure.

Levels of cellular and molecular organization

Basic Properties of Cells (4)
• Cells Are Capable
of Producing
More of
Themselves
– Cells reproduce, and
each daughter cells
receives a complete
set of genetic
instructions.

• Cells Acquire and Utilize Energy
– Photosynthesis provides fuel for all living
organisms.
– Animal cells derive energy from the products of
photosynthesis, mainly in the form of glucose.
– Cell can convert glucose into ATP—a substance
with readily available energy.

• Cells Acquire and Utilize
Energy
• Cells Carry Out a Variety
of Chemical Reactions
• Cells Engage in
Mechanical Activities
• Cells Are Able to
Respond to Stimuli

• Cells Are
Capable of
Self-Regulation
• Cells Evolve

Two Fundamentally Different Classes
of Cells
• Prokaryotic and
eukaryotic are
distinguished by their
size and type of
organelles.
• Prokaryotes are all
bacteria, which arose
~3.7 billion years ago.
• Eukaryotes include
protists, animals, plan
ts and fungi.

A Comparison of Prokaryotic
and Eukaryotic Cells

A Comparison of Prokaryotic and
Eukaryotic Cells

• Characteristics that distinguish prokaryotic
and eukaryotic cells
– Complexity: Prokaryotes are relatively
simple; eukaryotes are more complex in
structure and function.
– Genetic material:
• Packaging: Prokaryotes have a nucleoid region whereas
eukaryotes have a membrane-bound nucleus.
• Amount: Eukaryotes have much more genetic material
than prokaryotes.
• Form: Eukaryotes have many chromosomes made of
both DNA and protein whereas prokaryotes have a
single, circular DNA.

• Characteristics that distinguish prokaryotes and
eukaryotes
– Cytoplasm: Eukaryotes have membrane-bound
organelles ad complex cytoskeletal proteins. Both
have ribosomes but they differ in size.
– Cellular reproduction: Eukaryotes divide by mitosis;
prokaryotes divide by simple fission.
– Locomotion: Eukaryotes use both cytoplasmic
movement, and cilia and flagella; prokaryotes have
flagella, but they differ in both form and mechanism.

The structure
of a eukaryotic
cell

The cytoplasm of a eukaryotic cell is a
crowded compartment

Cellular reproduction in eukaryotes
and prokaryotes

• Prokaryotic Diversity
– Prokaryotes are identified and classified on the basis of
specific DNA sequences.
– Recent evidence indicates that prokaryotes are more
diverse and numerous than previous thought.

• Types of Eukaryotic Cells: Cell Specialization
–Unicellular eukaryotes are complex single-
celled organisms.
–Multicellular eukaryotes have different cell
types for different functions.
• Differentiation occurs during embryonic
development
in other multicellular organisms.
• Numbers and arrangements of organelles relate to
the function of the cell.
• Despite differentiation, cells have many features in
common.

• Multicellular eukaryotes have different
cell types for different functions.
–Model Organisms:
• Cell research focuses on six model organisms.
• These are the bacterium Escherichia coli, the
yeast Saccharomyces, the mustard plant
Arabidopsis, the nematode Caenorhabditis
elegans, the fruit fly Drosophila, and the mouse
Mus musculus.

The Human Perspective: The Prospect of
Cell Replacement Therapy (1)
• Stem cells are undifferentiated cells
capable of self-renewal and
differentiation.
–Adult stem cells can be used to replace
damaged or diseased adult tissue.
• Hematopoietic stem cells can produce blood
cells in
bone marrow.
• Neural stem cells may be sued to
treat neurodegenerative disorders.

The Human Perspective: The Prospect of
Cell Replacement Therapy (2)
• Embryonic stem (ES) cells have even
greater potential for differentiation
(pluripotent) than adult stem cells.
–ES cells must be differentiated in vitro.
–The use of ES cells involves ethical
considerations.

A procedure for obtaining differentiated cells
for use in cell replacement therapy

Steps taken to generate iPS for use in correcting
the inherited disease sickle cell anemia in mice

• The Sizes of Cells and Their Components
– Cells are commonly measured in units of
micrometers (1 μm = 10–6 meter) and nanometers
(1 nm = 10–9 meter).
– Cell size is limited:
• By the volume of cytoplasm that can be supported by
the genes in the nucleus.
• By the volume of cytoplasm that can be supported
by exchange of nutrients.
• By the distance over which substances can efficiently
travel through the cytoplasm via diffusion.

Relative sizes of
cells and cell
components

• Synthetic Biology is a field oriented to create
a living cell in the laboratory.
– A more modest goal is to develop novel life
forms, beginning with existing organisms.
– Possible applications to medicine, industry, or the
environment.
– Prospect is good after replacing the genome of
one bacterium with that of a closely related
species.

A model depicting
possible steps in
endosymbiosis

Think Back to Last
Class
 A cell is the basic structural and functional unit of all
living things
 Eukaryotic & Prokaryotic
 Animal & Plant
 How cells fit into the rest of the body’s organization
Cell Tissu
e
Organ System
Organ
Organism

Cell Membrane
 Provides support and protection
 Functions as cell
 Think of our school’s doors and intercom
system
and

Cytoplasm
 Jelly-like material that fills the cell
 Contains water and food for cell
 Holds organelles in place
 Think of the air that fills up this entire school

Nucleus
 Contains DNA, which makes you who you are
 Directs the activity of the cell – for example,
when it growsand d i v i d e s
 Think of the principal’s office as the nucleus and the
student files in the office as DNA

Endoplasmic Reticulum
(E.R.)
 The “highway” of the cell that moves materials
around to other parts
 Some parts of the E.R. contain ribosomes, which
create proteins
 Think of the school hallways where students and
teachers transport ideas to other parts of the school
If you drive
too fast,
you’ll end up
in the E.R.!

Golgi Apparatus
 Packages, stores, and secretes energy
for the cell
 Think of the lunch faculty who bring
cafeteria food into the school, then
pack and store it in the kitchen for
later use

Mitochondria
 Break down food and release energy to
cell – the “Powerhouse” of the cell
 Think of lunch time at school – food is
taken out of packages, cooked, and then
provided to students and teachers to
power them for the rest of the day

Lysosome
s
 Clean up the cell waste products
(Lysosomes clean just like Lysol!)
 Think of the janitors who clean up any
waste in the school at the end of the day

Why are there Organelles?
• Specialized Functions
• Act as containers (separate parts of the
cell from other parts)
• Sites for chemical reactions (ex.
Chloroplasts and Mitochondria)

Nucleus
• Control Center of the
cell
• Contains DNA and
RNA
• Large, roundish
organelle
• Can produce Proteins
City Hall/ Mayor’s Office

Endoplasmic Reticulum (ER)
• Folded membrane that
extends through the
cytoplasm to the nuclear
membrane
• 2 Kinds:
– Rough- Has ribosomes
attached and is involved with
protein transport
– Smooth- Lacks ribosomes and
is involved with detoxification of
poison and lipid synthesis
http://publications.nigms.nih.gov/insidethecell/images/ch1_roughER.jpg

Ribosomes
• Dot-like structures produced in the
nucleus
• Site of protein synthesis
• Each ribosome is composed of 2 sub-
units: small and large
• 2 type of ribosomes:
– Free: floating in the cytoplasm
– Attached: associated with the ER
Protein Factory

Golgi Apparatus
• Stacks of sacs with
vesicles pinching off
from the edges
• Packages materials for
export from the cell
• Will modify lipids and
proteins
• Stores and packages
materials for export out
of cell
http://www.sciencenews.org/view/download/id/48467/name/Golgi_apparatus
Post Office

Mitochondria
• Primary energy
producers of cells
• Double membrane
• Produces ATP via
aerobic respiration
• Have their own DNA
and method of
replication
• Endosymbiotic
Theory
Power Plant
http://shs.westport.k12.ct.us/asr/Bio%202/webquests/cell%20city/organelle%20links/mitochondria.gif

Chloroplasts
• Site of photosynthesis
• Chlorophyll = Green Color
• Endosymbiotic Theory
QuickTimeªand a
decompressor
are neededto see thispicture.
http://www.cbs.dtu.dk/staff/dave/roanoke/chloroplast.gif

Microtubules
• Made from proteins within eukaryotic
cells
• Provide the structure for the cell-
cytoskeleton
• Tracks for transporting organelles &
vesicles
• Pull apart chromosomes during division
• Ex: Cillia and flagella

Centrioles
• Found in eukaryotic cells
• Come in pairs
• Made from short microtubules
• Assist the cell with cell division

Vacuoles
• Single membranes that
surround solid or liquid
contents
• Vacuole will as a
container for the cell
• Plant cells usually have
1 large vesicle filled
with water
• 50-90% of a plant cell’s
volume is a vacuole
Storage Unit
http://education.kings.edu/dsmith/vacuole.jpg

Vesicles
• Sac surrounded by a single membrane
• Endocytotic- will bring contents into cell
• Exocytotic- takes materials out of cell
UPS/Delivery Service

Lysosomes
• Sacs within the cell that contains
digestive enzymes
• Encased within a single membrane
• Used to digest/breakdown complex
organic molecules
• Lysosome will merge with the “food” &
the contents will begin the digestion
Dump or Garbage Truck

Peroxisomes
• Resemble Lysosomes with structure
and function
• Sac with a single membrane that break
down amino acids, alcohol and fatty
acids
• Unique because it produces and
disposes of Hydrogen Peroxide, which
is fatal to cells

Cell Wall
• Thin layer of
cellulose that
surrounds the cell
• Permeable to many
substances
• Provides strength
and support to the
plant
http://www.desmids.nl/info/sheddingoftheprimarycellwall/images/Pleurotaeniumehrenbergii3.jpg
City Limit

Cell Membrane
• Semi-permeable membrane that lets some
things in and prevents materials from leaving
• Provides limited structure
• Lipid bilayer
http://wiki.chemprime.chemeddl.org/images/thumb/6/60/Lipid-Bilayer_Model_for_Membranes_.jpg/470px-Lipid-Bilayer_Model_for_Membranes_.jpg
City Limit

Cells
Structure and Function
1

2
Campbell et al, Biology; 2009.

Sizes of Living Things
http://amazedatbio.wordpress.com/2012/09/17/life-is-cellular/
Minimum resolution of a LM 2 microns, the size of a small bacterium
LM can magnify effectively to 1,000 times the size of the actual specimen.
3

Properties of life
 Reproduction :
o sexual : genetic variation, fertilization
o asexual : genetically identical, e.g. sporulation, budding,
regeneration, binary fission
 Metabolism : anabolism Vs. catabolism
 Growth and Development
 Response to environment
 Homeostasis : regulated via organ system
 Organization : Cell, tissue, organ, organ system, organism
o acellular
o unicellular : bacteria, yeast
o multicellular : plant, animal
4

Cell Theory
 All organisms are composed of cells
 All cells come only from preexisting cells (Rudolf Virchow)
 Cells are the smallest structural and functional unit of organisms
 Cells carry genetic information in the form of DNA
5
Robert Hooke (1665) Matthias Jacob
Schleiden (1838)
plant
Theodor Schwann
(1839)
animal
Antony van
Leeuwenhoek (1673)

Light microscope
6

Electron microscope
 To resolve smaller structures we use EM, which focuses a beam
of electrons through the specimen (TEM) or onto its surface
(SEM)
 TEM are used to study the internal ultrastructure of cells.
 A TEM aims an electron beam through a thin section of the
specimen.
o The image is focused and magnified by electromagnets.
o To enhance contrast, the thin sections are stained with
atoms of heavy metals.
 SEM are useful for studying surface structures.
 The SEM has great depth of field, resulting in an image that
seems three-dimensional.
7

8

Prokaryotic and eukaryotic cells
 All cells
o surrounded by a plasma membrane.
o have cytosol, containing the organelles.
o containchromosomes
o haveribosomes
 A major difference
o eukaryotic cell: chromosomes are contained in the
nucleus (within a membranous nuclear envelope)
o prokaryotic cell: the DNA is concentrated in the
nucleoid
9

A major difference...
 Cytoplasm
o All the material within the plasma membrane of a prokaryotic
cell is cytoplasm.
o Within the cytoplasm of a eukaryotic cell is a variety of
membrane-bounded organelles of specialized form and
function.
 Eukaryotic cells are generally much bigger than prokaryotic
cells.
o smallest bacteria, mycoplasmas, are 0.1 to 1.0 micron. (most
bacteria: 1-10 microns)
o Eukaryotic cells are typically 10-100 microns in diameter
10

11
Not presentin
bacteria
nucleus, membrane
bounded organelle,
cytoskeleton,
centriole

12
Eukaryotic Cells Prokaryotic Cells
“complex” organisms, including all
plants, protists, fungi and animals
“Simple” organisms, including
bacteria and cyanobacteria
Contain nucleus and membrane bound
organelles
Several chromosome
Lack nucleus and other
membrane-encased organelles.
Single chromosome (DNA + non-
histone protein)
Can specialize for certain functions,
multicellular organs and organisms
Usually exist as single, virtually
identical cells
Cellular respiration occur in
mitochondria
Cellular respiration occur in
mesosome (extended membrane)
Ribosome: 40s, 60S Ribosome: 30S, 50S
Photosynthesis occur in chloroplast Photosynthesis occur in
chlorophyll located region
Cell Wall present in Plants & Fungi only Cell Wall
Cyanobacteria (blue-green algae) e.g. Nostoc,

Cells
 Cell coat: Cell wall, Cell membrane
 Protoplasm
o Nucleus : nuclear membrane, nucleoplasm (chromatin fiber,
nucleolus)
o Cytoplasm
• cytosol
• organelle
– no membrane bounded: ribosome, centriole,
cytoskeleton
– single membrane bounded: ER, Golgi complex,
lysosome, peroxisome, vacuole
– double membrane bounded: mitochondria, chloroplast
13

Animal Cell Anatomy
14
http://traddude.blogspot.com/2008/06/cells-compendium-1.html

Plant Cell Anatomy
15
http://minhalogia.blogspot.com/2013_03_
01_archive.html

Plasma membrane
 Fluid mosaic model
o Phospholipid bilayer acts
more like a fluid than a
liquid
 Contains integral and
peripheral proteins
 Semi permeable membrane
 Like a city border they
surround the cell and are able
to regulate entrance and exit
16

Phospholipid bilayer
 polar heads face outward towards the watery environments both inside and
outside the cell
 non polar tails face inward away from the watery environment 17
http://alevelnotes.com/content_images/i38_phospholipid.gif
http://online.morainevalley.edu/WebSupported/BIO111-
Gibbons/membra29.jpg

1
control fluidity of
membrane
recognition of cell

Function of membrane protein
19

Function of membrane protein
Chandar et al, Lippincott’s Illustrated Reviews: Cell and Molecular Biology; 2010.
 Enzyme
 Mediate the passage of ions and most biological molecule
 Selective traffic of molecule
 Control the interactions between cells of multicellular organisms
 Serve as sensor (e.g. receptors, signal transductions)
20

Transport through membrane
 Passive transport: need no energy, downhill
o simplediffusion
o facilitated diffusion: channel protein, carrier protein
 Active transport: need energy, uphill
o primary active : direct hydrolysis of ATP
o secondary active : symporters, antiporters
 Vesicle transport
o endocytosis: receptor mediated, phagocytosis,
pinocytosis
o exocytosis
21

External environment
22
Ga
s
Hydrophobi
c
molecules
Large polar
molecules
Charged
molecule
s
CO2
O2 Benzen
e
Small polar
molecules
H2O
Ethanol
Glucos
e
Amino
acid
H+ Cl-
Na+
Ions
Ca2+
Cytoplasm

Diffusion
2
Campbell et al, biology; 2011.

Osmosis
2
Campbell et al, biology; 2011.

Passive
transport
2
Chandar et al, Lippincott’s Illustrated Reviews: Cell and
Molecular Biology; 2010.

Active transport
2
6
Na+-Ca2+antiporter
in cardiac
muscle
Na+-glucose
transporter
in intestinal epithelial
cell
Chandar et al, Lippincott’s Illustrated Reviews: Cell and Molecular Biology; 2010.

Vesicle Transport
27
http://www.shayda.us/WebCT/AP1/AP1_Ex2_Materials/GA_Pag2.jpg

28
Phagocytosis of microbes
Abbas et al, Cellular and Molecular Immunology; 2012.

29
Russell et al, Biology the dynamic science; 2008.

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