Transcript Intro to Cells Micro

Cells
Microbiology 2314
General Properties of Living
Organisms
• Metabolism
• Growth
• Reproduction
Characteristics of Life?????
• Responsiveness or
Irritability
• Conductivity
• Growth
• Respiration
• Digestion
• Metabolism
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Absorption
Secretion
Excretion
Circulation
Reproduction
Cell Theory
• Cells are the fundamental units of life
• Cells are the simplest unit capable of
independent existence
• All living things are made of cells
Note: Credit for developing Cell Theory is usually
given to two scientists, Theodor Schwann, a zoologist
and Matthias Jakob Schleiden, a botanist. In 1839
these two scientists suggested that cells were the basic
unit of life. In 1858, Rudolf Virchow concluded that
all cells come from pre-existing cells thus completing
the theory.
Modern Cell
Theory Expands
These Ideas…
• Cells contains hereditary information which
is passed from cell to cell during cell
division.
• Cells have similar chemical composition,
metabolic activities, and physiological
functions.
• Cell activity depends on the activities of
organelles.
Organizational Hierarchy
• Biology is hierarchial with
each level building on the
level below it.
• In order to understand how
something is built and how
something works, you
must look at all of its
components and analyze
them both individually and
together.
Life’s Hierarchy
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Atom / Element
Molecule / Compound
Organelle
Cell
Tissue
Organ
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Organ System
Organism
Population
Community
Ecosystem
Biosphere
• Atoms form all matter.
• Atoms are the basic
building blocks of
matter that make up
everyday objects. A
desk, the air, even you
are made up of atoms!
• There are 90 naturally
occurring kinds of
atoms. Scientists in labs
have been able to make
about 25 more.
Atom
• Groups of atoms form
molecules.
• Molecules come together
to form compounds and
compounds come
together to form
organelles
• Organelles can include
the nucleus, endoplasmic
reticulum, golgi
apparatus, mitochondria,
etc.
Atom
Organelle
Mitochondria are the 'power plants' of
cells that convert organic materials
into energy. Mitochondria have their
own DNA and may be descended
from free-living prokaryotes that were
related to Rickettsia bacteria
• The basic unit of life is
the cell.
• All living things are
composed of one or
more cells
• The human body
contains about 100
trillion cells.
• There are about 200
different types of cells
in the human body.
Atom
Organelle
Cell
• Tissue is a collection of
interconnected cells that
perform a similar function
within an organism.
• The study of tissue is known
as histology, or in
connection with disease,
histopathology
• There are four basic types of
tissue in the body of all
animals, including the
human body and lower
multicellular organisms such
as insects.
Atom
Organelle
Cell
Tissue
Types of Tissues
• Organs are the next level
of organization in the
body.
• An organ is a structure
that contains at least two
different types of tissue
functioning together for a
common purpose.
• There are many different
organs in the body: the
liver, kidneys, heart, even
your skin is an organ.
Atom
Organelle
Cell
Tissue
Organ
• Organ Systems
are composed of two or
more different organs
that work together to
provide a common
function.
• There are 10 major
organ systems in the
human body.
Atom
Organelle
Cell
Tissue
Organ
Organ System
• In biology and ecology, an
organism is an individual
living system (such as
animal, plant, fungus or
micro-organism).
• In at least some form, all
organisms are capable of
reacting to stimuli,
reproduction, growth and
maintenance as a stable
whole.
Atom
Organelle
Cell
Tissue
Organ
Organ System
Organism
Albino Peacock
• An organism may be
unicellular or made up,
like humans, of many
billions of cells
(multicelluar) divided
into specialized tissues
and organs.
• Based on cell type,
organisms may be
divided into the
prokaryotic and
eukaryotic groups.
• In biology a population is
the collection of organisms
or individuals of a particular
species located in a specific
area.
Atom
Organelle
Cell
Tissue
Organ
Organ System
Organism
Population
• A community includes
all the biotic (living)
organisms sharing an
environment, normally
with shared interests.
Atom
Organelle
Cell
Tissue
Organ
Organ System
Organism
Population
Community
• An ecosystem is a
natural unit consisting
of all the biotic and
abiotic elements that
composes it.
Atom
Organelle
Cell
Tissue
Organ
Organ System
Organism
Population
Community
Ecosystem
• The biosphere is the part of the
earth, including air (atmosphere),
land (lithosphere), and water
(hydrosphere), within which life
occurs, and which biotic
processes in turn alter or
transform.
• From the broadest point of view,
the biosphere is the global
ecological system integrating all
living beings and their
relationships.
Atom
Organelle
Cell
Tissue
Organ
Organ System
Organism
Population
Community
Ecosystem
Biosphere
Cells are 90% water. A mere 2%
drop in body water can trigger fuzzy
short-term memory, trouble with
basic math, and difficulty focusing
on the computer screen.
Cell Elemental Composition
Cells are 90% water. Of the remaining molecules
present, the dry weight is approximately:
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50%
15%
15%
10%
10%
Protein
Carbohydrate
Nucleic Acid
Lipid
Miscellaneous
• Proteins are found literally everywhere in
your system. From your muscle tissues, to
the enzymes that digest your food, to your
skin cells, and even within your blood.
• When we take protein in our body through
the foods we eat, it gets broken down into
smaller compounds called amino acids. Of
the 20 amino acids found in the foods we
eat, 9 of these are essential.
• All carbs end up
as sugar.
Starches, or
complex
carbohydrates,
are just longer
strings of sugar.
• Lipids are among the fundamental
categories of nutrients that are required by
our bodies for healthy functioning.
“We are a generation that is computer
literate but food illiterate.”
Brief History of Life on Earth
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4.5 Billion Years Ago
3.5 Billion Years Ago
1.5 Billion Years Ago
0.5 Billion Years Ago
Earth Formed
First Life (Prokaryotic)
Eukaryotic Cells Arise
Multicellular Eukaryotes
Comparing Prokaryotic and
Eukaryotic Cells
Similarities Between the Two
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Chemical Composition
Chemical Reactions
DNA
Membrane Bound
Ribosomes
Basic Metabolism
Occur in Diverse Forms
Differences Between the Two
• Procaryotic cells lack membrane-bound organelles
(Including a Nucleus)
• Procaryotic cell walls contain peptidoglycan
Classifying Life
Life
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Prokaryotes
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Archeabacteria Eubacteria
(Ancient Bacteria)
(True Bacteria)
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Eukaryotes
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Eukarya
(Everything Else)
Two Groups of Prokaryotes
• Archaebacteria
1. Methanogens
2. Halophiles
3. Hyperthermophiles
4. Thermoplasma
• Eubacteria
1. Cyanobacteria
2. Soil Bacteria
3. Nitrogen-Fixing
4. Pathogens
Eubacteria
• More Well Known
• Can be Pathogenic
Archaebacteria
• Ancient
• Non-Pathogenic
• Extreme
Environments
• Unusual Metabolizing
Abilities
• No Peptidoglycan
• Resistant to Lysozyme
The hot springs of Yellowstone National Park, USA, were among the first place Archaea were discovered
Methanogens
Anaerobic Methane
Producers
• Common in wetlands
• Responsible for marsh gas
• Found buried under km of
ice in greenland and under dry
deserts.
• They are known to be the
most common archaebacteria
in deep subteranean habitats.
Extreme Halophiles
Salt-Dependent Organisms
Anywhere with a concentration
of salt 5 times greater than the
salt concentration of the ocean
•The Great Salt Lake, Utah
•Owens Lake, California
•The Dead Sea
Hyperthermophiles
Heat-Dependent
Organisms
Hyperthermophiles were first
discovered in the 1960s in hot
springs in Yellowstone National
Park, Wyoming.
The most hardy hyperthermophiles
thus known live on the superheated
walls of deep-sea hydrothermal
vents, requiring temperatures of at
least 90 °C for survival.
Hyperthermophiles produce some of the bright colors of Grand Prismatic Springs
Thermoplasma
Heat and Acid
Resistant
Example: Thermoplasma Volcanium
What Happened to the
Dinosaurs?
Bacterial Shapes
Modified Shapes
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Diplo
Strepto
Staphylo
Vibrio
Tetrad
Pleomorphic – can assume more than 1 shape
Monomorphic – can assume only one shape
Spirillum
Glycocalyx/Slime Capsule/Slime Layer
Not Really the Same Thing
• Slime Capsule is a distinct Defined Layer
with a Distinct Outer Edge
• Slime Layer is a Poorly Defined
Concentration of Slime. It Lessens with
Distance.
• Glycocalyx Refers to a Gelatinous
Polysaccharide and/or Polypeptide Covering.
Purposes
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Protects Pathogens from Phagocytosis
Enable Adherence to Surfaces
Protects Against Desiccation
Stores Food Reserves
Case Study 1
• The patient was a 22-year-old female with a history of
mitral valve prolapse (a defect of the valve between the
left atrium and ventricle caused by a weakening of the
tough, connective tissue of the valve leaflets, which
allows the valve to project back into the left atrium). She
was admitted with complaints of intermittent fevers for 1
month and headaches for 3 weeks. Two weeks before
symptoms developed she had undergone a dental
procedure.
• Four blood cultures were performed on admission. All
four blood cultures demonstrated Gram-positive cocci in
chains.
The diagnosis is bacterial endocarditis (a bacterial
infection of the tissue lining the inside of the heart;
usually involves the heart valves).
The patient had recently had her 6 month dental
appointment to have her teeth cleaned.
• During dental procedures, transient bacteremia
occurs in up to 80% of individuals.
• Transient bacteremia is defined as the presence
of bacteria in the bloodstream for short
periods.
• The organisms that cause this are generally of
low virulence and are usually easily removed
by the reticuloendothelial [filtering and
phagocytic] system.
Case Study 2
• This 47-year-old man had a history of sickle cell disease
that resulted in many previous hospitalizations for the
management of painful crisis.
• The patient had been admitted 9 days prior to the current
admission for management of such a crisis, and a right
port-a-cath (a central venous catheter that is designed to
remain in place for a prolonged period) was placed in his
right subclavian vein.
• He was discharged (with port-a-cath remaining) after a
4-day hospitalization.
• On the day of readmission, the patient had right
arm discomfort and swelling, a temperature of
38.1C (normal is 37C), and chills. He presented to
the hospital emergency room, where he was
afebrile. Physical examination was remarkable for
right extremity swelling.
• Two blood cultures were obtained (one set
through the port-a-cath and one set via a
peripheral vein). The two sets of blood cultures
grew identical Gram-positive cocci that were
catalase positive. The diagnosis is in-line sepsis.
Any indwelling device introduced
through the skin places an
individual at risk for infection.
Bacteria can produce a slime
layer that can enhance their
adherence to a wide variety of
plastic surfaces.
Slime-producing strains of
staphylococci may also be more
difficult to eradicate by
antimicrobial therapy than nonslime-producing ones due to
antibiotic resistance.
Flagella
Hook is similar to a
universal joint
Basal Body
penetrates the cell and
causes the flagellum
to rotate. It serves as
a “motor”.
Filament is actually
an extension of the
plasma membrane.
Flagella
Occur In a
Variety of
Forms
Examples of
bacterial flagella
arrangement
schemes.
A-Monotrichous
(one flagella)
B-Lophotrichous (a
tuft of flagella)
C- Bipolar
Monotrichous (one
flagella at both ends)
D-Peritrichous (a
hair ball)
• Monopolar
Lophotrichous
• Bipolar
Lophotrichous
• Peritrichous
Identify This
Identify This
Identify This
Identify This
Flagella Allow for Motility
Bacterial
Movement
Taxis
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Positive Taxis
Negative Taxis
Phototaxis
Chemotaxis
Magnetotaxis
Plankton
Antigen
• Bacteria Flagella is
composed of protein
which acts as an antigen
when introduced into the
human body.
• What happens then?
• Why is this beneficial for
vaccines?
Axial Filaments
(Endoflagellum)
on a Spirochete
Spirochetes
• Spirochetes are long and slender bacteria that are
tightly coiled, and so look like miniature springs
or telephone cords.
Spirochetes Cause
Syphilis and Lyme
Disease
Are Spirochetes and Spirilla
the Same?
Fimbriae and Pili
Short, Rigid, Hollow,
Thin, Protein Appendages
They are NOT involved in
motility.
Fimbriae Help Cells Adhere To Surfaces
Pili Join Cells for the Transfer of DNA From
One Cell to Another
Together They
Produce
Biofilms.
This is Biofilm in
a Swamp Gas
Reactor
Biofilm on Teeth
The Cell Wall of Peptidoglycan
Gram Positive Bacteria
Have Thicker Layer of Peptidoglycan
and Have Teichoic Acids
Gram Negative Bacteria
Thinner Layer of Peptidoglycan
Gram + and – Cell Walls
Gram - Bacteria
• More susceptible to breakage
• Thinner layer of peptidoglycan
Outer membrane is
strongly negative
aiding is resisting
phagocytosis and
providing a barrier to
antibiotics and
digestive enzymes
Periplasmic space
containing specialized
proteins and enzymes
involved in nutrient
acquisition
It has Porins and
Specific Channel
Proteins
Osmotic Effects
Water Moves Freely Across Membranes to Try and
Equalize Concentration
Osmotic Differences in Blood Cells
Lysozyme and Penicillin
More Basic Structures
of Prokaryotic Cells
Cell
Membrane
Cell
Membrane
• Permeability Barrier or Selective Barrier
• Prevents cell contents from leaking away
• Impermeable to polar and charged
molecules
• Contains specific proteins to carry out
selective transport
• 50% lipid and 50% protein
Very delicate and easily ruptured
Phospholipid Bilayer
50% Lipid
50% Protein
Embedded Proteins
Fluid Mosaic Model of Membrane Structure
Cytoplasm Filled with Ribosomes
Ribosomes Utilize 25% Cell’s Volume – 90% Cell’s
Energy
Ribosomes
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Composed of RNA and Protein
Function to Make Protein (Mainly Enzymes)
Size is Measured in Svedberg (S) units
Bacterial Ribosomes are ~70S
Nucleoid
Plasmids are small circular DNA elements found
in virtually all bacterial cells.
They carry extra genes and are important in
Genetic Engineering.
Inclusion Bodies or Storage
Granules
Prokaryotic bacteria exist in very competitive
environments where nutrients are usually in short
supply, so they tend to store up extra nutrients when
possible.
• Fats
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Sugars
Phosphates
Sulfur
Metachromatic
Granules
Endospores
Survival Mechanism for Extended Periods in the
Absence of Food, Water, of Proper Growth Conditions
Endospores
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Can resist Sterilization
Can resist Boiling
Can resist UV Light
Can resist Dessication
Can resist Harmful Chemicals
Abundant in Bacillus and Clostridia
Germination in Minutes
Create a Problem with Canned Foods
We worry
about
canned
goods and
botulism.
Oval Terminal
Rectangular Terminal
Rectangular Subterminal
Rectangular Central
Circular Terminal
Circular Central
Club Shaped Terminal
Bacteria
Endospores
Schaeffer Fulton
Method of
Staining
Dorner
Method of
Staining
Dating Endospores
• Spores taken from prehistoric mosquitoes
suspended in Amber
• Roman Fort Vindolanda
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1976 Fort dating AD 90-95 was drained and excavated
Found viable endospores of Thermoactinomyces vulgaris
Thermophilic Aerobic Bacterium (Warmth and Moisture)
Had been sealed in a cold anaerobic environment (flooded)
Would date this particular endospore to being 2000 years old
Eukaryotic Cells
Cilia
Chromosomes and Chromatin
Nucleus with Double
Membrane
Mitochondria
Endosymbiotic Theory of Cellular
Evolution
• Proposed by Lynn Margulis in 1981
• Studied Mitochondria
• Saw association between Mitochondria and
Gram-negative Bacteria
Endomembrane System
• Endoplasmic
Reticulum
• Golgi Apparatus
• Various Vesicles
• Lysosomes
• Microbodies
• Nuclear Membrane
Rough E.R.
Functions In
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Compartmentalization
Chemical Homeostasis
Communication
Transport
Golgi Apparatus
Membrane Transport
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Small Molecules
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Passive Transport Active Transport
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Diffusion
Osmosis
Facilitated Diffusion
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Large Molecules
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Endocytosis
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Phagocytosis
Pinocytosis
Exocytosis
Exocytosis
Endocytosis
Phagocytosis
in Action
Endosymbiotic Theory /
Eukaryotes
• The endosymbiotic theory concerns the
mitochondria, chloroplasts, and possibly other
organelles of eukaryotic cells.
• According to this theory, certain organelles
originated as free-living bacteria that were
taken inside another cell as endosymbionts.
• Mitochondria developed from proteobacteria
such as Rickettsiales, and chloroplasts from
cyanobacteria.