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Microbes
Anything so small that a microscope is needed to study it
Major Groups
Fungi
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Characteristics:
o Absorb nutrients from environment
o Eukaryotic cells (complex)
o Can be single celled or multicellular
 Single celled – yeast & some molds (live in colonies)
 Multicellular – mushrooms & some molds
Uses: source of food, make food products, antibiotics
Pathogens: can get some fungal infections(diseases)
Location: soil, water, on/in organisms (trees)
Algae
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Characteristics:
o NOT PLANTS
o Eukaryotic cells (complex)
o Photosynthesis for energy
o Single celled
o Solitary (live alone) or in colonies
o Can move
Uses: source of food for other organisms, produce Oxygen
Pathogens:
o only one species of algae can cause a disease in humans
o Too much algae in water can put too much oxygen into the water,
kills aquatic life
Location: fresh and salt water
Protists
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Characteristics:
o Single celled
o Eukaryotic cells (complex)
o Some move on own, others stationary
o A few species are large enough to see with the naked eye
o Get food by eating other organisms
 Microbial predators
Uses: none
Pathogens: some cause disease (e.g. malaria & giardiasis)
Location: soil & water
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Characteristics:
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Bacteria
Single celled
Prokaryotic (simple)
3 basic shapes (rod, sphere, spiral)
Some move on own, other stationary
Food Sources:
 Some absorb nutrients from other organisms
 Some photosynthesis
 Some chemosynthesis
Uses: some help make food, others are used in industry,
Pathogens: many are harmless, but many cause diseases (use antibiotics)
Location: everywhere
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Viruses
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Characteristics:
o NOT LIVING
 Trick cells into reproducing viruses for them
o Too small to be seen with a light microscope (need electron
microscope)
o No cellular structure
 A few nucleic acids (part of a strand of DNA) and some
proteins
o Invade cells easily (because they are so simple and small)
Uses: none
Pathogens: cause many diseases
Cannot fight with antibiotics
A few antiviral medicines, mostly just treat the symptoms and let the body
get rid of it
Location: everywhere
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Characteristics of Life
Carbon based
Water
Respiration
Stimulus
Energy source
Reproduction
Adaptation
Organization of multi-celled living things
Cells tissues  organs  system organism
Single celled organisms
Can live alone or in colonies
6 Kingdoms
 Animal
 Plant
 Fungi
 Bacteria – prokaryotes (simple celled)
 Moneran – eukaryotes (complex celled)
 Archea – extremophiles
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Microscope 101
Robert Hooke – 1665
 3 lens in gold leather case
 poor quality (compared to a cheap microscope today)
 looked at cork, saw plant cells
Anton van Leeuwenhoek – 1700
 Improved accuracy and quality of lens
 Ground lenses himself
 First to name bacteria (animacuoles)
 Saw red blood cells
Compound Microscope
 Use either natural light or lamp
 Magnify power determined by multiplying of eye pieced and objective lens
 Eye piece (10) * Objective lens (30) = 300 magnifying power over
eyesight
Scanning Electron Microscope – 1970’s
 Beam electrons over the surface
 3D picture of surface
 Bt only get the surface
 60,000 magnification
Scanning Tunneling Microscope – 1980’s
 Beam electrons
 See atoms at objects surface
 Get a 3D image, still just a surface image
 100 million magnification
Transmission Election Microscope – 1990’s
 Beam electrons through specimen, denser portions allow fewer electrons
through, give a darker image to the denser sections
 Get a 2D image (a cellular x-ray)
 100,000’s times
New electron microscopes give greater detail, but do destroy the sample
Cell Theory / Cell History
Robert Hooke – 1665
 Used very simple microscope, poor quality, little detail
 Only saw cell walls
 Saw simple box structures, called them cells
Francesco Redi – 1668
 Before Redi people believed in spontaneous generation
o Living things could come from dead/non-living things
 Ex. maggots born from rotten meat
Redi proved that living things can only come from other living
things
 Put out three jars with meat in them
o One open top, one with a cork, one with cheese cloth (allowed air
to get to meat, but not the flies)
o Noticed flies hanging around
o Meat went rotten in all jars
o Only maggots formed on the open jars
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At time most educated people still did not understand disease or
that microbes came from other living microbes
* Many people still believed in spontaneous generation for microbes
* Something in the broth would make it go bad, they didn't think
that microbes did it
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Anton van Leeuwenhoek - 1700
 Improved lens for microscopes
 Expanded knowledge of microbes
 Looked at pond water (saw microbes), blood (saw red blood cells), cheek
cells
Matthias Schleiden (1830’s)
 Observed plants
 All plants made up of cells
Theodore Schwann (1830’s)
 Observed animals
 All animals made up of cells
Louis Pasteur (1850’s)
 Proved all living things come from living things
 Also helped to prove that microbes caused disease & ruined food
 Found out that if heated liquids like (milk, apple cider, and wine) that the
flavor didn’t change, but that the microbes that ruined the food were dead
(pasteurization)
 Used flasks with curved ends to show that microbes ruined food, microbes
were every where, and that only came from other microbes
o Curved flasks were open to the air
o Boiled to kill microbes
o Microbes trapped in curve
o Took some flasks and ran both into curve
o Later those tipped flasks had microbes
o There are still open flasks that are free of microbes 150+ years
later
Cell Theory
1. All organisms are composed from cells (One or more)
2. Cells are the basic unit of organization of organisms
3. All cells come from pre-existing cells
Types of Cells
Prokaryotes – Simple Cells
 Bacteria (Monerans)
 Lack internal membrane bound structures (organelles)
 Has no nuclear membrane
Eukaryotes – Complex cells
 Found in multicellular organisms (plants, animals, fungi)
 Protists (algae, yeast, paramecium, etc)
 Contain membrane bound structures (organelles)
 Has a nuclear membrane
Archea – Extremophiles
 Extreme loving single celled organisms
 Sort of a mix between prokaryotes and eukaryotes
 So different from both that are put into own category (own kingdom!)
Animal Cell Notes
Important chemicals needed for the Cell to Survive
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Lipids = fats
Carbohydrates = starch/stored energy
Glucose = sugar
Proteins = energy source, enzyme (starts reactions)
Organelles (“cellular organs”)
1. Membrane
2. Solid (mostly)
3. Microtubular (structure)
Inclusions
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Extra stuff in the cell
o Storage substances (ex. lipid droplets)
o Waste materials
o Products of the cell
o Pigment granules
o Foreign materials (ex. viruses)
Major Organelles
Cytoplasm – Goo stuff floats around in
 Fluid to jelly-like material that fills the cell
 Within the cell membrane
 EXCLUDING the nucleus
 Dissolved in the cytoplasm are simple sugars (ex. glucose), amino acids,
O2, CO2, ions, and large carbohydrates
 Suspended in cytoplasm: inclusions & organelles
Nucleus – Brain of the Cell
 Usually found in central part of cell
 Contains Chromatin
o DNA (genetic material) and proteins
o Genes (hereditary units) of the cell
Nuclear Membrane – Protects Nucleus
 Double membrane around nucleus
 Has pores in it, allows materials to pass in and out of nucleus
Nucleolus – Ribosome Maker
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Found within Nucleus
Makes ribosomes
Centrioles
 Present ONLY during cell division
 Microtubules that act
Endoplasmic Reticulum (ER) – Structure/Surface Provider
 Consists of highly folded sheets of membrane suspended
 Folded to form loose sheets or tubes
 Provides some physical support for cell
 Folds create inner compartments (cisternae) which are used to store some
of the produces synthesized by the cell
 Two types:
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Rough ER
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Has ribosomes on outer surface (hence “rough” ER)
Provides stable place where ribosomes can attach and make
proteins
Smooth ER
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Outer surface provides a tremendous amount of surface
area for synthesis (creating) of lipids and carbohydrates
Ribosome – Protein Producer
 Solid spherical particles of RNA (single strand of genetic info) and protein
 Frequently found on outer surface of ER
 Some are free floating
 Provides location for protein synthesis, ESSENTIAL for this purpose
 Ribosomes stabilize some of the molecules requires for protein synthesis
 Contain some of the enzymes needed for cellular respiration and electron
transport
Lysosomes - Garbage Men of Cell
Sacs made of a single membrane (balloon-like)
Contain hydrolytic enzymes that can break down large molecules into
smaller ones
 Enzymes destroy foreign material picked up by cell
 Also destroys worn out or injured cells (helps the cell “self destruct”)
Vacuoles – Storage Containers
 Sacs made up of a single membrane
 Store things in the cell
o Food and enzymes (for later use)
o Waste products made by cell
Golgi Apparatus (Golgi Complex) – Cells Mailman
 Stacks of discs (like pancakes)
 Always found close to ER and cell membrane
 Provide temporary storage to newly synthesized materials
 Vesicles – small sacs at the end of the Golgi stacks
o Contain a single membrane
o Can modify proteins into packages ready to be sent where they are
needed
 Modifies and sends proteins where they need to be
o Synthesis begins in ER  moves to golgi apparatus moves to
buds sent out of cell
Mitochondria – Energy Releaser
 Hollow structures, oval or rod shaped, double layer of membrane
 Inner membrane has intricate folds that project into a hollow cavity
o Provides more surface area
 Site of cellular respiration & electron transport
 Release large amounts of energy
o Can be released for immediate use or stored as ATP (high energy
compound)
 ATP = adenosine triphosphate
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Cellular Respiration (How the cell breathes & eats)
 Break down nutrients to CO2 and water
 Allows cell to take in different gases and release waste gases
 Major energy activity (How cells get some of their energy)
 C6H12O6 +6O2  6H20 + energy
(glucose)
Electron Transport Chain
 Uses part of the energy released in cellular respiration to form ATP (high energy
compounds)
 Use a bit of energy to make “super battery cells” used in almost all cellular functions
Cytoskeleton
 Network that provides structure and strength to cell
 Give it rigidity and provide for cell movement
o Microfilaments – solid rods/fibers that provide structure
o Microtubules – hollow tubes that provide structure, allow stuff
to flow through tube
Cillia and Flagella
 How single-celled organisms move
 Thread-like projections out of cell (microtubules filled with cytoplasm)
 Basically the same thing, only difference is the amount
o Cilia - Lots of little threads, wave-like motion
o Flagella - One single large thread, whip-like motion
Plant Cell Notes
Contain all of the same organelles as animals cells with a few
differences
NO CENTRIOLES!
Cell Wall
 Has pores
 Provides structure and rigidity to plant cells
 Made up of cellulose
Plastids
 Often contain other pigments the cell uses for energy production
 Used to store energy (like a vacuole)
 Some contain starch or lipids
 These other plastids are what we see when the leaves change color
Chloroplasts
 Capture light and produce food
 Where photosynthesis takes place
 Chlorophyll
o Actual pigment that captures light energy
o Green color
Important Actions of the Cell
Homeostasis
Process of maintaining a cell’s environment
Keeping everything in balance
Selective Permeability
Cell allows only certain things across membrane at certain
times
It’s selective
Movement of Materials Across Cellular
Membrane
Simple Diffusion
Movement of particles across cellular membrane
Caused by the concentration a specific material on one side of
the membrane being higher or lower than the concentration on
the other side
Happens automatically
High concentration low concentration
o (Ex. calcium ions)
Facilitate Diffusion
Assisted movement of particles across a cellular membrane
Protein carriers move materials
High concentration low concentration
Osmosis
Water moving across cellular membrane
Happens by simple diffusion
High concentration low concentration
Do not want this to happen unchecked
o Or cell could explode (takes in too much water) or deflate
(looses too much water)
Osmotic pressure – pressure required to stop the flow
Active Transport
Forced movement of particles across a cellular membrane
Low concentration high concentration
Requires a lot of energy
 Allows cell to take in substances that are in low concentrations in
the environment around the cell
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And allows cell to concentrate different substances within itself
How the cell takes in and remove particles
Done by using vesicles (small membrane bound sacs)
Allow large quantities of materials across the membrane
Endocytosis
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Cells take in materials using vesicles
Phagocytosis
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Cell takes in solid material
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Cell takes in liquids
Pinocytosis
Exocystosis
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Cells remove materials using vesicles
Fluid Types (based on how the cells react)
Isotonic
No change in the cell
Same amount of water and ions flowing into and out of the
cell
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*ions* atoms that have an electrical charge
Hypertonic
Cells shrink and shrivel
Lower water concentration out of the cell, higher conc. of
ions
Hypotonic
Cell swells & can burst, cell fills with water
Higher concentration of water outside the cells, lower conc. of ions
Cell walls prevent bacteria, algae and plants cells from bursting or
shrinking too much (wilt), unless the cell wall is weakened.
Energy Reactions
Photosynthesis
Only in plants, algae, and some photosynthetic bacteria
Occurs in the plastids, most commonly chloroplasts
Take in sunlight and turn it into glucose (stored energy)
o 6CO2 + 6H 20  C6H12O 6 (glucose) + 6O2
½ of all atmospheric Oxygen comes from algae
and photosynthetic bacteria
rest comes from plants
Cellular Respiration (How the cell breathes & eats)
Break down nutrients to CO2 and water
Allows cell to take in different gases and release waste gases
Needs to occur in the presence of oxygen
Major energy activity (How cells get some of their energy)
o C6H12 O6 +6O2  6H2 0 + energy
(glucose)
Electron Transport Chain
o Uses part of the energy released in cellular respiration to
form ATP (Adenine Triphosphate)
high energy compounds
Use a bit of energy to make “super battery cells” used in
almost all cellular functions
The phosphate groups can be broken off to release huge
amounts of energy
Glycolysis
Process used to break down glucose (sugar)
Does not require oxygen, but it can occur in the presence or
absence of oxygen
Cell gets a relatively small amount of energy
Fermentation
Process used to break down glucose or other sugars
Cannot occur in the presence of oxygen
Cell gets a relatively small amount of energy
Many types of fermentation (depends on type of cell and what it is
breaking down)
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Usually give off gas (CO2)
Some bacteria & cells create lactic acid
Cheese, yogurt, muscle pain
Yeast (& a very few bacteria) can create ethyl alcohol
Beer, wine, bread, pickled foods (sauerkraut