General Biology Lab
Diversity of Organisms: Bacteria, Protista and Fungi ​

The cell is the fundamental unit of life.  All living things are made up of one or more cells.

Cells can be Prokaryotic or Eukaryotic

All Living Organisms can be Divided into 3 Domains

            I.      Archaea                        
​                                                    i.      Used to be considered bacteria, but now seen as a distinctly different cells, having features in common                                                               with both prokaryotic and eukaryotic cells. 
                                                     ii.    They are thought to be the first life forms on Earth.
                                                     iii.    Example is cyanobacteria (also called blue-green algae, even though                                                                                                                            it is NOT an algae.)
               II.     Prokaryota (Prokaryotic Organisms)                         
                                                   i.      More primitive – simpler - smaller     
                                                   ii.     Evolved after archaea and before eukaryota             
                                                   ii.      Does not have compartmentalization – no membrane-bound                                                                                                                                            organelles and no membrane-bound nucleus
                III.   Eukaryota (Eukaryotic Organisms)         
                                                   i.      There are 4 types of eukaryotic organisms
                                                                        1.       Plants
​                                                                        2.       Animals
                                                                        3.       Fungi
​                                                                        4.       Protists                                
​                                                   ii .     The characteristics of eukaryotic cells are as follows:
​                                                                        1.      Has nucleus        
​                                                                        2.      Has membrane-bound organelles                                            
​                                                                        3.      Evolved much later                                                    
​                                                                        4.      More complex - larger

Cells are divided into two broad categories; 
​Prokaryotic Cells and Eukaryotic Cells.

PROKARYOTIC CELLS

A.    Prokaryotic  – DEFINITION: NO membrane-bound organelles                                                     and  NO membrane-bound nucleus
   - Prokaryotic cells (otherwise known as bacteria)... 
                               1.  have their contents just "floating around" in                                      the cell - (in other words, there is                                                           no compartmentalization.)
                                 2. evolved  WAY BEFORE eukaryotic cells!
                                  3. are smaller and simpler
                                  4. have DNA (genetic material) that is in the                                             shape of a circle (called a circular plasmid).

Prokaryotic (Bacteria) Cell

Eukaryotic Cells

  Eukaryotic Cells = DEFINITION - Have a membrane bound nucleus and have membrane-bound organelles
   Eukaryotic cells include both ​​both plant and animal cells.

Eukaryotic ANIMAL CELL

Eukaryotic PLANT CELL

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Modes of Nutrition

A.    Autotrophic (aka Producer)
                           a.   An organism that is able to make it own food by                                   either using sunlight (photosynthesis)                                                  or inorganic chemicals (chemosynthesis).                                           -Examples are most plants, certain                                                           bacteria and some protists.

photosynthesis

B.    Heterotrophic (aka Consumer)
                            a.    An organism that cannot manufacture its own                                      food and instead obtains energy by consuming                                     organic substances (plant or animal matter).

via GIPHY

BACTERIA

   Bacteria cells are exceedingly small and enormously numerous. Bacteria have been discovered in some of the most inhospitable environments on Earth. Bacteria have been found in not only is water and soil samples, but in sulfurous underwater sea vents, acidic hot springs, and even radioactive waste. A single tablespoon of soil or water can contain millions of bacteria cells.  They are, by far, the most numerous life form on Earth.
​Bacteria are prokaryotic, unicellular microorganisms, which lack chlorophyll pigments.

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3 Basic Shapes of Bacteria

COCCUS ​

    Cocci (spherical) 
            a.    Strep throat - Streptococcal                bacteria cause a variety of infections in the body, including pneumonia, meningitis,            ear infections, and strep throat.
                                            

BACILLUS

Bacillus (rod-shaped) - 
      a.    Anthrax is caused by Bacillus                   anthracis and Bacillus cereus can cause two distinct types of food poisoning.

​SPIRILLUM

Spirillus (spiral)
          a.    All are aquatic except for one               species (S. minus) that causes a type of rat-bite fever in man. Can cause Lyme Disease and Syphillis.

Bacteria’s Role in the Ecosystem
Bacteria act as decomposers and producers in ecosystems

 A.    Bacteria Act as decomposers in the Carbon Cycle  ​

        1.    Organic carbon, in the form of dead and rotting organisms, would quickly deplete the carbon dioxide in the atmosphere if not for the activity of decomposers.                             

        2. When organisms die, the carbon contained in their tissues becomes unavailable for most other living things UNLESS it is decomposed!

​        3. Decomposition is the breakdown of these organisms, and the release of nutrients back into the environment, and is one of the most important roles of the bacteria.

B.    Bacteria Act as Decomposers in the Nitrogen Cycle 
        1.    The cycling of nitrogen is another important activity of bacteria.

        2. Plants rely on nitrogen from the soil for their health and growth, and cannot acquire it from the gaseous nitrogen in the atmosphere.

via GIPHY

​ 3.  The primary way in which nitrogen becomes available to them is through nitrogen  fixation by bacteria such as Rhizobium, and by cyanobacteria such as Anabaena, Nostoc, and  Spirulina.

Cyanobacteria

     Cyanobacteria participate in the nitrogen cycle as decomposers. They are one of the very few organisms that can convert nitrogen (N2) into nitrates and ammonia which plants need to grow.   Cyanobacteria are sometimes referred to as "blue-green algae", but they ARE NOT ALGAE! In fact, they are not even in the same domain as algae! Algae belong to the domain Eukaryota, while cyanobacteria are in the domain Prokaryota.  Cyanobacteria get their blue-green color from the presence of green chlorophyll (green) and phycocyanin (blue-green).       

cynaobacteria

BAD BACTERIA

     When considering all the strains of bacteria that exist, relatively few are capable of making people sick.

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    Many species (strains) of bacteria are known to cause illnesses and disease. Some of these include cholera, syphilis, leprosy, anthrax and the bubonic plague (otherwise known as "the black death"). Developed countries combat these bacterial infections using antibiotics. Developing countries, however, still encounter millions of deaths per year due to bacterial infections such as tuberculosis.

Good Bacteria

     - Good bacteria assist the body’s immunity, making the body less hospitable to bad bacteria and other harmful pathogens. 

    Humans and other animals have a mutualistic symbiotic relationship with many species of bacteria that make their home in the our mouth, nose, throat, and intestines. A mutualistic relationship is beneficial to both organisms involved. In this situation, the bacteria benefit from using the host as a habitat that provides the nutrients bacteria need to survive. The human (or animal) benefits from this relationship, because the 'good' bacteria helps prevent harmful bacterial or fungal infections. 

      Bacteria are an integral (and even necessary) part of the human body. It is estimated that the human body itself consists of 10 times more bacteria cells than human cells! That comes to a whopping 100-trillion bacterial cells. The portion of our bodies that consist of these bacterial cells has been coined "the human microbiome".

     - In the human gastrointestinal tract, good bacteria aid in digestion. These bacteria are marketed to the public as PROBIOTICS!        

Illustration Courtesy of alivebynature.com/lactobacillus-gasseri-the-weight-loss-probiotic ​

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       Bacteria reside on our skin, in our mouth, in our lungs, in our nose, on our eyelashes and in in our eyes!  
​       Healthy bacteria in our gut allow for the proper digestion of food, for the movement of waste through the bowels and for proper elimination of waste.
​     Good bacteria help to defend against the invasion of bad bacteria by populating vulnerable areas (such as the mucosa of body cavities) and sequestering the available resources. ​

Vagistat is a medication used to cure vaginal yeast infections.

     Healthy bacteria reside in the vagina that function to regulate the growth of yeast and, thereby, help protect against yeast infections.

GOOD BACTERIA IN FOOD

 Good bacteria are used to make some of the foods we enjoy.

   (i)       Acidophilus milk is made with Lactobacillus acidophilus.

   (ii)      Butter is made from pasteurized cream, to which a lactic acid starter has been added.

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    (iii)     Cheese is often made with Streptococcus and Lactobacillus bacteria.

 (iv)     Yogurt usually requires the addition of Lactobacillus bulgaricus, Lactococcus thermophilus, and/or Streptococcus thermophilus to the milk.

COMMON AREAS OF BACTERIAL INFECTION include...
​ all of the moist body cavities!

a.    Ear Infection

​ b.    Lung Infection

c.    Throat Infection

d. Urinary Tract Infection

e.    H. Pylori – Ulcers

Protists

    Protists are eukaryotic organisms that are single-celled organisms that can usually be found in pond water. 

  The domain Eukarya is divided into the following four kingdoms.
1.   PROTISTA - Protists are a large diverse group of relatively simple organisms composed of usually just one eukaryotic cell, but can also be multi-cellular.   
2.   FUNGI - Fungi are organisms that secrete digestive enzymes onto their food which breaks it down. Once broken down, the fungi can then absorb the nutrients. 
3.   PLANTAE -  Plants produce their own food using sunlight through the process of photosynthesis.  
4.   ANIMALIA - Animals rely on consuming other organisms as a food source.

Water Flea with Volvox

Protists are microscopic eukaryotic organisms that made up of only one cell. Most protists can be found in pond water.

- The two major categories of protists are
1) Algae
2) Protazoa

ALGAE

      A.    Algae are simple plants that can range from the microscopic (microalgae), to large seaweeds (macroalgae), such as  giant kelp more than one hundred feet in length.
        B.    Algae  are plantlike organisms that contain chlorophyll and other pigments (coloring matter) that trap light from the         Sun. This light energy is then converted into food molecules in a process called photosynthesis. Most algae store energy as some form of carbohydrate (complex sugars). 
         C.    Most algae store energy as some form of carbohydrate (complex sugars). 

Photograph of Algae on Sea Bed COurtesy of... ​By Toby Hudson - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=18150674

Electron Micrograph of Gephyrocapsa oceanica courtesy of... Photo by NEON ja, colored by Richard Bartz - Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=6072505

Seaweed (Kelp)

 Uses of Algae in Food and Nutrients   

Watch this video that explains how we might be living off of a pure algae diet in the future!

    1.    It is a complete protein with essential amino acids (unlike most plant foods) that are involved in major metabolic  processes such as energy and enzyme production.
     2.    It contains high amounts of simple and complex carbohydrates which provide the body with a source of additional fuel.

      3.    It contains an extensive fatty acid profile, including Omega 3 and Omega 6. These essential fatty acids also play a key  role in the production of energy.
       4.    It has an abundance of vitamins, minerals, and trace elements in naturally-occurring synergistic design. ​

PROTOZOA

Common Protists include: 
                                     A.    Amoeba  
                                     B.    Paramecium  
                                     C.    Trypanosoma

Watch this amoeba eat two paramecium!

Short Video of Trypanosoma

A short video of an amoeba eating.

Short Video of Paramecium

   Illnesses Caused by Protozoa! Example = MALARIA
             A.    Plasmodium is a genus of parasitic protozoa, many of which cause malaria in their hosts.
             B.    Spread by mosquitos.

Symptoms include fever, vomiting, headache, jaundice, seizures or coma. Can be fatal. According to the World Health Organization, Malaria effected approximately 296 million people in 2015. Malaria is believed to have caused 730,500 of these infected people to die. (wikipedia)en.wikipedia.org/wiki/Malaria  

Fungi

    A fungus is any member of the group of eukaryotic organisms in the KINGDOM FUNGI. This includes unicellular microorganisms such as yeasts and molds, as well as multicellular fungi that produce familiar fruiting forms known as mushrooms. 
   
 A. Yeast

                            A.    Yeast is a microscopic fungus consisting of single oval cells that reproduce by budding, and are capable of converting  sugar into alcohol and carbon dioxide.
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                             B.    Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom.

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FOODS/DRINKS THAT ARE MADE POSSIBLE WITH YEAST INCLUDE...
                           
a)    Breads
    b)    Alcohols 
c)    Cakes and Other Baked Goods
       

MOLD

        A.    Mold grows on bread when the bread comes in contact with dust that is carrying fungi, which are tiny microorganisms. 
            B.    Mold spores remain airborne until they land on a piece of food, germinate and grow into a healthy fungus.
            C.    Mold lives off the food its growing on by eating away at it. It commonly grows right through whatever it's eating. 
             D.    Fungi secrete an enzyme onto their food source that breaks it down aiding digestion. They then grow microscopic roots into the food itself.

  Hyphae

                   A.    A hypha (plural hyphae, from the Greek word meaning “web”) is a long, branching filamentous structure of a fungus.
                            B.    In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Yeasts are a fungi that do not grow as hyphae.

Lichen

       A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of a fungus in a symbiotic relationship. The combined life form has properties that are very different from the properties of its component organisms.

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       I. Symbiosis of Lichen
                   a.    Symbiosis in lichens is the mutually helpful symbiotic relationship of green algae and/or blue-green algae (cyanobacteria) living among filaments of a fungus.
                   b.     The fungus benefits from the algae or cyanobacteria because they produce food by photosynthesis. 
                   c.    The algae or cyanobacteria benefit by being protected from the environment by the filaments of the fungus, which also gather               moisture and nutrients from the environment, and (usually) provide an anchor to it.