Monerans


prokaryoticecell.jpg
Prokaryotic Cells
  • Prokaryotes - cells that do not have a nucleus, small and common

Classification of Monacans
  • All prokaryotes are placed in the Kingdom Monera
  • Four phyla of the Kingdom Monera: Eubacteria, Cyanobacteria, Archaebacteria, and Prochlorobacteria
  • Bacteria - one celled prokaryotes, range in size from 1 - 10 micrometers (one micrometer = one thousandth of a millimeter)
  • Bacteria are smaller than eukaryotic cells, or cells with a nucleus
  • The reason for the difference in size is that bacteria and other Monacans do not contain the complex range of membrane enclosed organelles that are found in most eukaryotic cells

Eubacteria
  • The largest of all the Monacan phyla
  • Members of this phylum have always been referred to as bacteria
  • Eubacteria are surrounded by a cell wall composed of complex carbohydrates
  • Cell wall protects the bacterium from injury
  • Some eubacteria are surrounded by two cell membranes
  • Wide variety of organisms that have many different lifestyles
  • ^- infect organisms and produce disease, some live in the soil, and some are photosynthetic
  • Photosynthetic bacteria are bacteria that are capable of making their own food by using light energy

Cyanobacteria
  • Also known as blue-green bacteria
  • Contains membranes that carry out the light reactions of photosynthesis
  • These membranes contain the photosynthetic pigments and are quite different from and simpler than the chloroplasts in plant cells
  • Found throughout the world--in fresh and salt water and on land
  • Few species can survive extremely hot water, others can survive in the Arctic where they can even grow on snow
  • Very first species to recolonize the site of a natural disaster, such as a volcanic eruption

Archaebacteria and Prochlorobacteria
  • Archaebacteria - includes organisms that live in extremely harsh environments (ex. One group of archaebacteria lives in oxygen free environments such as thick mud and digestive tracts of animals)
  • Methanogens - Archaebacteria that produce methane gas
  • Other archaebacteria live in hot or salty environments
  • Prochlorobacteria - contains chlorophyll a and b as their principal pigments
  • The presence of these pigments makes prochlorobacteria more similar to chloroplasts of green plants than to cyanobacteria
  • Only two species of prochlorobacteria have been discovered

Identifying Monacans
  • Cell Shape - Bacteria have three basic shapes: rod, sphere, and spiral
  • Rod-shaped bacteria are called bacilli
  • Spherical bacteria are called cocci
  • Spiral-shaped bacteria are called spiralla
  • Individual bacterial cels can arrange themselves in a number of different ways
  • Cocci sometimes grow in colonies containing two cells, may form long chains
  • Others form large clumps or clusters
  • Three characteristics of bacteria that help us identify them: their cell walls, the kind of movement they are capable of, and how they obtain energy
  • Cell Wall
  • The bacterial cells with only one thick layer of carbohydrate and protein molecules outside the cell membrane are called Gram-positive bacteria
  • The bacterial cells with a second, outer later of lipid and carbohydrate molecules are called Gram-negative bacteria
  • Bacteria Movement
  • Can identify bacteria by how they move
  • Some bacteria are propelled by one or more flagella, others lash, snake, or spiral forward, others glide slowly along a layer of slime-like material that they secrete themselves
  • Some don’t move at all

cocci_1000x_P1092668.JPG
Cocci
baccilli.jpg
Bacilli

Spirillum_400x.JPG
Spiralla

How Monacans Obtain Energy
  • Autotrophs - Monacans that trap the energy of sunlight are called phototrophic autotrophs (ex. cyanobacteria and some photosynthetic eubacteria)
  • Monacans that live in harsh environments and obtain energy from inorganic molecules are called chemotrophic autotrophs (includes hydrogen sulfide, nitrites, sulfur, iron)
  • Nitrosomonas is an example of a chemotrophic autotroph that uses ammonia and oxygen to produce energy
  • Heterotrophs - Chemotrophic heterotrophs - bacteria that obtains energy by taking in organic molecules and then breaking them down and absorbing them
  • Most bacteria, as well as most animals, are chemotrophic heterotrophs
  • Many bacteria compete with us for food sources (ex. Salmonella, which grows on raw meat)
  • Phototrophic heterotrophs - use sunlight for energy and needs organic compounds for nutrition

Bacterial Respiration
  • Energy is supplied by the processes of respiration and fermentation
  • Respiration is the process that involves oxygen and breaks down food molecules to release energy
  • Fermentation enables cells to carry out energy production without oxygen
  • Obligate aerobes - require a constant supply of oxygen in order to live
  • Obligate anaerobes - bacteria that do not need oxygen
  • Some bacteria are unable to grow in the presence of oxygen, but if these bacteria find their way to expose themselves to oxygen, they will grow quickly and produce toxins/poisons that cause botulism
  • Botulism - rare form of food poisoning that interferes with nerve activity and can cause paralysis and possibly death
  • Facultative anaerobes - bacteria that can survive with or without oxygen

Bacterial Growth and Reproduction
  • Some types of bacteria can reproduce as often as every 20 minutes
  • Binary Fission - when bacteria has grown to nearly double its size, it replicates its DNA and divides in half, producing two identical daughter cells
  • ^-Asexual form of reproduction (ex. E.coli undergoes binary fission)
  • Conjugation - when bacteria exchange genetic information
  • During conjugation, a long bridge of protein forms between and connects two bacterial cells. Part of the genetic information from one cell(donor), is transferred to the other cell(recipient) through this bridge
  • When the conjugation is complete, the recipient cell has a different set of genes from before conjugation occurred
  • New combinations of genes resulted from conjugation increase the genetic diversity in that population of bacteria
  • Genetic diversity helps to ensure that even if the environment changes, a few bacteria may have the right combinations of genes to survive
  • Spore Formation - when growth conditions become unfavorable, many bacteria form structures called spores
  • Endospore - a type of spore formed when a bacterium produces a thick internal wall that encloses its DNA and a portion of its cytoplasm
  • The endospore can remain formant for months or years, waiting for more favorable growth conditions. When conditions improve, the endospore will open and the bacterium will begin to grow again
  • Spore formation in bacteria is not a form of reproduction because it does not result in the formation of new bacterial cells
  • The ability to form spores makes it possible for some bacteria to survive harsh conditions that would kill them


amoeba-fission-big.jpg
Binary Fission



Importance of Monacans
  • Bacteria are used in the production of a wide variety of foods and beverages, such as cheese, yogurt, buttermilk, and sour cream
  • Some bacteria are used to make pickles and sauerkraut, and some make vinegar from wine
  • Bacteria can be useful in the industry
  • One type of bacteria can digest petroleum, which makes them helpful in cleaning up small oil spills
  • Some bacteria remove waste products and poisons from water
  • Others can help mine minerals from the ground
  • Useful in synthesizing drugs and chemicals through techniques of genetic engineering
  • Symbiosis - many kinds of bacteria develop a close relationship with other organisms in which the bacteria or the other organism or both benefit from one another
  • Monacans form symbiotic relationships with organisms from all of the other four kingdoms
  • Our intestines are inhabited by large numbers of bacteria, including E.coli
  • The species name “coli” was derived from the fact that these bacteria were discovered in the human colon, or large intestine
  • In the intestines, the bacteria are provided with a warm safe home, plenty of food, and free transportation. In turn, we get help digesting our food and these bacteria also make a number of vitamins that we cannot produce on our own
  • Nitrogen fixation - many cyanobacteria and other bacteria can take nitrogen from the air and convert it to a form that plants can use. Monacans are the only organism capable of performing nitrogen fixation
  • Many plants have symbiotic relationship with nitrogen fixing bacteria (ex. Soybean)
  • Eukaryotes are dependent upon Monacans to fix nitrogen and release it into the environment
  • Because of the nitrogen-fixing ability of these organisms, more than 170 million metric tons of nitrogen are released into the environment every year

Diseases Caused by Viruses and Monacans
  • Only a small number of viruses and Monacans are capable of producing disease in humans
  • Pathogens - disease producing agents that are responsible for most of human suffering

Viruses and Disease
  • Viruses are the cause of such human diseases as small-pox, polio, measles, AIDS, mumps, influenza, yellow fever, rabies, and the common cold
  • As the virus reproduces, it destroys the cells that it infects, causing the symptoms of the disease
  • A vaccine is a substance that contains the weakened or killed disease-causing virus.
  • When injected into the body, the vaccine provides an immunity to the disease
  • Vaccines can only provide protection if they are used before an infection begins
  • Once a viral infection starts, there is often little that medical science can do to stop the progress of the disease, but sometimes the symptoms of the infection can be treated
  • Interferons - small proteins that are produced by the body’s cells wen the cells are infected by viruses
  • When interferons are released from virus-infected cells, they seem to make it more difficult for the viruses to infect other cells
  • Cancer - certain viruses cause cancer in animals which are called oncogenic
  • Not all cancers are caused by viruses, a few cancers are (cancer is generally not spread by a person-to-person infective process

Bacteria and Disease
  • Only few species of bacteria produce diseases
  • Some of the diseases caused by pathogenic bacteria include diphtheria, tuberculosis, typhoid fever, tetanus, Hansen disease, syphilis, cholera, and bubonic plague
  • Bacteria cause these diseases by damaging the cells and tissues of the infected organism directly by breaking down its living cells to use for food, or they may release toxins that travel throughout the body, interfering with the normal activity of the host
  • Antibiotics - a number of drugs that can attack and destroy bacteria
  • One of the major reasons for the dramatic increase in life expectancy in the last two centuries is an increased understanding of how to prevent and cure bacterial infections

Controlling Bacteria
  • Sterilization - potentially dangerous bacteria that is being controlled
  • This process destroys living bacteria by subjecting them to great heat or chemical action
  • Bacteria cannot survive high temperatures for a long time, so most can be killed in boiling water
  • A disinfectant is a chemical solution that kills bacteria.
  • Disinfectants are used in the home to clean bathrooms, kitchens, and other rooms where bacteria may grow and spoil food or cause disease

Body's Defence Against Viruses
  • The immune system protects the body from potentially harmful substances by recognizing and responding to antigens
  • Antigens - molecules (usually proteins) on the surface of cells, viruses, fungi, or bacteria
  • Nonliving substances such as toxins, chemicals, drugs, and foreign particles (such as a splinter) can also be antigens
  • The immune system recognizes and destroys substances that contain these antigens
  • Innate immunity - defence system you were born with; protects you against all antigens; has barriers that keep harmful material from coming into your body
  • Ex. cough reflex, skin, stomach acids, mucus (traps bacteria and small particles), skin
  • Humoral immunity - innate immunity in a protein chemical form (ex. body's complement system and substances called interferon and interleukin - which causes fever)
  • Acquired immunity - immunity that develops with exposure to various antigens, your immune system builds a defence that is specific to that antigen
  • Passive immunity - antibodies that are produced in a body other than your own (infants have passive immunity because they are born with antibodies that are transferred through the placenta from their mother)
  • Passive immunization may also be due to injection of antiserum, which contains antibodies that are formed by another person or animal
  • Provides immediate protection against an antigen, but does not provide long-lasting protection
  • The immune system includes certain types of white blood cells, it includes chemicals and proteins in the blood, such as antibodies, complement proteins, and interferon.
  • Some of these directly attack foreign substances in the body, and others work together to help the immune system cells.
  • Lymphocytes- a type of white blood cell. There are B and T type lymphocytes.
    • B cells produce antibodies. Antibodies attach to a specific antigen and make it easier for the immune cells to destroy the antigen
    • T cells attack antigens directly and help control the immune response. They also release chemicals, known as cytokines, which control the entire immune response
  • Inflammatory response - occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause
  • The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling. This helps isolate the foreign substance from further contact with body tissues
  • The chemicals also attract white blood cells called phagocytes that "eat" microorganisms and dead or damaged cells

Food Processing
  • Refrigerate foods to prevent it from spoiling and bacteria growth
  • Food kept in lower temperatures will keep longer because the bacterial will take much longer to grow and cause damage
  • Many kinds of food are sterilized by boiling, frying, or steaming them
8982spoiled_food.jpg


Immunization
  • A process that helps your body fight off diseases caused by certain viruses and bacteria
  • Can occur naturally or by exposing your body to vaccines
  • These shotes are used to help build an immunity against certain diseases that your body has trouble fighting on its own

Antibodies
  • Vaccines contain tiny amounts of material that make your immune system produce certain proteins called “antibodies”
  • Antibodies can attack and destroy viruses and bacteria
  • Your immune system stores this information on how to make certain antibodies to stop the virus or bacteria from making you sick

Immunization Protects Us All
  • Protects both individuals and the larger population by preventing the spread of infections
  • Polio has been eliminated in North and South America because most of hte population has been immunized

How Vaccines Work
  • Natural infection from certain diseases can kill or seriously harm a child before their body is able to mount an effective immune response
  • The vaccine triggers your body’s natural immune response into action to protect you against the disease without the risk of infection

Did you know ?

  • A less mature immune system and lack of physical development such as a smaller wind pipe means an infant or toddle is at a higher risk for serious complications and death from vaccine preventable diseases