BIOLOGY 11: UNIT 2: MicrobiologyChapters 1, 7, 8

UNIT 2 OBJECTIVES:VIRUSES: MOLECULES1. Describe the basic structure of a virus.

2. Evaluate the evidence used to classify viruses as living or nonliving.

3. Compare and contrast the lytic and lysogenic cycles.

4. Describe the body's basic lines of defense against a viral attack.

5. Give examples of ways to reduce the chance of contracting a viral disease.

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6. Define and give examples of viral specificity.

7. Evaluate the effects of virulence on human health.

KINGDOM MONERA: BACTERIA1. Describe the basic structure of the prokaryotic cell.

2. Examine members of the Kingdom Monera and describe characteristics that unify them.

3. Use examples to illustrate moneran diversity with respect to the following: form, distribution, motility, ecological role, nutrition, and human diseases.

4. Differentiate among fermentation, aerobic respiration, and photosynthesis in bacteria.

5. Contrast the ways in which bacterial decomposers and parasites obtain food.

6. Demonstrate sterile technique while preparing a streak plate.

7. Demonstrate the correct use of a compound microscope.

8. Evaluate the effectiveness of various antibiotics, disinfectants, and antiseptics on bacteria cultures.

9. Explain processes by which bacteria adapt to become resistant to antibiotics.

10.Give examples of the beneficial roles of bacteria.

KINGDOM PROTISTA: PROTISTS1. Examine members of the Kingdom Protista and describe characteristics

that unify them.

2. Prepare wet-mount slides.

3. Differentiate between phytoplankton and zooplankton by observing living protists.

4. Compare and contrast a prokaryotic cell (moneran) and a eukaryotic cell (protist).

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5. Demonstrate how knowledge of a pathogenic protist's life cycle can be used to control its spread.

6. Relate the structural adaptations of protists to their diverse roles in the food chain.

VIRUSES:

Is a virus classified as living or nonliving?

Viruses do not fit into the 5 Kingdom system of classificationThey are biological microscopic particles that are technically not considered to be living organisms. They are only capable of reproducing within living cells.

The nature of viruses: What is a virus?  Virus is the Latin word for poison.  Since the beginning of time, people have been plagued with viruses.  A virus is a clump of DNA contained within a protein coating. They can only become active inside a live host.

Viruses are smaller than bacteria and go dormant, to reappear later causing worse symptoms with each outbreak. Examples of viruses are rhinovirus (common cold), hepatitis, Epstein-bar, Ebola, HIV, influenza (flu), SARS, West Nile, small pox, and cold sores. Oncogenic viruses cause cancer by adding specific genes to an infected cell, making a cancer cell. Viruses have a large range of shapes some are spherical, elongated, or geometric. Viruses are specific to their hosts, so that the virus protein must match the protein of the host in order to be able to infect the host. This property is called viral specificity.

Timing seems to be very important in treating viruses.  They go through several stages, including the dormant stage, and can morph into stronger strains with each generation.  They are difficult to diagnose and are a challenge to fight.

Phylogeny of the Virus:, p. 204There is no fossil evidence to support the evolutionary history of viruses.

1) At one time viral ancestors were cellular organisms that lived as parasites on other cells. Due to their parasitic lifestyle, they gradually lost their own cellular components and became reduced to their parent form.

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2) Viral ancestors were once free-living, precellular forms that later became parasites of cellular organisms.

3) Viruses arose from detached fragments of genetic material of cellular organisms. *currently this is the most widely accepted explanation.

Classification of Viruses: Living or Nonliving?Viruses are lifeless chemicals and carry out no life functions on their own. The virus must invade a living cell in order to reproduce. Viruses are positioned between nonliving & living matter. Some biologists currently see the virus as a nonliving infectious particle. Other biologists disagree and suggest they are alive because of what happens inside the host cell.

Bacteriophages:, p. 200Viruses that are known as "bacteria killers" are called bacteriophages. Enterobacteria phage T4 is a bacteriophage that infects E. coli bacteria. Its DNA is held in an icosahedral head. T4 is a large phage, at ~ 90 nm wide and 200 nm long. Its tail fibers allow attachment to a host cell, and the tail is hollow so that it can pass its nucleic acid to the cell it is infecting during attachment. Describe the basic structure of phage viruses

Chemical Composition: All viruses are composed of nucleic acid and protein. Depending upon the phage, the nucleic acid can be either DNA or RNA but not both. The simplest phages only have enough nucleic acid to code for 3-5 average size gene products while the more complex phages may code for over 100 gene products. One or more proteins create the head or capsid.Structural Composition:

The bacteriophage virus consists of 2 regions: the head and the tail regions.

1) Head or Capsid Region: All phages contain a head structure which can vary in size and shape. Some are icosahedral (20 sides) others are filamentous. The head or capsid is composed of many copies of one or more different proteins. Inside the head is found the nucleic acid DNA for bacteriophage. The head acts as the protective covering for the nucleic acid.

2) Tail: Many but not all phages have tails attached to the phage head. The tail is a hollow tube through which the nucleic acid passes during infection. The size of the tail can vary and some phages do not even have a tail structure. In the more complex phages like T4 the tail is surrounded by a contractile sheath which contracts during infection of the bacterium.

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  The basic structure of phage viruses called bacteriophage

VIRAL REPLICATION:There are two types of viral replication:In viral replication the viral DNA is duplicated before a cell divides. Two of the ways viral replication can occur are the lytic cycle and the lysogenic cycle. Both cycles involve the same basic steps of replication but the outcomes differ.

Lytic Cycle: Lysis involves virulent phage because the virulent bacteriophage invades and destroys the bacterium by causing the cell to burst and die.

Lysogenic Cycle:The lysogenic cycle involves temperate phage because the temperate bacteriophage invades the bacterial cell and may coexist with the bacterial cell. The temperate phage does not kill the bacterium. A prophage forms when a temperate phage infects a bacterial cell. A prophage is formed when the nucleic acid of a temperate phage is combined with the bacterial chromosome and the viral nucleic acid acts as another set of genes.

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Describe the body’s basic lines of defense against a viral attack:

The human body constantly faces attack from foreign invaders that can cause infection and disease. These invaders range from living microbes, such as bacteria, fungi, parasites, to nonliving viruses, toxins, chemicals, and drugs. Fortunately, the body has a number of external and internal safeguards that prevent most dangerous invaders from entering and causing harm.

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The human body has several lines of defense against infection, which work to prevent germs from invading the body or to destroy them once they find their way in. DNA viruses cause chicken pox, small pox, RNA viruses cause polio, colds, rabies, flu. The cold virus is endemic (it is with us all the time). When a disease spreads very quickly it is called an epidemic. Viral infections are difficult to treat and are not destroyed by antibiotics. Some viruses remain dormant in the body for years before disease symptoms appear.

1. Non-Specific Defences : First Line of Defence:

The physical barriers that keep them at bay commonly are referred to as the body's first line of defence. 1) Skin, forms a protective layer that completely wraps around the body. When cuts or tears in the surface of the skin provide an entrance for infective agents, glands beneath the skin produce an enzyme that helps kill bacteria. 2) Mucus membranes, the moist linings of the respiratory system, trap irritants that enter through the nose. 3) Cilia: tiny hairs, line the body's airways and constantly wave foreign particles and mucus away from the lungs to where they can be swallowed safely. 4) Stomach acid, most harmful microbes that make it to the stomach are destroyed by HCl. In addition, tears and saliva both contain enzymes that destroy invaders. 5) Brain-blood barrier, a specialized "filter" that surrounds the brain and spinal cord and acts as a physical barrier to keep out proteins, toxins, and most microbes, while letting in glucose, the source of the brain's nutrients.

2. Specific Defences : Second Line of Defence:

A second line of defence is housed the immune system that recognizes and destroys foreign substances and organisms that enter the body. The immune system can distinguish between the body's own tissues and outside substances called antigens. This allows cells of the immune army to identify and destroy only those enemy antigens. The ability to identify an antigen also permits the immune system to "remember" antigens the body has been exposed to in the

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past so that the body can mount a better and faster immune response the next time any of these antigens appear.

Immunity is the condition of being protected against an infectious disease. Immunity often develops after a germ is introduced to the body. One type of immunity occurs when the body makes special protein molecules called antibodies to fight the disease-causing germ. The next time that germ enters the body the antibodies quickly attack it, usually preventing the germ from causing disease.

Lymphocytes, white blood cells that develop in bone marrow and circulate throughout the body in the lymphatic system, are a vital part of the immune system. Lymphocytes can be divided into two subgroups: B lymphocytes and T lymphocytes. B lymphocytes (or B cells) produce antibodies. These protein molecules attach themselves to specific antigens and work with another type of white blood cell, called phagocytes: scavenger cells that surround and digest infected cells or microorganisms to destroy the invaders. T lymphocytes (or T cells) help control the immune response and destroy foreign antigens directly.

In some cases, people have permanent immunity to a disease; for example, people who contract chicken pox usually will not have it again or, if they do, they will have a much more mild case. In some instances, people receive antibodies from another person to help their own immunity. This is known as passive immunity. Infants are born with immature immune systems and receive antibodies from their mothers, both during pregnancy (across the placenta) and after birth from breast milk. These antibodies usually disappear within 6 to 12 months, but until then they help protect the infant against a range of infections, including pneumonia, bronchitis, influenza, and ear infection. Active immunity exists when weakened strains of pathogens are injected into a person. Doctors can give people gamma

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globulin, an antibody preparation that offers temporary immunity to patients who might need this protection. When a person gets an immunization or vaccine the body's immune system learns to recognize that particular bacteria or virus.

Vaccines are solutions prepared from viral components or inactivated viruses. Vaccines prevent polio and small pox. When people are vaccinated, the body reacts to the vaccine as if it was a real virus and produces antibodies. If, sometime later, the person is exposed to the germ again, the body can fight it off and not come down with the disease.

<Homework - Review Questions, p. 205 (7-14)>

CASE STUDY: VACCINES: THE NEEDLE OF HOPE, p. 206-209

PRINCIPLES OF TAXONOMY:

What is taxonomy?

Taxonomy is a branch of biology that names and groups organisms according to their characteristics and evolutionary history. Taxonomy is the science of classifying organisms.

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Aristotle (384-322 B.C.) was the first to classify living organisms. This Greek philosopher grouped animals into two categories. The particular organism was classified as either plant or animal origin.

As time progressed, modern science and rapid research identified many new organisms. Aristotle’s classification was not sufficient.

The Swedish naturalist Carolus Linnaeus (1707-1778) realized that such a system was not conducive for modern biology. Linnaeus made two main contributions to taxonomy. Linnaeus developed a classification system of organizing organisms into hierarchal categories. He did this be using the physical appearances of organisms to group them. He was also instrumental in developing the binomial nomenclature.Biological classification systems have 2 main purposes: identifying organisms and providing a basis for recognizing natural groupings of living things.

Binomial Nomenclature:Biologists give each living thing a binomial or two part name. For example Homo sapiens is the Binomial name for humans. The first word is the Genus and the second is the species. These are universal among biologist to avoid confusion. Linnaeus realized that common names caused a problem as they varied from region to region. Binomial nomenclature: is the method for naming organisms by using a two-part Latin name, called the scientific name: the genus & species name.

Scientific name: Common name: Homo sapiens humanCastor canadensis Canadian beaverAcer rubrum red mapleMusca domestica housefly

Hierarchal Classification:This includes seven different levels of organization. Kingdom, Phyla, Classes, Orders, Families, Genera, and species are included in the seven. Kingdom is less specific and species is more specific.

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Kings Play Calgary On Friday Gretzky scores.For many years, most biologists favoured a Five-Kingdom system consisting of Kingdoms Monera, Protista, Fungi, Plantae, and Animalia. They were placed into categories by their type of cell (prokaryotic or eukaryotic), level of organization (unicellular or multicellular), and how they acquire their nutrition. It is suggested that Protists evolved from the Monerans who are the simplest organism. Fungus, Plants and Animals evolved from the Protists in three separate evolutionary lines. The five kingdom system of classification is based on structural differences and also on modes of nutrition among the eukaryotes.

The 5 Kingdoms: 1) Monera, 2) Protista, 3) Fungi, 4) Plantae, 5) Animalia

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A New Proposal: The Three Domains of Life In the 1970’s scientists began to find evidence for a previously unknown group of prokaryotic organisms. These organisms lived in extreme environments such as the Dead Sea, acid lakes, and salt evaporation ponds. These are environments that scientists never suspected of maintaining any life. Because they appeared prokaryotic, they were considered bacteria and named "archaebacteria" ('ancient' bacteria). However, it became obvious from biochemical characteristics and DNA sequence analysis that there were numerous differences between these archaebacteria and other bacteria. Before long, it was realized that these archaebacteria were more closely related to the eukaryotes than to bacteria. Today, these bacteria have been renamed Archaea. From this work scientists proposed that there should be a new category of classification of life, called the Domain. The Domain is a classification category above Kingdom.

The traditional 5 Kingdom system says nothing about how organisms within Kingdoms or between kingdoms may be related to each other via evolutionary relationships among the kingdoms.A New Proposal is the Three Domains of Life. The three domains are Bacteria, Archaea, and Eukarya. The three-domain system of classification is based on biochemical differences that show they are three vastly different groups of organisms.

Phylogenetic tree: scientists use a diagram to represent evolutionary relationships between organisms.

<Homework - Review Questions, p.199 (1-6)>

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KINGDOM MONERA: PROCARYOTES Chapters 7, 8

The Importance of Microorganisms : Most people only are aware of microorganisms when they get sick, such as the diphtheria bacteria that caused the Black Death and altered the course of human history. Most microorganisms are harmless, and many are helpful. Microbes decompose dead plants & animals.

Microbiology: is the study of microorganisms. Microbiology has contributed greatly to advancements in applied science & technology (development of certain antibiotics & manufacturing of dairy products, etc.). Most microbes are unicellular, but unlike viruses and cells of multicellular organisms, microbes are capable of independent life. Kingdom Monera, p. 215Monerans are the oldest and most abundant living organisms known to date. Monerans are single-celled organsims and include all bacteria & some simple photosynthetic and chemosynthetic organisms. Photosynthetic cyanobacteria, blue-green algae, appear in the fossil record as early as 3.5 billion years ago.

Describe the basic structure of a prokaryotic cell

Structure of Bacteria:Bacteria are prokaryotic and are found in the Kingdom Monera. Prokaryotes are very distinctive cells as they lack a nucleus and are very primitive cells. Prokaryotic cells contain a plasma membrane, which is usually surrounded by a cell wall and often a capsule. There are no cell organelles other than ribosomes. Cells that do contain a nucleus are known as Eukaryotic cells and are advanced cells.

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Bacteria exist in three different shapes:1) Bacilla (rods)2) coccus (spheres)3) spirilla (spirals)

After dividing, many bacteria form groups or clusters, **colonies, or chains (filaments) of cells. **colonies of bacteria are not multicellular

What do the members of Kingdom Monera have in common?Bacteria are very small, and with the exception of ribosomes, do not contain cellular organelles. They do have a chromosome, but it is contained in a

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nucleoid, which has no nuclear envelope. Because of this, bacteria are said to lack a nucleus. Bacteria are called prokaryotes because they lack a nucleus. Many bacteria have rings of DNA called plasmids, which are often used to carry foreign DNA into other bacteria for recombinant DNA engineering.

Bacterial Structure Function

Plasmid Ring of DNA

CapsuleProtective covering made up of polysaccharides (complex sugars). Keeps the bacteria from drying out and protect it from being engulfed

Cell Wall Gives cell its shape and surrounds the cytoplasm protecting it.

Plasma Membrane

A layer of phospholipids and proteins, which allows certain materials in and out of the cell

Ribosomes Only type of cell organelle found in bacteria. Small factories that translate the genetic code into proteins.

Fimbriae Small hair like projections that emerge from the cell membrane. These help the bacteria attach to their host.

Cytoplasm

Or protoplasm. This is where the functions of cell growth, cellular metabolism and replication are carried out. It is a gel like material that is composed of water, enzymes, nutrients, wastes, and gases and contains cell structures such as the ribosomes, chromosomes, and plasmids.

Nucleoid A region of the cytoplasm where the chromosomal DNA is located.

Flagella Hair like structures that provide locomotion. Not all bacteria have flagella.

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Endospores: Some times, under unfavourable environmental conditions, some bacteria form endospores. An endospore occurs when a portion of the cytoplasm plus the chromosome dehydrates. The rest of the bacterial cell deteriorates. This endospore is then highly resistant to the unfavourable conditions; conditions such as high temperatures, harsh chemicals and drying out. When good conditions occur, the spore then absorbs water and returns the cell to the typical stage.Reproduction of Bacteria:

1) Asexual Reproduction : Binary Fission:Bacteria reproduce by a way of asexual reproduction called binary fission. In one bacterium, the single circular chromosome duplicates. Then, the two resulting chromosomes attach to the inside of the plasma membrane. The cell elongates and separates into two strands. Finally, the cell membrane grows inward, the cell wall forms separating two daughter cells each with a chromosome.

2) Sexual Reproduction : Exchange of genetic materialBacteria reproduce with the exchange of DNA. When bacteria exchange DNA, it has a similar effect to sexual reproduction, because there is a blending of genes between two organisms. There are three ways in which bacteria exchange DNA.

Conjugation: donor cell passes DNA to recipient cell by a conjugation tube (sex pilus).

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. Transformation: bacterium takes up DNA released by dead bacteria.

Transduction: bacteriophages carry DNA from one cell to another.Bacterial Metabolism: Bacteria have three different ways to metabolize nutrients to produce energy: aerobic respiration, photosynthesis, and fermentation.

What are the differences among fermentation, aerobic respiration, and photosynthesis in Monerans?

1) Obligate aerobes : Aerobic RespirationMost bacteria are obligate aerobes. These bacteria require oxygen to survive. These bacteria will utilize cellular respiration to produce energy.Cellular Respiration is the breakdown of sugar molecules with the use of oxygen to release energy.

C6H12O6 + 6O2 --------> 6 H2O + 6 CO2 + Energy

2) Obligate anaerobe : Anaerobic Respiration Some bacteria are called obligate anaerobes. Obligate anaerobes are unable to grow in the presence of oxygen and must use photosynthesis or fermentation to release energy.Photosynthesis is the use of light energy to produce sugar molecules from carbon dioxide and water with the use of chlorophyll. Oxygen is the waste product. Cyanobacteria is an example of a photosynthetic bacteria.

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6 CO2+ 6 H2O -----light------>C6H12O6 + 6 O2

Fermentation is the breakdown of sugar molecules without the use of oxygen to release energy. Fermentation is 19 times less efficient than aerobic cellular respiration. In fermentation of sugar, the products are ethanol & carbon dioxide. Some bacteria produce acetone, acetic acid & methane by fermentation. Bacteria will ferment by one of these two equations.

Pyruvic Acid + NADH ---------->Lactic Acid + NAD+ (also used by animals) Pyruvic Acid + NADH ---------->Alcohol + CO2 + NAD+ (also used by plants)

3) Facultative anaerobe Other bacteria are facultative anaerobes. Facultative anaerobes are able to grow in the presence or absence of oxygen. These bacteria will use cellular respiration if oxygen is present and fermentation if oxygen is not present.

Bacterial Nutrition:Bacteria use all modes of nutrition except heterotrophism by ingestion. Some bacteria are autotrophic (able to produce their own energy) by photosynthesis or by chemosynthesis. Cyanobacteria which photosynthesize in the same manner as plants also give off oxygen. Other bacteria are autotrophic by chemosynthesis. They oxidize inorganic compounds to obtain their energy. These bacteria are very important to recycle the nitrogen in our ecosystem.

Most types of bacteria however, are heterotrophic by absorption. Bacteria that carry out external digestion of organic matter from dead material and absorb the nutrients are called saprophytes. Others absorb nutrients from other living things. When bacteria are absorbing nutrients from living things they are known as parasites. Saprophytic bacteria are able to feed on more food sources and contain a greater variety of enzymes used to digest different foods. Parasitic bacteria are limited in the number of enzymes designed to digest specific tissues in their host.

Bacteria are called decomposers because they break down organic material and have a role in digesting sewage and oil, production of alcohol, vitamins, antibiotics, and genetic engineering.

Symbiotic Bacteria:

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When bacteria live in association with other organisms they are known as symbiotic bacteria. There are three types of symbiosis, and different groups of bacteria employ all three.

1) In mutualistic symbiotic relationships, both the organisms benefit from the relationship. For example, nitrogen fixing bacteria live in nodules of legumes. They provide the plant with nitrogen, and the plant supplies the bacteria with other nutrients.

2) In a commensalistic relationship, one organism will benefit, and the other is unaffected. Bacteria live on human skin and do not harm us, but benefit from the warm moist environment.

3) A parasitic relationship means that one organism is benefiting while the other is being harmed. Parasitic bacteria harm the host and cause disease in plants and animals. Because some parasitic bacteria use a human host, the study of bacteria is of great importance to human beings.

Antibiotics:Alexander Flemming discovered in 1928 the first antibiotic accidentally when he had a moldy Petri dish that would not grow bacteria. The mold in the Petri dish was producing the antibiotic penicillin. Flemming could not convert the antibiotic to a usable form, but his work was later continued by other scientists to produce the variety of antibiotics today.

How do bacteria adapt to become resistant to antibiotics?Antibiotics are commonly used in an attempt to control bacterial disease. An antibiotic is a non-specific poison taken in a large enough amount to kill the parasite without harming the host. They are taken over a period of time to ensure that all of the parasites in the host will be killed. Because some bacteria are stronger than the others, they will require more exposure to the antibiotic before they are killed. However, because people will often feel they have overcome their parasite while a few still remain, the strongest of the original strain will reproduce creating a more resilient strain. With the antibiotic creating a selection pressure for strength, new strains of bacteria are stronger than the last, and eventually they are referred to as having an antibiotic resistance.

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What is sterilization?The process known as sterilization refers to the process in which all living cells, spores, and viruses are completely destroyed or removed from an object or environment. Once something is sterilized, it will remain sterile if properly sealed. Sterilization is performed on surgical equipment, needles, and certain lab equipment in order to prevent the spread of microorganisms. Methods used to sterilize objects involve the use of heat, radiation, filtration, and/or chemical means. Autoclaves are devices which use hot steam under high pressure to sterilize objects.

What is disinfection?The process known as disinfection is the killing, inhibition, or removal of microorganisms that cause disease. Disinfection may not necessarily eliminate spores or all of the microorganisms from an object or environment. While disinfection is not as extreme as sterilization, it is considered to be an adequate level of cleanliness for most situations.

What is the difference between an antiseptic and a disinfectant?Disinfectants are chemical agents used to disinfect inanimate objects and surfaces. Examples of disinfectants include iodine solution, copper sulfate, ozone, and chlorine gas.

Antiseptics are chemical agents applied to living tissues to prevent infection. Antiseptics are generally less toxic than disinfectants because they must not cause too much damage to the host living tissue. Examples of antiseptics include iodine, 70% ethanol and 3% hydrogen peroxide.The concentration of a chemical agent can determine if it can be used as a disinfectant or an antiseptic.

Roles Of Bacteria: Beneficial & Harmful:

Examples of beneficial effects of bacteriaORGANISMS BENEFICIAL EFFECTSClostridia Production of butanol & acetone from molassesAcetobacter Production of vinegar from alcoholIntestinal bacteria Synthesizes vitamins in humans

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Lactobacilli Production of lactic acid from sugarAzotobacter, Nitrobacter Fixation of nitrogen in soilsSteptococci, Lactobacilli Cheese productionStreptomyces group Source of antibiotics (neomycin, streptomycin,

erythromycin & terramycin)

Examples of harmful effects of bacteriaORGANISMS DISEASE/DESTRUCTIONBacillus anthracis Anthrax (a disease of domestic animals) Clostridium botulinum Botulism; other clostridia cause tetanus,

gangrene & lockjawStreptococci Strep throat & scarlet feverStaphylococci Boils, food poisoning, & skin infectionsLactobacilli Souring of milkPseudomonads Gasoline spoilageBacilli Destruction of silkwormsStaphylococci & Pseudomonads

Food spoilage

Coliform bacteria Pollution of water sources; causes soft rot in plants, gastroenteritis , & dysentery

Spirilla Cholera & syphilis

<Homework - Review Questions, p. 219 (1 - 7)>

CASE STUDY: FOLLOWING AN INFECTION, p. 220

Human Diseases:Pathogens are any type of virus or organism that causes disease. Pathogens cause disease symptoms in a variety of ways.

1) Number of pathogens : this places such a tremendous burden on the host's tissues that they interfere with normal function.

2) Destroying cells & tissues :3) Producing toxins : these are poisons produced by bacteria.

Bacteria cause some of the worst human diseases.

Infectious Diseases Spread in a Variety of Ways:Moisture droplets in air, dust, direct contact, fecal contamination, animal bites & wounds, (cuts & scratches). Usually protection from disease is provided by the body's own defense mechanisms. Other methods include sterilization, disinfection and use of antiseptics, extermination of animals that carry disease, immunization and administration of antibiotics.

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Frontiers of technology: bacteria & sewage treatmentBacteria and other microbes decompose the remains of dead organisms, and enable the chemicals of life to be recycled. These microbes and bacteria are now being used in the sewage disposal process.

Sewage: water that carries organic wastes from humans & industry (toilets, sinks, dishwashers, washing machines, & various types of industrial equipment).

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Sewage Treatment Involves 3 Steps:1) Primary Sewage Treatment : Mechanical process in which solids settle out

as sludge, but the liquid contains tiny particles & dissolved chemicals.

2) Secondary Sewage Treatment : biological process that uses aerobic bacteria. Filters remove 90% of biodegradable wastes and are broken down by aerobic bacteria. The remaining 10% is filtered & further broken down by anaerobic bacteria, disposed of by incineration and dumped into landfills, oceans, or used as fertilizers.

3) Advanced Sewage Treatment : Specialized chemical & physical processes are used to lower the quantity of specific pollutants before the sewage is released into the rivers or lakes. (Chlorination, ozone, hydrogen peroxide & UV light may also be used).

<Homework - Review Questions, p. 223 (8-10, 12-15)>

KINGDOM PROTISTA: PROTISTS Chapter 8

Protists first appeared in the fossil record about 1.5 billion years ago. They are more advanced than monerans.

Characteristics of protists, p. 226

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1) Eukaryotes with membrane-bound nuclei & generally unicellular.2) Cytoplasm contains organelles, such as ribosomes, mitochondria, and

lysosomes.3) Organelles help provide a more efficient way of using available nutrients &

carrying out metabolic activities.4) Protists are microscopic and found in moist habitats.

3 Groups of Protists: Plantlike, Animal-Like and Fungi-like

Plantlike Protists: EUGLENAThey are plant-like, photosynthetic autotrophs, such as phytoplankton, and produce a significant portion of oxygen supply in the earth's atmosphere.

Euglena Anatomy

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Phylum Euglenophyta (Euglena), p. 227Found mainly in fresh water, ponds & lakes and abundant in stagnant water and obtain food by photosynthesis, but in the dark they become heterotrophic

Characteristics of Euglena 1) Possesses a bright red eyespot with a photoreceptor (detects light)2) Flagellum moves in a whip-like fashion, propelling it through the water.3) Pellicle surrounds the cell, it is a thick flexible covering4) Autotrophs - use photosynthesis by chloroplasts 5) Vacuoles collect & remove excess water6) Starch granules is where food is stored7) Reproduction is by longitudinal fission

The euglena is unique because it is sort of like a plant and also like an animal. The euglena is able to make its own food like a plant when it is in the sunlight. When it is in darkness, it can get food like an animal. It ingests tiny plants and animals much like the amoeba and paramecium.

The euglena reproduces by longitudinal fission, splitting lengthwise in two. The flagellum goes with one part and the other part grows a new flagellum.

When it is too hot or cold for a euglena, it forms a protective casing called a cyst around its body that protects it until conditions outside the cyst become better.

ANIMAL-LIKE PROTISTS: (PROTOZOA), p. 228 AMOEBA, PARAMECIUM, AND SPOROZOANThey live in moist habitats and are more abundant than bacteria. Reproduction is usually asexual, by fission. In harsh conditions they can form cysts.All protozoa are heterotrophs, they must move to obtain food.

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Amoeba Anatomy

Phylum Sarcodina (Amoeba), p. 227Found mainly in fresh water and ponds, parasitic species are found in animal intestines. When they enter the bloodstream, they can cause liver and brain impairment that can be fatal.

Characteristics of Amoeba 1) Movement is due to cytoplasmic extensions & retraction of pseudopods

called false feet, they are fingerlike projections used for getting food. 2) Cytoplasm has 2 layers: ectoplasm (thin, semi-rigid layer under the

plasma membrane) & endoplasm (a more fluid part that fills the inside of the cell).

3) It feeds by phagocytosis (pseudopods flow around & engulf food particles & form a food vacuole).

4) Contractile vacuole = water vacuole- collects water within the organism. As the vacuole fills, it contracts and water is discharged through a pore in the plasma membrane.

5) Reproduction is asexual, by binary fission. Once the amoeba splits, the 2 organisms grow to full size and may split again.

Paramecium Anatomy

Phylum Ciliophora (cilliated protozoans) (Paramecium), p. 227Live in both fresh & marine habitats. They are the most advanced protozoans.

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Characteristics of Paramecia 1) Hairlike cilia are short & numerous & used for swimming. 2) Most common protozoan,"slipper animal" 3) The oral groove, mouth leads to a gullet, a cavity where food enters a food

vacuole, then food is digested wastes are expelled through the anal pore.4) Contractile vacuole collects excess water & expels it.5) There are two nuclei, a macronucleus (controls most cell activities) & a

micronucleus (controls reproduction). The macronucleus is the typical nucleus or "brain" of the cell. The micronucleus however is involved in conjugation (a primitive form of sexual reproduction).

6) Trichocysts (harpoons) with poisonous barbs to capture prey or drive away predators.These spear-like threads are positioned inside the cell membrane and are released upon stimulation to impale a threat or potential food.

7) Reproduction is usually asexual, but on occasion it will exchange the micronucleus with another Paramecium. This exchange is a primitive form of sexual reproduction called conjugation. It is considered sexual because there is an exchange of genetic material, but it is primitive because it is not a complete exchange.

Conjugation between two different Paramecia

Sporozoan Anatomy

Phylum Sporozoa (Sporozoan)

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These are the most simple parasitic forms of protozoans.

Characteristics of Sporozoan 1) Non-motile. At some point in their life cycle they become spores2) Some of these sporozoans have complex life cycles involving more than

one host. The life cycle of this protozoan is dependent upon having mosquito and human hosts.

The study of this life cycle has been used in attempt to control the parasite; however, Plasmodium vivax developed a resistance to many of the antimalarial drugs. Mosquito populations have been attempted to be controlled by use of insecticides. Because the mosquito reproduces quickly in large numbers as well, it has developed a resistance to many insecticides. Wide spread DDT use has developed DDT resistant mosquitoes, so the only lasting effects of the spread are to the other animals in the environment that are higher in the food chain. Because DDT takes a long time to break down, these animals will be affected for a long time.

FUNGILIKE PROTISTS: SLIME MOLD, p. 232

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All fungilike protists are in the Phylum Gymnomycota, called slime molds.

Slime Mold Anatomy

Phylum Gymnomycota (Slime Mold)They prefer cool, shady, moist places and are found under fallen leaves or on rotting logs

Characteristics of Slime Molds 1) During a stage of their life cycle, slime molds resemble protozoans &

become amoeba-like or have flagella and at other times2) They produce spores similar to fungi.3) It feeds on fungi, bacteria, protozoa, other micro-organisms, and decaying

organic matter.

<Homework - Review Questions, p. 232 (17 - 25)>

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