CHAPTER 1 - MICROORGANISMS AND THEIR EFFECTS ON LIVING THINGS

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CHAPTER 1 MICROORGANISMS AND THEIR EFFECTS ON LIVING THINGS

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The classification of microorganisms Microorganisms are living things which are also small and cannot be seen with the naked eye and are only visible under the microscope. The study of microorganism is known as microbiology. Microorganisms are also known as microbes. Microorganisms can be classified into five groups : a) Bacteria b) Fungi c) Protozoa d) Viruses d) Algae

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Characteristic of Bacteria Unicellular microorganisms A bacterium is a few µm in length. It has a cell wall made of peptidoglycan. Beneath the cell wall is its plasma membrane. A Bacteria cell does not have a nuclear membrane to enclose its DNA. A bacterium stores foods in the form of glycogen granules in its cytoplasm. Some Bacteria have one or more flagella and used for swimming and moving. Bacteria exist in different shapes and are named according to their shapes. Types of shapes for bacteria are : a) Spherical – Coccus, Diplococus, Streptococcus, staphylococcus. b) Rod- Shaped – Bacillus, Diplobacillus, streptobacillus c) Comma-shaped – Vibrio d) Spiral or spring- shaped – Spirilla. 10. Bacteria reproduce asexually by binary fission and favorable condition for the reproduction are dark, moist, moderately warm and with the present of nutrient.

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11. When conditions are unfavorable for reproduction, some bacteria will form spores. 12. There are four modes of nutrition among bacteria. a) Photosynthesis – some bacteria have chlorophyll and are able to make their own food by using light energy. b) Chemosynthesis – Some bacteria make their own food by using chemical energy obtained from oxidizing chemicals such as ammonia and nitrate. c) Saprophytic nutrition – A group of Bacteria known as putrefying bacteria obtain food from dead and decaying organisms / matter . d) Parasitic nutrition – some bacteria are parasites. They obtain food from other living organisms, and cause diseases. 13. Bacteria can found in a wide range of habitats and they exist in air, water, soil, on any surfaces such as table tops.

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Bacteria

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Characteristic of Fungi Some fungi are microscopic, such as yeast, bread moulds and Penicillium. They have sizes ranging from 10 µm to 100 µm. Some Fungi are large for example mushrooms. It has thread – like structures known as hyphae. It also has cell wall and it cell made of chitin. Some fungi are unicellular for example yeast. Most fungi reproduce asexually by formation of spores or sexually by conjugation. Yeast reproduces asexually by budding. Fungi do not have chlorophyll. Some fungi carry out saprophytic nutrition and parasitic nutrition. Fungi present in the soil, water, air and on the bodies of living things.

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Fungi

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Characteristic of Protozoa (singular- Protozoan) It is a unicellular animals. Their sizes range about 5 µm to 250 µm. They are found in aquatic habitat ( in ponds, drains and seas ) or semi- aquatic habitats ( in damp soil). The examples of protozoa are : a) Amoeba b) Paramecium c) Trypanosome. 5. Some protozoa carry out saprophytic nutrition. (Example : Amoeba , and Paramecium. 6. Some protozoa carry out parasitic nutrition. (Example : Plasmodium and Trypanosome are parasites of human beings and cause diseases.

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Protozoa

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Characteristic of Viruses 1. It is a smallest microorganisms. 2. Their sizes range from 20 – 400 nm (0.02 µm – 0.4 µm ). 3. Viruses come in various shapes. They may be spherical, rod shaped or rocket- shaped. 4. It does not have the structure of a general cell. 5. A virus is made up of two components, namely nucleic acids (either DNA or RNA) and a protective protein coat. 6. The nucleic acids contains information which is important for the reproduction of the virus. 7. Viruses have characteristic of both living and non-living things. 8. Characteristic of living things found in viruses ; a) They have nucleic acids b) They can reproduce. 9. Characteristics of non-living things found in viruses : a) They do not respire, feed or excrete and they can be crystallized.

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10. A virus can only reproduce in a living host cell because it uses materials from the host cell to make new viruses. Characteristic of Algae Algae are green plants and may be unicellular or multicellular. They may be spherical, oval- shaped or filamentous. Sea algae can be a few meters tall. They are not microorganisms. Algae cells contain chloroplasts and able to make their own food by photosynthesis. Algae can reproduce sexually by conjugation or asexually by either binary fission or fragmentation. Algae live in either aquatic or semi- aquatic habitats for example Chlamydomonas and Spirogyra can be found in drains, whereas Pleurococcus can be found on damp and rough bark of tree trunks.

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Factors Affecting the Growth of Microorganisms Temperature - ( become more active as temperature rises up to about 40 º C. Humidity - ( Microorganisms need water to live except viruses ). Light - ( Microorganisms active in dark condition) pH - ( Most microorganisms are active in neutral (pH 7) Nutrients - ( All Microorganisms need nutrients to live )

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Nutrient - Nutrients are essential for growth. - Some metallic elements such as calcium, potassium, magnesium and iron are required in small quantities. - Nutrients such as vitamins, amino acids, glucose and glycogen are also needed for the growth of microorganisms. - Several microorganisms which can manufacture food by themselves like algae through photosynthesis. - Microorganisms like saprophytes and parasites which do not have ability to produce food will obtain nutrients for growth and reproduction.

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b) Humidity Microorganisms need water to perform variety of functions. Microorganisms required water to carry out various life process such as growth and reproduction. Photosynthetic microorganisms required water as source of hydrogen to reduce the composition of carbon dioxide.

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C) Light Most microorganisms prefer growing in damp and dark places to prevent themselves from beings exposed to the sun. The ultraviolet rays (UV) from the sun may severely damage some of microorganisms however, microorganisms that has chlorophyll need sunlight to produce food to sustain growth.

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d ) Temperature (Refer in your Text book Page 9) The optimum temperature for microorganisms to grow is 37 ° C most microorganisms become non active and grow slowly at a temperature of 0-5 C. All microorganism live but do not grow or reproduce at a temperature of below -18 C most microorganisms will die when the temperature is over 60 C. Yet bacterial spores can still live till 120 C e) pH Value pH value most suitable for growth and reproduction of the majority of microorganism is around pH7

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1.3 Useful Microorganisms Food Digestion in Animals and Human Beings Decaying process Medical Agricultural Development Industrial Developments Potential Uses of Microorganisms in various Field.

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Food Digestion in Animals and Human Beings Microorganisms can help the herbivores to digest the cellulose in their food. Microorganisms such as protozoa and bacteria found in stomach and intestines of herbivores can help to convert the cellulose to glucose by releasing the cellulase enzyme. A type of protozoa in the intestines of termites secretes enzyme which helps in the digestion of cellulose. Some microorganisms found in human intestine produce vitamin K which is important in maintaining human health.

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b) Decaying Process Microorganisms such as bacteria and fungi decompose dead organic substances to simpler substances that can be absorbed by plants for growth Without these capable decomposers, carbon, nitrogen and other elements will accumulate in organic matter. Decomposers release enzymes which break down the dead bodies by extra cellular digestion and then they absorb the digested food. Nitrifying bacteria such as Nitrosomanas will act upon the ammonium ion in the soil. Nitrobacter, another type of nitrifying bacteria, then oxidise nitrite ions to nitrate ions.

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C) Medical The antibiotic Penicillin was first discovered in 1940s and there has been a considerable extensive advancement in the use of microorganisms to produce various pharmaceuticals. Antibiotic are substances produced chemically by microorganisms which are effective to preventing the spread of other harmful microorganisms Examples of antibiotic are penicillin ( Penecilium notatum ) and streptomycin ( Streptomyces bacteria). Viruses and bacteria are used to prepare vaccines to protect humans from certain diseases

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d) Agricultural Development Plants which need nitrogen for proteins, nucleic acids and amino acids are unable to use this gas directly from the air. Nitrogen can only be absorbed by plants when it is convert to nitrates. i- Ammonification. The bacteria and fungi decompose the dead organisms, faeces and urines into simpler molecules. ii- Nitrification The nitrifying bacteria then convert the ammonium ion into nitrates through oxidation. Two nitrifying bacteria are involved in nitrification, Nitromonas which oxidise ammonium ions to nitrite and nitrobacter which acts to oxidise the nitrite to nitrate.

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e) Industrial Developments Baking Wine production Cheese production Yoghurt production Butter Production

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Baking Yeast or saccharomyces cerevisiae are added to the bread to produce carbon dioxide. Yeast uses the glucose formed in the bread as respiratory substrate. The carbon dioxide then forms small bubbles which are trapped in the bread, slowly expanding the bread, making the bread bigger. 2. Wine Production The fermentation by yeasts produce wine according to the following equation : Glucose + yeast Alcohol or Ethanol + Carbon dioxide + Energy 3. Cheese Production Lactic acid bacteria are used to ferment the lactose in milk to lactic acid according to the following equation : Lactose + Water Lactic acid Lactobacillus and Streptococcus are two types of lactic acid bacteria that commonly used in the production of cheese.

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4. Yoghurt Production Yoghurt is made from pasteurised milk and its production also depend on lactic acid bacteria. Lactobacillus bulgaricus and streptococcus thermophilus are the examples of lactic acid bacteria added during the manufacturing of yoghurt. 5. Butter Production Butter Production, Streptoccocus lactis and Leuconostoc cremoris are added to help to sour the butter and give flavour to it. Besides, the microorganisms added can also aid in the separation of the butter fat.

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Potential Uses Of Microorganisms in Various Field. Biotechnology is defined as the use of living organisms or their products for commercial purposes include making bread, cheese and wine in selecting breeding of food crops and domestic animals. Besides playing roles in food production, biotechnology also have other applications : a) Several genetically-modified bacteria such as Pseudomonas, is used to clean up the spilled oil which can contaminate the ocean when there is an accident involving oil tankers. b) Microbes such as Zoogloea, Nitrosomonas and nitrobacter are used in waste disposal c) The aerobic fermentation of Methanobacterium a type of bacteria can produce useful fuel such as methane (biogas) that can be used for cooking lighting and heating.

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1.4. Harmful Effects of microorganisms Harmful Effects of Microorganisms Millions of microorganisms live in our bodies Among them are microorganisms that cause diseases These microorganisms are known as pathogens. Pathogens include viruses, bacteria, fungi and protozoa. Diseases caused by pathogens that can be transmitted to another human being are known as infections diseases. Examples of infectious diseases caused by microorganisms are tuberculosis, common cold, hepatitis, tinea and malaria.

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Types of Pathogens and The diseases Diseases Caused by bacteria Tuberculosis – bacilli (rod shape) Cholera / taun– ( Vibrios) Sexually Transmitted Diseases (STDs) – (cocci) Example : Gonorrhea – Cause by cocci syphilis – Cause by spirilla. 2. Diseases Caused by Virus Common Cold Dengue Fever / deman denggi Hepatitis Hepatitis B Acquired Immune Deficiency Syndrome (AIDS) – HIV virus

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Diseases caused by fungi Tinea /panau Ringworm / kurap Diseases Caused by Protozoa Malaria

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Types of Disease, symptoms and mode of Infections

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Ways Microorganisms Infect Human Being Disease causing microorganisms can be transferred from person to another person by various ways including through air, water, food, contact and vector. Air – through other air- such as dust and droplets. - through coughing, sneezing, and talking - Example diseases – tuberculosis and common cold. b) Water and Food – improper handling of food can cause contamination. Example diseases – hepatitis and cholera Pollute water can be the best breeding place for microorganisms c) Contact Physical contact through sexual activities, sharing personal belongings such as towel, comb, razor, or toothbrush. Examples : AIDS, GONORRHOEA, SYPHILIS, TINEA, RINGWORM.

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d) Vector Vector is defined as any living organisms that act as a carrier to transfer pathogen to other living organisms. Example : mosquito. - Vector will transmit the pathogen from their bodies to another organisms when they come in contact with it. For example when a mosquito bites a person the pathogen will be transferred to the person. The pathogen will then infect the person. Example diseases : Malaria and dengue fever Dengue fever – Dengue mosquito Malaria – female anopheles mosquito.

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Ways to Prevent Infections Caused By Microorganisms The life cycle of mosquito and housefly Eggs Larva pupa Adult Control of Vectors Destroy or reduce the habitats of mosquitoes by making sure the drains and rives flow freely and not blocked by rubbish, bottle and containers are not left open to collect rain water. Using biological control by breeding guppy fish which eats mosquito larvae Spraying oil on the surface of water. Using pesticide to destroy mosquitoes Using mosquito nets to protecting ourselves

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2. Sterilisation Sterilisation is the process of elimination of contagious agents such as bacteria, protozoa and viruses from a surface or piece of equipment. Sterilisation can be conducted physically and chemically. Physical sterilisation can be divided I - Heating ( Boiling and Autoclave) ii - Radiation ( Gamma ray, Ultraviolet light) Chemical Substances can be divided I – Antiseptics ii – Disinfectants Boiling - Boiling water for about six to seven hours at a fixed temperature of 100 º C is able to destroy most of microorganisms. - Boiling will kill most of the viruses and bacteria that found in the water but it is ineffective against many bacteria spores.

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2. Sterilisation Sterilisation is a process that is used to destroy microorganism Sterilisation can be conducted physically and chemically. Physical sterilisation can be divided I - Heating ( Boiling and Autoclave) -Boiling- Boiling can kill microorganism but not their spores. Examples : Sterilising surgical tools and milk bottles -Autoclave -A 20 minute sterilisation process using steam under high pressure to kill microorganism and their spores. Examples : Sterilising surgical tools

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d) Chemical substances - Antiseptics and disinfectants are chemical substances used to control or get rid of microorganisms i- Antiseptics - Have ability to ban the growth of potentially pathogenic microbes when applied to the surface of an organ or tissue, especially the skin. - There are many types of antiseptics used to treat wounds such as 1. Iodine solution 2. Boric acid 3. Hydrogen peroxide 4. Carbolic acid ii- Disinfectants - Chemicals substances used to destroy pathogenic microorganisms which might cause infections but it do not kill spores . - Example of disinfectants are formalin and calcium hypochlorite.

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b) Autoclave - is used to sterilise the equipment for devices used in a medical operation. - Equipments in an autoclave are heated at 121 º C for 15 minutes - This method can destroy microorganisms and their spores. c) Radiation - Radiation operates by imparting its energy to molecules in the microbes to disrupt them. - Its can be sorted into two main group : i- Non- Ionising radiation - Radiation such as ultraviolet light is absorbed by the microorganisms interfering with their growth. ii- Ionising radiation - Radiation such as gamma rays and X-rays produce oxidising ions which can easily break up the macromolecules in the microorganisms - This method is applied to sterilise some medical devices.

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b. Autoclave - A 20 minute sterilisation process using steam under using steam under high pressure to kill microorganism and their spores. Examples : Sterilising surgical tools c. Radiation - Ultraviolet rays are used to sterilise that the air in an operation theatre - Gamma rays are used to sterilise surgical tools d. Antiseptic - Chemical substances that prevent the growth of microorganism but at the same time do not destroy body tissue - Used to treat wounds - Examples : Soap and iodine solution

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e. Disinfectants - Chemical substances that can destroy microorganism - Examples : Floor detergent

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3 . Immunisation Immunisation is defined as the production of immunity in an individual. Immunity is the capability of the body to resist infection Immunisation can be divided into two types : a) Active immunity b) Passive Immunity Table : Comparison between active and passive immunity Active Immunity Factors Passive Immunity Antibodies produced by body in response to infections Definition Antibodies acquired from other bodies Longer Duration Shorter Slower Onset of immunity Faster Antibodies created under stimulation of pathogenic microbes during recovery from disease Natural Antibodies obtained by babies from mother through placenta or mother’s milk Antibodies induced through vaccination Acquired Antibodies received from other bodies including animals

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Immunity Active Immunity Passive Immunity

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How Diseases Caused By Microorganisms Are Treated a) Modern Method Antibiotic Chemical substances derived from microorganisms that can destroy or inhibit the growth of other microorganisms. Produced by bacteria or fungi Kill bacteria Different types of antibiotics are used in treating different diseases Table : Types of antibiotics and diseases Types of antibiotics Diseases Penicillin Sexually transmitted diseases including gonorrhea and syphilis Streptomycin Tuberculosis Chloramphenicol Typhoid Tetracycline Cholera

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2. Antiserums Antiserums are human or animal serums containing antibodies that are specific for one or more antigens to a particular infectious disease. 3. Synthetic Medicines Chemical medicines which are synthesised in laboratory to cure some pathogenic diseases 4. Radiotherapy Treatment of disease using radiation 5. Operations Surgical procedure carried out to treat an injury ailment or any dysfunctions of organ.

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b) Traditional Method Types of traditional medicines and their uses Aloe Vera Treat wounds and Muscle cramps Honey Treat common cold Turmeric Treat ringworm Garlic Treat high blood pressure Ginseng Build the body”s resistance against infection

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Dangers of Using Drugs without Medical Advice and Unauthorized Prescription Lead to allergies characterised by itchiness in some individual Damage some vital organs such liver and kidneys Destroy harmless microorganisms that found in your body Increase the resistance of microorganisms to antibiotics or any related medicines

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The uses of microorganisms in our daily life. Agricultures : The nitrifying bacteria play a very role in supplying nitrogen to plants. Decompositions : The bacteria decompose the dead bodies and transform them into humus compounds which help the growth in plants. Medicines : The discovery of antibiotics have helped to manage diseases better. Industries : Microorganisms such as yeast are used in producing daily products such as breads and cakes. Food Digestions : Intestinal bacteria play a role in food digestion.

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The importance of microorganisms in maintaining the balance of nature. Maintaining the composition of air in the atmosphere. Carrying out decomposition to maintain the composition of nitrogen compounds Help to decompose organic substances or domestic wastes which can cause pollution Play role as a biotic component in an ecosystem

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