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| = Concept Map = | | = Concept Map = |
| __FORCETOC__ | | __FORCETOC__ |
− | <mm>[[Bacteria.mm|Flash]]</mm>
| + | [[File:Bacteria.mm|Flash]] |
| | | |
| = Textbook = | | = Textbook = |
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| | | |
| | | |
− | ''''''Metabolism in bacteria''''''<br>
| + | =====Metabolism in bacteria===== |
| 4. '''Teaching outlines''':<br> | | 4. '''Teaching outlines''':<br> |
− | Mode of Nutrition:<br> | + | |
− | Nutrition,-- bacteria are either '''autotrophs''' or '''heterotrophs'''.<br> Autotrophic bacteria are again divided into two groups;<br> | + | '''Metabolism-''' Some substances are broken down for energy for vital processes while others are synthesized for necessities of life. ,br.This is called Metabolism. It is a chemical process necessary for the maintenance of life. <br> |
| + | '''Nutrition''' |
| + | Nutrition is a process, in order for an organism to sustain life, to obtain food with life supporting substances that can be digested and used by the organism. |
| + | '''Mode of Nutrition''':<br> |
| + | Nutrition in bacteria are either '''autotrophs''' or '''heterotrophs'''.<br> Autotrophic bacteria are again divided into two groups;<br> |
| (i) '''Photoautorophs''' trap solar energy for utilization CO2 and use H2S in place of H2O. Thus, O2 is never released.<br> | | (i) '''Photoautorophs''' trap solar energy for utilization CO2 and use H2S in place of H2O. Thus, O2 is never released.<br> |
− | (ii) '''Chemoautotrophs''' obtain energy from chemical by oxidation process for food synthesis and carbon from CO2.<br> This type include nitrifying bacteria, sulphur bacteria, iron bacteria etc.<br> Heterotrophs are also of two types- Photoheterotrophs and chemoheterotrophs. <br>Photoheterotrophs use light as energy source and an organic compound as source of carbon, e.g. Green and purple bacteria. <br>Chemoheterotrophs use chemical as energy and carbon may also be obtained from the same organic substances.<br> Most of the bacteria belong to this type. | + | (ii) '''Chemoautotrophs''' obtain energy from chemical by oxidation process for food synthesis and carbon from CO2.<br> This type include nitrifying bacteria, sulphur bacteria, iron bacteria etc.<br> Heterotrophs are also of two types- Photoheterotrophs and chemoheterotrophs. <br>Photoheterotrophs use light as energy source and an organic compound as source of carbon, e.g. Green and purple bacteria. <br>Chemoheterotrophs use chemical as energy and carbon may also be obtained from the same organic substances.<br> Most of the bacteria belong to this type.<br> |
| + | [[File:Mode of Nutrition in Bacteria.png|400px]] |
| + | |
| + | '''Nutritional types in bacterial metabolism |
| + | ''' |
| + | {|class="wikitable" |
| + | |- |
| + | |'''Nutritional type''' |
| + | |'''Source of energy''' |
| + | |'''Source of carbon''' |
| + | |'''Examples''' |
| + | |- |
| + | |Phototrophs |
| + | |Sunlight |
| + | |Organic compounds (photoheterotrophs) <br>or carbon fixation (photoautotrophs) |
| + | |Cynobacteria, Green sulphur Bacteria |
| + | |- |
| + | |Lithotrophs |
| + | |Inorganic Compounds |
| + | |Organic compounds (lithoheterotrophs) <br>or carbon fixation (lithoautotrophs) |
| + | |Thermodesulphobacteria,Nitrospirae |
| + | |- |
| + | |Organotrophs |
| + | |Organic Compounds |
| + | |Organic compounds (chemoheterotrophs) <br>or carbon fixation (chemoautotrophs) |
| + | |Bacillus,Clostridium |
| + | |- |
| + | |} |
| + | |
| + | ====Reproduction in Bacteria==== |
| + | The sexual or asexual process by which organisms generate new individuals of the same kind is '''reproduction.'''<br> |
| + | '''Asexual Reproduction''' |
| + | Asexual is a form of where an animal can make its own offspring with no mate. Asexual is the primary form of reproduction.<br> |
| + | Asexual reproduction in bacteria is very simple. The cell increases in size. A double wall develops across the midline of the enlarged cell. <br>The cell separates into two cells at the midline wall. <br>Each cell is then able to function as a separate entity. The process of multiplication can be quite rapid.<br> The bacterium E. coli may double in number every 20 minutes in ideal conditions. If you plot the graph of population over time, you get an exponential increase.<br> |
| + | '''Sexual reproduction''' |
| + | Sex in bacteria differs somewhat from what we consider sex in eukaryotes. It involves the plasmid, which has several important characteristics:<br> |
| + | 1. A plasmid is a loop of DNA. Plasmids can multiply autonomously within the cell. Thus we may find from zero to many of one or more plasmids in each cell.<br> |
| + | 2. Many plasmids can insert into the DNA of the nucleus, and detach from it. In doing so, <br>the plasmid may leave part of the plasmid DNA behind, and take some of the nuclear DNA with it.<br> |
| + | 3. plasmids can transfer from cell to cell. The cells need not be of the same bacterial 'species'. |
| + | |
| + | ====Effects of Bacteria==== |
| + | '''Economic Importance( Useful effects)''' |
| + | |
| + | Economic importance of any organism refers to the advantages and disadvantages of that organism to nature, the humans and the environment.<br> Bacteria, a prokaryote and microscopic organism, have the following economic importance:<br> |
| + | ==Beneficial effects of Bacteria== |
| + | Bacteria play important roles in different fields such as agriculture, industry etc. Some of them are mentioned below: <br> |
| + | ===Role in agriculture=== |
| + | a) '''Scavenging Role''' Saprophytic bacteria obtain food from organic remains such as animal excreta, fallen leaves, meat etc. <br>They decompose these substances by action of digestive enzymes aerobically or anaerobically (known as fermentation). <br>Thus they help in sanitation of nature, so also known as scavengers. E.g. Pseudomonas <br> |
| + | b) ''' Nitrification''' Rhizobium bacteria, living in root nodules of leguminous plant symbiotically, helps in fixing atmospheric nitrogen. <br>Similarly, Nitrosomanas and Nitrococcus convert ammonium salt to nitrites.<br> Nitrites are further changed to nitrates by Nitrobacter and Nitrocystis. It enables plants to uptake nitrogen. <br> |
| + | c) '''Production of Organic Manure''' As stated above, saprophytic bacteria help in breaking of complex organic substance to simpler forms. <br>Thus, in this process, they help to convert farm refuse, dung and other wastes to manure. <br> |
| + | d) '''Preparation of Ensilage''' Ensilage is preserved cattle fodder prepared by packing fresh chopped fodder sprinkled with molasses. <br>Fermentation activity of bacteria produces lactic acid that acts as preservative in ensilage.<br> |
| + | e) '''Production of fuel''' Bacteria, while converting animal dung and other organic wastes to manure, help in production of fuel that is a must in gobar gas plant. <br> |
| + | f) ''' Disposal of sewage''' Bacteria help in disposal of sewage by decomposing it and thus, help in environmental sanitation.<br> |
| + | |
| + | ===Role in Industry=== |
| + | a) '''Dairy Industry''' Bacteria such as Streptococcus lactis convert milk sugar lactose into lactic acid that coagulates casein (milk protein).<br> Then, milk is converted into curd, yoghurt, cheese etc needed for the industry. <br> |
| + | b) '''Production of Organic Compounds''' Fermentation (breakdown of carbohydrate in absence of oxygen) action of various bacteria produces organic<br> compounds like lactic acid (by Lactobacillus), acetic acid (by Acetobacter aceti), acetone (by Clostridium acetabutylicum) etc. <br> |
| + | c) '''Fibre Retting''' The action of some bacteria like Clostridium, Pseudomonas etc. help in fibre retting <br>i.e. separation of stem and leaf fibre of plants from other softer tissue.<br> |
| + | d) '''Curing''' The leaves of tea and tobacco, beans of coffee and coca are cured off their bitterness with the help of action of certain bacteria such as Bacillus megatherium. <br> |
| + | e) '''Production of Antibiotics''' Number of anti bacterial and anti fungal antibiotics such as Hamycin, Polymyxin, Trichomycin etc are obtained from <br>mycelia bacteria (like Streptomyces). Similarly, Bacillus is used for production of antibiotics such as Bacitracin, Gramicidin etc <br> |
| + | f) '''Production of Vitamins''' Different kinds of vitamins are produced from bacteria like Riboflavin from Clostridium butylicum, Vitamin B12 from Bacillus megatherium and Vitamin K and B-complex from Escherichia coli. <br> |
| + | ==Harmful effects of Bacteria== |
| + | Though bacteria plays important role in agriculture, industries and natural sanitation etc, it has the following harmful effects: <br> |
| + | a) '''Food Spoiling''' Saprophytic bacteria always not only help in decomposition of dead matters, but they also cause the rotting of vegetables, <br>fruits, meat, bread etc. <br> |
| + | b) '''Food Poisoning''' Bacteria like Staphylococcus aureus cause food poisoning and cause people diarrhea and vomiting.<br> |
| + | c) '''Damaging of domestic articles''' Spirochete cytophaga deteriorates cotton, leather and wooden articles.<br> |
| + | d) '''Denitrification''' Bacteria such as Thiobacillus and Microbacillusconvert nitrate of the soil to the gaseous nitrogen. This hampers plants very much.<br> |
| + | e) ''' Desulphurication''' Bacteria such as Desulfovibrio convert soil sulphates into hydrogen sulphide. <br> |
| + | f) '''Cause of Diseases''' It is known that over 90% of human diseases and over 10% of plant diseases are caused by bacteria.<br> |
| | | |
| ===Learning objectives=== | | ===Learning objectives=== |
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| #Classify bacteria on the basis of shapes. | | #Classify bacteria on the basis of shapes. |
| #Identify the structure and morphology of bacteria. | | #Identify the structure and morphology of bacteria. |
| + | #understand the modes of nutrition in bacteria. |
| + | #Identify differences between the asexual and sexual types of reproduction in bacteria. |
| + | #understand the economic importance of bacteria and its uses. |
| + | #describe about the harmful effects of bacteria. |
| | | |
| ===Notes for teachers=== | | ===Notes for teachers=== |
− | Teacher can introduce the lesson on bacteria by giving a brief introduction about monera and prokaryotes.<br> ( Internal link the lesson Click here [[:File:1. introduction to monera.pdf]]Introduction to monera for reference). <br>
| + | Teacher can introduce the lesson on bacteria by giving a brief introduction about monera and prokaryotes.<br> ( Internal link the lesson Click here [[:File:1. introduction to monera.pdf]]<br> |
| + | Introduction to monera for reference).<br> |
| + | Refer this link to show bacteria on Human Body and its effects.[http://t2.gstatic.com/images?q=tbn:ANd9GcSdG85L1SRf5DY-ptAg3VrowS8dwS2Cq4iAXG9p9Wy4NltDqUtc2g]<br> |
| + | '''It is better if teachers refer the websites concerned to the topic . Few links are given in web resources heading.'''<br> |
| 4. Teacher Should be familiar with the meaning of following terms related to bacteria.<br> | | 4. Teacher Should be familiar with the meaning of following terms related to bacteria.<br> |
| '''Words to Know''' <br> | | '''Words to Know''' <br> |
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− | ''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div> | + | ''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div> |
| |} | | |} |
| * | | * |
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| Time Required: 20 Minutes.<br> | | Time Required: 20 Minutes.<br> |
| *Multimedia resources<br> | | *Multimedia resources<br> |
− | Charts/ Diagrams
| + | Charts/ Diagrams |
| *'''Website interactives/ links/ simulations'''<br> | | *'''Website interactives/ links/ simulations'''<br> |
| Wesite interactions/links/ simulations | | Wesite interactions/links/ simulations |
− | Image credit-- Resources needed are Refer Link about images of habitat of bacteria in google search to show that bacteria is present everywhere. [http://www.google.co.in/#q=Images+of+habitat+of+bacteria] <br>Ppt. on structure of Bacteria [[:File:Bacterial Structures (1).pdf]]
| + | Image credit-- Resources needed are Refer Link about images of habitat of bacteria in google search |
| + | #[http://www.google.co.in/#q=Images+of+habitat+of+bacteria Habitat of Bacteria] <br> |
| + | #Ppt. on structure of Bacteria [[:File:Bacterial Structures (1).pdf]] |
| + | #[http://www.scribd.com/doc/6694153/Lecture-4-Bacteria-Nutrition-Metabolism-and-Growth Nutrition] |
| + | #[http://bugs.bio.usyd.edu.au/learning/resources/CAL/Microconcepts/moviePages/conjugation.html Animation of Sexual Reproduction in Bacteria] |
| + | #[http://bugs.bio.usyd.edu.au/learning/resources/CAL/Microconcepts/moviePages/Ecoli.html Reproduction in E.Coli.] |
| + | #[http://bugs.bio.usyd.edu.au/learning/resources/CAL/Microconcepts/moviePages/bacteriaDivision.html Bacteria Reproduction] |
| + | #[http://pdfsdb.com/ppt/economic-importance-of-bacteria-ppt Economic importance of Bacteria] |
| + | # Additional Information[http://www.scienceclarified.com/As-Bi/Bacteria.html#ixzz2WGcoDtB2 to know about bacteria] |
| + | #[http://www.scienceclarified.com/As-Bi/Bacteria.html#ixzz2WGcoDtB2 Effects of Bacteria] |
| + | #[http://truth-out.org/opinion/item/25241-all-the-blood-in-your-body A very scary article on the spread of the ebola virus in Africa in July 2014] |
| + | |
| + | Refer this link to show ppt on various topics in Science [http://www.worldofteaching.com/sciencepowerpoints.html] |
| + | |
| *'''Process/ Developmental Questions'''<br> | | *'''Process/ Developmental Questions'''<br> |
| Procedure:Add lemon juice to a cup of milk . See the changes. Milk changes into curds.<br> How did this change take place? (Lactococcus lactis is a microbe classified informally as a Lactic Acid Bacterium <br>because it ferments milk sugar (lactose) to lactic acid.)[[File:lactus bacteria.jpg|100px|left]][[File:Curds.jpg|100px|left]] | | Procedure:Add lemon juice to a cup of milk . See the changes. Milk changes into curds.<br> How did this change take place? (Lactococcus lactis is a microbe classified informally as a Lactic Acid Bacterium <br>because it ferments milk sugar (lactose) to lactic acid.)[[File:lactus bacteria.jpg|100px|left]][[File:Curds.jpg|100px|left]] |
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| | | |
| = Project Ideas = | | = Project Ideas = |
− | '''Do this activity at home''': About a cup of milk is taken in a vessel & kept for 1-2days. Similarly A lemon is cut into halves and kept for 2days.<br> After 2 days students will observe the changes and give the reasons for the change.) | + | '''Do this activity at home''': About a cup of milk is taken in a vessel & kept for 1-2days. Similarly A lemon is cut into halves and kept for 2days.<br> After 2 days students will observe the changes and give the reasons for the change.)<br> |
| + | '''Evaluation Activity: CCE''' |
| + | #Visit nearby hospital and Collect information of common harmful diseases caused by bacteria.<br> |
| + | #Collect information and pictures about various uses of fermentation(in preparation of food , gober gas etc)<br> |
| + | |
| + | Refer this link . Print the worksheets for Evaluation.[http://www.yourfilezone.com/signup?sf=search_books&ref=4947201&q=worksheets+bacteria+pdf Worksheet for Bacteria]<br> |
| + | Refer this picture and prepare notes on harmful bacteria, their effects on human body[http://t2.gstatic.com/images?q=tbn:ANd9GcSdG85L1SRf5DY-ptAg3VrowS8dwS2Cq4iAXG9p9Wy4NltDqUtc2g] |
| | | |
| = Fun corner = | | = Fun corner = |