Biology Grade 12 Handout Unit One and Two PDF

IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 UNIT ONE: APPLICATION OF BIOLOGY  Biology is a science that helps us understand every living organism. It studies about the function of living organisms, the evolution of species, the interac...

IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 UNIT ONE: APPLICATION OF BIOLOGY  Biology is a science that helps us understand every living organism. It studies about the function of living organisms, the evolution of species, the interaction between living things and their habitat, and the factors that produce diseases as well as the discovery of new drugs. 1.1 Application in conservation of natural resources  Conservation is the management of natural resources in a way which aims to restore and maintain in balance between human needs and those of other species.  Conservation biology focuses on how to protect and restore biodiversity. Ethiopia has many natural resources. Mention some of the natural resources of your country. Classification of natural resources: Natural resources can be classified as renewable and non-renewable resources.  The main sources of renewable resources are sun, wind, water, the earth‘s heat and biomass.  Renewable resources are mainly living things and their products. These can be used and reused and replaced.  Non- renewable resources are natural substances that can- not be replaced at the speed as that are used up. 1. Give examples of renewable and non-renewable resources. 2. How can we manage renewable resources?  Biology creates awareness on the natural resources conservation and play role in the development of natural resources and genetic resource conservation. 1. How can we combat climate change? 2. What should be done to conserve trees? 3. What is the role of biologists in conservation of natural resources? 4. What should be done to conserve plants? 5. How do you contribute to conservation of natural resources? 1.2 Food and nutrition security  Food is a complex mixture of different chemical substances which, provides requirements for growth and repair, supply energy, regulation of metabolism and health.  Food security is a state in which all the people have physical, social and economic access to sufficient, safe, and nutritious food that meets the food preferences and dietary needs for an activity and healthy life at all times.  Food insecurity on other hand is rooted in poverty and has long term impacts on the potential of families, communities and countries to develop and prosper. 1. What is the effect of prolonged undernourishment? 2. Designate the role of biology in food security? 3. Food insecurity can be chronic or transitory. Explain 4. Mention the causes of food insecurity? Nutrition security is the situation whereby individuals have access to sufficient, safe, and nutritious food, safe water, adequate sanitation, knowledge of household, food storage and preservation and hygiene. 1. What factors influence food availability? 2. What are the causes/effects of food and nutritional insecurity? Prepared Hirpa. H (M.sc Microbiology) Page 1  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 1.3 Creating conscious citizens and ensuring sustainable development Conscious citizens is one who values on being fully human, value human life and relationships with all living things and one who takes responsibility for transforming skills into actions through ethical decision making. In this regard biology helps to expand awareness of the social, global, and environmental conditions, empower people to assume personal responsibilities, work sparingly on sustainable development, diminution of degradation of nature and improve life and living. Conscious citizens/biologist facilitates sustainable development initiatives and implement innovative and cost effective biotechnologies that:-  Consume fewer resources  Incorporate recycling  Reduce production of waste  Sustain greener earth  Improve food production 1. Explain each of these and give examples? Sustainability is represented by three dimensions: economic, social and environmental. Biologists involve in sustainable development through:-  protecting, managing, monitoring the existing resources  finding ways to clean up pollution  identifying, recording and monitoring animals and plants  Using examples explain how you involve in these three issues 1.3 Applications of biotechnology Biotechnology is the application of technologies that involve the use of living organisms or their products for the development of products that benefit humans. Some of these are:- i. Single cell protein (SCP): refers to dead and dry cells of microorganisms like yeast, bacteria, fungi, and algae.  These SCPs serve as a food or feed supplement and can be an alternative to conventional protein sources. Some of the microbes used for the production of SCP are:-  Species of algae: Spirulina has become a viable alternative to green plants as a primary nutrient source.  The groups of fungi such as Fusarium venenatum is the source of Mycoprotein (meat substitution for human consumption).  Bacterial species Mathylophilus mathylotrophus, Fusarium venenatum are used as animal feed (pruteen). Fermentation process that involves propionic bacteria produce, vitamin B12 and vitamin B2. ii. Fermented meat: microbes such as Lactobacillus plantarum and Pediococcus cerevisiae add flavor by fermenting meat. Fungi such as Penicillium and Aspergillus give distinctive odor to hams. iii. Production of beer, wine and spirits: beer and wine are made by fermenting sugary juices; spirits such as whiskey, gin are made by fermenting juices and distilling the fermented product. Strains of Saccharomyces are the fermenters of all alcoholic beverages. 2. What is distillation? How is Tella and Areki (local beverages) produced? In the production of wine from juice, why do we treat the juice with sulfur dioxide? Spirits are made from the fermentation of foods such as barley (Scotch whiskey), rye (gin) corn Prepared Hirpa. H (M.sc Microbiology) Page 2  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 (bourbon), potatoes (vodka) and molasses (rum). iv. Dairy industry: microorganisms are used in making a wide variety of dairy products. Some of them are:- Organism/bacteria Role in dairy production Streptococcus cremoris Production of cultured buttermilk from skim milk S. lactis, S diacetylactis and Leuconostoc Make buttermilk with different flavors and citrovoum and L. cremoris production of sour cream Streptococcus thermophilus and Making yogurt from milk Lactobacillus bulgaricus Lactobacillus acidophilus Make acidophilus milk Lactobacillus bulgaricus More acidic milk and lacks flavor 1. What is the role of sterilization in dairy technology? v. Bread making: the following are the functions that are accomplished by microbes during bread making.  These are leavening is achieved through the release of gas to produce a porous and spongy product; kneading incorporates air into the dough and the microbial enzyme break down flour proteins (gluten) and give the dough elasticity, conditioning the dough to make it workable.  Bread fermentation generates CO2, alcohol and other volatile organic acids.  The bacteria Lactobacillus and Streptococcus species are responsible for pungent flavor of rye bread and L. sanfrancise for sour dough bread. Mention the material/substances and the steps to be followed in bread making. 1.5. Genetic Engineering What is a gene? Genetic engineering is the process of transferring DNA from one organism into another that results in a genetic modification; the production of a transgenic organism. . Genetic engineering is being used in :-  the production of pharmaceuticals  gene therapy  The development of transgenic plants and animals. A. Animal breeding and transgenic animals, and plants and disease, and pest management  Animal breeding addresses the genetic value of livestock.  Selecting for breeding animals with superior traits in growth rate, egg, meat, milk, or wool production.  A desirable trait has revolutionized the livestock and plant production throughout the entire world.  Animals can also be genetically modified (transgenic animals) for valuable traits  There are many potential applications of transgenic methodology in developing new and improved strains of livestock. Prepared Hirpa. H (M.sc Microbiology) Page 3  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023  Practical applications of transgenic technology in livestock production include: o enhancing the prolificac o reproductive performance o Increasing feed utilization. o growth rate o improving carcass composition o improving milk production and/or composition o modification of hair or fiber o Increasing disease resistance in animals.  Gene transfer is a relatively rapid way - of altering the genome of domestic livestock  Plants can be propagated quickly and in large quantity by tissue culture technique.  Tissue culture, a method of biological research in which fragments of tissue from an animal or plant are transferred to an artificial environment in which they continue to survive and function. The cultured tissue may consist of:-  a single cell,  a population of cells,  a whole or part of an organ. Plants produced in large amount using this technique include:- 1. palm trees 2. orchids 3. bananas 4. carrots. Tissues culture is seen as an important biotechnology for developing countries for the:-  production of disease-free  high quality planting material  rapid production of many uniform plants 1.6. Health and wellbeings  Human drugs such as insulin for diabetics, growth hormone for individuals with pituitary dwarfism, and tissue plasminogen activator for heart attack victims  Animal drugs like the growth hormones, bovine or porcine somatotropin, are being produced by the fermentation of transgenic bacteria that have received the appropriate gene from human, cow, or pig Prepared Hirpa. H (M.sc Microbiology) Page 4  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 A. The manufacture of antibiotics  micro-organisms are used for the production of antibiotics, it is not their fermentation products that are wanted, but complex organic compounds, called antibiotics  Most of the antibiotics we use come from bacteria or fungi that live in the soil.  One of the most prolific sources of antibiotics is Actinomycetes. These are filamentous bacteria that resemble microscopic mould  Antibiotics attack bacteria in a variety of ways  Some of them disrupt the production of the cell wall and so prevent the bacteria from reproducing, or even cause them to burst open; some interfere with protein synthesis and thus arrest bacterial growth.  Those that stop bacteria from reproducing are said to be bacteriostatic; those that kill the bacteria are bacteriocidal.  Animal cells do not have cell walls, and the cell structures involved in protein production are different.  Antibiotics do not damage human cells although they may produce some side-effects such as allergic reactions fungi.  The actinomycete Streptomyces produces the antibiotic streptomycin  The best known antibiotic is penicillin, which is produced by the mould fungus Penicillium and was discovered by Sir Alexander Fleming in 1928.  Penicillin is still an important antibiotic but it is produced by mutant forms of a different species of Penici/firm from that studied by Fleming.  The different mutant forms of the fungus produce different types of penicillin.  The penicillin types are chemically altered in the laboratory to make them more effective and to „tailor‟ them for use with different diseases. ‗Ampicillin‘, ‗methicillin‘ and oxacillin‘  Vaccines for Bordetella pertussis, Salmonella typhi, Vibrio cholerae, and Mycobacterium tuberculosis are produced in large batch cultures.  Corynebacterium diphtheriae and Clostridium tetani are propagated for the synthesis of their toxins, from which toxoids for the DT vaccines are prepared. Biosensor  In this field of bioelectronics, living microorganisms (or their enzymes or organelles) are linked with electrodes, and biological reactions are converted into electrical currents by these biosensors.  Biosensors are being developed to measure specific components in beer, to monitor pollutants, and to detect flavor compounds in food.  Applications include the detection of glucose, acetic acid, glutamicacid, ethanol, and biochemical oxygen demand (BOD).  The application of biosensors to measure cephalosporin, nicotinic acid, and several B vitamins.  These new biosensors will detect pathogens, herbicides, toxins, proteins, and DNA. o Many of these biosensors are based on the use of a streptavidin-biotin recognition system.  One of the most interesting recent developments using these approaches is a handheld aflatoxin detection system for use in monitoring food quality. Prepared Hirpa. H (M.sc Microbiology) Page 5  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023  The unit can detect from 0.1 to 50 ppb of aflatoxins in a 1.0 ml sample in less than 2 min.  Aflatoxins. Rapid advances are being made in all areas of biosensor technolonogy  Major improvements in the stability and durability of these units, which are being made more portable and sensitive.  Microorganisms and metabolites such as glucose can be measured, thus meeting critical needs in modem medicine. C). Forensic Science  Forensic biologists inspect crime scenes to examine potential sources of evidence of using blood, saliva, and hair, and then they analyze the specimens in a laboratory, focusing on DNA analysis  Fingerprints are also important tools to investigate crime and determine the paternity case of a child.  Forensic biologists write up their findings in technical reports and are called upon to testify in court.  Bioinformatics is widely acceptable in the field of forensic science because, with the help of computational tools, it has become quite easer and reliable to gather evidence regarding a particular crime When examining the variability at 5-10 different Variable Number of Tandem Repeat (VNTR) loci, the odds that two V). Applications in biomining 1). Microbiological mining  The availability of mineral-rich ores decreases; methods are needed to extract minerals from less concentrated sources.  This need spawned the new discipline known as biohydrometallurgy, the use of microbes to extract metals from ores.  Copper and other metals originally were thought to be leached from the wastes of random individuals would share the same genetic pattern by chance can be approximately 1 in 10 billion  Ores crushing as a result of an inorganic chemical reaction such as those reactions used to extract metals from ores.  it was then discovered that this leaching is due to the action of Thiobacillus ferrooxidans.  chemolithotrophic acidophilic bacterium lives by oxidizing the sulfur that binds copper, zinc, lead, and uranium into their respective sulfide minerals, with a resultant release of the pure metal.  Copper in low-grade ores is often present as copper sulfide. When acidic water is sprayed on such ore, T. ferrooxid obtains energy as it uses oygen the sulfur atoms in sulfide ores to sulfate.  The bacterium doesn‟t use the copper; it merely converts it to a water-soluble form that can be retrieved and used by humans.  Minerals also can be degraded by microbes, T. ferrooxidans releases iron from iron sulfide by the same process.  Combinations of T. ferrooxidans and a similar organism, T. thiooxidans, degrade some copper and iron ores more rapidly than either one does alone.  Combination of organisms, Leptospirillum ferrooxidans and T. organoparus, degrades pyrite (FeS2) and chalcopyrite (CuFeS2), although neither organism can degrade the Prepared Hirpa. H (M.sc Microbiology) Page 6  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 minerals alone.  Bacteria can be used to mine uranium, and bacteria may eventually be used to remove arsenic, lead, zinc, cobalt, and gold. However, of late, fewer mining companies are actually Vi. Application in the Environment A). Solid waste treatment: composting and landfill  Most of it ends up in landfill sites- huge holes in the ground where refuse is deposited to prevent it being a hazard.  The non-biodegradable components (metals, plastics, rubble, etc.) remain there more or less indefinitely; however, over a period of time biodegradable material (food waste, textiles, paper, etc.) undergoes a decomposition process.  The rate at which this happens is dependent on the nature of the waste and the conditions of the landfill, but can take several decades.  Aerobic processes give way to anaerobic ones and a significant result of the latter is the generation of methane.  Modern landfill sites incorporate systems that remove this to prevent it being a fire/explosion hazard, and may put it to good use as a fuel source.  Many householders separate organic waste items such as vegetable peelings and grass cuttings and use them to make compost.  Fungi and bacteria, particularly actinomycetes, break down the organic matter to produce CO2, water and humus, a relatively stable organic end product.  Compost is not really a fertiliser, since its nitrogen content is not high, but it nevertheless provides nutrients to a soil and generally helps to improve its condition.  Composting is carried out on a large scale by local authorities using the waste generated in municipal parks and gardens. B). Wastewater treatment  The aim of wastewater treatment is the removal of undesirable substances and hazardous microorganisms in order that the water may safely enter a watercourse such as a river or stream.  Sewage is the term used to describe liquid wastes that contain faecal matter (human or animal).  The effectiveness of the treatment process is judged chiefly by the reduction of the wastewater‘s biochemical oxygen demand (BOD).  This is a measure of the amount of oxygen needed by microorganisms to oxidise its organic content.  A high BOD leads to the removal of oxygen from water, a certain indicator of pollution.  Wastewater treatment usually occurs in stages. The first of which (primary treatment) is purely physical, and involves the removal of floating objects followed by sedimentation, a process that removes up to one-third of the BOD value.  Further purification procedures are required before it can be used as drinking water.  Wastewater treatment is fundamental to any developed society, and greatly reduces the incidence of waterborne diseases such as cholera. Prepared Hirpa. H (M.sc Microbiology) Page 7  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 Secondary treatment involves microbial oxidation, leading to a substantial further reduction in BOD.  This may take one of two forms, both of which are aerobic, the traditional trickling filter and the more recent activated sludge process.  The wastewater is passed slowly over beds of stones or pieces of moulded plastic.  These develop a biofilm comprising bacteria, protozoans, fungi and algae  The resulting treated water has its BOD reduced by some 80— 85%.  Activated sludge facilities achieve an even higher degree of BOD reduction.  Wastewater is aerated in tanks that have been seeded with a mixed microbial sludge.  The main component of this is the bacterium Zoogloea, which secretes slime, forming aggregates called fiocs, around which other microorganisms such as protozoans attach.  Some of the water‘s organic content is not immediately oxidised, but becomes incorporated into the flocs.  After a few hours‘ residence in the tank, the sludge is allowed to settle out, and the treated water passes out of the system. Before being discharged to a watercourse, it is treated with chlorine to remove any pathogenic microorganisms that may remain.  The principal operating problem encountered with activated sludge is that of bulking. This is caused by filamentous bacteria such as Sphaerotilus natans; it results in the sludge not settling properly and consequently passing out with the treated water.  Both secondary treatment processes result in some surplus sludge, which undergoes anaerobic digestion, resulting in the production of methane and CO2.  The methane can be used as a fuel to power the plant, and any remaining sludge is dewatered and used as a soil conditioner. Care must be taken in this context, however, that the sludge does not contain toxic heavy metals. C) Bioremediation  Bioremediation is the use of living detoxification and degradation of organisms their products for the environment pollutants.  Today many pollutants are degraded with the help of saprophytic microbes; this process is also known as biodegradation.  Genetically engineered bacterias are used to clean up pollutants from the environment.  The engineered bacteria metabolically breakdown toxic pollutants into harmless compounds.  Mercury resistant bacteria process metallic mercury (which damages the nervous system) into a nontoxic compound.  Bioremediation via microorganisms, enzymes produced by a microorganism modify a toxic pollutant by altering or transforming its structure. This event is called biotransformation.  Biotransformation results in biodegradation, in which the toxic pollutant is degraded, were yielding less complex, nontoxic metabolites.  Biotransformation without biodegradation can also occur. For example, toxic heavy metals can often be rendered less toxic by oxidation or reduction reactions carried out by microorganisms. Prepared Hirpa. H (M.sc Microbiology) Page 8  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 D). Biofuels  The need to become independent of fossil fuels is driven by both political and environmental concerns.  This has accelerated interest in and use of biofuels - fuel (chiefly ethanol) that is obtained by the fermentation of plant material.  Corn is currently the substrate of choice, the use of crop residues could significantly boost biofuel yields.  Crop residues are the plant material that is usually left in the field after harvest, and it consists of cellulose and hemicellulose.  Polysaccharides are polymers of five different hexoses and pentose: glucose, xylose, mannose, galactose, and arabinose.  While no microorganism naturally ferments all five sugars, a Saccharomyces cerevisiae strain has been engineered to ferment xylose and an E. coli strain that expresses Zymomonas mobilis genes is able to ferment all these sugars.  Another area of research focuses on degrading the cellulose and hemicellulose to release these monomers.  This is commonly done by heating the plant material and treating it with acid, which is both expensive and corrosive.  Work to harvest cellulase- and hemicellulase-producing fungi as well as bioprospecting for enzymes from thermoacidophiles are ongoing in an effort to replace the harsh thermochemical approach with a biological treatment. E). Biogas production  Biogas is produced by bacteria and Achaeans from organic matter in fermenters.  Biogas is a combustible gas produced from the anaerobic breakdown of organic matter such as manure, waste plant matter from crops and household organic waste by the activities of the microorganisms.  Depending on the construction of the fermenter, biogas is mostly methane with some carbon carbon dioxide and hydrogen.  These first dioxide, though other gases may be two communities are Eubacteria. The last present.groups is Archaea called methanogens. Three different communities of anaerobic the methanogens produce methane by microbes are required. Advantages of biogas  Biogas is a fuel used to cook food, and light lamps.  Slurry left after biogas production forms a soil conditioner (manure).  Biogas is much cheaper than Liquefied Petroleum Gas for home use. F) Composting  Composting is anaerobic microbial driven process that converts solid organic wastes into a stable, sanitary, humus-like material that has been considerably in bulk and can be safely returned to the environment.  In large-scale operations using largely domestic solid organic wastes  The final product is mostly used for soil improvement, but in more specialized operations using specific organic raw substrates (straw, animal manures, etc.) Prepared Hirpa. H (M.sc Microbiology) Page 9  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023  The final product can become the substrate for the worldwide commercial production of the mushroom Agaricus bisporus.  Composting has only recently become a serious waste management technology, and both theoretical and practical development of the technology is still in its infancy.  The primary aim of a composting operation is to obtain, in a limited time within limited compost, final compost with a desired product quality.  A composting plant must function under environmentally safe conditions.  Composting is carried out in a packed bed of solid organic particles in which the indigenous microbes will grow and reproduce.  Free access to air is an essential requirement.  The starting materials are arranged in static piles (windrows), aerated piles or covered tunnels, or in rotating bioreactors (drums or cylinders).  Some form of pre-treatment of the waste may be required, such as particle size reduction by shredding or grinding.  The basic biological reaction of the composting process is the oxidation of the mixed organic substrates with oxygen to produce carbon dioxide, water and other organic by-products.  After the composting process is completed, the final product most often needs to be left for variable time periods to stabilize. Vii. Application in Industry A). Enzymes  Enzymes can be produced by commercial fermentation using readily available feed stocks such as corn-steep liquor or molasses.  Fungi (e.g. Aspergillus) or bacteria (e.g. Bacillus) are two of the commonest organisms used to produce the enzymes.  These organisms are selected because they are non-pathogenic and do not produce antibiotics.  The fermentation process is similar to that described for penicillin.  If the enzymes are extracellular then the liquid feedstock is filtered from the organism and the enzyme is extracted.  If the enzymes are intracellular, the micro-organisms have to be filtered from the feedstock.  They are then crushed and the enzymes extracted with water or other solvents. Some commercial uses of enzymes are:-  Proteases: In washing powders for dissolving stains from, e.g. egg, milk and blood; removing hair from animal hides; cheese manufacture; tenderising meat.  Lipases: Flavors enhancer in cheese; in washing powders for removal of fatty stains.  Pectinases: Clarification of fruit juices; maximizing juice extraction.  Amylases: Production of glucose from starch. B). Biological washing powders  The majority of commercial enzyme production involves protein-digesting enzymes (proteases) and fat-digesting enzymes (lipases) for use in the food and textile industries.  When combined in washing powders they are effective in removing stains in clothes caused by proteins, e.g. blood, egg and gravy, and fats, e.g. grease.  Protein and fat molecules tend to be large and insoluble.  Biological washing powders save energy because they can be used to wash clothes at lower temperatures, so there is no need to boil water.  if they are put in water at higher temperatures the enzymes become denatured and they lose their effectiveness. Prepared Hirpa. H (M.sc Microbiology) Page 10  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 Viii. Applications in agriculture A). Bio-pesticides  There has been a long-term interest in the use of bacteria, fungi, and viruses as bioinsecticides and biopesticides.  These are defined as biological agents, such as bacteria, fungi, viruses, or their components, which can be used to kill a susceptible insect. Bacteria: Bacillus thuringiensis and Bacillus popilliae are the two major bacteria of interest.  Bacillus thuringiensis is used on a wide variety of vegetable and field crops, fruits, shade trees, and ornamentals.  B. popilliae is used primarily against Japanese beetle larvae.  Both bacteria are considered harmless to humans.  Pseudomonas fluorescens, which contains the toxin-producing gene from B. thuringiensis, is used on maize to suppress black cutworms. Viruses: Three major virus groups that do not appear to replicate in warm-blooded animals are used:  nuclear polyhedrosis virus (NPV)  granulosis virus (GV)  Cytoplasmic polyhedrosis virus (CPV).  These occluded viruses are more protected in the environment. Fungi : Over 500 different fungi are associated with insects.  Infection and disease occur primarily through the insect cuticle.  Four major genera have been used:-  Beauveria bassiana and Metarhizium anisopliae are used for control of the Colorado potato beetle and the froghopper in sugarcane plantations.  Verticillium lecanii and Entomophthora spp have been associated with control of aphids in greenhouse and field environments. B). The use of Ti plasmid as a vector  Use of tumour-inducing (Ti) plasmid of Agrobacterium tumefaciens to introduce glyphosate resistance into soybean crops.  To introduce transgenes into plants is to use agrobacterium tumefaciens  this species of bacteria that has a plasmid, called the Ti plasmid, that causes tumours in the plant it infects.  The glyphosate resistance gene is inserted in to the Ti plasmid along with an antibiotic resistance gene.  The construct then re inserted in to a bacterium.  Plant cells are then exposed to transgenic bacterium a cultured on a plate containing antibiotic the only plant cells that grow are those that have taken up by the plasmid.others are killed by antibiotics A) Insect-resistant crops  Another important agricultural development is that of genetically modified plants protected against attack by insect pests. Prepared Hirpa. H (M.sc Microbiology) Page 11  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023  Maize is protected against the corn borer, which eats the leaves of the plants and then burrows into the stalk, eating its way upwards until the plant cannot support the ear.  Cotton is protected against pests such as the boll weevil.  In both plants, yield is improved.  Insect-resistant tobacco also exists, and is protected against the tobacco bud worm, but as yet it has not been grown commercially. The most likely detrimental effects on the environment of growing an insect-resistant crop are:  The evolution of resistance by the insect pests  A damaging erect on other species of insects  The transfer of the added gene to other species of plant. Less pesticide is used, reducing the risk of spray carrying to and erecting non-target species of insects in other areas. Remember also that only insects that actually eat the crop are a erected. B) Pest Resistant Crops  Pest attack is one of the very common problems in a number of different crops all around the globe; these crops may include fodder crops or other crops for the purpose of getting food.  One the example of such crops is BT-Cotton.  The genes of Bacif/uS thuringiensis (Bt), a very common, are inserted in cotton crop in order for development of certain protein in it.  The protein is very toxic to a number of different insects. With this aid of biotechnology, the developed BT-Cotton leads to a less pest attack ultimately leading to a significant more production. C) Transgenic Animals  Several recombinant proteins used in medicine are successfully produced in bacteria; some proteins require a eukaryotic animal host for proper processing.  For this reason, the desired genes are cloned and expressed in animals, such as sheep, goats, chickens, and mice.  Animals that have been modified to express recombinant DNA are called transgenic animals.  Several human proteins are expressed in the milk of transgenic sheep and goats, and some are expressed in the eggs of chickens.  Mice have been used extensively for expressing and studying the effects of recombinant genes and mutations. D).Transgenic Plants  Manipulating the DNA of plants (i.e., creating GMOs) has helped to create desirable traits, such as disease resistance, herbicide and pesticide resistance, better nutritional value, and better shelflife.  Plants are the most important source of food for the human population.  Farmers developed ways to select for plant varieties with desirable traits long before modern-day biotechnology practices were established. Attention:  Transgenic crops are being created that resist disease, are tolerant of herbicides and drought, and have improved nutritional quality.  Plants are also being used to produce pharmaceuticals, and domesticated animals are Prepared Hirpa. H (M.sc Microbiology) Page 12  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 being genetically modified to produce biologically active compounds.  Plants that have received recombinant DNA from other species are called transgenic plants. Because they are not natural, transgenic plants and other GMOs are closely monitored by government agencies to ensure that they are fit for human consumption and do not endanger other plant and animal life.  Foreign genes can spread to other species in the environment, extensive testing is required to ensure ecological stability.  Staples like corn, potatoes, and tomatoes were theirst crop plants to be genetically engineered F). Pest resistance Pest resistance: caterpillars and other insect larva are killed by the toxic produced by Bacillus thuringiensis.  The gene for the toxin has been successfully introduced into some plant species using a bacterium vector.  The plants produce the toxin and show increased resistance to attack by insects larvae. G) Herbicide resistance: is the inherent ability of a weed to survive treatment with an herbicide that would normally kill it. If a resistance plant is allowed to reproduce, the resistance spreads resulting in more and more plants that are resistant to that particular herbicide. H) Cloning: cloning describes the process used to create an exact genetic replica of another cell, tissue o organism. The copied material, which has the same genetic makeup as the original, is referred to as a clone. Example: identical twins, asexual reproduction offspring Animal cloning: What are the advantages of cloning? Advantages  Producing organisms with a desired quality  producing genetically compatible tissues  Treat genetic disorders/diabetes  prevent extinction of species  Solve problem of infertility  resistance to disease and drought  improve yield Disadvantages of cloning  Abnormalities associated with subsequent development include failure of immune system  Structural abnormalities of brain  Digestive dysfunction: enteritis, and umbilical infections. There is also question of true biological age of clones and the potential for premature aging. Other risks include:-  Low success rate  serious genetic malfunctioning  Decreases gene diversity  May bring about new diseases  Problem of organ rejection  lead to disruption of paternity and family life Prepared Hirpa. H (M.sc Microbiology) Page 13  IFA BORU MELKA HAYU SECONDARY SCHOOL BIOLOGY HANDOUT FOR GRADE 12 SCIENCE STREAM STUDENTS IN 2023 The first successful reproductive cloning of an adult with known characteristics is Dolly the sheep Biological warfare  Biological warfare is the use of biological toxins or infectious agents with the intent to kill or incapacitate humans, animals or plants as an act of war. If the environment is contaminated, a long term treat to the population could be created. Unit-two Microorganism  Microorganisms are organisms too small to be seen clearly by the unaided eyes.  Micro means very small—anything so small that it must be viewed with a microscope (an optical instrument used to observe very small objects).  Microbiology can be defined as the study of microbes.  microbes can be observed only with the use of various types of microscopes.  They are very small life forms so small that individual microorganisms cannot be seen without magnification. Microorganisms Include:-  Fungi  Bacteria  Algae  protozoa  Viruses. Some microorganisms however, like the eukaryotic microorganisms are visible without magnification. Microbiology is concerned with the study of microorganisms which include: bacteria, viruses, fungi, protozoa, algae, and helminthes (parasitic worms). A. Bacteria B. fungi C. Algae D. Virus Prepared Hirpa. H (M.sc Microbiology) Page 14