Que método es mas recomendado para trabajar el suelo a la siembra?

Método de cultivo poco profundo

Método de cultivo a profundidad del suelo

La relación de endosimbiosis significa:

Una relación interna de la planta con el microorganismo

Una relación externa de la planta con el microorganismo

Una de las funciones de los microorganismos benéficos en el suelo es:

Ayudan al crecimiento de las plantas por proporcionar nutrientes

Ayudan al crecimiento de las malezas o arvenses

Ayudan en la evapotranspiración de las plantas

Microorganisms from soil

A solution is a mixture in which one or more substances are uniformly distributed in another substance. Solutions can be mixtures of liquids, solids, or gases. For example, plasma, the liquid part of blood, is a very complex solution. It is composed of many types of ions and large molecules, as well as gases, that are dissolved in water. A solute (SAHL-YOOT) is a substance dissolved in the solvent. The particles that compose a solute may be ions, atoms, or molecules. The solvent is the substance in which the solute is dissolved. For example, when sugar, a solute, and water, a solvent, are mixed, a solution of sugar water results. Though the sugar dissolves in the water, neither the sugar molecules nor the water molecules are altered chemically. If the water is boiled away, the sugar molecules remain and are unchanged. Solutions can be composed of various proportions of a given solute in a given solvent. Thus, solutions can vary in concentra- tion. The concentration of a solution is the amount of solute dis- solved in a fixed amount of the solution. For example, a 2 percent saltwater solution contains 2 g of salt dissolved in enough water to make 100 mL of solution. The more solute dissolved, the greater is the concentration of the solution. A saturated solution is one in which no more solute can dissolve. Aqueous (AY-kwee-uhs) solutions—solutions in which water is the solvent—are universally important to living things. Marine microorganisms spend their lives immersed in the sea, an aqueous solution. Most nutrients that plants need are in aqueous solutions in moist soil. Body cells exist in an aqueous solution of intercellu- lar fluid and are themselves filled with fluid; in fact, most chemical reactions that occur in the body occur in aqueous solutions. Copyright © by Holt, Rinehart and Winston. All rights reserved. Liquid water Solid water Ice (solid water) is less dense than liquid water because of the structure of ice crystals. The water molecules in ice are bonded to each other in a way that creates large amounts of open space between the molecules, relative to liquid water. FIGURE 2-12 solvent from the Latin solvere, meaning “to loosen” Word Roots and Origins CHEMISTRY OF LIFE 43 ACIDS AND BASES One of the most important aspects of a living system is the degree of its acidity or alkalinity. What do we mean when we use the terms acid and base? Ionization of Water As water molecules move about, they bump into one another. Some of these collisions are strong enough to result in a chemical change: one water molecule loses a proton (a hydrogen nucleus), and the other gains this proton. This reaction really occurs in two steps. First, one molecule of water pulls apart another water molecule, or dissociates, into two ions of opposite charge: H2O ∏ H OH The OH ion is known as the hydroxide ion. The free H ion can react with another water molecule, as shown in the equation below. H H2O ∏ H3O The H3O ion is known as the hydronium ion. Acidity or alkalin- ity is a measure of the relative amounts of hydronium ions and hydroxide ions dissolved in a solution. If the number of hydronium ions in a solution equals the number of hydroxide ions, the solution is said to be neutral. Pure water contains equal numbers of hydro- nium ions and hydroxide ions and is therefore a neutral solution. Acids If the number of hydronium ions in a solution is greater than the number of hydroxide ions, the solution is an acid. For example, when hydrogen chloride gas, HCl, is dissolved in water, its mol- ecules dissociate to form hydrogen ions, H, and chloride ions, Cl, as is shown in the equation below. HCl ∏ H Cl These free hydrogen ions combine with water molecules to form hydronium ions, H3O. This aqueous solution contains many more hydronium ions than it does hydroxide ions, making it an acidic solution. Acids tend to have a sour taste; how- ever, never taste a substance to test it for acidity. In concentrated forms, they are highly corrosive to some materials, as you can see in Figure 2-13. Bases If sodium hydroxide, NaOH, a solid, is dissolved in water, it dissociates to form sodium ions, Na, and hydroxide ions, OH, as shown in the equation below. NaOH ∏ Na OH Copyright © by Holt, Rinehart and Winston. All rights reserved. Eco Connection onnection Acid Precipitation Acid precipitation, more commonly called acid rain, describes rain, snow, sleet, or fog that contains high levels of sulfuric and nitric acids. These acids form when sulfur dioxide gas, SO2, and nitrogen oxide gas, NO, react with water in the atmosphere to produce sulfuric acid, H2SO4, and nitric acid, HNO3. Acid precipitation makes soil and bodies of water, such as lakes, more acidic than normal. These high acid levels can harm plant and animal life directly. A high level of acid in a lake may kill mollusks, fish, and amphibians. Even in a lake that does not have a very elevated level of acid, acid precipitation may leach aluminum and magnesium from soils, poisoning water- dwelling species. Reducing fossil-fuel consump- tion, such as occurs in gasoline engines and coal-burning power plants, should reduce high acid levels in precipitation. Sulfur dioxide, SO2, which is produced when fossil fuels are burned, reacts with water in the atmosphere to produce acid precipitation. Acid precipitation, or acid rain, can make lakes and rivers too acidic to support life and can even corrode stone, such as the face of this statue. FIGURE 2-13 44 CHAPTER 2 This solution then contains more hydroxide ions than hydronium ions and is therefore defined as a base. The adjective alkaline refers to bases. Bases have a bitter taste; however, never taste a substance to test for alkalinity. They tend to feel slippery because the OH ions react with the oil on our skin to form a soap. In fact, commercial soap is the product of a reaction between a base and a fat. pH Scientists have developed a scale for comparing the relative con- centrations of hydronium ions and hydroxide ions in a solution. This scale is called the pH scale, and it ranges from 0 to 14, as shown in Figure 2-14. A solution with a pH of 0 is very acidic, a solution with a pH of 7 is neutral, and a solution with a pH of 14 is very basic. A solution’s pH is measured on a logarithmic scale. That is, the change of one pH unit reflects a 10-fold change in the acidity or alkalinity. For example, urine has 10 times the H3O ions at a pH of 6 than water does at a pH of 7. Vinegar, has 1,000 times more H3O ions at a pH of 3 than urine at a pH of 6, and 10,000 times more H3O ions than water at a pH of 7. The pH of a solution can be measured with litmus paper or with some other chemical indicator that changes color at various pH levels. Buffers The control of pH is important for living systems. Enzymes can function only within a very narrow pH range. The control of pH in organisms is often accomplished with buffers. Buffers are chemi- cal substances that neutralize small amounts of either an acid or a base added to a solution. As Figure 2-14 shows, the composition of your internal environment—in terms of acidity and alkalinity— varies greatly. Some of your body fluids, such as stomach acid and urine, are acidic. Others, such as intestinal fluid and blood, are

SOIL COMPOSITION SOIL •Soil is the top layer of the earth in which plants grows. •It is made up of organic (living) and inorganic (non living) parts. •It is made up of 4 components: ✓Air(25%) ✓Water(25%) ✓Organic matter(5%) ✓Mineral matter(45%) Soil composition air water organic matter rock particles or mineral matter Air 25% Water 25% mineral matter 45% Organic matter 5% Functions of soil components 1. Mineral matter • Provides nutrients such as zinc, nitrogen and potassium. •It comes from rocks that would have broken down to form soil. •It is the main component in soil. 2. Soil Organic matter • Provides nutrients to the plants/ increases soil fertility •Improves soil structure •Improves soil temperature •Improves water holding capacity •Improves aeration •Soil air is needed by roots for their respiration •It is needed by soil organisms like earthworms, fungi and bacteria •Is needed for germination of seeds Soil water •Provides plants with water for growth •Dissolves plant nutrients •Is needed for germination of seeds •Keeps the soil moist so that micro-organisms can work

Lipids are large, nonpolar organic molecules. They do not dissolve in water. Lipids include triglycerides (trie-GLIS-uhr-IEDZ), phospho- lipids, steroids, waxes, and pigments. Lipid molecules have a higher ratio of carbon and hydrogen atoms to oxygen atoms than carbohydrates have. Because lipid molecules have larger numbers of carbon-hydrogen bonds per gram than other organic com- pounds do, they store more energy per gram. Fatty Acids Fatty acids are unbranched carbon chains that make up most lipids. Figure 3-10 shows that a fatty acid contains a long carbon chain (from 12 to 28 carbons) with a carboxyl group, —COOH, attached at one end. The two ends of the fatty-acid molecule have different properties. The carboxyl end is polar and is thus hydrophilic or attracted to water molecules. In contrast, the hydro- carbon end of the fatty-acid molecule is nonpolar. This end tends not to interact with water molecules and is said to be hydrophobic (HIE-droh-FOH-bik), or “water fearing.” In saturated fatty acids, such as palmitic acid, which is shown in Figure 3-10, each carbon atom is covalently bonded to four atoms. The carbon atoms are in effect full, or saturated. In contrast, linoleic acid, also shown in Figure 3-10, has carbon atoms that are not bonded to the maximum number of atoms to which they can bond. Instead, they have formed double bonds within the carbon chain. This type of fatty acid is said to be unsaturated. Triglycerides Three classes of lipids important to living things contain fatty acids: triglycerides (fats), phospholipids, and waxes. A triglyceride is composed of three molecules of fatty acid joined to one molecule of the alcohol glycerol. Saturated triglycerides are composed of saturated fatty acids. They typically have high melting points and tend to be hard at room temperature. Common dietary saturated triglycerides include butter and fats in red meat. In contrast, unsaturated triglycerides are composed of unsaturated fatty acids and are usually soft or liquid at room temperature. Unsaturated triglycerides are found primarily in plant seeds where they serve as an energy and carbon source for germinating plants. Phospholipids Phospholipids have two, rather than three, fatty acids attached to a molecule of glycerol. They have a phosphate group attached to the third carbon of the glycerol. As shown in Figure 3-11, the cell membrane is made of two layers of phospholipids, called the lipid bilayer. The inability of lipids to dissolve in water allows the mem- brane to form a barrier between the inside and outside of the cell. Hydrophilic “head” Phospholipids Hydrophobic “tail” Phospholipids Water Water The lipid bilayer of a cell membrane is a double row of phospholipids.The “tails” face each other.The “head” of a phospholipid, which contains a phosphate group, is polar and hydrophilic.The two tails are two fatty acids and are nonpolar and hydrophobic. FIGURE 3-11 H C H C O OH H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H H C H C H H H H C H H C H H C H H C H H C H C O OH H C H H C H H C H C H C H C H H C H H C H C H H C H H C H C H H H H C H Fatty acids have a polar carboxyl head, highlighted in purple, and a nonpolar hydrocarbon tail, highlighted in green. FIGURE 3-10 Palmitic acid Linoleic acid mb06se_bchs02.qxd 5/18/07 10:49 AM Page 59 60 CHAPTER 3 1. Compare the structure of monosaccharides, dis- accharides, and polysaccharides. 2. How are proteins constructed from amino acids? 3. How do amino acids differ from one another? 4. Describe a model of enzyme action. 5. Why do phospholipids orient in a bilayer when in a watery environment, such as a cell? 6. Describe how the three major types of lipids differ in structure from one another. 7. What are the functions of the two types of nucleic acids? CRITICAL THINKING 8. Applying Information Before a long race, run- ners often “carbo load.” This means that they eat substantial quantities of carbohydrates. How might this help their performance? 9. Recognizing Relationships High temperatures can weaken bonds within a protein molecule. How might this explain the effects of using a hot curling iron or rollers in one’s hair? 10. Applying Information You want to eat more unsaturated than saturated fats. Name examples of foods you would eat more of and less of. SECTION 2 REVIEW Waxes A wax is a type of structural lipid consisting of a long fatty-acid chain joined to a long alcohol chain. Waxes are waterproof, and in plants, form a protective coating on the outer surfaces. Waxes also form protective layers in animals. For example, earwax helps pre- vent microorganisms from entering the ear canal. Steroids Unlike most other lipids, which are composed of fatty acids, steroid molecules are composed of four fused carbon rings with various functional groups attached to them. Many animal hor- mones, such as the male hormone testosterone, are steroid com- pounds. One of the most familiar steroids in humans is cholesterol. Cholesterol is needed by the body for nerve and other cells to func- tion normally. It is also a component of the cell membrane. NUCLEIC ACIDS Nucleic acids are very large and complex organic molecules that store and transfer important information in the cell. There are two major types of nucleic acids: deoxyribonucleic acid and ribonucleic acid. Deoxyribonucleic acid, or DNA, contains information that deter- mines the characteristics of an organism and directs its cell activi- ties. Ribonucleic (RIE-boh-noo-KLEE-ik) acid, or RNA, stores and transfers information from DNA that is essential for the manufactur- ing of proteins. Some RNA molecules can also act as enzymes. Both DNA and RNA are polymers, composed of thousands of linked monomers called nucleotides (NOO-klee-uh-TIEDS). As shown in Figure 3- 12, each nucleotide is made of three main components: a phosphate group, a five-carbon sugar, and a ring-shaped nitrogenous base.

MCQ from NCERT Science Grade 8 Chapter Microorganisms ..Friends or Foe topic bacteria

Lide 1: Introduction to Bioreactor A bioreactor is a vessel used for growing microorganisms, plant or animal cells Provides controlled conditions for biological reactions Maintains optimum pH, temperature, oxygen, and nutrients Widely used in fermentation, enzyme, vaccine, and antibiotic production Ensures sterile and aseptic environment Scale ranges from laboratory to industrial production Slide 2: Basic Design Requirements of a Bioreactor Must be constructed with non-toxic, corrosion-resistant materials Should allow effective mixing and mass transfer Provision for sterilization (in situ sterilization) Must maintain uniform temperature and pH Easy sampling without contamination Should support scalability and automation Slide 3: Materials Used in Bioreactor Construction Stainless steel (SS-316) for industrial bioreactors Glass for laboratory-scale bioreactors Plastic (polycarbonate) for disposable bioreactors Materials must withstand heat and pressure Should be smooth to prevent microbial attachment Resistant to chemicals and cleaning agents Slide 4: Main Parts of a Bioreactor Vessel: holds the culture medium and microorganisms Agitator (impeller): provides mixing Sparger: supplies sterile air Baffles: prevent vortex formation Sensors: monitor pH, temperature, dissolved oxygen Ports: used for inoculation, sampling, and feeding Slide 5: Agitation System Ensures uniform mixing of nutrients and cells Improves oxygen transfer rate Common impellers: Rushton turbine, marine propeller Speed controlled by motor Prevents settling of cells Affects shear stress on cells Slide 6: Aeration System Supplies oxygen for aerobic fermentation Air introduced through sparger Types of spargers: ring, nozzle, sintered Maintains dissolved oxygen concentration Air is filtered for sterility Essential for high cell density cultures Slide 7: Temperature and pH Control Temperature controlled by heating/cooling jackets pH maintained using acid or alkali addition Sensors continuously monitor parameters Automated control systems used Ensures optimal microbial growth Prevents enzyme denaturation Slide 8: Foam Control System Foam formed due to protein and agitation Excess foam reduces oxygen transfer Mechanical foam breakers used Chemical antifoam agents added Foam sensor detects foam formation Maintains efficient fermentation Slide 9: Types of Bioreactors – Based on Mode of Operation Batch bioreactor Fed-batch bioreactor Continuous bioreactor Choice depends on product type Widely used in industrial fermentation Controls productivity and yield Slide 10: Batch Bioreactor All nutrients added at the beginning No addition or removal during process Simple and easy to operate Low risk of contamination Used for antibiotics and enzymes Limited control over nutrient depletion Slide 11: Fed-Batch Bioreactor Nutrients added during fermentation Prevents substrate inhibition High product yield Widely used in industrial fermentation Allows better control of growth rate Used in insulin and enzyme production Slide 12: Continuous Bioreactor Fresh medium continuously added Culture removed at same rate Maintains steady-state conditions High productivity Risk of contamination is high Used in wastewater treatment and SCP production Slide 13: Types of Bioreactors – Based on Design Stirred tank bioreactor Airlift bioreactor Bubble column bioreactor Packed bed bioreactor Fluidized bed bioreactor Photobioreactor Slide 14: Stirred Tank Bioreactor (STR) Most commonly used bioreactor Mechanical agitation using impellers Suitable for aerobic fermentation Excellent mixing and oxygen transfer Used for bacteria and fungi Easy scale-up Slide 15: Airlift Bioreactor Mixing achieved by air circulation No mechanical agitator Low shear stress Energy efficient Suitable for shear-sensitive cells Used in wastewater treatment Slide 16: Bubble Column Bioreactor Air bubbles provide mixing Simple design and low cost No moving parts Limited mixing efficiency Used for microbial fermentation Suitable for large-scale operations Slide 17: Packed Bed Bioreactor Contains immobilized cells or enzymes Substrate flows through packed matrix High cell density Used in continuous processes Limited oxygen transfer Used in enzyme and wastewater treatment Slide 18: Fluidized Bed Bioreactor Immobilized particles kept in suspension Better mass transfer than packed bed Reduced clogging Suitable for continuous operation Used in biotransformations Higher operational complexity Slide 19: Photobioreactor Designed for photosynthetic organisms Provides light source Used for algae and cyanobacteria Controls light, CO₂, and temperature Used in biofuel and pigment production Can be tubular or flat-plate design Slide 20: Applications of Bioreactors Production of antibiotics and vaccines Enzyme and organic acid production Single cell protein production Wastewater treatment Biofertilizer and biopesticide production Biopharmaceutical manufacturing

Acetic acid – a chemical substance with an inhibiting effect on the growth of microorganisms and which is present in vinegar.Acetic Acid Fermentation Fermentation preserves food through the metabolic activities of selected groups of microorganisms. During the process, compounds such as lactic acid, acetic acid and alcohol are developed and result in a more or less stable food form. It makes food more nutritious as dietary source of proteins, vitamins and minerals.Vinegar is an example of the product of acetic acid fermentation which also undergoes alcoholic fermentation to complete the process.Filter – is a device, substance (like paper or charcoal), or process that separates unwanted components from a fluid Cheesecloth-is a loose-woven, gauze-like cotton fabric used for straining liquids from solids.Decant- gradually pour (liquid, typically wine or a solution) from one container into another, especially without disturbing the sediment. Sediment-is solid material (like sand, silt, clay, rocks, organic matter) broken down by weathering, transported by wind, water, or ice, and deposited in a new location, settling at the bottom of water bodies or on land.How to make vinegar?1.Grind or crash the fruit, then boil in water of the same amount as the ground flesh, peels and cores. Boil until soft, and then strain the juice through a cheesecloth2.Add ¼ (one-fourth) pound of sugar for every liter of juice extracted from fruit peels and cores. Do not add sugar when using ripe fruit.3.Add ¼ of a cake of fresh yeast that has been well-broken up, for every liter of juice. Stir very well, and then place in glass jars. Cover with a clean cloth and let the mixture stand for about two weeks .4. After two weeks, separate the clear liquid from the sediment. Prepare fresh, unpasteurized vinegar also called “mother vinegar” which is the white gummy mass that usually forms in vinegar. Add this to the liquid and mix very well. Over the container with cloth, then allow to stand in a warm place until it has acquired a flavor strong enough to use.5.Filter the clear liquids, then pour in a bottle and cover tightly.USES OF VINEGAR1. Insect salve and repellent. 2. Kill weeds and remove ants. 3. Enhance bricks. 4.Open a tight jar. 5.Clean scissors. 6.Remove smoke odors. 7. Remove pit stains. 8. Make hair shine. 9. Fruit fly trap. 10. Car care.

4. Food Storage Methods Food storage means keeping food safely for future use. 🌍 A. Indigenous (Traditional) Storage Methods 4 These are methods used long ago and still used in rural areas: Drying (Sun drying) – removing water from food (e.g. vegetables, meat) Smoking – preserving meat or fish using smoke Salting – adding salt to prevent spoilage Fermentation – changing food using microorganisms (e.g. sour milk) Use of granaries – storing grains in raised structures Clay pots – keeping food cool and fresh 🧊 B. Modern Storage Methods 6 These use technology to keep food fresh: Refrigeration – keeping food cold in a fridge Freezing – storing food at very low temperatures Canning – sealing food in tins Bottling – storing liquids in sealed bottles Vacuum sealing – removing air from packaging Use of preservatives – adding chemicals to prevent spoilage ⭐ 5. Importance of Food Storage Prevents food from going bad Reduces food wastage Saves money Ensures food is available in times of shortage Maintains food quality and safety

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