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*IJMB BIOLOGY*
(3i)
Chemosynthesis is process by which some organisms manufacture their food by converting carbon molecules into organic substances using the oxidation of inorganic substances or hydrogen sulphide,ammonia and methane as a source of energy without the use of sun light or solar energy.
(3ii)
Respiration is the process by which living things breakdown or oxidise food nutrients glucose or organic substances to release energy for metabolic activities of the body with or without the use of oxygen.
(3iii)
Plasmolysis is defined as the process of contraction or shrinkage of the protoplasm of a plant cell and is caused due to the loss of water in the cell. Plasmolysis is an example of the results of osmosis and rarely occurs in nature
(3iv)
Fermentation is the conversation of aqueous glucose or sugar to ethanol or alcohol and release of carbon (iv) oxide as a by product.
```IJMB BIOLOGY```
*NUMBER 4 SOLUTIONS*
4A)
*1.) Pasteurization*
Although complete sterilization is ideal for many medical applications, it is not always practical for other applications and may also alter the quality of the product. Boiling and autoclaving are not ideal ways to control microbial growth in many foods because these methods may ruin the consistency and other organoleptic (sensory) qualities of the food. Pasteurization is a form of microbial control for food that uses heat but does not render the food sterile. Traditional pasteurization kills pathogens and reduces the number of spoilage-causing microbes while maintaining food quality. The process of pasteurization was first developed by Louis Pasteur in the 1860s as a method for preventing the spoilage of beer and wine. Today, pasteurization is most commonly used to kill heat-sensitive pathogens in milk and other food products (e.g., apple juice and honey). However, because pasteurized food products are not sterile, they will eventually spoil.
The methods used for milk pasteurization balance the temperature and the length of time of treatment. One method, high-temperature short-time (HTST) pasteurization, exposes milk to a temperature of 72 °C for 15 seconds, which lowers bacterial numbers while preserving the quality of the milk. An alternative is ultra-high-temperature (UHT) pasteurization, in which the milk is exposed to a temperature of 138 °C for 2 or more seconds. UHT pasteurized milk can be stored for a long time in sealed containers without being refrigerated; however, the very high temperatures alter the proteins in the milk, causing slight changes in the taste and smell. Still, this method of pasteurization is advantageous in regions where access to refrigeration is limited.
*2.) Refrigeration and Freezing*
Just as high temperatures are effective for controlling microbial growth, exposing microbes to low temperatures can also be an easy and effective method of microbial control, with the exception of psychrophiles, which prefer cold temperatures (see Temperature and Microbial Growth). Refrigerators used in home kitchens or in the laboratory maintain temperatures between 0 °C and 7 °C. This temperature range inhibits microbial metabolism, slowing the growth of microorganisms significantly and helping preserve refrigerated products such as foods or medical supplies. Certain types of laboratory cultures can be preserved by refrigeration for later use.
Freezing below −2 °C may stop microbial growth and even kill susceptible organisms. According to the US Department of Agriculture (USDA), the only safe ways that frozen foods can be thawed are in the refrigerator, immersed in cold water changed every 30 minutes, or in the microwave, keeping the food at temperatures not conducive for bacterial growth.[1] In addition, halted bacterial growth can restart in thawed foods, so thawed foods should be treated like fresh perishables.
Bacterial cultures and medical specimens requiring long-term storage or transport are often frozen at ultra-low temperatures of −70 °C or lower. These ultra-low temperatures can be achieved by storing specimens on dry ice in an ultra-low freezer or in special liquid nitrogen tanks, which maintain temperatures lower than −196 °C.
*3.) Desiccation*
Drying, also known as desiccation or dehydration, is a method that has been used for millennia to preserve foods such as raisins, prunes, and jerky. It works because all cells, including microbes, require water for their metabolism and survival. Although drying controls microbial growth, it might not kill all microbes or their endospores, which may start to regrow when conditions are more favorable and water content is restored.
In some cases, foods are dried in the sun, relying on evaporation to achieve desiccation. Freeze-drying, or lyophilization, is another method of dessication in which an item is rapidly frozen (“snap-frozen”) and placed under vacuum so that water is lost by sublimation. Lyophilization combines both exposure to cold temperatures and desiccation, making it quite effective for controlling microbial growth. In addition, lyophilization causes less damage to an item than conventional desiccation and better preserves the item’s original qualities. Lyophilized items may be stored at room temperature if packaged appropriately to prevent moisture acquisition. Lyophilization is used for preservation in the food industry and is also used in the laboratory for the long-term storage and transportation of microbial cultures.
*4.) Radiation*
Radiation in various forms, from high-energy radiation to sunlight, can be used to kill microbes or inhibit their growth. Ionizing radiation includes X-rays, gamma rays, and high-energy electron beams. Ionizing radiation is strong enough to pass into the cell, where it alters molecular structures and damages cell components. For example, ionizing radiation introduces double-strand breaks in DNA molecules. This may directly cause DNA mutations to occur, or mutations may be introduced when the cell attempts to repair the DNA damage. As these mutations accumulate, they eventually lead to cell death.
Both X-rays and gamma rays easily penetrate paper and plastic and can therefore be used to sterilize many packaged materials. In the laboratory, ionizing radiation is commonly used to sterilize materials that cannot be autoclaved, such as plastic Petri dishes and disposable plastic inoculating loops. For clinical use, ionizing radiation is used to sterilize gloves, intravenous tubing, and other latex and plastic items used for patient care. Ionizing radiation is also used for the sterilization of other types of delicate, heat-sensitive materials used clinically, including tissues for transplantation, pharmaceutical drugs, and medical equipment.
*5.) Sonication*
The use of high-frequency ultrasound waves to disrupt cell structures is called sonication. Application of ultrasound waves causes rapid changes in pressure within the intracellular liquid; this leads to cavitation, the formation of bubbles inside the cell, which can disrupt cell structures and eventually cause the cell to lyse or collapse. Sonication is useful in the laboratory for efficiently lysing cells to release their contents for further research; outside the laboratory, sonication is used for cleaning surgical instruments, lenses, and a variety of other objects such as coins, tools, and musical instruments.
*IJMB BIOLOGY*
*NUMBER 5 SOLUTIONS*
_AN ESSAY ON ENVIRONMENTAL POLLUTION_
The environment is the surrounding of an organism. The environment in which an organism lives is made up of various components like air, water, land, etc. These components are found in fixed proportions to create a harmonious balance in the environment for the organism to live in. Any kind of undesirable and unwanted change in the proportions of these components can be termed as pollution. This issue is increasing with every passing year. It is an issue that creates economic, physical, and social troubles. The environmental problem that is worsening with each day needs to be addressed so that its harmful effects on humans as well as the planet can be discarded.
*Causes of Environmental*
Pollution With the rise of the industries and the migration of people from villages to cities in search of employment, there has been a regular increase in the problem of proper housing and unhygienic living conditions. These reasons have given rise to factors that cause pollution.
Environmental pollution is of five basic types namely, Air, Water, Soil, and Noise pollution.
*Air Pollution*: Air pollution is a major issue in today’s world. The smoke pouring out of factory chimneys and automobiles pollute the air that we breathe in. Gases like carbon dioxide, carbon monoxide, and sulphur dioxide are emitted with this smoke which mixes with air and causes great harm to the human body, flora, and fauna. The dry-farm waste, dry grass, leaves, and coal used as domestic fuels in our villages also produce harmful gases. Acid rain occurs due to an excess of sulphur dioxide in the air.
_IN ANOTHER WORDS_
*Essay on Environmental Pollution:* Environment is the surroundings in which we live. But the contamination of our environment by pollutants is environmental pollution. The current stage of the earth that we are seeing is the cause of centuries of exploitation of earth and its resources.
Moreover, the earth cannot restore its balance because of environmental pollution. The human force has created and destroyed life on earth. Human plays a vital role in the degradation of the environment.
*Effect of pollution on the health*
The environmental pollution, directly and indirectly, affects the lives of humans and other species. These living beings co-existed on the earth with human from centuries.
*Effect on Air*
Carbon and dust particles string up with the air in the form of smog, damaging respiratory system, haze, and smoke. These are caused by the emission of industrial and manufacturing units by burning of fossil fuels, vehicle combustion of carbon fumes.
Moreover, these factors affect the immune system of birds which become a carrier of viruses and infections.
Besides, it also affects the body system and body organs.
*Effects on Land, Soil, and Food*
Human’s organic and chemical both waste harm the land and soil with its decomposition. Also, it introduces some chemical in the soil and water. Land and soil pollution mainly caused by the use of pesticides, fertilizers, soil erosion, and crop residues.
*Effect on Water*
Water gets contaminated easily with any pollutant whether it is human waste or chemical discharge from factories. Also, we use this water for irrigation of crops and drinking. But, because of infection they become contaminated too. Besides, an animal dies because they drink this same contaminated water.
Moreover, around 80% of pollutants of land such as chemical, industrial and agricultural waste end up in the water bodies.
Besides, these water bodies ultimately connect to the sea which means it indirectly pollutes the biodiversity of the sea.
*Effect on Food*
Because of contaminated soil and water, the crop or agricultural produce also get toxic. Furthermore, this contaminated food effect our health and organs. From the beginning of their life, these crops are laced with chemical components that reach a mass level until the time of harvest.
*Effect on Climate*
Climate change is also a cause of environmental pollution. Also, it affects the physical and biological components of the ecosystem.
Moreover, ozone depletion, greenhouse gases, global warming all these climate changes are a cause of environmental pollution.
Besides, their effect can be fatal for our upcoming generations. The irregular extreme cold and hot climate affect the ecological system of the earth.
Furthermore, some unstable climate changes are earthquakes, famine, smog, carbon particles, shallow rain or snow, thunderstorms, volcanic eruption, and avalanches are all because of climate change that happens all because of environmental pollution.
In conclusion, man has exploited the wealth of nature at the cost of his and environments health. Also, the effect that is now emerging rapidly is all because of the activities of humans for hundreds or thousands of years.
Above all, if we wish to survive and continue our life on earth then we have to take measures. These measures will help is securing our as well as our next generation future.
CONTACT COOLBOY FOR YOUR SURE WAEC, NECO, NABTEB,NABTEX,BECE,IJMB, JUPEB,AND PRIVATE WASSCE (GCE) QUESTIONS AND ANSWERS BEFORE EXAM
COOLBOY
WHATSAPP NUMBER
08035452768
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